Question for you all of you Ampeg experts. I just picked up an Ampeg V4B (new but it was sitting on the floor at the Vancouver Long & Mcquade for who knows how long) to try out and compare to a Traynor YBA-300. I like the tone but the Ampeg has a great deal of hiss which is impacted much more by the master volume than it is by the gain. i.e. to get rid of the hiss I've had to turn the gain up and keep the master lower... but then the tubes break up at a lower volume than I'd prefer. At house volume (which for me is still house rattling) the hiss can be heard over the notes, so the hiss is quite loud. At low volumes (i.e. I can talk over the music I'm playing) the hiss is tolerable. Any thoughts? I haven't tried it in a band setting so the hiss may not be audible when other instruments are layered in, but I'm really surprised at how much hiss there is. In comparison the YBA-300 is basically silent. If this isn't normal, any ideas what might be causing it? Edit - one other thing... when the amp comes off standby the hiss is low and then ramps up over a few seconds then stays loud. Also, when I put the amp on standby it takes a few seconds for it to actually go into standby, the lamp stays red then flips over about 2-3 seconds later. The YBA-300 appears to go to standby instantly.
response depends on the circuit used for the standby switch. Most just cut the B+ voltage to silence the amp but there are other circuits that can and are used. If the B+ is switched off there is still some residual voltage hiding in the caps that keep the amp alive for a few moments. Hiss is a normal thing in high gain amplification circuits. It could be from a failing tube but there are other components that can contribute to the level of hiss.
If your speaker cabinet has a tweeter, turn it off if you can. Failing that, I’d swap out the preamp tubes one at a time. Hiss is one of the signs of a failing tube. From the TB Prtaflex Wiki: Tubes | TalkBass.com
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