Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Jennings on November 25, 2023, 04:10:31 am

Title: Anyone got an Ampeg SVT layout?
Post by: Jennings on November 25, 2023, 04:10:31 am
Recently my Bugera BVV3000 (sort of an SVT “clone”) packed up…personally I’d found all the surface mount components, plug in connectors and automatic valve monitoring circuitry to be a bit of a pain. So I’m inclined to junk the PCBs, and use the iron and chassis to rebuild a tagboard SVT circuit in its place. Before I delve into sketching out a layout for the circuit I thought I’d ask whether has one to hand which I can go from? Many thanks 👍
Title: Re: Anyone got an Ampeg SVT layout?
Post by: HotBluePlates on November 28, 2023, 05:46:34 am
... I’m inclined to junk the PCBs, and use the iron and chassis to rebuild a tagboard SVT circuit ...

Not to burst your bubble, but the vintage SVT was a PC board amp (multiple PC boards, in 2 separate chassis-sections):


(https://irationaudio.files.wordpress.com/2016/07/ampeg-svt-chassis.jpg?w=1250&h=780&crop=1)
Title: Re: Anyone got an Ampeg SVT layout?
Post by: Jennings on November 30, 2023, 11:19:48 am
Yeah, I hear you…I did know it was, but the Bugera uses a tonne of flimsy connectors, sun miniature components and has a load of valve monitoring circuitry etc…so I wanted to take the opportunity to go back to basics and just build a turret board version of the amp, minus the extra gubbins and clippy connectors etc.
Title: Re: Anyone got an Ampeg SVT layout?
Post by: kagliostro on November 30, 2023, 12:13:02 pm
May this be of interest ?

https://www.frontiernet.net/~jff/SonOfSVPCL/DIYSVTBassPreamplifierMainBoard.html (https://www.frontiernet.net/~jff/SonOfSVPCL/DIYSVTBassPreamplifierMainBoard.html)

https://music-electronics-forum.com/forum/amplification/guitar-amps/build-your-amp/debugging-your-build/40428-svt-clone-power-supply-high-b (https://music-electronics-forum.com/forum/amplification/guitar-amps/build-your-amp/debugging-your-build/40428-svt-clone-power-supply-high-b)

Franco
Title: Re: Anyone got an Ampeg SVT layout?
Post by: PRR on November 30, 2023, 01:17:01 pm
> Bugera BVV3000 .. packed up…

Fix it and sell it. Not many were made. Eventually they will be rediscovered and the value go back up.

If you must whack it up: find pix of HiWatt guts.
Title: Re: Anyone got an Ampeg SVT layout?
Post by: HotBluePlates on November 30, 2023, 05:49:52 pm
I've built a few amps.   :icon_biggrin:  There is nearly no amount of money that would be enough to entice me to build a handwired 300w amp.

Separately, if the chassis was p.c. board & surface-mount parts before, it's probably not big enough for you to use bigger parts.  And there's nothing inherently bad about surface-mount, nor Bugera's tube monitoring/biasing circuitry.  I've seen other people trash-talk things like it that they either didn't grok, or didn't have the tooling to repair.
Title: Re: Anyone got an Ampeg SVT layout?
Post by: Jennings on December 02, 2023, 03:13:23 am
May this be of interest ?

https://www.frontiernet.net/~jff/SonOfSVPCL/DIYSVTBassPreamplifierMainBoard.html (https://www.frontiernet.net/~jff/SonOfSVPCL/DIYSVTBassPreamplifierMainBoard.html)

https://music-electronics-forum.com/forum/amplification/guitar-amps/build-your-amp/debugging-your-build/40428-svt-clone-power-supply-high-b (https://music-electronics-forum.com/forum/amplification/guitar-amps/build-your-amp/debugging-your-build/40428-svt-clone-power-supply-high-b)

Franco


That’s great…many thanks 👍
Title: Re: Anyone got an Ampeg SVT layout?
Post by: Jennings on December 02, 2023, 03:16:09 am
> Bugera BVV3000 .. packed up…

Fix it and sell it. Not many were made. Eventually they will be rediscovered and the value go back up.

If you must whack it up: find pix of HiWatt guts.


I might well keep it as-is. It’s a great sounding amp, and well built, which I’ve kept for some years now. Although there’s an auto-standby function which is a bit trigger happy that I’ll probably end up changing at least. I’ve yet to open it up (others in the queue) to pinpoint the “packed up” issue…but I’m suspecting it’s the HT supply, standby switching or a connection in that region. We’ll see.
Title: Re: Anyone got an Ampeg SVT layout?
Post by: Jennings on December 02, 2023, 03:21:53 am
I've built a few amps.   :icon_biggrin:  There is nearly no amount of money that would be enough to entice me to build a handwired 300w amp.

Separately, if the chassis was p.c. board & surface-mount parts before, it's probably not big enough for you to use bigger parts.  And there's nothing inherently bad about surface-mount, nor Bugera's tube monitoring/biasing circuitry.  I've seen other people trash-talk things like it that they either didn't grok, or didn't have the tooling to repair.


If I was scratch building I’d probably just use a pair of KT88, not bother with the monitoring circuitry, and I wouldn’t need the PCB mounted clip connectors since I’m not a production line…interestingly the chassis has plenty of room for bigger parts. Mostly because the main amp circuit uses traditional sized components and boards. The monitoring circuitry etc uses surface mount and IC components, as you’d expect. As do many great sounding effects pedals etc. It’s a well built and great sounding amp, which is why I’ve kept it so long. It’s a slight PITA to remove the control section to work on though due to the cab construction. But it’s not like that’s an everyday issue.