June 2, 201412 yr I'd check the bottom just to be sure. Then you can start replacing parts. Problem solved. I started testing resistors and found 2 bad ones R35 and R37 both 100R, measured 140K and 450K. Considering these 2 probably saw 450V, I also pulled the adjacent Q13 and Q14. One tested bad; replaced them both. This is in the vicinity of the 1000V film cap that shorted to ground. Both balance and offset now set near zero. Thanks for all the tips guys!
June 2, 201412 yr Author there is a thread over at diyaudio saying that since wima has moved production to china, quality has turned to absolute shit. time to buy caps from vishay
June 3, 201412 yr Author no idea. probably china too. what evidently happened to wima is that when they switched to china they changed the sizes of most products, making them smaller with different films that are more tightly wound.
June 3, 201412 yr Good thing I stick with my surplus of Russian and German NOS caps for high voltage applications. Or modern Epcos and CDE, Wimas and Siemen mkts are good enough for low voltage stuff. Pretty sure the Vishays are Taiwan or Malaysia. Anyway I'm doing a 2 box solution for my kgsshv with the trafos and psu board in a separate enclosure whats a good connector for the umbilical connection?
June 3, 201412 yr Author the same connectors used in the diy-t2 but less pins. ugly but rated for the voltage and not plastic crap amphenol industrial circular connectors
June 3, 201412 yr Cant find that thread. Where are Vishay made Needing a few 1KV caps and not wanting to trouble Mouser for a small order from England, I got EPCOS - B32653A104J - CAP, FILM, PP, 100NF, 1KV, made in Spain VISHAY ROEDERSTEIN - MKP1840422104M - CAP, FILM, PP, 220NF, 1KV, made in Portugal from Farnell who do sell in the USA. as Farnell Element 14
June 5, 201412 yr I decided to try something new for the next round of HV's: I like the "black line" look and it will fit with the next batch of amps using some exciting transistors.
June 5, 201412 yr Even as a notorious Silverist, I will concede that that looks pretty fucking trick.
June 11, 201412 yr Turned on my kgsshv today, heard some louder than normal lamination hum along with some crackling, opened things up and nothing seems to be amiss except for the transformer being extremely hot, and a particularly acrid smell. I used the specs in ujammerstad's BOM so I don't think the specs are at fault... 450VAC output for +/-500VDC rails Sumr part #: RC0100 050 3 100VA / 117V primary 2 x 450V (@125mA output ea) secondaries 1 x 30VCT (15V-0-15V) 10VA secondary Core band Static shields I didn't realize these transformers retain heat for so long too...makes me worried about the SumR units I had potted. Is this retention normal, or is something happening inside? Edited June 11, 201412 yr by nopants
June 11, 201412 yr The specs are just fine as I have SumR units here which worked just fine with that spec. Richard just did something wrong somewhere and we are paying the price. The units I have that actually work were after I got rather cross with him... The BHSE units I was having trouble with got very warm on the Blue Hawaii so we'll see soon how they are on the KGST. The transformers I had made in Hong Kong were designed from the point of keeping max temp rise low so they run cool and very few have any noise at all. Not cheap but as if I care.
June 11, 201412 yr What's extremely hot? It is sitting on a thick rubber mat? A short to ground may explain the sudden heat...? I've measured my SumR in my BHSE at 70C. I've since re-housed it in a well ventilated metal box, temps are much better after a few hours (40 - 45C). They're rated max 105C, so I'm not too worried, and they are relatively noise free. However... The two SumRs in my FX5 buzz if I push the current up to the Amps optimum range. I've had to dial it down because the piss poor quality of the transformers.
June 11, 201412 yr I usually go for no more than 35°C above ambient. That's at max load which I'd never run a transformer at.
June 11, 201412 yr the SumR traffos in my two KGSSHVs (when I had them) ran just slightly warmer than ambient. My SumR traffos in my T2 are at about 25-30C above ambient, but they have a 1 inch clearance from the top of the case (whereas the spec calls for something in the neighbourhood of 4-5 inches - going by memory).
June 11, 201412 yr My transformer also ran slightly warmer than ambient under normal conditions, which is why there was some alarm on my part when I touched the case underside. I didn't have something on hand to measure the heat, and I didn't want to leave it on long enough to check. During that period, the amplifier LEDs were all light as normal. I used the insulating mats that Richard provided. The real red flag was that smell...I still can't figure out what exactly was burning. I'll find out once I pull the transformer tonight. I understand that ambient temperature may affect this as well, as it has been ~90s at my place recently. However, I've been pointing a fan in its general direction (to cool my SDR2000, whose feet melted during normal operation) Richard has implied that he can build a replacement, and has offered to install a reset fuse in case of overheating. Any thoughts on this? Spritzer, in the past you've mentioned some sort of construction fix to pass to Richard (larger diameter wire)? I'm a bit concerned about using another SumR as a replacement, but if that falls through I can scrape together two hammond 269GX's as a substitute.
June 12, 201412 yr I replaced a SumR transformer on my first build and no problems after that. Free of charge. Richard mentioned something about problems with the first unit so I bought the Megatron transformer from him. It works well without load. Will see how it works when completed.
June 12, 201412 yr One of my KGSSHV transformers melted so Richard replaced it. That replacement cost me about 300$ in customs fees as it was declared as if I had just bought them... The replacements seem to work just fine but I've only done brief tests.
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