Helium Posted June 24, 2015 Report Share Posted June 24, 2015 Ordered off board version of golden reference boards from seeedstudio 1.6mm 2oz copper Will have some extras for grab when my order gets here. Kevin, are Golden reference boards finalized? You mentioned that there is oscillation unless some parts are not omitted... Quote Link to comment Share on other sites More sharing options...
kevin gilmore Posted June 24, 2015 Report Share Posted June 24, 2015 (edited) the oscillation was in the ltspice simulation. board run now, will know for sure once i build it. possibility of z-foil .15 spacing resistors, going to screw up the ground plane on the back will try later no 20 ohm z-foil resistors that i can find... Edited June 24, 2015 by kevin gilmore Quote Link to comment Share on other sites More sharing options...
G600 Posted June 24, 2015 Report Share Posted June 24, 2015 Texas components make them to order with no additional cost. Quote Link to comment Share on other sites More sharing options...
G600 Posted June 24, 2015 Report Share Posted June 24, 2015 Texas components make them to order with no additional cost. Quote Link to comment Share on other sites More sharing options...
kevin gilmore Posted June 24, 2015 Report Share Posted June 24, 2015 it fits just barely http://gilmore.chem.northwestern.edu/dynahibal17.jpg Quote Link to comment Share on other sites More sharing options...
G600 Posted June 24, 2015 Report Share Posted June 24, 2015 It looks good all SMT. And quite straightforward. I have just finished Sjostrom's Qrv-08 today, which is trickier with it's massive PS. Quote Link to comment Share on other sites More sharing options...
b0bb Posted June 24, 2015 Report Share Posted June 24, 2015 it fits just barely http://gilmore.chem.northwestern.edu/dynahibal17.jpg Very cool, much appreciated. Thanks! Quote Link to comment Share on other sites More sharing options...
nopants Posted July 18, 2015 Report Share Posted July 18, 2015 (edited) one of my boards can't be adjusted below 1.3v/-.4v, can/should I change r26 to get the values closer to 0? Also getting like 3V input DC, is this normal? Right now I'm floating everything and tying IEC ground to earth, amp boards are taking com from the power one supply (equivalent) Edited July 18, 2015 by nopants Quote Link to comment Share on other sites More sharing options...
kevin gilmore Posted July 18, 2015 Report Share Posted July 18, 2015 those are bipolar inputs, with a bit of offset current, so you really need a 10k input pot, or 10k resistors to ground. other than that I listened to my latest set of boards on the new power supply, and there is definitely a noticeable difference in noise with iem's. Quote Link to comment Share on other sites More sharing options...
nopants Posted July 19, 2015 Report Share Posted July 19, 2015 I'll throw in a tkd then, you think that will help both input and output dc? does the input dc even need to be zeroed? Quote Link to comment Share on other sites More sharing options...
kevin gilmore Posted July 19, 2015 Report Share Posted July 19, 2015 can't really zero the input dc. some of the that340 are better than others. if you can get the lsk170/lsj79 parts, those sub directly. and have much lower offset currents. on the 8 boards I have done, all adjust to less than 1mv. Quote Link to comment Share on other sites More sharing options...
mdr30 Posted July 20, 2015 Report Share Posted July 20, 2015 Anyone tried a mini xlr as headphone out? Quote Link to comment Share on other sites More sharing options...
spritzer Posted July 20, 2015 Author Report Share Posted July 20, 2015 The conductors are too small to let the bass molecules though... Quote Link to comment Share on other sites More sharing options...
JimL Posted July 20, 2015 Report Share Posted July 20, 2015 Back when Monster cable was first selling their cables with 3 sizes of wire (fat for the bass and thin for the treble), Frank van Alstine offered to wire the thin ones to an AC plug and plug it in while a Monster salesperson held on to one wire in each hand. For some unfathomable reason, the salesperson declined. 2 Quote Link to comment Share on other sites More sharing options...
mdr30 Posted July 20, 2015 Report Share Posted July 20, 2015 Thinking wear and tear. Don't want these pairs of 3pin xlr anchors hanging down my neck. Quote Link to comment Share on other sites More sharing options...
mvwvm Posted August 22, 2015 Report Share Posted August 22, 2015 What's the intended current through Q6 and Q9? Simulated THD seems to be minimal (0.021%) at ~4mA. Still getting high 3rd harmonic (-64.5dB, the 2nd is -77.8dB). Quote Link to comment Share on other sites More sharing options...
kevin gilmore Posted August 22, 2015 Report Share Posted August 22, 2015 (edited) balanced in, balanced out, 7vrms out into 50 ohms 1khzgoldenreference power supply at +20.0000, -20.0000(hand trimmed resistors)thd is .011% which is actually the base line of this particular metertypically .003% on the quantasylum400and less on the audio precision Edited August 22, 2015 by kevin gilmore Quote Link to comment Share on other sites More sharing options...
mvwvm Posted August 22, 2015 Report Share Posted August 22, 2015 typically .003% on the quantasylum400and less on the audio precisionNeat. Still curious about the currents through Q9 and Q6. Could someone measure voltage drop across R3 and R15? Thanks. Quote Link to comment Share on other sites More sharing options...
kevin gilmore Posted August 23, 2015 Report Share Posted August 23, 2015 1.25 volts160 ma current draw on each rail at 20v Quote Link to comment Share on other sites More sharing options...
MLA Posted September 2, 2015 Report Share Posted September 2, 2015 (edited) I happened to order 3 extra amp board sets when building this amp and I won't be using them.Anybody needs a set, send me a PM and I'll ship them your way for cost of postage. These are rev 9, with smd ptza06/56 and the rest through hole. UPDATE: all board sets spoken for. Edited September 4, 2015 by MLA all boards gone Quote Link to comment Share on other sites More sharing options...
mwl168 Posted October 28, 2015 Report Share Posted October 28, 2015 (edited) 1.25 volts160 ma current draw on each rail at 20v Hi Kevin: How hot do the heatsinks on your GoldenReference PS get at this condition?I just tried running my SUSY Dynalo with the GR PS running on 18V rails and about 18mA per output mpswx6 devices (360mV voltage drop on the 20 ohm emitter resistors). I was using the same heatsinks as shown on your pic but they got too hot to the touch and I had to put much larger heatsinks on. I am a bit surprised. Edited October 28, 2015 by mwl168 Quote Link to comment Share on other sites More sharing options...
kevin gilmore Posted October 28, 2015 Report Share Posted October 28, 2015 i had a variac on the power transformer and lowered the voltage to about 3 volts above the regulation minimum.So it really depends on how much voltage is on those transistors. With a total of about .5 amp, they can get warm. Quote Link to comment Share on other sites More sharing options...
mwl168 Posted October 28, 2015 Report Share Posted October 28, 2015 Thanks Kevin. I did not think of the variac idea, I'll give that a try. My toroid has 22v secondaris so the voltage drop on the pass resistor is quite high. I did test the PS without load and the heatsinks didn't even get warm. Quote Link to comment Share on other sites More sharing options...
kevin gilmore Posted October 28, 2015 Report Share Posted October 28, 2015 one other thing, i went to bigger heatsinks since that picture when i'm driving both boards.the heatsinks are the ones from the blackhole amp driver Quote Link to comment Share on other sites More sharing options...
Pars Posted October 28, 2015 Report Share Posted October 28, 2015 Hmmmm... I was going to do about the same thing as Michael, though I was planning on 20V outputs with 22/23V toroid. Must look up this blackhole amp driver to see what heatsinks I will need to get. Quote Link to comment Share on other sites More sharing options...
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