Home Guitars Amplifiers Accessories About Contact
Home :: Blog

Hand Wired Guitar Amps: Point-to-Point and Other Constructions

April 22nd, 2018

We recently became acquainted with the Little Walter amplifier line, and after hearing them and meeting their creator Phil Bradbury, we decided to jump on board. Truth be told, amplifiers are a tough product to sell, and many players are enamored with purchasing more guitars rather than purchasing another amplifier. While we would hardly not sell a customer a guitar, we are firm believers that amplifiers are a critical and overlooked component to a player’s tone.

Little Walter "59" Head

Little Walter “59” Head

Among other interesting features and attributes of the Little Walter amplifiers is that they are point-to-point (PTP) construction. Due to the labor-intensive nature of this construction style, PTP is quite rare and constitutes a tiny fraction of total amplifier production. But before we get to PTP, let’s cover the other more popular methods, their benefits and drawbacks. And we are only addressing tube amplifiers, not comparing solid state to tube amplifiers.



Printed Circuit Board (PCB)

The vast majority of amplifiers are constructed using printed circuit boards, from lowly practice amplifiers to high end products from Mesa, Fender, Marshall, etc. PCB’s are cost effective, permit assembly automation, and also allow for higher levels of complexity not possible with other methods. Multi-channel amplifiers, on-board effects, processor chips and modeling are just not possible without PCB construction. While most PCB amplifiers utilize “through hole” components similar to those used in older styles of construction, newer surface mount devices (SMD) can radically shrink the size of certain components, allowing for even greater levels of functionality with minimal impact on space.

While newer technology lowers cost and increases functionality, there can be compromises in sound. Some components do have a “sound,” most notably capacitors, transformers, and some believe even resistors. A paper-in-oil capacitor has a particular sonic characteristic that is unique to its construction, but the size and configuration make it unsuitable for volume production, not to mention cost. You might scoff at the idea of one capacitor type sounding better than another, but make a speaker cone out of the wrong paper and it will sound bad. The same is true with passive electronic components. An amplifier’s price is a function of its components, but also its assembly method, and some components are only practical on a hand-wired amp.

The layout (schematic) of a printed circuit board is also a compromise between assembly efficiency and optimal circuit path. If you’ve ever seen a PCB, it’s a myriad of thin copper traces laid out in usually logical parallel lines and right angles. Good circuit board layout is part skill and part art, and tightly packed component layouts can create capacitive losses, impact certain frequencies, add noise, and overall have an impact on the sound. That may sound like tone snobbery, but having been in the business of manufacturing PCB-based products, schematics have consequences.

Eyelet and Turret Board Construction

Eyelet and Turret Board construction utilize an epoxy or fiberboard card as a platform to lay out the various small components of an amplifier. The larger components such as transformers and tub sockets are generally affixed directly to the amp chassis. These types of amps can accommodate a wide range of component configurations and allow quite a bit of design freedom. Most of today’s “hand-wired” amps use this type of construction, and examples include Dr. Z, high end Fender and Marshall models, and many other boutique brands. Fender used eyelet board construction on all its amps right through the seventies (more a lack of investment than tonal concerns). Being hand assembled is not without cost though: A standard PCB Fender Deluxe Reverb is around $1100, while the hand wired version using a fiberboard will set you back $2400. If you plan to keep an amp a long time, a non-PCB amplifier is much easier to service, and if you are a tweaker, also easier to mod. While PCB’s are repairable they are often fragile and fussy to service, especially for an amateur. If the PCB contains SMD devices, just throw it out and get a new board.

Eyelet board amplifier

Eyelet board amplifier

Do hand-wired amps sound better than PCB? By virtue of their component flexibility, often less complex and less crowded layouts, they certainly have the potential to sound better. Of course, the actual circuit design matters too, and nobody is going to go to the trouble of making a hand-wired amplifier with cheesy components. There is a little of chicken & egg going on here, but it’s understandable why many discerning players gravitate towards this style of amplifier.



Point-to-Point Amplifiers (PTP)

PTP is in many ways the most primitive type of construction, and dates back to when modern materials for circuit and turret boards did not even exist (the fiberboard is a waxy carboard material that predates the PCB). In PTP construction, the components are wired directly to their intended connections with no type of component board. Some builders may use terminal strips to for structural support, but the circuit path is very direct, and you can see exactly where everything is going. Due to the labor-intensive nature of construction, PTP amplifiers are typically single channel amplifiers with limited bells and whistles. In another instance of chicken & egg, they are simple designs because the nature of their construction drives them in that direction.

BC Audio Point-to-Point amp

BC Audio Point-to-Point amp

The selling point of the PTP amp is that the pure, direct circuit path along with optimal wire routings and broad component freedom have a beneficial impact on tone.  Technically speaking, PTP amps have the least amount of “stuff” clogging up the circuit, hence the potential for better sound quality.

The concept behind the PTP amp is what we like to call “directionally correct.” If you put 15 pedals between your guitar and the amp – or in an effect loop — there is a degradation in tone. Every additional circuit and feature in an amplifier – including reverb – has some impact on the amp’s natural tone (if your amp has a switch to bypass the tone controls, note the jump in gain). The PTP amp is the shortest distance between guitar and speaker.

Can you hear the difference? Like most things with music, it’s a highly subjective question. And like other hand-wired amps, PTP amplifiers are not going to skimp on component quality. The best thing to do is listen to a lot of amplifiers, and ideally if you can listen to them through the same speaker cabinet, as this also has a big influence on sound. We have the luxury of being able to try a lot of amps, and our own experience has led us in the direction that the fewer the knobs, the better. Maybe we’re just bad at adjusting knobs, but our ears tell us to keep it simple.

Life tends to drive us in the direction of increasing complexity, and music is no exception. But your guitar is not a smart phone. Ideally, it’s an analog tool to create art that requires an intimate connection between the creator (you) and the medium (your guitar and amplifier). Oftentimes simplicity is the key to creativity.

Discovering Octal Preamp Tubes for Guitars Amps

March 12th, 2018

Little Walter model 50 HeadFor most players using tube guitar amplifiers, the ubiquitous 12AX7 may be the only preamp tube they have ever used. It’s the highest gain of the 9-pin dual triode preamp tubes, although the lower gain 12AY7 and 12AT7 show up in various functions such as phase inverters and reverb drivers. There is also the pentode EF86 9-pin tube that has been used by Dr. Z., Bad Cat and others. But it’s a safe bet that the 12AX7 is king of guitar preamp tubes.

Early guitar amplifiers from Fender, Gibson, and others used what are known as “octal” preamp tubes (such as the 6SL7, 6SN7 and 6SC7), which use the same 8-pin base as the 6V6 and 6L6. This tube pre-dated the development of the 12AX7, and is essentially what there was for early guitar amp builders to use.

When the 9-pin designs came along, builders quickly changed over to them for the simple reason that it helped make louder, tighter amplifiers at lower cost. Distortion was not a feature back then, it was a problem, and the 12AX7 was part of the solution. Early amp builders were not obsessing over the “sound” of a particular tube. The goal was amplification, plain and simple.

Octal preamp amplifiers are still around, but they represent a tiny sliver of overall amplifier production. While there are a handful of amp builders using them, BC Audio did a lot to put them back on the map. The BC Audio products won great praise in the guitar magazines, especially for their great crunch tones.

Octal tubes have lower gain factors than the 12AX7, run at lower voltages, and are felt to have a warmer more complex tone. While a 12AX7 amplifier with two 6L6 power tubes will produce about 50 watts, an octal design with the same power tubes will be in the mid-30’s.

We’ve recently become exposed to octal guitar amplifiers through our association with Little Walter tube amps. We’ve also had the ability to directly compare the Little Walter 50 octal head with their “59” head (50 watts, nine-pin 12AX7 preamp).

While the 50 and 59 are not the same amplifier with different preamp tubes, they do highlight the characteristics of the two platforms. The octal 50 has a more organic feel, a slightly softer attack, and a smooth top end. It’s not spongy and loose in the way of a small Tweed, but it’s remarkably tactile. It’s got a enough clean headroom to work in almost any band situation, and distortion pedals produce a detailed linear crunch that is devoid of sharp peaks or emphasized frequencies.

The 59 has a more familiar feel, and while it’s not a “blackface” amplifier, the attack and response is more in line with a mid-power 12AX7 American-style amplifier. The 59’s cleans have more sparkle than the 50, and the low end is big, rich and percussive. Distortion pedal response is not as smooth as the 50, and there is more high end sizzle with the 59.

Without choosing sides, octal amplifiers offer the guitar player a demonstrably different feel and tone. With mainstream production dedicated towards 12AX7-based designs, octal amplifiers are decidedly more expensive, and limited to “boutique” builders. However, for a  player looking for more a more dynamic and tactile response without resorting to the limited headroom and squashed attack of a low powered amp, octal amplifiers offer a solid alternative.


Interesting Amp Find Part 1 – The Mesa Stiletto 50W

October 22nd, 2016

mesa-shotI would normally categorize myself as a “less is more” person when it comes to amplifiers. I tend to favor rather simple amps, usually single channel, and use a couple pedals. Most of the time I’m using a Dr. Z Remedy, but also have a Bassman, a Custom Vibrolux and as of recent a Mesa F50 (the next blog topic).

But along comes this Mesa 50W Stiletto that we took in trade. I once had a 100w/50w Lone Star Combo, and it shares a lot of the options, knob assignments and tweaking possibilities. So even though I have never played a Stiletto, I somewhat knew my way around it.

This amp was Mesa’s answer to the Marshall sound, and as such sports EL-34 power tubes, a Plexi/Bassman style circuit, and a sealed cabinet with a Vintage 30 speaker. It has the Mesa “spongy” switch that drops the amp voltage for more touch response, and the ability to switch between tube and solid state rectifier (individually on each channel). Also like many Marshall amplifiers there is no reverb.

Initial impressions of the amp was that it was extremely bright and tight. On regular power and solid state rectifier, this amp as very little give, and if you’re a “spongy” amp guy like me it’s a little disconcerting. But between the tube rectifier, the spongy switch, and the three position “character” switch for each channel, there is something for everyone.

I like EL-34’s, and they have a very complex and harmonically rich top end. This helps the Stiletto pump out some awesomely good clean tones. By running on spongy with the gain and master around noon, and using the tube rectifier, it’s not hard to get some sweet touch-induced tube crunch. The amp also has an overall level control, and you can get these tones at reasonable volumes. But if you want your own personal Twin, run it on solid state rectifier and full power and you’ll have ample clean headroom. It’s likely that if you ask a typical Mesa player how they like their clean channel they’ll say, “I don’t know.” The Stiletto has a clean channel worth knowing.

The gain channel is naturally quite bright (like a Marshall) and don’t be afraid to twist the tone controls to tone it down a bit. But once you have it dialed in, it’s got some amazing Brit-crunch that has overtones and character out the wazoo. The sealed back cabinet helps to tighten up the sound, and the enclosure is not a parallel box, we assume in order to reduce standing wave forms. The total gain potential is end-of-days crazy, and we can’t imagine a usable scenario. But if you like tight, harmonic crunch you can cut with a knife, it’s freak’in awesome. You can’t model this….

Drawbacks? The Stiletto combo must weigh around 70 pounds, so it’s a good thing it has casters. Also the Vintage 30 has an inherent midrange spike, and some EL-34 tubes are likewise, and we found the standard Mesa power tubes were a bit too forward in this respect. We are using some groove tubes that we like, and if we can find some Winged C’s we’d probably be really happy. We also tried a Warehouse Reaper HP in the Mesa, as we’ve like the Reaper in the past. We could not get it out of the cabinet fast enough. Just goes to show that Mesa really does engineer the amplifier, and you can’t just stick anything in there. Same with pre-amp tubes: They are not easy to get at, and just leave the Mesa tubes in there. If you can find a NOS 5U4GB, go for it.

I sort of thought that we’d move this Mesa along as soon as it came in the shop. But it sounds awfully good, and we’ve taken it on gigs where we don’t have to haul it up stairs. On cleans it comes close to our beloved Dr. Z. Remedy, and it can break up a lower levels. If you don’t want to bring any pedals and just use the gain channel — and if you can open it up — it’s other-worldly.

The Stiletto does not really EQ or respond like your typical Mesa, and in that respect it was probably somewhat misunderstood, and underappreciated. But it’s probably our favorite Mesa so far, and highly underrated. They are out there anywhere from $800 to $1300 and represent a true bargain.

Guitar Amplifiers – How Many Watts Are Enough?

October 28th, 2014

If you’re an active guitar player, you’ve certainly noticed the continuing trend towards smaller, lower powered amplifiers. This has occurred for a number of reasons: Popularity of boutique clones of early amplifier designs, older players downsizing to focus on playing at home rather than performing, and the advent of very good affordable sound reinforcement systems.

Historically, the first guitar amplifiers were pretty small because the guitar was not necessarily the lead instrument of the band, and in many cases the band itself was not amplified. Plus the technology of the time – tubes – dictated smaller low power systems.

As rock music and the electric guitar became more popular, both the volume levels and the size of the venues increased. But true high quality “house” sound systems like today did not exist. So the guitar amplifier was not for “tone”, but was also the primary vehicle for what the audience heard. Amplifiers also did double or triple duty: Check out the input panel of many early amplifiers and you’ll see input jacks for multiple guitars and microphones. Adjusted for today’s dollars, pro gear back in the day was vastly more expensive than now, and sharing was a practical necessity.

So like the Space Race, the power race was on, and by the end of the 50’s the larger guitar amplifiers were pushing 50 watts or more. Fender’s introduction of the blackface amps in the early 60’s addressed the need for louder, cleaner sound. The blackface amps differed from their tweed predecessors in a number of ways, but features such as fixed bias design, higher plate voltages, and solid-state rectification had more to do with volume and headroom than tone. The largest amps topped out at 100 watts, which is really the practical limit of four 6L6 or EL-34 power tubes. This is pretty much true today for tube amps, and anything more than that gets very heavy and hot (bass players had it tough then). Today a bass player can get a 500-watt Class D solid-state amplifier that’s the size of a phone book.

But back then if you were going to play an arena, you needed stacks of amplifiers because they were doing a lot of the heavy lifting. Plus it’s kind a macho thing and looks really cool too. Today, you can play an arena with a 15-watt amplifier, and some performers do. While there is a certain visceral sensation to the sound of a 4×12, the need for a row of Marshall stacks is essentially visual. And unless you’re Yngwie Malmsteen, many of those cabs on stage aren’t even on.

So how much power do you actually need? Unless you require extremely high levels of clean volume without the assist of a PA, 50 watts is the most you’ll ever need. How much volume an amplifier produces is a function of its design: Fixed versus cathode bias, amount of negative feedback, plate voltage, rectifier type, etc. It’s hard to generalize, but a 15-watt amplifier with no negative feedback and a solid-state rectifier can be very loud and clean. My main amp head has (4) 6V6 tubes, solid state rectifier and a 20/40-watt switch. The only time it’s on 40 watts is when the band is playing outside.

If you are playing clubs and typically put the guitars through the PA, 15-30 watts will likely do it. While early amplifier designs were guided by power output, choosing an amplifier today is more about how you want it to sound, rather than how loud it will go. If you play mostly at home or jam with friends, 10-30 watts is where a lot of the amplifier market is targeted these days. Finding the right amount clean headroom – which is important if you use pedals – is an important selection criteria. If you regularly jam with a drummer, 30 watts is probably a better choice than 10. Five-watt amplifiers can be fun, if all you want is loose, old school grind. But with a humbucker-equipped guitar, there will be little in the way of decent clean volume.

Many modern amp designs have the ability to vary total amplifier output. Some do this by actually dropping out power tubes (4-to-2 for example) while others vary the amount of voltage to the power tubes or phase inverter. These features cut volume as well as headroom, allowing the ability to clip the power tubes at reasonable volumes. The Traynor Ironhorse amplifier has a fixed/cathode bias switch that changes the output of the amp from 37 to 17 watts, respectively. This not only affects total volume and headroom, but also the feel (I like the softer nature of cathode bias).

If you have a large amp that you don’t want to part with, there are of course power attenuators, which are available as an add-on accessory. These work by absorbing some of the energy that would normally go to your speakers. In effect, you can crank the amplifier but the attenuator “soaks up” some of the energy (volume). Attenuators work by placing some type of resistance/inductance network in the signal path to the speakers. Without getting technical, even the best ones mess with the feel of the amp, and how the guitar interacts with the amplifier. It’s hard to explain but it’s a disconnected feeling. They sound good on YouTube, but so does everything. My suggestion is to buy a smaller amplifier.

The trend towards lower stage volumes, and the affordability of good sound reinforcement and monitoring systems has been a boon to amateur and pro players alike. Using a guitar amp as the sole amplification source is very rare, and your band will actually sound better if you turn down and let the PA and the monitors do their job. And your band mates will appreciate it. Which brings us to the guitar player’s favorite lament of “I can’t hear myself.” Which is a topic we’ll address shortly.


Two neat EL34 guitar amplifiers from Traynor

July 5th, 2014

If you crave the sound of the classic big British amplifiers, then you should check out amplifiers using the EL34 type power tube. The EL34 power tube was originally released by Mullard-Phillips in the 1950’s and in most common amplifier applications produces about 25 watts per tube. This is the power tube associated with the big British amps of the 60’s and 70’s produced by Marshall, Orange, Hiwatt and others.

The EL34 power tube has great harmonic detail, and a broad upper midrange that really fattens up the unwound strings of a guitar without making it sound muddy. Single note lines tend to have a lot of “meat” to them making amplifiers using these types of tubes sound both bright and thick at the same time. Traynor has two affordable amplifiers using the EL34 power tube, each with it’s own unique features.

Traynor Ironhorse – This Ironhorse is a “lunchbox” style of amplifier that uses (2) El34 power tubes and is switchable for either cathode or fixed bias. The fixed bias mode produces 40 watts, and is the tightest/brightest setting with the most available clean headroom. The cathode bias setting produces fewer than 20 watts and while still providing a good amount of clean headroom, has a little softer attack and a bit more “feel” to it. With a gain, master volume control and a three-way tone stack control it’s easy to dial in some natural crunch, or keep it clean and get your jollies with pedals. The Ironhorse is honest and tasty El-34 tone for great classic rock crunch in an affordable and lightweight package. It’s on the mark  for all sorts of live situations, and with the money you save on this amp you can go get yourself a nice set of new or NOS power tubes. It comes with a nice soft gig bag too.

Traynor YBA Mod 1 – In Traynor-speak, YBA means “Yorkville Bass Amplifier, which is what the 40-watt YBA was originally designed as. But the YBA found favor with guitar players too, and the Mod 1 version adds the ability to place the bright and normal channels in series or parallel, and adds an attenuator. In series the volume controls act like a master/gain control, while in parallel they function like normal/bright channels that you can blend just like a Tweed Fender. The attenuator can vary the ouptut power from .5 watts all the way up to 40 watts. At low wattage settings you can get all sorts of massive rock clang at very reasonable levels, while 20 watts is good for even the loudest of stage volumes. It’s hard to imagine even needing the 40 watt setting. Like the Ironhorse, the YBA has the complex crunch and texture that EL-34 tubes do best, and the added attenuation feature makes it good for practice and recording. Not quite as portable as the Ironhorse and pretty darn loud, but the attenuator can essentially size this amp from a large club down to a bedroom.

If you are looking to change up your sound, think about your amplifier too, and not just your guitar. With the EL84 dominating the small amplifier market, many players have never sampled the brawnier more harmonically rich tones of the EL34. So for less than a high quality solid body, you can get a taste of the tone that powered the British Invasion.

Are vintage guitars, amps and pickups really better?

June 28th, 2014

There is no denying that vintage musical equipment holds great allure for many players. Famous players and people of means often have prized vintage gear and swear by it. There is a general unquestioned belief that old gear is just inherently better, but is it really?

Humans by nature are nostalgic, and are predisposed to believe that the old days were always better. You know, things like Polio, Segregation, and AMC Gremlins. And once people perceive a change from the way things were, there is a reflexive yearning for whatever it was that is no longer the way it was. With Fender, this was of course the purchase by CBS. With Gibson I suppose it was the move from Kalamazoo to Nashville, and the Norlin era of ownership. I’ve even had a customer opine that any post-1999 Taylor isn’t as good because they changed their neck joint technique. Really?

These days, mid-70’s Fenders have asking prices well over $2000. Frankly, I was around in the 70’s and nobody thought much of a 70’s Strat. The 70’s was a true low point in American product quality, and manufacturers were trying to reduce costs and compete with the likes of the Japanese, but did not have the tools and processes to do so effectively. But now these indifferently assembled products of the 70’s are over thirty years old, and suddenly they are vintage? No, they are just old. So before you consider plunking down three grand on a post-CBS Strat with a wobbly micro-tilt neck and a 1/4″ thick finish, let’s somewhat objectively consider whether vintage really should mean anything to you in regard to playing value.

Guitars – In terms of solid body electric guitars, there really is no technical reason why a modern guitar can’t be as good or better than a vintage guitar. Why? Because basically all the materials that go into building an electric guitar 50 years ago — the woods, hardware, electronics, pickups, nitrocellulose lacquer etc. — still largely exist today in the same form (we’ll get to vintage pickups later). If you want to build a guitar just like it was 50 years ago, for the most part you can. Except today we have CNC machines, better hardware, and much better process control than ever existed 50 years ago. Guitar companies have gotten very good a letting machines do what they do best, and having people do what they do best. That’s why you can buy a $400 guitar that plays amazingly well and sounds good to boot. While some of this value is tied to low cost labor, it’s more a function of advancements in manufacturing.

Interestingly, there was a test in 2012 involving professional violin players that in double-blind testing could not reliably tell a prized Stradivarius violin from a high quality modern violin. Their ability to identify which instrument was the Stradivarius (they were wearing dark goggles) was virtually no better than random. When asked for their preference, most players chose the newer violin, but thought they were playing the vintage instrument.

There are various intangible reasons for owning a vintage guitar: The look, history and feel of an old instrument is hard to quantify but compelling for many players. Have a piece of gear with a sense of history can be a cool thing, and any instrument purchase is a combination of head and heart. But like many products today, the price-to-value ratio for new guitars is at a very high level (even for American gear) so don’t buy into the “only vintage is good” argument. Sometimes old stuff is just old stuff.

Pickups – Much like guitars, the materials available to build pickups the way they were built in the good old days still largely exist. The great pickups of yore were largely a function of good fortune.  Guitar manufacturers sourced wire and magnet materials based mostly on availability, the tension of the winding machine was generally controlled by hand, and the number of windings was approximate. On other words, not all pickups were created equal. Today’s boutique winders have studied the characteristics of a good pickup, and can faithfully reproduce a “good day” in Fullerton in 1957 on a consistent basis. And large pickup manufacturers utilize process controls and modern equipment to produce consistent product that can also sound awfully good. Spending $200 – $400 on any single pickup is probably never necessary, and spending that kind of money on a parted-out vintage pickup is basically a crap shoot.

Amplifiers – Compared to guitars and pickups, amplifiers are probably least likely to be truly reproduced in the exact manner of materials and construction as their vintage counterparts. Partly this is due to the complexity of an amplifier and myriad of components and materials used. Some of chemicals used in capacitors, speaker adhesives, transformers, etc. can’t be used anymore because they are hazardous or even carcinogens. Vacuum tubes, while still available new, differ from their vintage counterparts for either reasons of cost, health, or availability of materials (and some of the NOS tubes really are magical, and never to be made again). But that does not mean that there are not lots of fantastic sounding new amplifiers using available modern materials.  I’ve personally gone through a “must have blackface” phase only to come to the conclusion that they really weren’t for me, no matter how much I was told I would like them.

Plus even more than vintage guitars and pickups, older amplifiers varied widely in component selection, tolerance and speaker type. Fender used several different speaker brands depending on what they could get a good deal on (vintage Utah speaker anyone?) and Marshall was equally cavalier with component values and sources. Lastly  given the fact that few vintage amplifiers survive without some amount of component drift, component replacement, or “improvement” and it’s easy to imagine plunking down a good deal of cash for a box of rocks. Then there is just the whole reliability issue of of gigging a 50 year old amplifier. Now if you want an old amp purely for historical vibe, go for it, but sonic nirvana is not guaranteed.

Wrap Up – The great mystery of analog sound, is that everything does matter to some degree. Sound is an interaction of guitar, amplifier, and player. And within that there is a subset of pickups, components, speakers, cables, tubes….everything. Chasing the perfect sound can be fun, inspiring, and sometimes obsessively frustrating. And as Frank Zappa said, sometime you just have to “Shut up ‘n play yer guitar.” Because as we all know, the greatest variable is the player. I’m not down on vintage equipment, and sometimes owning something only for its aesthetic value is reason enough. Guitars and amps can be art, or at minimum great examples of industrial design. But like our 70’s Strat, buying “vintage” equipment guarantees nothing but age, and a little objectivity can save you a lot of money and frustration.

Vacuum Tubes – Favorite Power Tubes for Guitar Amps

September 23rd, 2013

Two 6V6 with a GZ-34 rectifier is a great recipe for clean to crunchy rock and roots music

Despite all the progress in digital modeling and analog circuit design, for some people a guitar amp isn’t a guitar amp without a few glowing glass bottles heating up the room. Technically obsolete but sonically beloved, tubes are still with us. And the crazy thing is they all sound different from type to type, and even brand to brand. Depending on your point of view this is a tweaker’s delight or nightmare.

Truth be told, there is some great sounding digital stuff, and if you are generally immersed in very high gain sounds or lots of effects, I’m not sure tubes are essential. There is just so much other signal processing going on that the subtle qualities of vacuum tubes can get lost. My friend’s Eleven Rack sounds pretty darn good pounding out raging “SLO” crunch, but as a semi-clean Fender Deluxe? Not so much. So if you are still chasing clean to slightly dirty tones, I think analog and vacuum tubes still hold the edge. Speaking of “The Edge:” By the time his guitar has run through fifty feet of effects and remote switching gear, does it matter that it’s plugged into a vintage Vox? No, especially not in a stadium. Sometimes it’s all about what you’re seen playing, which is why most of those stacks at a typical concert aren’t even plugged in (unless you are Yngwie).

If you are deciding to go the tube route, or are looking at a new tube amp, you also have to think about what types of power tubes. Preamp tubes are almost always the venerable 12AX7 — with an occasional EF-86 — so that choice is usually made for you. But with power tubes you have some decisions to make. Here are some comments and thoughts:

6V6 – The mainstay of the 30 watt and under Fender amplifiers, especially from the Tweed and Blackface era. Some of the newer small Fenders today like the Junior and Deville series use EL-84, so check under the hood. Sweet sounding with a high end that is complex and not overly bright, they are a great tube for small amplifiers. Maligned by some as not having strong bass response, that can be as much cabinet size and circuit design as the tube itself. A great tube for Strats and Teles. Less popular today than the EL-84, but a Dr. Z Remedy on half power is one of my all-time favorites. The ValveTrain Trenton is also another great recent 6V6 amp, and Rivera is also a proponent of this tube (they don’t make an EL-84 amplifier).

6L6 – The mainstay of the larger American amplifiers, the 6L6 can put out up to 25 watts per tube and is found in higher powered amps like Twin Reverbs, and many Mesa amplifiers. A little harder sounding and less complex than a 6V6, but it’s got a lot of low end. Great for chunky tones, sparkling loud cleans, and high gain.

5881 – A lower output alternative to the 6L6, the 5881 is often used interchangeably and is felt to have a little more delicate top end, and be a touch more musical. Amps with a 6L6 may be running at higher voltages not suitable for a 5881, so do your homework before you swap.

EL-84 – Developed by Philips, probably the most popular tube for amps under 30 watts, and the darling of boutique builders. Many of the small Fender amps today use this “European” tube rather than the 6V6. Personally not my favorite, especially not for gigging. They do have a lovely round “bouncy” tone that is really cool at low volumes, but these tubes tend to get shrill when cranked up, and have flubby, weak bass. YouTube is full of videos of people playing totally cranked small EL-84 amps through attenuators in their home studios. That may be fun, but not for your vocalist, or the crowd. This tube may be the “sound” of a Vox, but gimme a 6V6 any day.

EL-34 – This tube is the crunch of the big Marshall amplifiers: Punchy, with a strong upper midrange bite and lots of harmonic content. Most big Mesa 6L6 amps will also accept the EL-34, and it’s worth making the swap.  The problem is that any Class AB amp with these tubes is going to be pushing 50 watts or more. So they are fun but loud. There are some specialty Class A amps that will take a single EL-34, so you can have some fun without peeling the paint.

Wrap Up – Depending on the size range of amplifier you are shopping for, your choice of tube may be per-determined by the power rating. On the sub 40 watt end, my recommendation would be the 6V6. Not as ubiquitous as EL-84, but worth it for overall sound quality and flexibility. The 6V6 has a different pin arrangement than the EL-84, so they cannot be swapped unless you purchase adapters.

For larger amps, my pick is the EL-34, and a number of big rigs can flip a switch and accept an EL-34 or 6L6. For a 6L6 amp that cannot use an EL-34, check with the manufacturer and see if it is compatible with the 5881. This can be a nice tweak for a little less headroom and power output. A lower-voltage Fender Bassman running 5881’s is a delectable clean-to-mildly-crunchy tone machine.

For amp offerings at Upfront Guitars:  www.upfrontguitars.com

Pedal Amps – What’s a Pedal Amp?

September 22nd, 2013

Nearly every guitar player today uses some type of effect pedal, either for practice, recording or  playing live. Safe to say there is hardly anyone who does not own some type of effect pedal, making them both a great market for manufacturers, but also a real consideration when deciding what type of amplifier to use.

One of the frequent questions asked these days on the gear pages is what’s a good “Pedal Amp?” So what is a Pedal Amp? I would define a Pedal Amp as an amplifier that does not add extreme tonal coloration, and is able to handle high signal inputs without adding additional coloration or distortions. To some that does not sound like a particularly good amplifier, as for many old-school players the amplifier is an essential part of the sound equation. But for players that increasingly use various types of effects and digital modeling, the amplifier becomes more of an “amplification system” and less of a tone source.

Going back a few decades, the early amplifiers were instrumental to the developing sound of rock music. The happy accident of distortion, and then the use of lots of distortion as the essential rock guitar sound was not what the Founding Fathers intended. But as recording techniques, sound systems, and musical styles evolved, the concept of a pure unaffected guitar tone became increasingly rare. From the early days of cranking up small wattage amplifiers to get grindy tone, practically everyone today — well maybe not Neil Young — is using some type of effect to generate anything from mild to insane distortion. And while there are zillions of multi-channel amps out there, for flexibility’s sake pedals just allow much more room to mix and match tone.

So what makes a good Pedal Amp? In a word: Headroom. From a design standpoint, early amplifiers were notoriously short of headroom, both in the preamp and power sections. This of course gave them their warm creamy tone, but pump a high gain pedal into a Fender Tweed and the net result will be mushy distortion with very loose undefined low end. Practically speaking the pedal is creating distortion, and the higher input signal from the pedal is also distorting the preamp of the guitar amplifier. Distortion-on-distortion is not always desirable or musical.

Generally speaking, low powered cathode biased amplifiers (Tweeds, small Vox’s, lots of other low power EL-84 amplifiers) are not super candidates for pedals that have the capability of generating fairly high input levels. Even the relatively brawny 45 watt Fender Bassman won’t handle a lot of input signal without getting floppy. Hot input signals can come from distortion pedals or frequency modulation pedals (chorus, flangers) that tend to increase the signal level. Now boost pedals are made specifically to increase the signal, often for the purpose of overdriving the front end of an amplifier. But a boost pedal it typically only increasing the signal, and not adding its own distortion or other artifacts.

The boutique amp craze, with its plethora low power Tweed and Vox inspired designs (Dr. Z, Matchless, Badd Cat, Victoria etc) created some awesome sounding amplifiers that well-heeled baby boomers were craving. However they were not necessarily great at handling pedals, and even at 18 watts a Maz 18 is still damn loud. And this inspired the attenuator craze….and now everybody just buys pedals.

Fixed biased amplifiers — like Fender Blackface or similar designs — by virtue of their circuit topology have higher headroom and tolerate pedals better. Fender of course was trying to make louder and cleaner amplifiers to fill the larger venues that rock bands were playing. For that reason amplifiers that follow the higher powered Fender Blackface 6L6 tube lineage tend to be pretty good pedal amplifiers.

Once amplifier designers discovered master volume techniques and cascading gain (preamp distortion) techniques, amplifier designs became “stiffer” cleaner and louder. The general elimination of tube rectifiers in favor of diode rectifiers also increased headroom, and made the amplifiers sag less, and play cleaner under heavy loads. Distortion was now a design goal, not a by-product of marginal design or power handling capability. But to some, all these improvements — including dreaded solid state — took away some of the “organic” nature of the early amplifier sound.

Fast forward to the boutique amp craze and builders were putting all this “marginal” stuff back into amplifiers: Cathode bias, low power, and tube rectifiers. And at the opposite end of the spectrum some players are now using a totally digital preamp source — like an Axe Effect Fractal or Eleven Rack — and a powered full-range speaker system from JBL, QSC, or EV.

So back to the original topic: Good Pedal Amps tend to be more modern or higher powered designs that can tolerate strong signal inputs, and if they use a tube power amp section, have a solid state rectifier. If you are playing live or play at high volumes and want to use gain pedals, it’s advisable to avoid lower powered designs in the mold of a Tweed or Vox. Nothing against these amps — Robert Cray through a Matchless is a great sound — but it’s not a pedal sound. There are always exceptions to the rules of course, and some of the boutique designs using the EF-86 preamp tube (Dr Z. Z-28 for example) have quite of bit of clean headroom despite modest power outputs. It’s always dangerous to generalize.

Speaking of which, what about the Mesa Dual and Triple-Rec designs. Don’t they also violate the low power/tube rectifier rule? Yes, sort of. Up around 100 watts, tube rectifiers are pretty marginal AC-to-DC converters for creating the high voltage DC that power tubes need. By wiring two rectifiers in parallel, each rectifier is only carrying half the current, and therefore can share the load and maintain headroom (Fender did this on some 50’s amps for the same reason). A Triple-Rec adds one more rectifier for handling even higher powered designs. Mesa could have just used solid state diodes, but a Mesa Diode Roadking lacks marketing pizazz. Most Mesa — and modern metal — amplifiers are characterized by very “clean” clean channels and the distortion is produced by various combinations of tube and solid state wizardry.

Finally, here’s a personal example with the two amps I like to play the most: A Fender Reissue Bassman, and a Dr. Z Remedy head plugged into a Mojo Pine 4×10 cabinet with Jensen P10R/Eminence Blueframe speakers. Both are using virtually identical speaker arrangements, speakers, and cabinet materials. But the Bassman is an early cathode bias design with a tube rectifier, and the Remedy is a solid state rectifier design using four 6V6 tubes (not a “reissue” design but billed as having Marshall Plexi-style tone). They both have the same power output, about 40 watts. I love the Bassman tone, but in gigging situations using pedals for various levels of gain and effects, the amp loses definition, attack, and can get sloppy. Even on half power, the Remedy has better attack, low end firmness, and is overall tighter. Crunchy gain is crunchy gain. On full power the Remedy is really too clean for most situations except outdoor gigs. But both are 40 watt amps.

My general rule of thumb for any amplifier selection is to find the best clean tone that makes you happy and then go pedal shopping. If your favorite tone is clean to slightly crunchy, you may never need pedals and a smaller lowered powered “old school” amplifier may be the ticket. But if you are like most players, make sure the amplifier of your dreams has sufficiently stout headroom to serve as a suitable platform for whatever pedals you decide to use down the road.

For more information on platform and pedal options at Upfront Guitars:  www.upfrontguitars.com

The Guitar Pedal Boom – Too much of a good thing?

July 21st, 2012

As anyone who is even a casual player has noticed, the last few years have been truly explosive for the guitar effects market. The rise of stomp box mania has defied current economics trends — sales even grew during the recession —  and is now over a $60 million segment of the MI industry. The number of brands and selection is dizzying, and just browsing one particular online guitar website revealed that they carried over 120 brands!

Why are pedals so popular?

Well for starters, as far as guitar gear goes, pedals are cheap thrills. With the vast majority of pedals being priced under $150, it’s not a big investment to try out a pedal, and if it’s not the cat’s pajamas you can sell it to a friend, put it on the shelf, or stick it on eBay. To some degree it’s pretty hard to wear out a pedal, so a used one on eBay is typically a smart choice. I have a theory that pedals are like the proverbial Christmas Fruitcake; there is actually only one, and everybody just keeps passing the same one around.

For a budding manufacturing or mad scientist, going into the pedal business has a fairly low barrier to entry. Practically everyone uses the same die cast box — now that guy is making a killing — silk screening and painting is pretty low tech (some people even skip the paint) and the actual cost of the components are pretty low too. If you don’t mind hand soldering, there is no need for fancy assembly or wave soldering equipment. It’s also pretty easy to find schematics online, or just back engineer your favorite stomp box. Now there are obviously many serious companies out there doing lot’s of research and making significant investments in R&D and manufacturing. But for somebody who just wants to get into the business, it’s a lot easier than making guitars, amps, or speakers.

One other factor — at least to me anyway — is that if you are looking for great sounding distortion or gain, which is by far the most popular effect type, a pedal is quite often better sounding than most “gain” channels on two or three channel amps. There are many players out there with multichannel amplifiers that tend to play only the clean channel, and rely on pedals for distortion and modulation effects. Why is this so?

Well if you look back to the early amplifiers and the onset of distortion, the distortion was caused by the power tubes clipping, which turned out to sound really good; warm, sweet and very musical. A low powered amplifier with limited headroom such as a Fender Tweed would distort at a reasonable volume level. It sounded great, and everyone saved their hearing. But bands were playing ever larger venues and needed larger amplifiers, with more wattage, and more headroom. Now the amps were louder, which was good, but that warm power tube clipping was gone. Try and get a Fender Twin to distort, I dare you. Players needed volume and distortion that they could control.

But some clever engineers came of with the master volume control. This allowed the player to essentially overdrive a section of the amplifier, but control the overall volume level with the master volume. Presto! distortion at listenable levels. But the characteristic of the distortion was different. It was not warm and creamy but more harsh and fizzy. This is the because the distortion is produced by clipping the preamp tubes, and this distorted sound is then fed into the power tube section for amplification. It’s a sound, but not the sound of an amp being played at the limits of its clean headroom.

Early master volume amplifiers were often harsh and raspy, with an edgy tone that was anything but musical. Fender’s foray with master volume controls in their 70’s Silverface amps were vile, sounding somewhat like a Kazoo Orchestra playing Smoke On The Water. Obviously amplifier designers have gotten much better in producing musical overdriven sounds, typically still by using preamp distortion. The famous Mesa high gain sound is essentially multiple preamp tubes each over-driving the other to produce a thick chunky distortion tone. This is sometimes called cascading gain, and it can sound really good. If you’re a fan of metal, it’s where it’s at.

But this type of distortion is actually fairly easy to emulate using solid state components. It’s not so easy to make a pedal that really sounds like a small amp working hard on a Saturday night, but fuzz and higher gain distortion sounds can be quite convincingly created in a small metal box. It looks a hell of a lot more impressive to have a half stack, but a 1×12 or 2×12 combo with good headroom and a couple pedals can sound pretty mean.

My apologies for a highly compressed and somewhat biased view of amplifier history, but many players have found that an amplifier with a good sounding clean channel is the perfect “canvas” to paint on with the pedal of your choice. Often a well-crafted little box will sound better than an amplifier using preamp distortion to achieve high gain sounds. That’s my experience anyway, and my choice in selecting an amplifier is totally focused on finding the best natural tone possible, and using pedals to color the sound in a way that suits my musical leanings. I also happen to like a little “natural” tube grit to my tone, so I tend to play fairly low powered amplifiers, but even so I’m never going to turn my amp up to “10” for a solo. I’ll use a pedal. As far as I can tell, the only people who turn their amps up to “10” are on YouTube, and live in very small bedrooms.

So pedals are inexpensive, they are plentiful both new and used, and the low investment required to get in pedal business means that lots of people are making them. So it’s all good, right? Sure, there is nothing essentially wrong with having too much of a good thing, and over time the number of pedal makers will reach some sort of natural Darwinian limit: The really good builders with grow and thrive, and the hacks and pure copycats will fade away. I’m of the opinion that pedals are somewhat like pizza: None of it is truly bad, and everyone finds their favorite. There are however many bad amplifiers, and spending $300 on some boutique distortion pedal with rare germanium diodes will not hide the fact that your amp sounds like crap. Start with the amplifier and speakers first. Get your core sound down to where you really love what you hear with nothing more than a guitar, a good cable, and your amp. Then go forth and experiment with the little die cast boxes of your choice.




In Defense of Good Guitar Amplifiers

April 13th, 2012

This is somewhat a continuation of an earlier blog regarding the benefits of a good guitar amplifier, owning more than one amplifier and also the general state of amplifier sales.

Over the past decade we’ve witnessed a couple significant trends in amplifiers. One of those trends was the rise of the boutique amplifier business. This trend may have peaked at the during the recession of 2009, but there has been an explosion of small builders making everything from faithful vintage reproductions, to interesting and creative new designs. The boutique boom may have also reinforced the realization that 15-30 watts is typically more than enough for most jamming or club situations.

The rise of digital modeling amplifiers was not originally a topic that I was going to address, but it at least deserves honorable mention. Early pioneers like Johnson and Line 6 drove the concept that a player could in theory have many historic amplifiers in one cabinet. This has become a permanent fixture in the amplifier world, culminating in high end audio products like the Eleven Rack and the Fractal Axe-FX. Some of these products have frighteningly good emulations, although typically the more “processed” the sound you are emulating the better they perform. Getting a Fractal to sound like The Edge is more satisfying than getting it to really sound like a Deluxe Reverb.

The other significant trend over the past 5-7 years is the rise of really inexpensive tube amplifiers. In my opinion, once the boutique industry proved that simple low-powered amps were a great way to get wonderful tone at reasonable volumes, manufacturers with access to low cost sourcing took that concept to overseas with the idea of offering much lower cost with the same features. If you think about it, a 15 watt amp with three tubes and four knobs is not technically hard to make, and in China it’s also incredibly cheap to make. So now instead of paying $1500 for a hand-wired Tweed Deluxe clone, a player can go to their local big box and get a 10 watt all-tube Chinese screamer for $299.

So the trend these days is that players are buying fewer amplifiers, and they are also buying cheaper amplifiers. In 2008 the average price paid for an amplifier was about $340, and there were 1.1 Million sold. In 2011 amplifier sales were 900,000, and the average cost had dropped to $255, 25% drop in average price (in contrast the average guitar price over this period dropped only 9.8%). This is a significant trend over a short period of time, and higher end amplifier builders must be feeling it. While the drop in average price may be partly due to post-recession caution and less disposable income, I think there is also a perception that, “Hey, it’s got tubes and it’s a grand less, why spend more?”

Why indeed. Guitar players incessantly focus on their axe, but often treat the amplifier as an appliance that will instantly transform the wonderfulness of their guitar into beautiful music. It’s almost as if you could plug into your washing machine and essentially get the same tone. Truth be told, the amplifier is at least 50% of “your sound,” maybe more. Heck, the just the speaker in the amp is a major determining factor in how you sound.  Amplifiers are inherently complex and every component — transformers, capacitors, type of tubes, layout, speakers, component values — has a contribution to the overall quality of your tone. Every manufacturer has a cost target they need to meet, but there is no way that the $299 amplifier manufacturer pays the same attention to detail regarding component selection than the guy making the $1000 amplifier does. When a manufacturer chooses to save $1.50 by installing an inferior speaker or transformer, they risk making an otherwise reasonably good product into something flat and uninspiring.

With amplifiers it’s not just the labor that costs money, it’s the hardware. A worker in China can solder just as well as a worker in the USA. They can probably fabricate a cabinet and apply tolex just as well too. It’s not as important that you can solder, it’s what are you soldering. Is it a transformer made by people who really know what makes a quality product optimized for guitar, or is it a transformer that went out for bid and was chosen because it was $.15 cheaper?

Historically, China’s edge has of course been labor. And while the landscape in China is changing, in general labor has been cheap, and the majority of their costs are in the materials. When it comes to manufacturing, they are much less sensitive to labor cost as they are to material cost (in many ways the complete opposite to the US). When a Chinese manufacturer needs to reduce cost, there is much more leverage in reducing material cost than labor cost (this is changing too: See Indonesia). The plain truth is that China is a very good place to assemble product. The risk in China is not the ability to assemble quality products, but the quality and reliability of the material supply chain. With material cost being king, there is intense pressure to squeeze every cent out of material cost, often to the detriment of product quality.

The point is that component quality and selection is critically important to the sound qualities of a guitar amplifier, and  the costs of these materials are essentially the same regardless of where the product is manufactured.  The $299 guitar amplifier is not using the same components as the $1000 amplifier, period. The parts really matter, and at this time, most of  the top quality amplifier components are not being made in Asia. Can you assemble a “kit” of top quality components and ship it to China for assembly? Sure, and you will pay to ship the components to China, and then you will pay to ship the amplifier on a boat back to the US. It will still cost less, but probably not a lot less, and that amp will have a pretty large carbon footprint.

Ultimately, good amplifiers cost money, and good amplifiers matter just as much as your guitar. I’m not suggesting that in order to be happy and have good tone you must spend at least $1500 on an amplifier. But to some degree cost and quality of sound are inextricably linked. Take the Vox AC 30 for example: They are made in China and run anywhere from $999 to $1500. Vox/Korg is taking advantage of lower cost labor, but they are also not skimping on components, including shipping British-made speakers to China. These amps are made in China, they are not junk, but they are also not inexpensive.

A quick story: We were recently displaying at a guitar show that had a lot of custom builders in attendance. So this was not an amp show, it was a guitar show. But some of these builders were displaying guitars that cost thousands of dollars, but all they brought to demo product were $150 10 watt modeling amps. Result: They sounded like garbage. What were they thinking? On the other hand, we brought a couple Rivera heads, a Rivera 1×12 cab (and to be to “PC” a Rivera RockCrusher Attenuator). When somebody tried any of our guitars, people stopped and listened. The guitars sounded good because the amps were good.

Playing through a really good amplifier that melds with your tone and style is a transformative and immensely satisfying experience. Choosing an amp needs to be taken seriously, and placed on the same level as choosing your guitar. You may even find that one  amplifier — just like one guitar — does not adequately address the range of tones that you are looking for. However, once you find an amplifier that speaks to you, you may find that the constant urge to experiment with pedals, pickups and guitars suddenly becomes much less urgent.