Liverpool HISS.....

[gtrcollectr]

I just finished up a Liverpool build and have a slight hiss in the background that seems to vary with the volume knob on the guitar. I can back off the volume knob about 10% and it almost goes away completely. But in the upper 10% its apparent.

Got any hints on where to look, or is this somewhat normal for high gain amps like this to have a certain amount of hiss? I do have shielded cable on the input and followed all of the grounding advice from Ruby's site.

Thanks,
Todd

[dartanion]

High gain amps can tend to have some background hiss to them. I would suspect a noisy preamp tube or carbon comp resistors in the preamp. Try some known low noise 12AX7s and remove any CC resistors in the preamp and replace them with carbon films or metallic oxides.

[gtrcollectr]

All carbon film and metal film......got any recommendations on tubes and where to put them in the PRE? I have Tung Sols in V1-V3.

[dartanion]

It doesn't really matter what brand of tubes you have in there as any brand can be noisy. I usually buy new tubes in bulk and find the best of the batch noise and tone wise then dispose of the remaining tubes. If you have another amp that has a known low noise 12AX7, try substituting it in V1, then V2, then V3. It might just be one tube, it could be all of them. You just never know until you try a known low noise tube.

[Allynmey]

GTR, it will hiss. That is normal for this and all TW amps! I've heard real ones that hiss more than some clones. It is designed that way and the hiss is a normal by-product.

Allyn

[gtrcollectr]

I guess I will stop screwing with it then...The amp is amazing, it is very touch sensitive and sounds killer. I can just about dial in any sound I need with the volume on my guitar. It will take some getting use to but its worth the effort.

Thanks,
Todd

[dartanion]

Ahh! I assumed it was louder than would be expected. My bad...

[Allynmey]

If you want to bring hiss down a little, check with Jeremy (LastwinJ). He has some low ESR caps that tames the hiss a little. The gain structure of the amp guarantees some hiss.