when you choose just part of picture to think of, you can also choose whatever rationale you want, without responsibility how it pans in overall picture.......
what is your idea - how to implement SJEP (made just as N Channel part) in complementary output stage, and in which way that is going to decrease noise figure of complete amp?
go to https://www.firstwatt.com/products/ , there is nice AMPLIFIER COMPARISON CHART
look at those having highest noise figure numbers, think what's common for them .......
look at those with lowest noise figure numbers, think what's common for them
what is your idea - how to implement SJEP (made just as N Channel part) in complementary output stage, and in which way that is going to decrease noise figure of complete amp?
go to https://www.firstwatt.com/products/ , there is nice AMPLIFIER COMPARISON CHART
look at those having highest noise figure numbers, think what's common for them .......
look at those with lowest noise figure numbers, think what's common for them
My experience with M2X is that it can be made very silent if Edcor transformer is screened so it will not pickup any noise from environment (power transformer, rectifiers etc.).
Further to what MEPER said, I'm not sure if it is the IRFPs that cause the 500 uV noise figure. I have built my M2 with Toshiba 2SJ201 / 2SK1530. To get the noise lower than 500 uV, and in order to have it nearly silent on my 100 dB/W speakers, I had to magnetically shield the Edcors. I also had to work with careful wire routing, and have put a magnetic shield between power transformer and rectifiers on the one side and CLC and the amp boards on the other side.
Best regards, Claas
Best regards, Claas
All good feedback - my question with the output devices really stems back to the idea of removing as much noise as possible.
I asked ChatGPT for an estimated summary of performance. I guess this is a good indication? I can say with confidence that MyRef is fine without any form of mains treatment, it just sounds great, but a SE tube amp definitely needs a DIY strom/balanced transformer or something similar as it only has 20-30dB of PSRR. Without mains treatment, on 93dB sensitivity speakers, there's still no noise/hum out of the speaker with the SE tube amp BUT the sound is much flatter and compressed due to the noise floor being higher (higher noise floor is not the same as speaker hum / mains buzz?).
Is this a fair summary? Understanding and talking about the different types of unwanted noise that can be experienced is certainly a challenge!
I asked ChatGPT for an estimated summary of performance. I guess this is a good indication? I can say with confidence that MyRef is fine without any form of mains treatment, it just sounds great, but a SE tube amp definitely needs a DIY strom/balanced transformer or something similar as it only has 20-30dB of PSRR. Without mains treatment, on 93dB sensitivity speakers, there's still no noise/hum out of the speaker with the SE tube amp BUT the sound is much flatter and compressed due to the noise floor being higher (higher noise floor is not the same as speaker hum / mains buzz?).
| Amplifier | PSRR (dB) | CMRR (dB) |
|---|---|---|
| Typical SE Tube Amp | 20 - 30 dB | 20 - 30 dB |
| Aleph J | 50 - 70 dB | 50 - 70 dB |
| MyRef | 60 - 80 dB | 60 - 80 dB |
| M2 Power Amp | 50 - 60 dB | 60 - 70 dB |
| Amplifier | Estimated Noise Floor (µV RMS) |
|---|
| Typical SE Tube Amp | 50 - 100 µV |
| Aleph J | 10 - 20 µV |
| MyRef | 10 - 20 µV |
| M2 Power Amp | 10 - 15 µV |
Is this a fair summary? Understanding and talking about the different types of unwanted noise that can be experienced is certainly a challenge!
Unfortunately no, that's hallucination 😛
Why don't you go to the source - see Zen Mods recommendation in post #7061 ...
Why don't you go to the source - see Zen Mods recommendation in post #7061 ...
@stretchneck
in 2 previous posts you got all practical experience you need pre hoc
build it, make your own final testing and judgement
regarding PSRR, M2 is way better than usual wimpy SE amp; that's sort of amps where PSU needs to be more complicated than amp itself
in 2 previous posts you got all practical experience you need pre hoc
build it, make your own final testing and judgement
regarding PSRR, M2 is way better than usual wimpy SE amp; that's sort of amps where PSU needs to be more complicated than amp itself
🙄 🙄 🙄 🙄 🙄
Completely unsubstantiated information, scraped from random parts of the internets, complied by something that knows nothing of the subjects.
- - -
Now, that said, you have very good reason to pursue low noise, and that is a laudable effort worth doing.
In all of these amplifiers, PSU layout and isolation from interacting with the amplifier circuit will be the dominant factor in noise, not the inherent circuit noise. Specific to M2X, look at what @chede said - PSU isolation of the power transformer and bridges, wire routing, and shielding of the signal transformers will make the amplifier significantly quieter. This is echoed by @pfarrell , @SkyPirate , and other builders throughout this thread.
Throw out all the stuff people say, all the specs, the noise levels, and just listen to the amp. I have heard some amps costing more than my house and thought, some were great, some fair, some made me cringe. It's all about your ear, your room, your speakers, your amp, your chain. Nelson builds some of the most pleasing amps, to me, but if you look at the specs, they are not the most quiet, nor the best this or that, but they sound very very pleasing to my ear. Could he make an amp with Grail specs? Sure, but he found what sounds good to him, and many of us and made a living doing it.
I think people need not toss specs in the river, nor should they be an indicator of the happy ending. 😎
JT
I think people need not toss specs in the river, nor should they be an indicator of the happy ending. 😎
JT
Rebuilt my M2X into one of the new 2025 Deluxe chassis. Also built a new PSU with RC filters. Man this thing is dead quiet now. I 3d printed some cable management standoffs which worked out great.
That looks great !
If we were to make the PSU to be out of the amplifier, wouldn't it be better as well?
Also, point to point wiring with the edcor in this version could also help by making a bigger and appropriate shielding as well.
So far, I love the M2 without any preamplifier, straight from the attenuator/controler even with a phono preamp.
If we were to make the PSU to be out of the amplifier, wouldn't it be better as well?
Also, point to point wiring with the edcor in this version could also help by making a bigger and appropriate shielding as well.
So far, I love the M2 without any preamplifier, straight from the attenuator/controler even with a phono preamp.
I'm moving along with a M2X build but having a bit of trouble sourcing a few things for daughter boards . . . have everything for Ishikawa and Norwood but was hoping to build the whole set. What are you guys using for as a replacement for KSC3503DS BJT on Mt View?
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I can send ya some KTC3503-Y @blue360cuda. Should be a drop in replacement as far as I'm aware.
PM headed your way.
PM headed your way.
Plugging away on the M2x and decided to make things more complicated than they needed to be 😀
I like swapping parts and tinkiering so I just knew I'd be playing with the different daughter boards a bunch, part of the fun for me. Was trying to come up with a way to just pop the boards in/out without worrying about screwing up the mount holes with star nuts on and off over and over. Found these cool connections online from Mill Max - had to hunt their product line a little to find ones that would fit the application but these worked great!
The receptacle part on the main board that would fit happened to also have a solder cup for wire so I ran a J loop of 20g through both jump holes and out the bottom into the cup. Sounded like a good idea to me so why not There was one size nail head pin that wouldn't fall through the mount holes and it also worked perfectly. There's just enough clearance underneath with the standoffs and at that height there's still just enough room to mount the mosfets. Good stuff. So yeah, it works, seems more elegant than screws/nuts and the mill max stuff is slick - not too hard to pop on/off but holds very solidly.
Mounting the nail heads to the board was a little tricky but worked fine - soldered the plugs in the amp board first and then pins into daughter card, mounted it using board as a jig for alignment and held by hand to tack soldered each before flowing it out and got the iron underneath to hit the bottom and "fill er up"
Went ahead and got nail head pins for the power +/- , ground and signal out with matching solder cup receptacles, smaller than the ones for the boards though.
Daughter board nail head: 4886-0-00-80-00-00-03-0
Main board receptacle w/ solder cup bottom: 0616-0-18-15-07-27-10-0
pardon my flux 😉
I like swapping parts and tinkiering so I just knew I'd be playing with the different daughter boards a bunch, part of the fun for me. Was trying to come up with a way to just pop the boards in/out without worrying about screwing up the mount holes with star nuts on and off over and over. Found these cool connections online from Mill Max - had to hunt their product line a little to find ones that would fit the application but these worked great!
The receptacle part on the main board that would fit happened to also have a solder cup for wire so I ran a J loop of 20g through both jump holes and out the bottom into the cup. Sounded like a good idea to me so why not There was one size nail head pin that wouldn't fall through the mount holes and it also worked perfectly. There's just enough clearance underneath with the standoffs and at that height there's still just enough room to mount the mosfets. Good stuff. So yeah, it works, seems more elegant than screws/nuts and the mill max stuff is slick - not too hard to pop on/off but holds very solidly.
Mounting the nail heads to the board was a little tricky but worked fine - soldered the plugs in the amp board first and then pins into daughter card, mounted it using board as a jig for alignment and held by hand to tack soldered each before flowing it out and got the iron underneath to hit the bottom and "fill er up"
Went ahead and got nail head pins for the power +/- , ground and signal out with matching solder cup receptacles, smaller than the ones for the boards though.
Daughter board nail head: 4886-0-00-80-00-00-03-0
Main board receptacle w/ solder cup bottom: 0616-0-18-15-07-27-10-0
pardon my flux 😉
