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Amplifier Construction types

I’d like to kick off by saying that purely from the perspective of tone or sound, I have not seen any objective tests or evidence to support any theories that one type of construction sounds better than another. Furthermore, as somebody who has some experience in electronics, there is no scientific evidence to support these theories either.

So therefore it is my opinion that anything that suggests that “true point to point sounds better than PCB” is 100% myth concocted by guitarists and audiofiles to support their own spending habits, or by manufacturers in an attempt to support marketing statements.

So why are some of my own amps point to point? I have very good reasons (which are discussed later), but they don’t relate to tone. I think that good tone is the result of good design. If you believe otherwise, I would suggest you question those beliefs, and perhaps avoid forums (they are full of people with beliefs…).

So here are a few construction types, along with why their relative pros and cons (relative to one another).

Printed Circuit Boards (PCBs)

PCBs can be manufactured in a number of ways, including “through hole” and “SMD”, or a combination of both. Through hole implies that the legs of the component go through the hole in the PCB. Kind of obvious when you think about it. SMD = Surface Mount Device. These devices mount on the surface of the PCB – again, when you know, it’s obvious.

Pros
  • Fast and easy to manufacture, especially if all the components are on a single board
  • SMD construction makes manufacture even quicker as it can be automated – a lot of mass manufactured current production equipment is made this way
Cons
  • Labour intensive design process (unless you infringe copyright laws!)
  • Most difficult to repair/modify etc
  • Susceptible to joint movement so potentially less reliable
  • Structurally weak if not designed correctly

Turret/Eyelet boards

Eyelets feature in early Fenders, turrets feature in early Marshalls, and some of the amps that we make here at Sutcliffe Amplification.

Pros
  • Servicing and modification fairly easy
  • Robust construction
Cons
  • With turrets, sometimes the interconnect wiring is done underneath in order to look neater
  • This can cause issues when soldering, in that the wiring can then become loose or even fall out from underneath the turret. I have had this happen to some repairs – not ideal!
  • Getting underneath the boards can be extremely difficult, again down to design
  • Over time, some eyelet boards have been known to become conductive, causing all manner of problems

Tag Boards

Vox used this constructions extensively in the AC15 and AC30 amps

Pros
  • Whilst we’re being open about things, I’m not a fan, but they can look quite tidy
Cons
  • Whilst they do come in a number of pitch sizes, I’ve only seen the smaller boards which for someone with big hands, are a bit of a ball ache!
  • Only smaller components will fit within the space between the tags (especially on the smaller pitch boards)
  • Rarely able to lift the board up to inspect underneath without disconnecting all outside wires

True point-to-point

My preferred method of construction as it really is a bit of an art (and a lost art at that)

Pros
  • Easy to service and modify
  • By far the sturdiest type of construction and structurally should outlive any of the components installed
Cons
  • Labour intensive (and hence costly)
  • Can look messy – depends on technique and requirements

Just another note about point-point. Generally the equipment that has been made using this technique is quite old. Consequently there’s a chance that if you buy a very old piece of kit, it has been made using wax signal capacitors and carbon composite resistors. Neither are known for reliability so whilst the gear might be ok in the short term, in the long term the chances are that it will need an overhaul.

For the amps that we create here, we use components that have been chosen for their longevity and low noise characteristics (rather than NOS components that are likely to fail). We also over-specify some components to add to reliability too.

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