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Paul S wrote:

Lamm did choose to use some of the driving ideas from his proven SET amp…

The ML3’s input stage around two plates of 12AX7 is fine, it is a very good sounding tube, particularly if it chosen a right brand and vintage. Still it is tube with very low bias and any more or less strong line level signal will send the tube out A1.  When 12AX7 tube deals with phonostage signal then it is fine but line level signals nowadays are 3-5V that would melt the 12AX7 grid with classical bias. So, to deal with it you need to inject a feedback into the 12AX7 cathode to raise the virtual grid voltage. That was what Lamm did in ML2 with global feedback and it worked fine. In ML3 he claims that he changed something with input stage. Well, I personally feel that when manufactures make such statement but do not elaborate on detail then they always lay and make the statement only for marketing purposes. I have no idea what was changed in the ML3’s input stage it was most likely some absolutely trivial thing. Most likely Lamm ran not global feedback into the 12AX7 ass but from the second stage. It even most likely did make sound better but it did not eliminate the fact that the amp input stage is IDHT and flows on feedback…. Hmmm… it is not horrible thing itself but I would like have in there a good tube with let sat 4V-5V on grid that would not need any help from feedback. This is too far from an idea of ultimate amp design in my view.

The ML3’s driver stage looks like a massive buffer or gain stage (I do not know how the tubes are connected) but it is very self-evident that Vladimir went for a very strong current producing with 8x6H30 plates. It is very obvious what Lamm was trying to accomplish – to let the people with 93dB sensitive acoustic systems and to use his amps. Because GM70 is IDHT and it to a degree might work on negative side of curve, however as it goes there it run with grid currents and it need a very strong push from the driver stage to be able to operate with grid currents. Here is when 8x6H30 plates come to live and sustain the amp driving ability, making all of those Wilson, Marten Coltrane, Kharma and the rest folks to feel that ML3 has “better bass”. Well, that all fine but it ML3 looks from the pictures have driver and output stage couple with capacitor. As the amps run at near max power, the GM70 dives in A2 and driver stage pumps a lot of current to keep the GM70 happy the voltage over the coupling cap before the out stage change polarity. Before it was positively charged and then it goes over zero and become negatively charged. The re-charged cap works fine but changing the cap polarity by re-recharging is while it handles the signal is not a very good idea in my view. All that dialectic in the cap needs to be re-polarized – it sound too unattractive for in idea of an ultimate power amp.

For sure is a person use let say 105dB sensitive acoustic system and if room if too large then and power the LF section by a different amplification then a person would not overdrive the ML3 input stage into the actual use of feedback and will not send GM70 into plate current. However if so then why do we need 35W of GM70? The point is that if a person pays $130K for power amp then he is in the realms where very different architectural designs are available and there is no need to have “one feet all bills” and in a way compromised power amp. It would be interesting if Lamm would make a pure “for sound only” amp with moderate power with only IDHT, preferably vintage, some sort of “sonic jewelry” vision of amplifier, something similar to what Shindo used to do. The problem is that who would buy them. How many people out there would pay for 2-3W amp the money that Lamm want to change for his electronics? For sure Vladimir did not and would not go this way and he made a powerful SET with idiotic feedback adjusting toy, specifically to entertain the people with a lot of money, with a lot pomposity and a lot of desire to blub online about own supremacy. I do feel that it was right move for Lamm’s business but it was no event in my view in advancing the idea of better amplification.

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