M2 is singing
Hi All.
Big Thanks for all given Tipps by members here, for Teabags quality UMS- Boards.
To use my big heat sinks i have to send first the Aleph J in vacancy 😛.
With all advices careful reading i could lucky set up the M2 with the Toshibas
SJ201; SK1530.
The modification to 0,33 Ohm Degeneration and without 221 Ohm works from
first switch ON in stable 560mV.
With Offset i have tried 3 times, because negativ offset; first change- one site 47k to 53,6k was to much; second change 53,6k to 56k works perfect on
both Channels to zeroing offset.
Time to listen music. 🙂 😛.
After any days, burning in:
So much impressed with clarity, smooth brilliant tonality, wide open image.
The dynamic jumps are impressing me too- there is not all quit flat presented since digitally possibilities.
I only have to rework for better cooling the Transistors- for my opinion 70°C
or more is a bit to hot- seems i'm a bit scary. 😀
Next step is to spend creativity for real nice case.
Now i know why ZM is falling in love for M2.
Yes, only to say Thank you very much Mr. Nelson Pass- awesome Genius!
Because that i understand a bit more the way it comes to DEF- Amp topology.
Begin was any years earlier, i know.
Hi All.
There is only to say: it's true!
Big Thanks for all given Tipps by members here, for Teabags quality UMS- Boards.
To use my big heat sinks i have to send first the Aleph J in vacancy 😛.
With all advices careful reading i could lucky set up the M2 with the Toshibas
SJ201; SK1530.
The modification to 0,33 Ohm Degeneration and without 221 Ohm works from
first switch ON in stable 560mV.
With Offset i have tried 3 times, because negativ offset; first change- one site 47k to 53,6k was to much; second change 53,6k to 56k works perfect on
both Channels to zeroing offset.
Time to listen music. 🙂 😛.
After any days, burning in:
So much impressed with clarity, smooth brilliant tonality, wide open image.
The dynamic jumps are impressing me too- there is not all quit flat presented since digitally possibilities.
I only have to rework for better cooling the Transistors- for my opinion 70°C
or more is a bit to hot- seems i'm a bit scary. 😀
Next step is to spend creativity for real nice case.
Now i know why ZM is falling in love for M2.
Yes, only to say Thank you very much Mr. Nelson Pass- awesome Genius!
Because that i understand a bit more the way it comes to DEF- Amp topology.
Begin was any years earlier, i know.
Attachments
Very good point, wattage is also critical (and hopefully correct)
Attachments
Hi.
I also built M2 with the Toshibas SJ201 & SK1530 but with the original values of degeneration resistors = 0.47 Ohm and R11 = 221 Ohm (to get zero offset I increased the value of R7 to 51K). PSU voltage under load is +/- 22V, Iq = 1.46A.
I use M2 with 4 Ohm speakers, should I perform the modifications and reduce the degeneration resistors to 0.33 Ohm and R11 to 0 Ohm?
Is it recommended modification or not worth it?
Last edited:
If I read Hagen correctly, he runs his MOSFETs at 0.56/0.33 = 1.7A.
This is not something I plan to do.
Anywhere i have read for better linearity in frequency they should go for higher
bias, also they have lower gm- therefore lower degeneration- is that right?
If i add the 221 Ohm i can go for lower bias and not loos audible quality?
bias, also they have lower gm- therefore lower degeneration- is that right?
If i add the 221 Ohm i can go for lower bias and not loos audible quality?
STOP PRESS - STOP PRESS
Yesterday the custom ordered Noratel toroidal arrived 240V - 300VA - 2 X 18 fitted with flux shielding ring
Today is Wednesday in Australia. and I wasted no time and fitted it to my M2
Very neat and tidy job if I say so myself
Result - The hum has exited the building
Experiencing - Total bliss as in a noiseless vacuum kind of way -
Now I can truely enjoy the beauty of the M2 and the music I like to listen to
Will post a photo when I tie back the cables ect
I would also like to express my sincere thanks to all the members that helped with this puzzling issue
In the end, the best explanation I can come up with is that the previous toroidal was not a good match for this amp
The new toroidal fixed the hum issue in a snap, So let that be a lesson to you all
FR
Yesterday the custom ordered Noratel toroidal arrived 240V - 300VA - 2 X 18 fitted with flux shielding ring
Today is Wednesday in Australia. and I wasted no time and fitted it to my M2
Very neat and tidy job if I say so myself
Result - The hum has exited the building
Experiencing - Total bliss as in a noiseless vacuum kind of way -
Now I can truely enjoy the beauty of the M2 and the music I like to listen to
Will post a photo when I tie back the cables ect
I would also like to express my sincere thanks to all the members that helped with this puzzling issue
In the end, the best explanation I can come up with is that the previous toroidal was not a good match for this amp
The new toroidal fixed the hum issue in a snap, So let that be a lesson to you all
FR
Hi FR,
Great to know that your issue with the hum is now history, and you are able to enjoy the amp. 🙂
Great to know that your issue with the hum is now history, and you are able to enjoy the amp. 🙂
Thanks mate
Also thanks for all the assistance with earth schemes
We got to the bottom of the issue in the end, and that gives me a good feeling and closure
Let the music play
FR
Good to hear that you sorted your problem with huming out Full Range! Enjoy your listening! I'm waiting for my torodials to arrive to finish my own M2 build. I ordered them from Toroidy, whom have a good reputation, so I'm hoping not to have any issues...
I have been using a F5 with a 27V rails power supply. I would like to use this power supply for my M2 boards.
Is this possible? And if so, is there a way to lower the bias (r11 value?)?
All help will be greatly appreciated.
Is this possible? And if so, is there a way to lower the bias (r11 value?)?
All help will be greatly appreciated.