Peter Daniel said:
Thanks. Some mothers do have them...
Measuring the power supply without the amp boards connected, both measure approx 25VDC across both pos and neg.
Voltage at the wall is approx 216VAC
Now I have connected the amp boards, both amps read approx 29V and 33V across positive and negative respectively.
The chip gets pretty hot pretty quickly. I have changed the pcu heatsinks for pieces of aluminium sheet measuring 4" x 8" x 1/8" which hopefully will dissipate heat better.
Tested amps through two four ohm speakers from a pc speaker system using ipod as a source. Barely audible badly distorted sound from both amps. What to check next?
Thanks as usual
Matt
Are you sure you didn't mixed up resistors on amp PCBs?
The values should be according to schematic here: http://www.diyaudio.com/forums/attachment.php?s=&postid=1508778&stamp=1210693738
The values should be according to schematic here: http://www.diyaudio.com/forums/attachment.php?s=&postid=1508778&stamp=1210693738
I thought it may be a good idea to post a link here to a place in Poland that produces affordable and very good transformers: http://www.toroidy.pl/index.php?page=shop.browse&category_id=18&option=com_virtuemart&Itemid=2
Ask for a special audio version:
TS300VA PRI:115V SEC:2x22V for AUDIO:
- secondary at the core with 50% higher diameter, single wire (1,8mm)
I used such transformer in my best amp yet: http://www.diyaudio.com/forums/showthread.php?s=&threadid=76609&highlight= althought it was amorphous core, which I hear is not available any longer.
Ask for a special audio version:
TS300VA PRI:115V SEC:2x22V for AUDIO:
- secondary at the core with 50% higher diameter, single wire (1,8mm)
I used such transformer in my best amp yet: http://www.diyaudio.com/forums/showthread.php?s=&threadid=76609&highlight= althought it was amorphous core, which I hear is not available any longer.
Peter Daniel said:
I have checked this and it was not the problem. I'm a bit stuck now. I'm considering making up the stereo config as in your pictures. If that works, then I will work backwards (or just leave it as it is...) The ony non standard bit of kit is the LED and RLED which I salvaged from a PC. Can this be jumpered or left out to eliminate it?
Thanks
Matt
If they were with amorphous core, they would be better, otherwise, they are certainly comparable.
BTW, I also used those tranformers in my Zv9: http://www.diyaudio.com/forums/showthread.php?s=&threadid=85590&highlight=
BTW, I also used those tranformers in my Zv9: http://www.diyaudio.com/forums/showthread.php?s=&threadid=85590&highlight=
thx Peter
very good hint
Is that transformer build for audio use - It Is not encapsulated
I am very sensitive to noise - hate mechanical, buzz that some transformers make
have somebody used www.amplimo.com transformers
are they In relation with Plitron
very good hint
Is that transformer build for audio use - It Is not encapsulated
I am very sensitive to noise - hate mechanical, buzz that some transformers make
have somebody used www.amplimo.com transformers
are they In relation with Plitron
Subwoofer on my 3875 amp
I just finished a chipamp.com LM3875. Thanks for the coaching and guidance Peter. I'm running a pair of FR Tangband speakers (3CR-Ti on the PE speaker projects page). I'd like to add a sub to get a little more bass. What is the best way to connect the sub to my amp? Is running the sub in parallel with my speakers, off the speaker jacks, the right way?
Thanks.
Mike
I just finished a chipamp.com LM3875. Thanks for the coaching and guidance Peter. I'm running a pair of FR Tangband speakers (3CR-Ti on the PE speaker projects page). I'd like to add a sub to get a little more bass. What is the best way to connect the sub to my amp? Is running the sub in parallel with my speakers, off the speaker jacks, the right way?
Thanks.
Mike