Hand wire or PCB in tube guitar amp?

[teemuk]

...combine turrets with a PCB holding the turrets. ...nobody does that one, do they?

At least Matamp (modern) and MAKO do it, though the Matamps are often critiqued for the turrets actually breaking loose from the PC board. Ironically, plain basic components seem to be more reliable solder-wise; especially the modern SMT ones.

[raiken]

If you simply must have ease of modding, it makes a great deal of sense to combine turrets with a PCB holding the turrets. Easy to repair. Easy (ish) to mod, and consistent. Funny - nobody does that one, do they?

Somebody does - that is how all Aiken amps have been constructed since 2000 - 0.125" thick turret board with full ground plane on top, plated through-holes, 50-mil thick traces underneath (2A to 6A current capability), soldermask and silkscreen with component designators, pots, tubes, and jacks all mounted to chassis and connected with flying wires. A breeze to work on, extremely reliable. The turrets are both swaged in and soldered top and bottom, so they never break loose.

Having said that, I am switching to full PCB construction on my next line of amps...

[raiken]

Ironically, plain basic components seem to be more reliable solder-wise; especially the modern SMT ones.

I still say full SMT would be best for guitar amps - you can easily remove components from the top of the board, so servicing is a breeze. The biggest problem is finding high-voltage SMT poly caps that don't fall apart when hand-soldered...

[mooreamps]

Somebody does - that is how all Aiken amps have been constructed since 2000 - 0.125" thick turret board with full ground plane on top, plated through-holes, 50-mil thick traces underneath (2A to 6A current capability), soldermask and silkscreen with component designators, pots, tubes, and jacks all mounted to chassis and connected with flying wires. A breeze to work on, extremely reliable. The turrets are both swaged in and soldered top and bottom, so they never break loose.

Having said that, I am switching to full PCB construction on my next line of amps...

If I had gerbers ready to go, that's the way I'd do it..

-g

[jpfamps]

Somebody does - that is how all Aiken amps have been constructed since 2000 - 0.125" thick turret board with full ground plane on top, plated through-holes, 50-mil thick traces underneath (2A to 6A current capability), soldermask and silkscreen with component designators, pots, tubes, and jacks all mounted to chassis and connected with flying wires. A breeze to work on, extremely reliable. The turrets are both swaged in and soldered top and bottom, so they never break loose.

Having said that, I am switching to full PCB construction on my next line of amps...

I always thought using hybrid PCB turret construction was a great way to build an amp.

What has provoked the change?

[jrfrond]

I've worked on a broad spectrum of audio products in 30+ years, and even non-audio when doing mil-spec wiring/tech work. Yes, tough and hardy PCB designs CAN be done, but you will never see it at the consumer level, and THAT is where I earn my living. You can spout and execute great designs from now until doomsday, but I am sorry to say that all of the wonderful boutique amps out there utilizing this construction probably constitute less than 1% of guitar amp sales. The other 99% still requires service. And you'd better be building a tube amp that no one will want to mod, because I haven't seen a PCB yet, even in the aforementioned mil-spec gear, that could withstand the multiple soldering heat cycles without having copper delaminate from the board substrate.

I think Leo Fender had it 99% correct. The 1% is for the use of an eyelet board substrate that, under the right conditions can become hygroscopic and partially conductive, but not always. However, it was cheap and easy to work with.

Like I said, I'm old-fashioned, and yet I AM familiar with PCB design. However, I will take PTP in tube amps on eyelet boards, turret boards or terminal strips any day over ANY PCB construction.

[R.G.]

... Yes, tough and hardy PCB designs CAN be done, but you will never see it at the consumer level, and THAT is where I earn my living. You can spout and execute great designs from now until doomsday, but I am sorry to say that all of the wonderful boutique amps out there utilizing this construction probably constitute less than 1% of guitar amp sales. ...

Not really spouting - just correcting a technical issue. I see that we have no real technical disagreement - reliable PCB designs for amps can be done.

What I interpret you as saying that that very few amp companies get it right. I also completely agree with that. Very few people understand the special needs of tube amps, and those that do seem to self-select themselves out of understanding PCBs.

What I object to is any blanket statement that PCBs per se are bad, unreliable, or unsuited to (in this case) tube amps. Damning PCBs as unreliable in tube amps is like saying cars are no good because Ford made the Edsel, or saying that icing on cakes is bad because it makes you fat. They are what they are, for better or worse. What matters is the skill of the designer and his understanding of the special needs - how the technology is applied.

So, I fully disagree with "PCBs in tube amps are bad." unless it's further qualified. I fully AGREE with the statement that "on an overall numbers basis, very few PCBs in tube amps are well designed for the task."

Like I said, I'm old-fashioned, and yet I AM familiar with PCB design. However, I will take PTP in tube amps on eyelet boards, turret boards or terminal strips any day over ANY PCB construction.

As you've expressed it, you have a personal preference for non-PCB construction the way it's (usually and clumsily) done. That's fine. I don't like okra, fried or otherwise. I consider those statements to be equivalent.

[mooreamps]

I always thought using hybrid PCB turret construction was a great way to build an amp.

What has provoked the change?

YouTube - Marshall factory tour 1