July 11, 201312 yr Yesterday I fired up the PCBs of a on board versión (rev: 0.2) with good results IMHO (+441.5v, -442.1v, 571v of bias, 14.9v and -15.05v), only I had a little problem in the pcb of one channel, the led nearest of the balance pot not light, I revised this board and saw that 0.47uf/50v capacitor was defective (Mouser 810-FK16X7R1H474K), in fact, I bought more capacitors than I need and all are defective (only the capacitor of this batch used in the other board is fine !!!) The cap of this photo is new (unused), and the rest that I bought have similar values. I removed the defective capacitor and board adjusts balance and dc offset smoothly. -- o -- Rodrigo
July 11, 201312 yr Congratulations on your power up. I am curious as to what was it that you saw in the cap that made you think that it was defective. I have always assumed that when it comes to parts from mouser I never have to worry. I guess nothing can be taken for granted.
July 11, 201312 yr Great work Rodrigo! Glad to see to finally found the time to complete the boards. Now on to the casework. And I test everything, whether from Mouser or Bdent or anywhere else (except 8-pin dip packages - don't know how to test those). A few more extra minutes at the front end can save a lot of time and grief in troubleshooting.
July 11, 201312 yr Many thanks Congratulations on your power up. I am curious as to what was it that you saw in the cap that made you think that it was defective. I have always assumed that when it comes to parts from mouser I never have to worry. I guess nothing can be taken for granted. When I connected the board to the PSU, +15 v output dropped to 1.4v so clearly had an excess of consumption, only had to find a shorted component or with a very low resistance that was connected to +15 v line. I need some time to make the box because I want to try a different arrangement to which I have seen so far. My intention is to put a Alpha pot near inputs and make ventilation holes near the heatsinks because I use a 2U box. Not sure if I will be able to align the pot with the volume knob on the front, but I want to try -- o -- Rodrigo Edited July 11, 201312 yr by PICaudio
July 13, 201312 yr Many thanks I need some time to make the box because I want to try a different arrangement to which I have seen so far. My intention is to put a Alpha pot near inputs and make ventilation holes near the heatsinks because I use a 2U box. Not sure if I will be able to align the pot with the volume knob on the front, but I want to try -- o --RodrigoThis case is fine -but I would consider the air flow through. I decided to use fully ventilated top and bottom.Amazingly in England we have two weeks of summer at the moment. My desk is at 27deg C (80F) and the top of the fully v case is 40deg C (104F). The amp is working fine although I haven't tried to measure the HS temp under these conditions.(Normally the ambient in our house is nearer 16-20C)
July 13, 201312 yr Fully vented top and bottom is not a bad idea. Not needed here because we never get above 20°C... ever.
July 13, 201312 yr I found that I had inserted the bridge backwards on the last PSU that I recently posted. Instead of matching for the "notch" on the bridge to the markings on the board I mistakenly put it in with the positive towards the + mark that was actually for the nearby capacitor. Seems like a rather silly mistake, but there you go. After considering stripping that board to find out the full extent of the damage, and considering I was not happy with some of the joints I went ahead and built up another PSU since I had the parts. Eventually I'll go back and see if I can salvage that other PSU On testing today +/-504V, +/- 15V Edited July 13, 201312 yr by shipsupt
July 14, 201312 yr Does anybody want to see what serial testing of KGSSHV boards looks like? That's the pile of fail from Hennyo all tested and working plus the new HVk (k for kompakt) boards verified working. I still have to test the servo but I forgot to order the caps... The new input fet didn't work for me but it was probably my soldering. It's tiny... to say the least.
July 15, 201312 yr Excellent! Those kompact boards look good and with the mini PS the on-board version will fit a smaller case.(if a suitable one can be found) Edited July 15, 201312 yr by headinclouds
July 15, 201312 yr Got the heat sinks in today. Here's how it's going to lay out... Kerry, any new developments on this? Really interested in seeing this one to completion. Now if you could mount the transformer on its edge...
July 16, 201312 yr No. I was traveling on business last week and I'm only just getting settled. I've got a few things in front of this at the moment, but will definitely get back to it.
July 16, 201312 yr Excellent! Those kompact boards look good and with the mini PS the on-board version will fit a smaller case.(if a suitable one can be found) The 350mm Modushop Slim boxes will work just fine. Maybe even a bit too big but we'll know next week when I'll fit the boards into one of those.
July 17, 201312 yr Before connecting a headphone for the first time I want to connect a dummy load to the amplifier and see how it works with the oscilloscope (I have a x100 probe) but I'm not sure what kind of component should I use. I suppose a capacitor of 100 or 120 pF could be worth? -- o -- Rodrigo
July 17, 201312 yr Author a pair of 120pf caps rated 500v or more stator to bias to stator Edited July 18, 201312 yr by kevin gilmore
July 19, 201312 yr My second KGSSHV is done. Still need to tidy up all the wirings though. Wachara C.
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