Tremoverb, Running HOT Power Tubes

I don't pretend to know much about this, but:

Normally Mesa runs the power tubes cold or cold power tube or something to do with the bias...resulting in a very clean power section, where all gain is from the preamp.

I wondered, what if I ran HOT power tubes or tubes that don't run cold.

Would this give me what I am looking for?

Here is what my goal is.

I use two EL34s for 50 watts.

I play at a loud volume to engage the power section.

I want that power section to provide me dynamics or "touch sensitivity".

This type of break up or set up is something I would like to experiment with.

Will using a tube that will be considered "HOT" do this for me.

In other words I guess it would be like using a 15-18 watt amp and cranking it, but also using the preamp for break up too.

I run the Tremoverb's gain at about 50%.

I run the RC Booster as a clean boost, and boost 800Hz in the front of the amp.

I also use a Parametric EQ in the loop for overall tone shaping and cut the 200Hz and shelf some of the highs starting at about 1.2KHz just to bring out the notes etc.

What do you think? Thanks

IMO, a lot of the "touch sensitivity" you get from a 15-18 watt amp being driven hard is due to the preamp and not the power amp. Ideally, it's either staying clean or just starting to overdrive as the power amp starts to hit it's limits and compresses. The net result is the ability to transition from clean to overdrive using your fingers and attack, which you're not typically going to get if you're running a Recto with the gain around 50% and a boost on top. That's relatively akin to plugging a DS-1 into a Deluxe Reverb, which is great if you want a compressed solo, but I don't know anyone who'd call the results "dynamic" or "touch sensitive".

Conversely, when people talk about low powered high gain amps you don't usually see people talk about "touch sensitity". Most either love the additional compression, or they complain about the lack of "oomph" (aka, the lack of dynamics).

Anyway, IMO there's no reason not to try a set of power tubes that run hotter. I did it myself, was indifferent to the results and am back to running Mesa spec'd tubes again. Truthfully, I don't think you'll get the results you're looking for (difference is too subtle). If your goal is to drive the power amp on your T-Verb harder, use spongy mode to lower the headroom even further. That should drop your 50w down to around 32w. Blues mode, FX loop bypassed, master volume wide open, and slowly bring up the gain until it starts to overdrive.

IMO... YMMV.

Thanks, I will try that.

I went ahead and switched to spongy from bold.

It allowed me to increase the master volume a little bit, which I assume further engages the power section.

I have to say, it did improve my tone.

It sounds really good. I am able to max the guitar volume pot for a great classic rock tone and then back off of the pot for a great clean that is sensitive to how I play.

Sure, it may not be exactly what I was looking for...kinda like using a sledge hammer on a nail, but it works if you proceed with caution.

To be honest it really sounds very good.

I will try to get a recording for you and post.

Thanks, as I never thought of that, and in fact I thought by using the bold setting I was really pushing the power section, oh and the clean channel sounds great too, maybe not as much head room, but still really clean for a recto.

Class A/B power amps split the signal in half and send each of them to a tube, or set of tubes, which work in a push/pull motion with the tube(s) on the other side, akin to a 2-cycle engine's pistons and valves. The split occurs in the phase inverter. The P.I. is producing its own distortion when pushed. By splitting the signal and inverting the phase of one half, power tubes cancel out the second harmonic, even though it could be producing quite a bit. This cancellation causes the 3rd harmonic to become the dominant harmonic.

In a Recto, the P.I. has reduced headroom compared to some other designs. This makes it easier to overdrive and it is more compressed and fat than, say, a classic Marshall design. Since it is designed to have an imbalance, a P.I. passes some of the second harmonic, since the phase cancellation is not as complete as matched power tubes working in opposition to each other. The P.I. also has 3 treble shelving filters to help keep the treble and harmonics from running amok like little Gremlins into the power tubes, which would make it oscillate and shriek like a banshee.

In the Recto, the power tubes are biased super cold to prevent inter-modulation (or crossover) distortion when the tubes are being driven hard and to keep things fairly clean. Inter-modulation is the kind of distortion heard when you play a cowboy chord with a fuzz pedal. Given enough drive, inter-modulation distortion can cause a dissonant sound. That's why power chords and single notes sound better through a hot amp than more complex tones; the combination of complex notes will cause a bunch of math which ends up creating harmonics that are not "in tune" with the original notes and they clash.

Mesa went around that by offering ways to drop the power being sent to all the tubes. As the power goes down, the headroom for all the tubes becomes shorter. A signal might bump its head on the doorway when going from room to room (tube to tube). This causes overdrive or distortion, depending on how hard it hits the door frame and the size of the frames and the signal. Since the P.I. has the least headroom, it's going to have the smallest door to get through.

So, the signal is banged up after the P.I. and enters the power tubes. They aren't biased hot enough to cause crossover, but they'll distort if the headroom is exceeded, the same as the others, only it's more difficult to do so, because the bias point moves with the power setting to keep things relatively stable. It won't sound like a hot power amp, but it isn't supposed to. You still get distortion without buying hearing aids at 30 years of age and, as you said, it sounds good.

Cleans benefit most from headroom if loud volume is required. Depending on how sharp it needs to be, the headroom considerations for dirty sounds are less demanding.

I hope this makes sense.

You loose a lot of dynamics, punch, fullness and the transformer is never going to get saturation like a pushed small amp when you pull power tubes. It sounds like you are fighting what you want by pulling power tubes to me.
The volume difference of 2 or 4 tubes in a amp is about nothing. First thing I would do is try a direct A/B of 2 and 4 tubes.

Stephen, can you elaborate.

For example I read that power tube break up is easily confused with PI break up.

I don't pretend to know that for sure...just what I read on the Marshall forum.

I thought that by pulling two tubes, it would work the other two harder and therefore make them break up a little and be more sensitive.

I am looking for touch sensitivity and dynamics at loud volumes, NOT super loud, but pretty loud actually.

I am able to roll back the volume and it cleans up really nice, and it is usable as a clean with a little break up, if I dig in.

I am more than willing to try putting back the other two tubes and rectifier tube, I just wanted a little more understanding is all, thanks.

A Tremoverb isn't going to naturally have the same level of touch dynamics as a Fender or medium gain Marshall. The first reason is, because there are two preamp stages which provide a large boost to the signal and one stage which clips the signal almost all of the time. The boost keeps the preamp up at a more steady rate. When the preamp goes up to drive the tubes, it has a more even signal than an old two or three stage amp design. The near-constant preamp clipping keeps it dirty for a longer period of time.

The second reason is the power amp negative feedback. Clean and Blues will have more feedback than the other modes. This makes them eliminate distortion much more quickly than Vintage or Modern. Perhaps Blues, with the 2 power tubes out might give you a desirable response (reduce headroom to make it dirtier, but not thick), but 4 tubes will transition it better. Vintage could work. Modern has the least variable power amp response; Don't use it for that. It is meant to be a monster.

(Fun Fact: Fender uses more negative feedback in their old designs than Marshall. Fender is also what comes to my mind when I think of dynamics.)

If you're using Vintage, a lower Gain setting 9:00 to 11:00 and a really low Presence setting might do it. The idea is to only use enough Gain to crunch it while keeping the filtering on the power section as high as possible.

However, it is a high gain amp and the trade off for high gain is reduced dynamics.

Also, the PI is part of the power amp. It will always distort before the power tubes, because a 12ax7 has less capability to remain clean. Even when power tubes do go into overdrive, the PI has been there and bought the t-shirt. Running power tubes hot makes them break up sooner, but they are driven by the PI. If it isn't cooking, they aren't either.

My advice to the original poster is to leave the amp stock. Installing hot biased power tubes will not improve the tone.

Direct A/B and go only by the sound and decide if you like the sound of pulling tubes.

It is impossible to saturate a transformer when pulling tubes. The sound of a small amp pushed is the transformer being saturated.

O.K., all good points.

I plan to test this Saturday.

Remember, I play loud, use a clean boost, clone to orange on the gain channel, and tone shape with a parametric eq in the loop.

The eq in the loop cuts 200Hz by 4db, increases 100 Hz by 4db and sort of shelves 1-5 KHz, oh and in the front of the amp i boost 800Hz using the Radial JX-2.

Again, I only use about 50% of the gain available in the preamp.

I run EL34s and rectifier and it is on spongey.

I do get a great tone that is tight, clean, musical and I feel, responsive or a little touch sensitive...I just want more and to know I am on the right track.

When on the gain channel I can clean up the guitar easily by turning it's volume back...and I love that about this setup.

Thanks guys...I will let you know if adding back the other two tubes helps at all.

Mullard EL34 typically have early gain and will work well in a cold bias amp, However, the clarity or definition you would get from a tube that has average distortion characteristics will not be the same as a hot tube or early distortion tube. I did not buy them to intentionally have an early distortion characteristic but that is how they behave. I did try them in a hot biased amp (Mark V) and it did not take much to get the onset of red plate conditions (heated seams). I had better results with them in the RA100 than I did with the other amps. The hot tube may not provide you with the characteristics you are desiring as the clean channel character will no longer be clean when pushing up the volume. As the case for a rectifier type amp as described earlier, the hot tube or early distortion tube may not be the best choice for your application.

If you want a change in touch sensitivity, look into a ALNICO type speaker as there tends to be little or no lag in response when compared to ceramic type drivers.

Yes, I have abandoned the idea of hot tubes.

I pretty much have exhausted my tone search for the Tremoverb.

It does what it does flawlessly and to perfection.

I have it tight, clean and very close to vintage, but hey it is a recto.

My sights are on a plexi with an attenuation device to control volume.

A 1968 Super Lead 100 and a THD Hot Plate will get me where I want to be.

I will run that clean and use the Tremoverb for wet.

Thanks everyone.

A Recto and a Plexi are a powerful pair. 8)

I can't f'n wait man.

I have my eyes on a Metro Plex, or a Bray, or a Landry next.

Then maybe a vintage fender for super pristine cleans.

Time to get a second job...LOL!