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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.