Tonight, I thought I'd try rolling some tubes in v1 of my Liverpool. I noticed some very dramatic differences between different tubes. Much more than I've ever noticed in any of my other amps. So, for curiosity sake, I thought I'd take some oscilloscope measurements. I've never done this before, and I found the results very interesting. I ran a 150mv sine wave into the input, all amp knobs at noon, measuring after the 2n2 coupling cap, right before v2b.
RFT - 3.5V
Mullard - 4.5V
EHX - 1.2V
Genalex - 3.2V
I never realized how much different each tube's gain could be. And I've never noticed how dramatically different they can affect the tone in any other amp before this one.
So I'm curious... What is everyone's preference of tubes in a Liverpool? Or an Express?
Liverpool preamp tube differences
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- Ledvedder5150
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Liverpool preamp tube differences
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Re: Liverpool preamp tube differences
I like the Sylvania 12AX7WA in both Express and Liverpools. I also have had good luck with Amperex,Mullard and Tungsram in the Express, I haven’t tried any of the newer made tubes in either.
Re: Liverpool preamp tube differences
can we see pictures of all those tubes? are they all 12AX7? EHX has always the highest gain, so probably is almost dead..
expected voltage gain is 50 so, measured voltage must be around 4.50VAC, all what is less indicating worn tube
expected voltage gain is 50 so, measured voltage must be around 4.50VAC, all what is less indicating worn tube
- Ledvedder5150
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Re: Liverpool preamp tube differences
I'll try to get some pictures of them today.
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- Ledvedder5150
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Re: Liverpool preamp tube differences
Ok, here are the tubes from left to right. RFT, EHX, Genalex, Sylvania, Mullard.
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- Ledvedder5150
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Re: Liverpool preamp tube differences
And here are the readings I'm getting at the spot noted.
RFT EHX Genalex Sylvania Mullard
RFT EHX Genalex Sylvania Mullard
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Re: Liverpool preamp tube differences
first, EX tube is 12AY7, it is lower gain tube , so it is normal.
other are here somewhere
other are here somewhere
- Ledvedder5150
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Re: Liverpool preamp tube differences
Oh you're right! Why was I thinking it was a 12ax7?
Last edited by Ledvedder5150 on Wed Feb 08, 2023 3:00 pm, edited 1 time in total.
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