Hi X, One more question about the Mfet snubber boards ( the long/big ones). I have looked at all the pics I can find (on the Nirvana thread), and it looks like to me that no nylon shoulder washer is needed for the snubber board, just a bolt right thru. Is this correct ?
The FQA40N25 I am using the snubber board with, has plastic both sides, so no shoulder washer needed ( just mica pad and thermal grease).
Thanks for the help,
MM
The FQA40N25 I am using the snubber board with, has plastic both sides, so no shoulder washer needed ( just mica pad and thermal grease).
Thanks for the help,
MM
Hi fellow builders,
Received my transformers from Antek: 300VA model 3432. I think I got confused by Antek terminology as I wanted 32V dual secondaries only, and ended up with dual 32V and dual 15 V secondaries (hence the "4" in the 3432 model). Should have ordered a 3232 model.
So, I did some research, and it seems that I can either tape or use heat shrink tube, and isolate the 15V secondaries so they are not in use. I would rather do this than cut them off which was another suggestion.
Question: Is it OK to perform this operation ? Seems to me it would not cause a problem if coiled up and out of the way.
Thank you for the help
MM
Received my transformers from Antek: 300VA model 3432. I think I got confused by Antek terminology as I wanted 32V dual secondaries only, and ended up with dual 32V and dual 15 V secondaries (hence the "4" in the 3432 model). Should have ordered a 3232 model.
So, I did some research, and it seems that I can either tape or use heat shrink tube, and isolate the 15V secondaries so they are not in use. I would rather do this than cut them off which was another suggestion.
Question: Is it OK to perform this operation ? Seems to me it would not cause a problem if coiled up and out of the way.
Thank you for the help
MM
My VSQA amp lives. I have finished my proof of concept, and applied power to one channel from mains>>variac>>dim buld tester>>IEC inlet>>soft start>>transformer>>CRC psu>>amp. No smoke and no noise. I have only listened for a short time with computer / amazon music playing, but what I heard was very pleasing. I will wait until I have the other channel built, and then will bias them both, and think about a nice chassis for this amp. I am happy and fulfilled.
Thank you Hugh, Christian, DacZ, and all whom I have received guidance from. Once I finish the second channel, I am moving on to some pre amp construction and I would like to start xrk971's floor standing TL - 10F/R225 project. This will be slow work as we have our winter vacation in Mexico. So much, so little time
Here is a pic
Thank you Hugh, Christian, DacZ, and all whom I have received guidance from. Once I finish the second channel, I am moving on to some pre amp construction and I would like to start xrk971's floor standing TL - 10F/R225 project. This will be slow work as we have our winter vacation in Mexico. So much, so little time
Here is a pic
Hello Members,
I need a bit of help to make sure I understand about biasing and setting offset voltage on the VSQA. I am using the DacZ pcb. See the pic in post #2650
1. When it says " set bias across the R20 the 0.33R resistor" does this mean connect one DMM probe to one lead of the R20 resistor and the other DMM probe to the other lead of R20. Then adjust the trimpot to required +/- 42mV. I am used to using test points. If correct, does it matter which probe (black or red) is attached to which lead.
2. To adjust the offset voltage, do I hook up black probe to the ground spade on the amp pcb and the red probe to the speaker spade on the pcb, and adjust the readings as close to 0V as possible.
3. Also, can this be done with no load on the amp output?
Thanks for the help, would hate to do something crazy at this point.
MM
I need a bit of help to make sure I understand about biasing and setting offset voltage on the VSQA. I am using the DacZ pcb. See the pic in post #2650
1. When it says " set bias across the R20 the 0.33R resistor" does this mean connect one DMM probe to one lead of the R20 resistor and the other DMM probe to the other lead of R20. Then adjust the trimpot to required +/- 42mV. I am used to using test points. If correct, does it matter which probe (black or red) is attached to which lead.
2. To adjust the offset voltage, do I hook up black probe to the ground spade on the amp pcb and the red probe to the speaker spade on the pcb, and adjust the readings as close to 0V as possible.
3. Also, can this be done with no load on the amp output?
Thanks for the help, would hate to do something crazy at this point.
MM
does this mean connect one DMM probe to one lead of the R20 resistor and the other DMM probe to the other lead of R20. Then adjust the trimpot to required +/- 42mV
Yes,exactly.
If correct, does it matter which probe (black or red) is attached to which lead.
It dowsn't matter,connect either way.
To adjust the offset voltage, do I hook up black probe to the ground spade on the amp pcb and the red probe to the speaker spade on the pcb, and adjust the readings as close to 0V as possible.
D.C volt on output(offset) can be positive(+) or negative (-) so connect either way.
Also, can this be done with no load on the amp output?
This Must be done without load ,OUTPUT open and with INPUT shorted.
Thanks once again Thimios, but I think I am confused :
To set the bias, I should have the inputs connected to the amp pcb ? Correct?
Should I use an alligator clip between +in and sgnd to short them if setting the bias.?
If this is proper, then I leave it like that and then set the offset voltage.?
Sorry, but confused.
To set the bias, I should have the inputs connected to the amp pcb ? Correct?
Should I use an alligator clip between +in and sgnd to short them if setting the bias.?
If this is proper, then I leave it like that and then set the offset voltage.?
Sorry, but confused.