crate vitage club 2110r tube location

[ecoman35]

I am fairly new with tube amps and have a crate vintage club 20.I need to know which tube is for the gain,reverb phase inverter. I have some schematics but the just say v1 v2 v3.Thanks for any help in advance.Have some nos tubes I want to try in the phase inverter.

[Jazz P Bass]

Crate V20

The phase inverter typically is right next to the power tubes.
The first input tube, V1 is the farthest from the power transformer.
Can you post the schematic?

[ecoman35]

27602SCH_4[1].pdf
here is the schematic.

thanks

[Jazz P Bass]

Crate VC 2110R

So much for typical.
Are the tubes lined up in a straight line.
(3) 12AX7s then (2) 6BQ5 output tubes?
The preamp tubes are V1, V2 & V5.
The output tubes are V3 & V4.
Here is the signal chain: 12AX7 dual triode.
Input to V1A to V1B to V2A to V5A & then the phase inverter is V2B.
V5B is the reverb drive tube.

[ecoman35]

yes they are 3 12ax7 then 2 el84 i have some old hammond organ tubes 12ax7 from great britian and holland and 1 12au7 made in usa I heard the 12au7 would do well in the pi.

thanks

[Enzo]

The schematic doesn't tell you the tube order.

Look on the layout for that.

V numbers refer to positions on the schematic, they do not refer to tube order across the chassis. Sometimes they are the same, but often they are not - as is the case here.

[Jazz P Bass]

Crate

Without having the amp in front of me I cannot tell you which tube is in what location.
You would have to sit down with a meter & figure it out.
What a goofy numbering arraingment.
I think you may have an issue with trying out a different tube specifically for the phase inverter. It uses one half of V2. The other half, V2A, is linked to the tone control, mid boost & level set.
V1A & V1B are the first stage & volume control.
V2A: Tone & Level
V2B: Phase Inverter
V3 & V4: 6BQ5 output
V5: Reverb

[Enzo]

Jazz, dude, that is why I put up the layout pictorial just above you.

[ecoman35]

Thanks guys so from what i read v1 gain/tone v2 pi v5 reverb in that order 123.
would the 12au7 be a good choice for the pi.I used the hammond tube made in great brittian (mullard ?) in v1 and the 1 made in holland (amperex-phillips?) in v2 and v5,was reading that the 12au7 was a good tube for the pi position.the 1 I have says made in usa these are all out of a hammond e-1oo.

[Jazz P Bass]

Fast typing

Jazz, dude, that is why I put up the layout pictorial just above you.

Enzo, thanks for the board layout.
Your post appeared as I was typing.

[Enzo]

I know, I checked the time stamp when I posted that. I was just banging on your cage.

[deluxmon]

Enzo - a long time ago you posted a PDF that I think gave the tube order on a layout for a Crate VC20. I've tried clicking on that link but it is dead at this point. Do you still have that info? If so, I would love to get a copy of it....thanks in advance

The schematic doesn't tell you the tube order.

Look on the layout for that.

V numbers refer to positions on the schematic, they do not refer to tube order across the chassis. Sometimes they are the same, but often they are not - as is the case here.

[Enzo]

Assuming it is the same circuit as the VC2110, he has it here:
Guitar Amplifier Schematics and more

[PeanutNore]

You wouldn't really get the benefits of a 12AU7 in the PI unless you changed R15 and R18 from 100K, which is right for a 12AX7, to somewhere in the 22K to 47K range. I just built an amp with a cathodyne PI like this one and I'm using a 12AU7, but I have, I think, 33K resistors there. I can't remember exactly, but it's somewhere in that range.

EDIT: I also didn't notice that the PI shares the same bottle as the triode driving the tone stack. Swapping in a 12AU7 there would change the amp a lot. I'm not sure if it's laid out right for a normal 12DW7 to be an option, which is a 12AX7 triode and a 12AU7 triode in the same bottle, but JJ makes an ECC832 and an ECC823 which are the same but have the order of the triodes reversed, so you could, i suppose, pick the right one if you really want to mod your amp to use a 12AU7 in the PI.