Tremoverb Preamp Tube Positions Defined "Help"

I have a question for you Tremoverb owners and/or knowledgeable gurus.

I have the Tremoverb manual and can easily see tube positions for V1-V6, but they don't completely explain what is going on.

If you have this information available I would really appreciate it.

For example which position is a cathode follower etc.

Which position(s) is/are responsible for tone overall. I know V1 is hot, but maybe V2 & V3 would benefit from a tube roll other than Mesa Stock.

I know V6 is the Phase Inverter or as Mesa puts it "Phase Splitter"/Output.

If I put a better tube than a Mesa 12AX7 in V4 would it provide a better unity gain and cleaner signal to my G-Major, thus producing better results, and what would that be...a 12AT7?

Would V5 produce better reverb with an upgrade from Mesa stock and what would this tube be...a 12AT7.

I guess what I am asking is how can I know what to upgrade if I do not know what the expected outcome might be depending on the tube or direction of tube I select, whether it be an upgraded 12AX7 or a lower gain 12AT7 upgrade?

Please advise and thanks a bunch.

This is a slightly awkward amp because it has an odd tube configuration in that there is no 'reverb' tube - the reverb send is half of V5 and the reverb return is half of V1 (really!). So you can't just tweak the reverb alone.

The tube functions are:

V1A - first gain stage
V1B - reverb return
V2A - second gain stage
V2B - third gain stage (split-load, although output is from plate only)
V3A - fourth gain stage
V3B - tone stack driver (cathode follower)
V4A - FX loop return
V4B - FX loop send (cathode follower)
V5A - reverb driver
V5B - post-FX loop gain recovery stage
V6A & B - phase inverter

I have found that I prefer a 12AT7 in both V5 (even though half of it is signal-path, not reverb) and V6 - gives a deeper reverb and a cleaner/fuller overall tone.

You must not use 12AT7s in either V3 or V4, their cathode voltage rating is not sufficient for a cathode follower (90V rated, with 200V+ on the cathodes). You *could * use a 12AU7, which like the 12AX7 has a cathode voltage rating of 250V. But in a cathode follower, the gain is just (slightly) under unity no matter what the tube, so changing to a lower-gain one would not affect the signal to the FX unit anyway; it would reduce the available gain on return though, since the other half of the tube is used for this in a straight plate-load config.

Hope that helps!

The pre amp tubes are probably more "personal" than the power tubes since there are limitless combinations. You are just going to have to try some things for your self.

I certainly don't have a tremoverb, but the general princibles still apply. I'd target things in the folling order, but that doesn't mean it will work best for you, just a guide... You will discover many effects that happen indirectly.

V1, generally you want a low noise, low microphonics tube with good gain. Any noise just gets amplified further by the other stages. Good gain will allow it to drive the other stages hard to develop good overdrive. If you don't want so much gain then you can look at lower gain tubes.

V6, I have found the phase splitter to have a much bigger effect on tone than you would expect. I think a lot of people underestimate this. In my amps it I can push the tone in the direction I want in terms of eq. If your amp is to bright, put a warm sounding tube in that slot, or whatever else you need.

For reverb and the loop I like to use a tube with good clarity. The Tung-sol RI is my favorite here, but your thats just what I like.

V2 and V3 will have less effect on tone, but I still experiment if I am looking to fine tune.

One other thing to keep in mind is that when you make a change in one place you may have to revisit another to maintain the general balance.

As an example, my Express has a Tungsol RI in V1 and V2, a Tungsol RI in the reverb and a JJ longplate in the phase spliter. The Tungsol's give me good gain with clarity and more top end which I think the Express lacks. The JJ tube helps warm things back up, but also helps keep the clarity. The one thing that is a bit of an issue is that I have to be a little careful with the gain as things get compressed quickly with higher gain tubes. If it ever bothers me enough I will probably look at replacing the second gain stage with a lower gain tube.

Very good information. I can't wait to get started.

I already have some Tung-Sol 12AX7 and Jan Philip 12AT7 tubes to roll.

Thanks

I also don't have a Tremoverb , I have a Mark IV, but I use this configuration

V1 - Tung-Sol RI
V2 - JJ
V3 - JJ
V4 - stock mesa 12AT7
V5 - Mullard RI

I find the Mullard rounds out some of the grainy/gainyness of the JJ's which work well in the gain stages of my amp. The Tung-Sol is just extra special in the V1 with it's clarity, and the V4 is the reverb driver.

Hope this helps.

This is on Mesa's site, somewhere:

SOUND “DROP-OUTS” / INTERMITTENT SIGNAL
One Possible Cause

Most (but not all) Mesa/Boogie amplifiers have one or two “cathode follower” tube
stages in their preamps. Tube selection is CRITICAL in these stages.

Specifically, in a 12AX7 tube used as a “cathode follower”, the voltage difference
between that present at the cathode, as compared with the heater voltage, can be
withstood or tolerated by certain types of tubes, whereas other tubes will fail. The
failure of a “cathode follower“ tube will cause sound dropouts or signal loss.

For the past few years, Mesa has been using two types of 12AX7 tubes: ones
originating in Russia (Sovtek EH), and ones originating in China. The Russian (Sovtek)
tube is NOT reliable as a cathode follower. Of the tubes we are using today (March
2008), ONLY THE CHINESE 12AX7 IS RELIABLE AS A CATHODE FOLLOWER.

In conclusion, if you are troubleshooting for signal dropout in a Mesa/Boogie amp,
suspect a cathode follower tube, and try replacing it with a Mesa 12AX7 that is marked
as “CHINESE” (silk-screened on the tube itself).

Below is a partial list of Mesa amps and cathode follower tube locations:

Lone Star & LS Special: V3
M-Pulse: V2
Stiletto: V3 & V4
Venture: V2
Road King I: V3 & V4
Big Block 750: V4
Road King II: V3 & V5
Titan: V4
Roadster: V3 & V5
M2000: V2
Dual & Triple (2ch or 3ch): V3 & V4
Bass 400+: V2
Tremoverb: V3 & V4

ANOTHER POSSIBLE SCENARIO may occur in the “SPONGY” (or on some models,
“TWEED”) power setting: the reduced filament voltage may cause very low output from
a RUSSIAN preamp tube. Again, the recommended fix is to replace the “sagging” tube
with the CHINESE type of Mesa 12AX7 - which are more immune to this type of failure.

The right solution is just not to use crap Russian tubes in your amp .

For reference, *all* NOS 12AX7s (unless actually faulty) will work fine in cathode-follower positions because the design spec cathode voltage rating for the tube type is 250V; it's just that a lot of these Russian tubes fail to meet the correct design spec.

Just to repeat before anyone fries a decent tube - DO NOT try 12AT7s, 12AY7s or 12AV7s of any age or brand in any cathode-follower position. These all have a 90V cathode voltage rating, by design, and will fail.

12AU7s and 5751s are 250V like 12AX7s.