Hi - I just built a M7 clone using nobsound board. just by chance, I looked at the kondo site today and the real M7 has different tubes. Does this mean that the nobsound circuit is not a very good clone? Their m77 board at least has all the right tubes.
thank you for your help
Philip
How does it sound?
I donât know yet. Rob at hifi-hangar is kindly helping me out with checking its safety first.
M7 has changed over the years. Some info here https://cheaptubeaudio.blogspot.com/2012/02/review-my-kondo-system-part-ii-kondo.html?m=1
LOL, the M7 tube complement has never changed, has it?
Btw, it will also have different âeverythingâ
Which âtubesâ does your version have?
the nobsound has 4x12ay7 tubes
Is it just the M77 line stage circuit? That uses 4 X 12AY7.
hi - yes I think youâre right. I found this on the internet. they put on the pub that it is a Kondo M7 instead of M77 line. thank you.
does anyone know where I can buy a proper m7 clone pub?
Hi Philip
I have now built two of these kits. I have discussed the cct at length with Pete (ISC) and yes it is actually more of an M77 line stage. Having said that it is also a bit M7 so really a hybrid I guess. I used to have an M7 and it did have 6072s in it but not this cct. To be fair the kit really does remind me of my M7, I think the best word is âlovelyâ.
I built the first kit with the suppled parts, just adding Nichicon PSU caps and Miflex coupling caps. It sounded excellent. The second one I replaced all the resistors and used AN Caps on the PSU but still Miflex on coupling. This one is more refined and maybe slightly soft, still very good though. It is fascinating, the effect of components. The combinations must be endless.
I was with Rob on Friday and he said he should have the final check on yours done on next Weds Build Along. If you donât mind I will pop along and take a look at it. Whereabouts are you? You are welcome to come and have a listen to mine. I went a bit Steam Punk.
Which 12AY7âs have you settled on? NOS, EH or JJ?
Isnât the real M7 a SIT circuit? He only went valve when the supply of transistors ran out. Ironic really.
I have gone with General Electric NOS on both the 12AY7 and the 6X4. They were a significant step up from the EH that I started with.
Yes I think that was the case. Is that the one that Simon has?
Not SIT, just some conventional high voltage JFETs.
How banal!
It sounds good, incredibly low distortion. But nothing like a tube M7. I have a stash of the transistors. 
obviously donât know my SITs from my JFETs
Well, SITs are JFETs, the term SIT means Static Induction Transistor, which is another way of saying Field Effect Transistor (with subtypes like MOSFET, JFET, etc.)
However, âSITâ seems to have been adopted to specifically mean JFETs with triode-like characteristics, to distinguish from the one with pentode style characteristics as per most other transistors. Theyâre also called VFETs which is derived form the construction method (vertical structure rather than lateral structure).
Confused yet?
Rare FET = Best FET.
Haha, adds a certain piquancy to every listening session.