I bought and await delivery of a quad set from 6L6's recommended source, thanks 6, i think. Another project, need to finish the F6 first, I think I have to do the M2 after reading several posts saying the M2 sounds better! It's all subjective of course, maybe the person with a counter top single speaker radio, who is satisfied with that, is the smart (or lucky) one!
Hi angrypat I have built both the F6 and M2. My F6 has a 400VA supply and my M2 has 2x 300VA supply. Both are great amps in my system and I could easily live with either ( I also have hypex Ncore and PP and SE valve monoblocks to compare). I listen to more rock, funk, blues and prog than classic music and currently favor the F6. Maybe it is also because I bult it first and it gave me a lot of wow moments, where I got new insights into, by me, well known music. Im not stopping and will build a SissySIT and probably F2X (to try different buffers - as I already have the boards) and probably also Nelsons SIT once awailable through the store. We are the lucky ones as building is fun 
Take the M2x idea of building the unity gain input stage on a field-swappable daughter card, and generalize it.
One possibility is to partition a power amplifier into "N" separate pieces; each piece represents one block in the power amp's block diagram. Now implement each of those pieces on a separate, field-swappable daughter card. Voila, mix-and-match power amps! Immerse your bewildered self in a swirling miasma of JFET LTPs, BJT LTPs, dueling banjo LTP quads, current mode operation, voltage mode operation, Miller compensation, Two Pole compensation, Output Inclusive compensation, Class A, Class G, Class AB, Thermal-Trak, unity gain output stages, Gain>1 output stages, interstage transformers, auto transformers, optical bias, sliding bias, microprocessor controlled bias, nuvistor tube voltage amplifying stages, folded cascode voltage amplifying stages, Rush cascode stages, Hawksford error correcting stages, current dumping stages.
I realize that the idea of swapping an output stage might seem needlessly radical. If you feel this way, imagine that only (N-1) pieces are on daughter cards, and the final piece, the output stage, is fixed. But I would remind you that quite a few 8.1 channel power amps for home theater uses, do indeed have swappable output stages. Everything including the heatsink, comes out.
Timid builders afflicted with "I dare not be the first to try something" paralysis, will have to sit and wait a good long time, before other non-paralyzed folks try each and every possible combination & publish their listening impressions for all to read. However, in exchange for waiting patiently, the timid are rewarded with a clear idea of what to try first: build the option that other people seem to prefer the most. I want what other people want. It's a conformist's dream come true. On the other hand, the non-timid, the brave trailblazers, are rewarded too. They create brand new listening experiences that nobody else has ever had. The joy of discovery! The thrill of exploring the unknown! A win-win for everyone.
One possibility is to partition a power amplifier into "N" separate pieces; each piece represents one block in the power amp's block diagram. Now implement each of those pieces on a separate, field-swappable daughter card. Voila, mix-and-match power amps! Immerse your bewildered self in a swirling miasma of JFET LTPs, BJT LTPs, dueling banjo LTP quads, current mode operation, voltage mode operation, Miller compensation, Two Pole compensation, Output Inclusive compensation, Class A, Class G, Class AB, Thermal-Trak, unity gain output stages, Gain>1 output stages, interstage transformers, auto transformers, optical bias, sliding bias, microprocessor controlled bias, nuvistor tube voltage amplifying stages, folded cascode voltage amplifying stages, Rush cascode stages, Hawksford error correcting stages, current dumping stages.
I realize that the idea of swapping an output stage might seem needlessly radical. If you feel this way, imagine that only (N-1) pieces are on daughter cards, and the final piece, the output stage, is fixed. But I would remind you that quite a few 8.1 channel power amps for home theater uses, do indeed have swappable output stages. Everything including the heatsink, comes out.
Timid builders afflicted with "I dare not be the first to try something" paralysis, will have to sit and wait a good long time, before other non-paralyzed folks try each and every possible combination & publish their listening impressions for all to read. However, in exchange for waiting patiently, the timid are rewarded with a clear idea of what to try first: build the option that other people seem to prefer the most. I want what other people want. It's a conformist's dream come true. On the other hand, the non-timid, the brave trailblazers, are rewarded too. They create brand new listening experiences that nobody else has ever had. The joy of discovery! The thrill of exploring the unknown! A win-win for everyone.
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M2x boards are in the Store and shipping to customers
On Monday Sept 10th I went to the diyAudio store website and placed an order for an M2x board set. They were delivered at noon today, Wednesday Sept 12th. The boards were nicely packaged, well protected, and the PCB manufacturing work appears to be very high quality, photo below. Congratulations to the team!
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On Monday Sept 10th I went to the diyAudio store website and placed an order for an M2x board set. They were delivered at noon today, Wednesday Sept 12th. The boards were nicely packaged, well protected, and the PCB manufacturing work appears to be very high quality, photo below. Congratulations to the team!
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Attachments
They look fantastic!!! I'm drooling over here!
(I have to admit that the Austin board looks intimidating!
)One day I'll build the M2x... one day! Thanks for the pic.
Rafa.
And by the same token, the Tucson board looks small and simple and quick and the very opposite of intimidating.
True story: 6L6 completely assembled and soldered one of his Tucson boards in 120 seconds while he was talking to me on Face Time. I saw him do it. And the board worked flawlessly -- he's listening to it right now.
True story: 6L6 completely assembled and soldered one of his Tucson boards in 120 seconds while he was talking to me on Face Time. I saw him do it. And the board worked flawlessly -- he's listening to it right now.
Linear Systems matched NP pairs are now available again in the store. Limit of 1 set per customer per month until further notice, however if you need more for a particular build, please email contact@diyaudiostore.com and we will work things out.
Linear Systems Matched LSJ74/LSK170 JFET pairs (Grade B) – diyAudio Store
Linear Systems Matched LSJ74/LSK170 JFET pairs (Grade B) – diyAudio Store
I'd suggest finishing your M2X first, it is very versatile. Mark Johnson made sure that each of the multiple input stages has unique merit and signature. Remember to evaluate and listen to both normal and reversed speaker polarity with each input stage. Most probably your need will be fully met. You may satisfy your curiosity later, perhaps by building the F5 or F7 (it is current production but you can build something from the info on the F7 thread or wait for the time it is officially released for DIY).
Just grabbed a set to have an extra pair. Thank you for working so hard to make these available again. We all appreciated it!