[dq12guy]

Hello everyone,

I recently purchased a used  BAT VK 31SE preamp. The amp sound nice. It actually sounds very much as many members has describe the BAT VK tube sound. Full yet slightly heightened punchy base, detailed (almost lush) vocals and a the high are rolled off a bit. This works for me because although I love detail, I must feel the music is tangible and if the decay on the highs is too long by ears get fatigued.

The issue I am having is that when I turn the turn off the preamp by putting it into standby mode the is a very noticeable thump (or pop) sound that comes from speakers. This happens even when the source for the preamp is muted or shutdown prior to turning off the preamp. The amp I am using the Odyssey Stratos Mono's if that matters?  Is there a procedure that I should follow when shutting down my system to stop this from happening? 

Thanks everyone

[FullRangeMan]

This pop is the activation noise of the switch.
Obviously there is no softstart for this switch.
Did this pop appear a short time ago or has it always been since new?
There is any dust that you can clean in this switch?

[borism]

One procedure is for start-up  of system to begin with the source, followed by preamp and amplifier last and for shut-down the reverse - amplifier first, followed by preamp and source last.

[I.Greyhound Fan]

Hello everyone,

I recently purchased a used  BAT VK 31SE preamp. The amp sound nice. It actually sounds very much as many members has describe the BAT VK tube sound. Full yet slightly heightened punchy base, detailed (almost lush) vocals and a the high are rolled off a bit. This works for me because although I love detail, I must feel the music is tangible and if the decay on the highs is too long by ears get fatigued.

The issue I am having is that when I turn the turn off the preamp by putting it into standby mode the is a very noticeable thump (or pop) sound that comes from speakers. This happens even when the source for the preamp is muted or shutdown prior to turning off the preamp. The amp I am using the Odyssey Stratos Mono's if that matters?  Is there a procedure that I should follow when shutting down my system to stop this from happening? 

Thanks everyone

I have a VK-51se  and it had the same problem.  I spoke with Victor Khomenko from BAT and he said that the the output caps were bad.  I replaced them all and the problem was fixed.  Apparently they had a problem with those older PIO Jensen caps going bad. I had an EE friend do the work for me but BAT will fix it for you with free labor but you will have to pay for the parts if I remember correctly. 

You can still use your preamp, just turn your amp off first and wait about 5-10  seconds before turning the preamp off.

Larry

[Drummerboy2]

I had a BAT VK30 preamp that I bought at Audiogon. When I got it and checked it out it popped like this as well. I checked the output and there was DC offset on the output, so I changed the BAT Caps (Jensen) to Jensen Copper Foil PIO and all was good after that.

[dq12guy]

Thanks everyone for your feedback.

By shutting down the amplifier first, it definitely solves the problem but it is a pain in the butt. I have Odyssey dual mono amps that are located behind my wooded stereo console to keep them out of sight. So, manually shutting them down is not a fun task.

I will give BAT a call to see what is involved in having the pre-amp serviced to have the output CAPs upgraded/replaced. If too much trouble, I will have my local HiFi shop perform the repair.

Thanks again for sharing your knowledge.

[Drummerboy2]

I had the BAT VK30 preamp bought it from ebay and had the same issue. It was the output Caps were bad and I replaced the all the problem was gone. I don't know why but the Jensen Copper Foil PIO caps were know for this.