Why did it take me 15 years to try a 12ay7 in my Liverpool?

[bcmatt]

I've messed with so many mods on my Liverpool in the 15 years since I built it. It's always remained my most used amp, and I most often kept a 5751 in V1. Meanwhile, I always wondered if I'd prefer a Rocket or Z-Wreck... even though I find this Liverpool significantly more versatile than my DC30.
I often wanted the ability to have an easier to dial in clean setting for use with a pedalboard.

(I should point out that this is with VVR- I find dialing down the plate voltage has a similar characteristic to dialing up the gain knob a bit.)

But ya, with my typical voltage settings using a 12ay7 in v1:
below 11am is pretty spanky clean
11am-12pm-ish is a great rich character-filled cleanish pedal-platform. (what I imagine the Rocket it giving everyone). This is where I may dial back the mids a little and go to the 2nd bright switch setting
1:30ish on the Volume knob is the Brad Paisley lead area.
3-4pm-ish is the ideal Kuykendall clean to mean setting like how I would have my Express. (mids up a bit and full bright switch)

I shape and accentuate the gain characteristics with the bright switch and mid control.
With my Cut knob (instead of presence) I can get the right amount of brightness.

If I didn't have VVR or just played super loud all the time, I think a 5751 or 12ax7 in V1 would be needed to get the really gainy stuff, but I am most often not ripping the roof off anymore. I need to play quiet enough to make sure it's the drummer or bass player that's troubling the sound guy instead of me.

Anyways, with all the changes I've made over the years, it's embarrassing that I never tried one of the most obvious things to get the right range of gain.

Oh ya, and with all my trials of different 5e3 mods... who would have guess that a simple pre-PI MV would solve all its challenges? Actually, a phase inverter grid stopper resister probably would have been fine... since I basically just keep that MV at about 2/3s and never touch it.

[ViperDoc]

So.... What were your findings/comparisons with the 12AY7?

[bcmatt]

Sorry, I went back and clarified clarified that this is what a 12ay7 gives me:

below 11am is pretty spanky clean
11am-12pm-ish is a great rich character-filled cleanish pedal-platform. (what I imagine the Rocket it giving everyone). This is where I may dial back the mids a little and go to the 2nd bright switch setting
1:30ish on the Volume knob is the Brad Paisley lead area.
3-4pm-ish is the ideal Kuykendall clean to mean setting like how I would have my Express. (mids up a bit and full bright switch)

With a 12ax7, all usable possible settings are squashed below noon.

[Mark]

Did you try the vintage/fast switch. That reduces the output from the second stage.

[bcmatt]

Did you try the vintage/fast switch. That reduces the output from the second stage.

I tried a few of those sorts of things over the years. To be honest I can't remember exactly the values I played with in that spot but I did have a switch on it. I think I mostly put the preamp back to stock now... but I should double check all my values now to see where I landed.

[Mark]

Did you try the vintage/fast switch. That reduces the output from the second stage.

I tried a few of those sorts of things over the years. To be honest I can't remember exactly the values I played with in that spot but I did have a switch on it. I think I mostly put the preamp back to stock now... but I should double check all my values now to see where I landed.

The resistor values are 82K and 22K.

[bcmatt]

The resistor values are 82K and 22K.

Yes, that's the values I currently have in there.. with no switch.. just hardwired in with a 0.005uF cap and a 150K resister to ground. The 82k is not visible in the picture because it is wired over the edge of the board right to the tube socket.

20240424_221042.jpg

Would that be considered the fast or gradual setting? So many mods tried, it's good to look once in a while and see where I ended up.

I was swapping from a presence to cut control on my Express tonight (and ditching NFB) because I prefer it on my Liverpool so much. Anyways, I noticed that my Express actually has the 1M volume pot swapped out for a Gibson Historic 500K pot in series with a 470K resister over to the treble pot.

17140208050301842754857276639941.jpg

This gives my Express such a useable Volume pot sweep. I wonder if this is what I should do on my Liverpool to get the same thing I am chasing with the 12ay7.

[Mark]

In the diagram the switch is set to fast ( higher gain) mode.

https://ampgarage.com/forum/files/Expre ... iation.jpg

[bcmatt]

In the diagram the switch is set to fast ( higher gain) mode.

https://ampgarage.com/forum/files/Expre ... iation.jpg

OK, thanks. So I guess since I'm wired to the plate load being split, I'm in the lower gain mode as far as the plate is concerned.
But mine's not that circuit otherwise, because of my smaller .005 cap and signal feeding directly to the next grid through just the 82K resister above 150k to ground. I guess that would be like a 250k volume pot letting 2/3 of the signal through... maybe?