Juma's Head Amp

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#141
I think the major reason is the cost of PCB, cost of 50mmx50mm board (10usd) versus cost of say 100mmx100mm (25usd) or 150mmx 150mm (81usd).
I did make a 100mmx72mm board for +15v/g/-15v but no one showed interest. but there is plenty of interest for a universal regulator giving +15v or a -15V.

if this is the last piece of audio equipment that i am going to build, it makes sense to include psu and stero amp on a single pcb.
 
#142
Then design every PCB as if it is your last ! 🙂

If one has to choose between cost of 50mmx50mm board (10usd) for a single PSU versus cost of 100mmx100mm (25usd) for a symmetrical PSU that lousy 5$ difference is paid back by less hassle and all the other things mentioned. Forget "universal" and "cheap". We need "excellent for a specific purpose" and cheap = expensive in the long run.
 
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#143
The interest in the Universal +/-15v regulated cap multiplier is real. I want one. I would have also liked (and I think many others too) a universal cap multiplier for Juma's cap multiplier with an IRFFP240. Can handle many amps up to typical 25w class A loads. Using two of these in series gives dual rail so no need to make an IRFP9240 version, although it's handy to have both +/- rails on one small PCB. This is not regulated and is typically 4v drop from rail. Dead simple though and very very low ripple (my Fluke 101 measures 0.0mV AC) at 1.5A quiescent from a 33mF/0.1R/33mF CRC upstream.

http://www.diyaudio.com/forums/solid-state/297921-jumas-easy-peasy-capacitance-multiplier.html
 
#147

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#153
The reason that I asked for the single rail board is that I have too many LM317's to use. I like to use what I have instead of dumping to the land fill 🙂

I am in total agreement that, if anyone is not in the situation as me and buys new parts and needs +/- PSU, the dual rail board is the way to go. LT reg can be used as long as they are pin compatible to the LM. One can also uses this as a generic 3 pin req board if the Nazar "extension" is not needed.
 
#155
If you couple this to the one in the previous post one can omit 4 connectors and 6 wires when using it in stereo config. Then you have a very compact mono amp board with PSU. Boards have same width. Turn the output transistors 90 degrees and mount them the same way as with the PSU board. No "generic" and no "universal" FWIW.

If you double this setup on one board and add room for holes for mounting the transistors + couple the AC sides with PCB tracks ....sorry, I get carried away 😉
 

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#157
Has anyone received their Juma HA boards yet? I am still waiting for mine - should be here soon. I wonder how it will sound vs a JFET input?

Thanks for the Gerbers Prasi. Sometimes I wonder if I should try the nail polish mask trick (hand painted tracks). Possible on a small simple board like the PSU.
 
#158
xrk971 said:
Has anyone received their Juma HA boards yet? I am still waiting for mine - should be here soon. I wonder how it will sound vs a JFET input?
Click to expand...

Mine should arrive in about 1 week, I haven't tried the original F5 HA so your feedback would be appreciated. I'm planning to put 2 HA in a single enclosure with a switch to select which amp will receive the +/-15Vdc power. The second HA will be a great sounding HA by Fab.
 
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