SR-200
My Sr-200 has been assembled and I have tested 1channel . It works great . I have yet to test it with music as I have not mounted the outputs on heatsinks . I do not have DC on the outputs . Can someone tell me what are the tests I need to carry ? Voltages ? I am also doubtful of the caps and the zener diodes . The 1N4140 and the 15v zeners look the same . Can someone help .
My Sr-200 has been assembled and I have tested 1channel . It works great . I have yet to test it with music as I have not mounted the outputs on heatsinks . I do not have DC on the outputs . Can someone tell me what are the tests I need to carry ? Voltages ? I am also doubtful of the caps and the zener diodes . The 1N4140 and the 15v zeners look the same . Can someone help .
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The Zeners I've purchased are usually glass and look like a larger version of the 1N4148.
Looking at some images of the 1N4140 on Google, their appearance is like a typical black plastic diode with a white band near one end.
Yes , even I had the glass version first , then I swapped it out as I was confused since the 15v zener and the 1n4140 ( i was given that instead of 1n4148 ) .
First of all, don't do any testing without the output transistors at least clamped to some sort of heatsink. You can blow an output in seconds. As for the zeners, use a magnifying glass. There should be a number printed on it. Most likely 4144. That would be a15v.
Sorry , i did the testing with the outputs connected on a heat sink using wires . After I found it working I started populating the outputs . Yeah ! my magnifying glass is too blurred . Need to get another one .
Slim FR50
Hi, here is my new FR50. I wanted to use this heatsink, so the PCB could be only 50mm wide. I tested the amplifier with + -28V. Without any settings the offset with matched inputs is 3mv and the quiescent current is 35 mA.
The sound is very clean and detailed. A crisp bass and very pleasant middle.
I will finish the second board and then test with + -40V. I have made a few small changes for the second board. The layout I will upload when the second channel is running.
The layout has two free wires.
Thanks Mile for the nice amplifier and if it is true - happy birthday!!!
regards Olaf
Hi, here is my new FR50. I wanted to use this heatsink, so the PCB could be only 50mm wide. I tested the amplifier with + -28V. Without any settings the offset with matched inputs is 3mv and the quiescent current is 35 mA.
The sound is very clean and detailed. A crisp bass and very pleasant middle.
I will finish the second board and then test with + -40V. I have made a few small changes for the second board. The layout I will upload when the second channel is running.
The layout has two free wires.
Thanks Mile for the nice amplifier and if it is true - happy birthday!!!
regards Olaf
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nice format olaf! can be put in a cabinet 1.5U, I think, along the sides. Is that your plan?
It will be a selfmade cabinet. Not higher then 50mm. And yes, the heat sinks will be along the sides. I made one with A9. Very nice amplifier (picture).
regards Olaf
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Very nice and slim layout. Do you mind sharing Sprint or Gerbers file ?
p.s. I'm dealing with PCBWay.com when it's time to get some PCBs, according to their website they don't accept Sprint file yet. Who can I use that accept Sprint file and are good/affordable ?
Thanks,
Eric
Hi, I want to test the second channel on the weekend, then I will upload the Sprint-file and also the gerbers. So far I have ordered only Seeedstudio with Gerbers, but that was with a very good result.
regards Olaf
FR50
Hi,
the second channel is ready. Here are the files and a few photos and measurements (see schematic).
I have now tested with + -36V. The sound is really very good. No transistor is hot, slightly warm (BD139 / 140). The offset started with around 20 mV and is after a few seconds stable at 2 mV (all inputs are matched). The quiescent current I set to 50mA in the positive path.
regards Olaf
Hi,
the second channel is ready. Here are the files and a few photos and measurements (see schematic).
I have now tested with + -36V. The sound is really very good. No transistor is hot, slightly warm (BD139 / 140). The offset started with around 20 mV and is after a few seconds stable at 2 mV (all inputs are matched). The quiescent current I set to 50mA in the positive path.
regards Olaf
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