I can see the forward voltage drop of these diodes I use can be quite high and maybe voltage drop is not very stable after warm-up. Heatsinks never gets very hot.
For the bridge rectifiers the max. voltage drop is about 1.1V.....and maybe more stable.
For the bridge rectifiers the max. voltage drop is about 1.1V.....and maybe more stable.
Could be bridge rectifier weirdness or bad joints/contacts causing intermittent problems.
Thoroughly check all electrical joints.
Just the first thing that comes to my mind.
Feeling a bit unwell today.
Thoroughly check all electrical joints.
Just the first thing that comes to my mind.
Feeling a bit unwell today.
I see the same issue on both amps and I was very careful when soldering and mounting the diodes on the heatsink. Space is very tight when using the single diodes approach so difficult to get a probe down to measure on Universal PCB. It will be a lot easier with the "bridge" approach. I have ordered 4 x 35A bridges together with a lot of J113 and other silicon for the IPS6 including ZTX558. As I have regulated AC it is easy to measure if I get higher rails (lower voltage drop over the bridge) and then hopefully very stable rails.
Hopefully you feel better during the coming days......
Hopefully you feel better during the coming days......
I think I have reached a final conclusion for my "problem".
I think the root cause turned out to be the Schottky diodes I used as rectifiers for my M2X mono blocks. It was those:
https://www.wolfspeed.com/media/downloads/73/C3D10065A.pdf
Schottky diodes seems to have rather large forward voltage drop and it also raises with temperatur and current a lot more than standard diodes. At least compared to the standard 35A bridges I use now.
After I installed the 35A bridges I got 0.9V higher rail voltage so I went up from +-22.85 to +-23.70. I know that because I have regulated AC.
I have had my M2X blocks on for some hours now and it seems very stable. DC offset adjusted and it stays stable. But I have to watch during the coming days to be 100% sure.....as I have been mistaken before.
The Schottky diodes seems to get to a point where forward voltage drop gets a bit unstable. Probably a combination of the peak current when charging the caps and the temperature.
I can probably re-use the universal PSU diode modules for other projects where PSU caps loading is a bit less like preamps etc. But don't think I am a big fan of Schottky diodes anymore. They were also designed for switching purpose but I thought I might get a bit less noise from them. I still look forward to make new noise/distortion measurements. Amps sounds very good! .....very "silent" amps....I have the feeling that bass response is a bit more "tight" now.
I think the root cause turned out to be the Schottky diodes I used as rectifiers for my M2X mono blocks. It was those:
https://www.wolfspeed.com/media/downloads/73/C3D10065A.pdf
Schottky diodes seems to have rather large forward voltage drop and it also raises with temperatur and current a lot more than standard diodes. At least compared to the standard 35A bridges I use now.
After I installed the 35A bridges I got 0.9V higher rail voltage so I went up from +-22.85 to +-23.70. I know that because I have regulated AC.
I have had my M2X blocks on for some hours now and it seems very stable. DC offset adjusted and it stays stable. But I have to watch during the coming days to be 100% sure.....as I have been mistaken before.
The Schottky diodes seems to get to a point where forward voltage drop gets a bit unstable. Probably a combination of the peak current when charging the caps and the temperature.
I can probably re-use the universal PSU diode modules for other projects where PSU caps loading is a bit less like preamps etc. But don't think I am a big fan of Schottky diodes anymore. They were also designed for switching purpose but I thought I might get a bit less noise from them. I still look forward to make new noise/distortion measurements. Amps sounds very good! .....very "silent" amps....I have the feeling that bass response is a bit more "tight" now.
Attachments
Bridges I use now are these (35A version):
https://docs.rs-online.com/b7af/A700000006404573.pdf
400V version was in backorder so I got the 600V version.
https://docs.rs-online.com/b7af/A700000006404573.pdf
400V version was in backorder so I got the 600V version.
Happy you seem to have found the problem. When I hear Schottky diodes,
I usually think of relatively low voltage parts with lower forward voltage drops
than silicon diodes, so that Cree parts seems different.
I usually think of relatively low voltage parts with lower forward voltage drops
than silicon diodes, so that Cree parts seems different.
It was also my assumption that Schottky diodes had lower feed forward voltage drop than conventional diodes. I must dig a bit deeper into the "Schottky world" 🙂
I know "tube guys" like the 1200V Wolfspeed Cree diodes types for B+ PSU's but that is another purpose with much higher voltage and much lower current.
I would like to watch spec. for a "real" low voltage drop Schottky type......
I know "tube guys" like the 1200V Wolfspeed Cree diodes types for B+ PSU's but that is another purpose with much higher voltage and much lower current.
I would like to watch spec. for a "real" low voltage drop Schottky type......