Easy killing Liverpool hiss

[Guus]

I've build a nice liverpool with 2x EL84 and it sounds great.

Like many others I had (some) problems with the great amount of hiss which was imo to much. I measured 60 dB (C) at 1 meter.
It had to be reduced without attacking the sound and feeling of the amp.
Mostly is recommended the find good tubes but even then there is a lot of hiss.

The upping of the gain is mainly caused by V2. V2 pulls the level and the noise/hiss of V1 to a much higher level. So it is clear that V1 has to be a noise free tube.
I've tested with different tubes in V2 and found out that an ECC82 reduces the hiss to a normal level and the feeling and sound of the amp stays good.

grtz
Guss

[RJ Guitars]

It's tough to get rid of it... but I starting using the new Tungsol 12AX7's that are supposed to be minimal in hiss in test comparisons they posted over at Antique Electronics.

[Guus]

Hi,
Yes, you are right. The new Tung Sol 12AX7 is imo one of the best you can get nowadays of all new productions.
I've tried them in the Liverpool and compared them with different exemplares of NOS Philips, Telefunken, Valvo and Teonex.
In the Liverpool I got the best results with: V1 (Tung Sol 12AX7) , V2 (Philips ECC82), V3 (Telefunken long plate ECC83).
With the ECC82 and volume at '7' (one o'clock) the hiss level dropped from 60 dB to ~ 45 dB (C) at one meter.

grtz
Guss.

PS
The ECC82 has an Av of 17-20.
I also tried a 12AY7 (Av=44) and a 5751 (Av=60) in V2, the amp sounds also very fine with only a part of the white noise you get with a ECC83 (Av=100).
Resume: you have a range of tubes you can use to bring the noise down.