paul_5 Posted May 9, 2011 Share Posted May 9, 2011 (edited) Hi All, I've got two Ampegs - A B2RE solid state and an old SVP PRO preamp. I'd like to use the SVP as my main pre (for obvious reasons) and use the B2RE as a slave amp. I'm currently going from a preamp OUT (1/4" socket) on the SVP to the poweramp IN (1/4") on the back of the B2RE, I know this shouldn't be rocket science, but the pre is really noisy when connected like this. When I use it at home or studios (it's my main recording kit) it's practically noiseless. I'd like it to be noiseless live too, but so far that luxury has escaped me. It's been retubed with quality tubes, and had new power supply caps and a new mains transformer fitted (both from authorised Ampeg suppliers), and the fact that it's quiet when it's just being used as a pre leads me to believe that the problem isn't wit the SVP. Any thoughts? Does it make a difference twisting the two wires that go from the AC inlet socket to the On/Off switch together to act as a 'choke' (of sorts)? is this even safe? [b]edit:[/b] I should add that everything is coming from the same 13A ring - heads, pedalboard supplies etc.. Edited May 9, 2011 by paul_5 Quote Link to comment Share on other sites More sharing options...
paul_5 Posted May 10, 2011 Author Share Posted May 10, 2011 Sorted, swapped V4 and V5 over and voila, no noise. Whodathunkit? Quote Link to comment Share on other sites More sharing options...
dan670844 Posted May 10, 2011 Share Posted May 10, 2011 [quote name='paul_5' post='1226601' date='May 10 2011, 07:01 PM']Sorted, swapped V4 and V5 over and voila, no noise. Whodathunkit?[/quote] Cool you solved it, i was thinking it was a ground loop, If it comes back it will def be this and you will need to ground lift the preamp a lot of preamps have this facility, usually a little switcher-roo on the back, if it doesn't have this you will need to use some kind of isolation transformer etc, but I would think your Peg-pre has one. Prob teaching yah to suck eggs and what not but studio stuff is usually pretty well isolated Quote Link to comment Share on other sites More sharing options...
paul_5 Posted May 10, 2011 Author Share Posted May 10, 2011 cheers for the advice. I thought it was a ground loop and tried all posts of gadgets to get rid of it. Isolating transformer, di boxes to lift the ground, resoldering leads etc... The valve in question is an old one that i was using to attenuate the output (12au7 instead of 12ax7) to eliminate a tiny bit of noise that i had in protools. At the moment it's redundant, as that valve just controls the 'drive' circuit, so as long as i don't use it it's clean as a whistle. Oddly enough the svp doesn't have a ground lift option anywhere. Oops Quote Link to comment Share on other sites More sharing options...
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