What is the most aggressive transformer you could put in a superlead, and why in your opinion?

[roberto]

May I? Marshalls with higher voltages in the preamp are IMHO the worst sounding ones.
Something around 280-320 V on the PI is the perfect range IMHO, and where it was supposed to work.

Other circuits will benefit from higher voltages.

[Leo_Gnardo]

May I? Marshalls with higher voltages in the preamp are IMHO the worst sounding ones.
Something around 280-320 V on the PI is the perfect range IMHO, and where it was supposed to work.

Other circuits will benefit from higher voltages.

You sure may! And I agree with your observation. But what's pleasing for some isn't enough for others. "More horseradish please!" Our OP might try bumping up the supply voltage to the preamp stages first, while leaving the PI alone. I would start with that. If he decides there's no joy to be found that way, easy enough to return to previous condition, at least it's a cheap & quick experiment.

[Roe]

May I? Marshalls with higher voltages in the preamp are IMHO the worst sounding ones.
Something around 280-320 V on the PI is the perfect range IMHO, and where it was supposed to work.

Other circuits will benefit from higher voltages.

An clear, obvious counter-example would be a healty 45/100. these sound great with high preamp voltages. lowering the preamp voltages works ok with the later superleads and 1987s however

[pdf64]

With the KT66 and KT88 amps, the LTPs need a higher HT node voltage than with EL34 amps, otherwise it clips before putting out sufficient signal to drive the output valve control grids up to an instantaneous level of Vg1=0V

[roberto]

OP talked about his preference for early 2203s and late 1959 (so EL34 only), that's why I suggested to lower the voltages to those levels.
IMHO they are more aggressive with lower voltages than higher. Other circuits may benefit of higher supply voltages.

[Leo_Gnardo]

IMHO they are more aggressive with lower voltages than higher. Other circuits may benefit of higher supply voltages.

Try both. Settle on what satisfies the ears. Still easier & cheaper than swapping OT's. And I'll wager, more effective.

I keep in mind what Ken Fisher did, dialing in the response of his Trainwrecks by altering power supply node voltages. He sure didn't stick to Marshall's 10K resistor string. It's an approach worthy of experimentation.

[roberto]

Voltages, RC times and impedances of each node as well, and how the amp reacts to them.

[Roe]

OP talked about his preference for early 2203s and late 1959 (so EL34 only), that's why I suggested to lower the voltages to those levels.
IMHO they are more aggressive with lower voltages than higher. Other circuits may benefit of higher supply voltages.

fair enough. but the aggression of a fast, punchy power amp really benefits from a strong phase inverter, which is easier to achieve with 300+v anode voltage.

[roberto]

I don't agree that the voltage of the PI is the way to get a punchy PA, but we'd go OT.

[Nickerz]

You didn't say power or output transformer, but I'm guessing you meant output. Personally I think this is a fool's errand (no offense), and that changing a transformer out for one you already think sounds fine and is good quality is a lot of effort and expense for an imperceivable difference in sound. I don't even think you could perceive at all without a direct A/B comparison.

That said, I take your tonequest seriously, and would play around with the NFB. You said that when you changed from SLO to SL power amp. Well, they are the same power amp besides the amount of NFB, so there's probably some more experimentation to be had there. You could also try a .47 or .68 presence cap like some Marshalls had. The SLO preamp itself has a ton to play with, and there could be a book written about the subject. In fact there's a whole forum started devoted to it: http://www.slocloneforums.com/viewtopic.php?f=6&t=6724

You know there's something weird here. So I've got a head that has a NFB sweep knob AND a presence knob. One of the amp techs I was talking to was sort of flaborghasted and said "presence IS NFB." What do you make of this? I suppose if an amp DOESN'T provide NFB sweep, what would they use for presence? Schematic attached. Schematic doesn't include NFB circuit which was added as a mod.

Head in reference is a Randall RM100.

[martin manning]

I've got a head that has a NFB sweep knob AND a presence knob. One of the amp techs I was talking to was sort of flaborghasted and said "presence IS NFB." What do you make of this?

Presence adds a tone control to the NFB by dumping some high frequency to ground.

[Nickerz]

IMHO they are more aggressive with lower voltages than higher. Other circuits may benefit of higher supply voltages.

Try both. Settle on what satisfies the ears. Still easier & cheaper than swapping OT's. And I'll wager, more effective.

I keep in mind what Ken Fisher did, dialing in the response of his Trainwrecks by altering power supply node voltages. He sure didn't stick to Marshall's 10K resistor string. It's an approach worthy of experimentation.

My theory is this. I have spent A LOT of time going over all the different rigs that I think sound the absolute best. And when it came down to it, there were only a couple things shared in common, and a couple amps really. All I know is the JCM came up as both an amp and as a slave. The Marshall 9200 came up a lot. The 5150 sometimes. Jose 1959s etc. Bogners. So almost all Marshall derived preamps. But even in the case of for instance Master of Puppets, using the JCM as a slave. There's something to the JCM power section, in the way it sits in the mix. The 5150 just the same. And then on the flip side, I always disliked the way the SLO sounded in the mix. Too sweet, too creamy. But it plays better than any amp on earth, to me at least. Yet I put the SLO through a superlead style poweramp with a modern voiced transformer and it sounds great. So yeah, it's a pain, it's a small detail, but it something my ear picks up for some reason.

And lets be real, there is a small part of faith involved in this quest\journey. At the end of the day, you can change one component in these amps, just one, and they're very different animals. And I've spent a lot of time chaising those things down systematically so that I can say to myself and believe it, this is the sound I want, from a component level.

And maybe the next SLO, or Dual Rectifier, or Jose is around the corner. Maybe. But until then, I know the sound I hear in my head and the records I listen to with a sound I identify with. And that's the soup or dish I can play around with.

When it comes to EQ, my belief is that you can EQ the amp and you can do post EQ. But I don't believe you can EQ "voicing" effectively. I think voicing, in terms of EQ, is equal to tubes and analog sound design. You can try to emulate voicing by adjusting NFB, or post EQ or whatever, but I don't think it'll ever be as organic and good sounding to the ear as an OT that just sounds good.

And those the the OTs that my ear hears. Early Marshall, Bogner, 5150s (for super downtuned stuff). I like the strategy 400 too and the DSL\TSL but not as much. So now I'd be interested to hear how the Bogner, 5150 and Strategy OTs are spec'd and what they may share in common with the early Marshalls. That being said, I know the 5150s are inherantly more higher mid focused, the strategy has a lot of negative feedback (dark), and I know Bogners are described in a similar fashion. The recto poweramp is also legendary, so an avenue I might explore but something I'm trying to avoid. Fender Twin for cleans.

There's something inherently satisfying in knowing what you like and realizing out of the thousands of options that maybe 8 or 10 of them are the amps you truly want and could be happy with for the rest of your life. So I'm okay with fetishizing the OTs. Not only do I think that's a correct way to look at it, I think it's freeing in its own way. Amps I can trust to sit in the mix and track consistently well.

Andy Sneaps amp wall seems to match my ear in that regard.

[Nickerz]

I've got a head that has a NFB sweep knob AND a presence knob. One of the amp techs I was talking to was sort of flaborghasted and said "presence IS NFB." What do you make of this?

Presence adds a tone control to the NFB by dumping some high frequency to ground.

Super helpful. So I will adjust NFB with presence wide open then back it down to taste from here on out.