Yeah figured that out. Polarity switched so should search for something between 47k and 56k. Will search for 51k.
OK set and done.
Parallelled 4x133R0 with R4 (10R0) so about 7R7 and EDGOR offset is down to 2-3mV. I think I will solder a 7R5 in.
Also parallelled 442k wit 56k R7 (resulting in 49k7) and was able to trim DC offset at outputs to 0mV. Will order something suitable between 50k-52k for this position.
Connecting one driver of my Mini Karsonator (so one TC9FD 8Ohm)... Music! 😀
Had to max out volume pot on my FocusRite though for any decent volume though.
Q1/Q2 get smoking hot, heatsink too (too small for this application I know).
Baking eggs will be a new hobby when this beast is finished 😀
Steef
Parallelled 4x133R0 with R4 (10R0) so about 7R7 and EDGOR offset is down to 2-3mV. I think I will solder a 7R5 in.
Also parallelled 442k wit 56k R7 (resulting in 49k7) and was able to trim DC offset at outputs to 0mV. Will order something suitable between 50k-52k for this position.
Connecting one driver of my Mini Karsonator (so one TC9FD 8Ohm)... Music! 😀
Had to max out volume pot on my FocusRite though for any decent volume though.
Q1/Q2 get smoking hot, heatsink too (too small for this application I know).
Baking eggs will be a new hobby when this beast is finished 😀
Steef
Attachments
besides placing heatsink in proper position , with some clearance from below ..... you can always toss entire shebang in bucket of oil .....
🙂
🙂
Zenmod's M2 voltage chart
I never measured these voltages before, amp seemed to work fine. did so with these results. Most pretty close, a couple a little off. Should anything be tweaked?
Left channel Right channel
offset: 1.8 mV offset: 1.4 mV
A: 75.7 mV A: 77 mV
B: -66.9 mV B: -67.9 mV
C: 3.7 mV C: 4.5 mV
Seems like "B" measurements are a little low?
Russellc
I never measured these voltages before, amp seemed to work fine. did so with these results. Most pretty close, a couple a little off. Should anything be tweaked?
Left channel Right channel
offset: 1.8 mV offset: 1.4 mV
A: 75.7 mV A: 77 mV
B: -66.9 mV B: -67.9 mV
C: 3.7 mV C: 4.5 mV
Seems like "B" measurements are a little low?
Russellc
Last edited:
if offset seen by xformer and output offset are in proper range , everything is fine
assuming input JFets are BL , just chill
assuming input JFets are BL , just chill
avoid source resistors for them , chill ......
and search for BL while chilling
better to drive autoformer with lower impedance , in any case
and search for BL while chilling
better to drive autoformer with lower impedance , in any case
Have a silly question. How much voltage at "C" (going to Edcor transformer)
is considered acceptable?
Presumably if needed, one can slightly adjust R3/R4?
Thanks,
Dennis
is considered acceptable?
Presumably if needed, one can slightly adjust R3/R4?
Thanks,
Dennis
Hi Steef,
Somehow I had missed your post. Thanks.
Not familiar with transformers, I'm curious how much DC is too much for the Edcor.
Thanks,
Dennis
Somehow I had missed your post. Thanks.
Not familiar with transformers, I'm curious how much DC is too much for the Edcor.
Thanks,
Dennis
My M2 build
Thanks to Grimberg for the M2 boards. I have completed my build. As suggested by Nelson, I added a regulated supply for the input portion to minimise DC offset with supply voltage fluctuations. I used shunt regulators built onto a couple of proto boards and attached to the main boards. Cut traces at a few places and added jumpers. Totally quiet with no hum pickup. The input transformer was kept far away from mains transformer. Main transformer is 500VA with separate windings for left and right channels.
I have built Aleph, Xa, F5 and ACA. I find that the M2 is such a sweet little amp. Wonderful mid with such depth and space. Just WONDERFUL.
One question: because of the large value of C3 (3,300uF), the amp almost took a minute for output current to flow and music to start playing. Anybody knows what is the smallest value of C3 to use without compromising sound quality?
Thanks to Grimberg for the M2 boards. I have completed my build. As suggested by Nelson, I added a regulated supply for the input portion to minimise DC offset with supply voltage fluctuations. I used shunt regulators built onto a couple of proto boards and attached to the main boards. Cut traces at a few places and added jumpers. Totally quiet with no hum pickup. The input transformer was kept far away from mains transformer. Main transformer is 500VA with separate windings for left and right channels.
I have built Aleph, Xa, F5 and ACA. I find that the M2 is such a sweet little amp. Wonderful mid with such depth and space. Just WONDERFUL.
One question: because of the large value of C3 (3,300uF), the amp almost took a minute for output current to flow and music to start playing. Anybody knows what is the smallest value of C3 to use without compromising sound quality?