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.
