Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Opry Audio on May 20, 2025, 11:38:51 am

Title: Turrets on PCB (image request)
Post by: Opry Audio on May 20, 2025, 11:38:51 am

Hey everyone,

I hope y’all are well. I am doing some product dev for a new amp, and one thing I am looking to try is to construct a turret board, but due to their being some amount of solid state circuitry in the build, I would like the board to be a PCB for convenience/new construction style with a classic look.

I know Marshall JMP’s from the early 80’s attempted this (successfully?) for handwired connections to the PCB. I have had them on my bench in the past but never thought to document how they implemented it. Double sided plated through hole and swaging the turret and finally soldering the underside is my plan. Does anyone know if there were long term design issues with this construction style? Does anyone have images from the underside of that board? Just curious what they did. Or any similar amps to reference. Thank you!

Title: Re: Turrets on PCB (image request)
Post by: kagliostro on May 20, 2025, 03:33:39 pm

VOX realized tube amps with PCB with turrets on board

Franco

Title: Re: Turrets on PCB (image request)
Post by: Opry Audio on May 20, 2025, 04:39:38 pm

Which production vox? Just wanting to see some underside PCB shots so I can see how a proven and reliable method was done

Title: Re: Turrets on PCB (image request)
Post by: Opry Audio on May 20, 2025, 04:48:20 pm

Also wondering if anyone here has done this with plated through holes. There is one short thread about this on ampgarage. Someone mentioned soldering underneath the board with higher melting point solder so it doesn’t melt while you’re working on component connections.

Title: Re: Turrets on PCB (image request)
Post by: shooter on May 20, 2025, 06:24:47 pm

Quote

so it doesn’t melt while you’re working on component connections.

strip the under-side wire enough that it metal thru the turret, "J-hook" it out the top, done.
helps when you're "proofing" the turret components n wires BEFORE adding solder.


edit;
here's a Peavey with board layout top n bottom.

Title: Re: Turrets on PCB (image request)
Post by: Rontone on May 20, 2025, 06:52:34 pm

Here's a few pics of a 70's amp board with some circuit traces on, as Shooter said J-hook the component lead through, I've done that to get a good fix onto the copper track with the component lead from above,

I don't like under board wiring and prefer to bring it through a hole to the top side and around the turret, as can be seen with the red wire in the photo

One thing to consider is does the PCB board width fit with commonly available turrets, in my case the board came to ~2.7mm, not the usual 3mm so I had to file each turret down and measure with Vernier calipers

It looks a bit rough and need to clean some flux off there, but it gets good continuity from top side component lead to the copper track

Title: Re: Turrets on PCB (image request)
Post by: kagliostro on May 21, 2025, 06:51:06 am

On my archive I've found the photo of the amp I remembered, unfortunately there are only photo taken from component side and no refer to the VOX amp model, it is one among the "new" handwired models

Quote

EDIT: Seems I've find the source of the photo

https://www.voxshowroom.com/uk/amp/ac30h2_2007_hood.html (https://www.voxshowroom.com/uk/amp/ac30h2_2007_hood.html)

Franco