Ok ... PCB's ordered
also will order pre drilled heatsinks from modu (well done Gianluca) and many thanks to prasi for being so helpful
also will order pre drilled heatsinks from modu (well done Gianluca) and many thanks to prasi for being so helpful
I am looking to buy a pair of boards plz.
I have some Dale Mills MRA-05 0.56 ohm/4w resistors suitable for this amp , take a look here: https://www.diyaudio.com/community/threads/some-components-for-sale.314633/
I have some Dale Mills MRA-05 0.56 ohm/4w resistors suitable for this amp , take a look here: https://www.diyaudio.com/community/threads/some-components-for-sale.314633/
There are 2 versions of the pcb with gerber files available - the original Nelson Pass version and the one prasi has done.
Details of both are in this thread.
Nelson's gerbers are in post #463 and prasi's are in post #812.
Details of both are in this thread.
Nelson's gerbers are in post #463 and prasi's are in post #812.
Last edited:
2 oz is overkill, it is not a class A design. As Nelson has stated in post #1, the bias is only 80mA per channel.
I unfortunately will not be building one of these amps due to other projects yet to be finished due to ongoing health issue's BUT I always find your (Mr. Pass) generosity amazing. You have provided folks with SO many projects without ever asking for anything, and then also all the time to reply to all the questions thrown your way. Very nice man indeed!
Freecrowder,
Even though you are using Nelson’s gerber’s, cannot that be changed when you send them to a PCB shop? Or would that change the thickness of the traces and there for the layout (needing it to be changed)? Thanks.
Even though you are using Nelson’s gerber’s, cannot that be changed when you send them to a PCB shop? Or would that change the thickness of the traces and there for the layout (needing it to be changed)? Thanks.
you can definitely change the thickness when ordering. The 2oz was a significant increase. there is nothing wrong with the quality of the boards though. they build excellent amps. now if you want the Prasi version I'm assuming he has gerbers for his.
Goodness, its the last time that I clad a frame, using 3mm aluminum, it is such a lot of work, measuring, drilling, tapping, screwing together, and the same sequence over again and again and some more, plenty plenty of times... But getting there soon !😉
Attachments
DaveFred, the VU meters will be driven from a Rod Elliott circuit.
https://sound-au.com/project55.htm
https://sound-au.com/project55.htm
The left channel of my AB100 let the smoke out after about a year of playing in my garage. The day it quit, the temperature was 78 degrres in the garage and the stereo was playing at a moderately high volume level. I heard the left channel quit and went to check it, the left channel was hot.
When I removed the cover, I found the two rail fuses blown. I use 5 amp fuses on the rails. I replaced the two fuses and powered it up and it smoked R16 in the diagram below. See also the picture.
I then checked all the outputs for shorts to ground and to verify they were still good using a meter on diode check.
I then checked R6 and R5, both good.
I then checked T6, T7, T1 and T2, T8, T3, all good. I checked these by removing and checking with a meter on diode check and in a cheap chinese tester.
I also checked C5, it shows high resistance across it and correct capacitance.
It's pretty obvious to me that the issue is in the front end, but so far everything is checking out.
Does anyone see something that I have missed? To smoke that large Vishay resistor I would think something would be very obvious, but I'm not finding anything.
When I removed the cover, I found the two rail fuses blown. I use 5 amp fuses on the rails. I replaced the two fuses and powered it up and it smoked R16 in the diagram below. See also the picture.
I then checked all the outputs for shorts to ground and to verify they were still good using a meter on diode check.
I then checked R6 and R5, both good.
I then checked T6, T7, T1 and T2, T8, T3, all good. I checked these by removing and checking with a meter on diode check and in a cheap chinese tester.
I also checked C5, it shows high resistance across it and correct capacitance.
It's pretty obvious to me that the issue is in the front end, but so far everything is checking out.
Does anyone see something that I have missed? To smoke that large Vishay resistor I would think something would be very obvious, but I'm not finding anything.