Have you guys seen the quality of the MiniA power supply board from BrianGT on ChipAmp.com?
Its beautiful and hefty and cheap. 6 snap in caps, 4 diodes with placements for diode heatsinks, and room for inductors or resistors as well as on/off indicator LED. I use them for my chip amp but they are wonderful and you could wire up 2 of them for 12 caps if you wanted.
Uriah
Its beautiful and hefty and cheap. 6 snap in caps, 4 diodes with placements for diode heatsinks, and room for inductors or resistors as well as on/off indicator LED. I use them for my chip amp but they are wonderful and you could wire up 2 of them for 12 caps if you wanted.
Uriah
He unfortunately has no pics but I guarantee that for snap in caps and a max of 6 caps its about the best board I have seen. It will take radial leads of course. Max of 40mm diameter caps. Leads can be 10 or 23mm apart and 18mm apart if cap is offset towards outside of the board.
Black with Gold pads and white silkscreen.
They are about $9 each and just a great deal.
Uriah
edited lead spacing
Black with Gold pads and white silkscreen.
They are about $9 each and just a great deal.
Uriah
edited lead spacing
I got a second power supply board from Peter Daniel and added it to my Aleph-J so I am running 1 supply board per channel, 88000uF for each channel. I am using 2 50A/1000v bridge rectifiers and then splitting the DC from there to each PS board. I was hoping that somehow the extra capacitance would help bring up my rail voltage which is still sagging from an unloaded 25.2v down to ~22v with the amp boards connected. Is there anything I can change to get my voltage up? I'm concerned that running the voltage this low could have a negative effect on performance. This is with an Antek 600VA 18Vx2 transformer and my wall voltage is a steady 120v.
Also I tried hooking up my Zaph Audio BAMTM speakers to my Aleph-J last night which are 4 ohm speakers and the results were pretty poor. I was hearing some nasty distortion in music with a lot of bass. Is this because the amp was running out of current and clipping? That's why I'm concerned about the voltage. I didn't even have to turn it up very loud to reproduce it. I know that this amp isn't designed for 4 ohm speakers so maybe its just a bad idea to try using it with 4 ohm speakers at all.
Also I tried hooking up my Zaph Audio BAMTM speakers to my Aleph-J last night which are 4 ohm speakers and the results were pretty poor. I was hearing some nasty distortion in music with a lot of bass. Is this because the amp was running out of current and clipping? That's why I'm concerned about the voltage. I didn't even have to turn it up very loud to reproduce it. I know that this amp isn't designed for 4 ohm speakers so maybe its just a bad idea to try using it with 4 ohm speakers at all.
Yes its CRC, 22kuF -> four .51r in parallel -> 22kuf
I used .51r resistors because digikey was out of stock on the .47r 3w panasonic metal films, only 0.01 ohm difference so I figured that was ok. I had some .47r vishay wirewound resistors but unfortunately the leads were too thick to fit through the board.
It was weird though, last night was the first time I tried running my BAMTM speakers with the Aleph-J, and I have just gotten done moving to a new house and hadn't played the speakers since I moved so I thought something might have happened to the crossovers in transit. Hooked up the MyrefC chipamp I have and they sounded perfect though. Then I hooked up a pair of Infinity bookshelf speakers to the Aleph-J and there was no distortion issue there either. Seems the two of them just don't get along.
Thanks for the advice thanh1973, I'll have to think about whether I want to do any more tinkering with the amp, or just find a speaker design that is a better match.
You might be right on that point. I have two Js, one I built with an extra fet pair and one stock. I have 4ohm spkrs also but they are pretty efficient. Either amp has no problem with them.
My bigger amp has the 600va Antek and the rails are the same, 22v. The smaller amp has a 400va Antek and its rails are 23.5v, go figure.
mechanical and electrical buzz
OK, I have a situation very much like CoreyK78 had. I built a stereo J using Peter Daniels boards. Power supply is also PD board (x1) with 33Kuf, 4x .47Ohm, 33Kuf per rail. Trafo is Antek 600VA with dual 18V secondaries. Bridges are 27A IXYS freds. With no load, I got 25.3V each rail. Hooked up, I get exactly 20V each rail. The trafo is buzzing quite noticeably and I am also getting buzzing in each speaker (just noticeable at listening seat with no music - not terrible, but I always heard this amp was dead quiet). I also had CL60's on live and neutral primaries but after reading prior posts, removed the neutral - still buzzing. Can a grounding issue cause the trafo and speakers to buzz? I have earthed the power cord ground to chassis and then used CL60 off that to signal ground all other ground connections. The amp sounds great (still breaking in), but the buzzing should not exist - something is wrong. Can the low voltage cause trafo to buzz? How do I troubleshoot? Any help would be greatly appreciated. Thanks!
-Alex
OK, I have a situation very much like CoreyK78 had. I built a stereo J using Peter Daniels boards. Power supply is also PD board (x1) with 33Kuf, 4x .47Ohm, 33Kuf per rail. Trafo is Antek 600VA with dual 18V secondaries. Bridges are 27A IXYS freds. With no load, I got 25.3V each rail. Hooked up, I get exactly 20V each rail. The trafo is buzzing quite noticeably and I am also getting buzzing in each speaker (just noticeable at listening seat with no music - not terrible, but I always heard this amp was dead quiet). I also had CL60's on live and neutral primaries but after reading prior posts, removed the neutral - still buzzing. Can a grounding issue cause the trafo and speakers to buzz? I have earthed the power cord ground to chassis and then used CL60 off that to signal ground all other ground connections. The amp sounds great (still breaking in), but the buzzing should not exist - something is wrong. Can the low voltage cause trafo to buzz? How do I troubleshoot? Any help would be greatly appreciated. Thanks!
-Alex
bias current
Left channel:
R16 .530
R17 .525
R18 .535
R19 .529
Right channel:
R16 .538
R17 .523
R18 .521
R19 .535
Details of grounding scheme: Power cord earth to chassis screw; chassis screw to CL60; other side of CL60 star grounded to each neg binding post and to ground of power supply and to ground of each PD signal board; negative/ground of each rca (no xlr input) to signal ground on PD board jumpered with negative-in on PD board.
I can't figure this out...help! Thanks
Left channel:
R16 .530
R17 .525
R18 .535
R19 .529
Right channel:
R16 .538
R17 .523
R18 .521
R19 .535
Details of grounding scheme: Power cord earth to chassis screw; chassis screw to CL60; other side of CL60 star grounded to each neg binding post and to ground of power supply and to ground of each PD signal board; negative/ground of each rca (no xlr input) to signal ground on PD board jumpered with negative-in on PD board.
I can't figure this out...help! Thanks
Thanks for the replies. Last night I revisited the grounding and have fixed the electrical hum in the speakers - I made an error, mea culpa The speakers are now quiet. However, the trafo still hums very noticeably and based on comments in this thread, a 600VA trafo should be sufficient to avoid mechanical stress. I am really perplexed.
The speakers are now quiet. However, the trafo still hums very noticeably and based on comments in this thread, a 600VA trafo should be sufficient to avoid mechanical stress. I am really perplexed.algg,
A lot of the Antek trannies have secondary voltage taps like 12v for accessories. What have you done with these wires. It is possible that they are contributing to the hum. Make sure they are electrically isolated and out of the way, not in the center of the toroid.
You could try reversing the AC leads on one channel rectifier. It should not make a difference but it once worked for me.
Tad
A lot of the Antek trannies have secondary voltage taps like 12v for accessories. What have you done with these wires. It is possible that they are contributing to the hum. Make sure they are electrically isolated and out of the way, not in the center of the toroid.
You could try reversing the AC leads on one channel rectifier. It should not make a difference but it once worked for me.
Tad
I actually had some mechanical buzzing coming from the transformer even after going up in size from the 400VA to the 600VA transformer. Thats when I checked the MUR860 rectifiers I was using and found they were running extremely hot. I decided to switch to chassis mounted 50A/1000v bridge rectifiers and the buzzing completely disappeared. Worked for me, YMMV.