What preamp tube dominates the tone chain?

[markuslee]

In a four preamp tube configuration which tube of the four most influances the overall tone?

[M Fowler]

Depends on the circuit design, talking about a 3 preamp tube circuit with 4th being the PI?

In the four tube plexi I built the tone stack is CF off V3b then out of MV into PI.
I have to say that I tube rolled through all four positions until I hear what I liked. The gain from V1 was too crazy so I backed it off with 5751 tube, V2 high quality high gain tube, V3 high quality high gain, V4 non matched 12AX7 but rugged. Each contributes to the tone and especially the power tube section.

Hard questions to answer really, but I leave it up to the experts to interject their knowledge at this point.

We have a lot of talent on this forum and I'm interested to read what they say.

Mark

[Reeltarded]

Best tube forward and then what works in the other positions. You can only affect what you start with, I think.

[martin manning]

This is kind of like asking which topping contributes the most to the overall flavor on a four-topping pizza. If none of them really sticks out, then it's the sum of all four. If one of them is anchovies, then likely that will be it. Then there's the crust, and the sauce, and the cheese... Paraphrasing Mark, it depends on the recipe. Tube rolling changes tone because tubes vary, but even if you could find four identical tubes, the components around them can turn them into different ingredients. If one stage is either driven very hard or biased very cold, that can turn it into an anchovy.

[Leo_Gnardo]

If one of them is anchovies, then likely that will be it.

Wow are you ever right about that!

I'd have to say the first tube in the series is most important, especially regarding any negative aspects. Should the first be making noises or be in some other way deficient, that will be amplified by subsequent stages. And there's no way to panel-beat the sound of a lousy tube into sounding good; it can't be "fixed" by later stages. OK I'm off the soap box. What Martin wrote is also wise & true & worthy of consideration.

Geez now I'm gonna have to get some anchovy pizza this week, as well as a Ruben sandwich. Just as well, for a little shakeup in the usual choice of comestibles. mmm, good!

[tubeswell]

Another vote for V1

[rp]

V1 for me too, in theory certainly. In practice different tubes tubes of the same type or even brand can have different gain so rolling V1 hits you the most.

In theory it reminds me of Hifi that first in chain is the most important. That theory started with Linn in the 70s was that most of your money should go into the source and then decreasing w/ the speakers last. Granted Linn back then was trying to sell turntables, but even w/ sticking within their product line (partnered w/ Naim at the time) they strongly insisted you spend $5000 on the TT / arm / cart, $1500K on an integrated amp and $500 on the speakers. Bass-akwards to what most people had been doing for the last 100 years. The wrong way became known as mullet systems - short in front, long in back. I can attest Linn had it right. If the first in the chain isn't cutting it it's all downhill from there.

Admittedly, guitar amps is an other ball game, where bad is often good, wrong is often right. If a perfectly balance NOS telefunken in the PI and a cheapo Chinese in V1 makes your amp sing, then that's that.

[martin manning]

For sure V1 is the most critical for noise like hum, hiss, and micrphonics. Hi-Fi stuff. In a guitar amp each stage contributes to the tone by introducing some distortion, which varies in large part as a function of the chosen operating point. Different tubes of the same type will settle on different operating points with the same passive components around them and this is part of the effect of tube rolling. Gain and frequency response also vary, and some will sound more or less distorted, darker or brighter, etc. The circuit is designed to create distortion in various ways along the signal path, with the overall result being the sum of the distortions created by all stages. There are two lines of discussion here, and I'm not sure which one the OP was interested in.

[markuslee]

That is some seriously good information. Nice forum.

The reason I ask the original questions is because I’m getting ready to replace 3 of the 4 preamp tubes in my Marshal with jet City Retrovalves. So in the interest of tone (mostly dirty) and giving this scenario which of the 4 tubes slots would be best to leave as an actual tube? I’m pretty sure the tubes go like this: V1 gain, V2 gain, V3, tone stack, V4 PI. It’s a Marshal DSL40c

[Leo_Gnardo]

jet City Retrovalves.

What are Jet City Retrovalves? Solid state tube replacements? Well give it a try & let us know what ya think.

Late 70's Mesa sent out some of their amp with Fetrons - the SS tube replacement of the time in a metal cylinder riding a 9-pin plug-in header. Then they quit doing that. Didn't catch on. Customers decided actual tubes sounded better, with all the accompanying headaches. I still have a couple Fetrons rattling around here somewhere. Seems nobody wants 'em. Maybe these Jet City gadgets will do better, who knows?

What's old is new again...

[Reeltarded]

Just a brand.

Wow. $33 bucks a tube. Someone got a picture? Are they those $7.95 chinese jobbies? Likely.

Totally wrong and you are right. Freaky.

[markuslee]

This is what I bought. I imagine I’ll try variations of one or more actual tubes integrated with the cocktail. This is why the new interest in what the various tube positions do. I’ve watched several videos from some noted pros and most say they can’t tell the difference in these and real tubes. The exception being these high gain ones sound like someone put a tube screamer in front of the amp. So with the already pretty high gain structure of the Marshal DSL40c I might be using less of my TS9. I sing lead and play allot of crazy guitar stuff and need a drama free extremely low noise rig. That’s the excuse I’m giving my GF anyways…LOL.

[martin manning]

I might start by rolling one of these things through the four positions and see what happens. If you find a spot where it improves the tone, then leave it there and roll another one through the other positions, and etc. Then you could go backwards and swap a tube back in for each SS gizmo in turn and see if there is a combination you like better.

[rp]

What are Jet City Retrovalves? Solid state tube replacements? Well give it a try & let us know what ya think. Late 70's Mesa sent out some of their amp with Fetrons - the SS tube replacement of the time in a metal cylinder riding a 9-pin plug-in header.

So where does the power go when you drop ~200V to 12-24V? Would these things glow red like a toaster?

[markuslee]

I’m not really sure how they work, but I do know they don’t heat up, and or use near as much power. You can "hot" swap these out without powering down your amp. And they remain cool to the touch. Mine arrive Wednesday, I'll let ya know. I've got gigs all weekend so that will be the real test.