Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Paul_5 on December 29, 2011, 08:36:17 am

Title: aMpeg SVP PRO
Post by: Paul_5 on December 29, 2011, 08:36:17 am
Hi All, I'm an Ampeg user in the UK and have a wonderful (if a little noisy SVP PRO). is there any information fixing the wiring near the power inlet?

I've read the thread on here from last year where a user was advised to do this, but am after more details.

I've retubed, re-transformered and recapped the PSU board, but to no avail.

any advice or diagrams, cake or photographs would be appreciated.

Cheers, Paul
Title: Re: aMpeg SVP PRO
Post by: HotBluePlates on December 29, 2011, 01:38:24 pm
Is the preamp not functioning?

If you can take a close-up photo of the area of the wiring in your preamp that need repair, please post it. Wiring repair should be an easy matter (assuming that is the actual problem).
Title: Re: aMpeg SVP PRO
Post by: Paul_5 on December 29, 2011, 02:11:06 pm
thanks for the quick response Blue. It's functional, but a bit noisy. I remember reading somewhere that the power supply can be tampered with to reduce the noise through the 'preamp out' sockets, but I'm not sure which bits to move.
Title: Re: aMpeg SVP PRO
Post by: HotBluePlates on December 29, 2011, 06:53:10 pm
If you do a Google search for this preamp (like I did to find the schematics), everyone's complaint about this preamp is that it's noisy. I even found a 4-5 page discussion by some technically knowledgeable folks on another site, who were trying to find the reason for the noise and ways to reduce it. I got the impression that they were not successful.

So am I right to think there's no overt symptom of malfunction right now with your preamp, but just excessive hiss/noise that you'd like to reduce?

I'll try looking over the schematic to see if there's anything that sticks out to me.