March 8, 201214 yr Author comment_502556 http://gilmore.chem.northwestern.edu/blackholebd.jpg The critical stuff fits. Now on to massive parts ordering binge. Report
April 28, 201214 yr Author comment_511735 Yep, that one is virtually done too. I've been spending time on other stuff, but the prototype definitely works. And works well. Report
June 13, 201214 yr comment_520248 Any more progress in this area? I'm in the market for a nice and cheap instrumental amp. Report
June 13, 201214 yr Author comment_520260 just have not had the time to test the final version. i can give you the board layout, have a few made and test. Biggest problem is that i'm moving my lab beginning of august, and i'm working 10 hour days in prep. Plus the stax mafia seem to be doing every possible electrostatic tube amp at the moment, all at the same time. Edited June 13, 201214 yr by kevin gilmore Report
June 29, 201214 yr comment_523067 So... How do we mount the chip to the sink? Drill two holes on the Ohmite sinks and screw it on? Report
June 29, 201214 yr Author comment_523073 Buy the ohmite clip that is designed for the heatsink You also need a thermal insulator because the tab is Electrically hot. Will post the part number later. Report
June 30, 201214 yr comment_523201 Great! Will add it to my BOM. Also, what's the bjt between the output transistors? Report
October 24, 20187 yr comment_797052 I'm sorry to rescue this old thread. I've seen some schemes in the Stax mafia circuit boards but I don´t know if this ampli step finally "production". The fact is that I would not mind doing one of these amps and maybe someone else is attracted to the proyect. Report
October 24, 20187 yr Author comment_797057 The company that made the output transistors went out of business Report
October 25, 20187 yr comment_797072 Do you mean OPA541? Mouser has stock (OPA541AP) from TI. OPA541AP Report
October 25, 20187 yr comment_797073 No, the opa is an IC, not the transistors Kevin referred to. Report
October 25, 20187 yr comment_797074 Oh I'm sorry I was looking at this scheme and I thought it was about that Opa. I guess it's a dead end. Edited October 25, 20187 yr by jose Report
October 25, 20187 yr comment_797078 1 hour ago, spritzer said: Wasn't that the pile of shit Ray did? I'm not sure if that's Ray's amp. I have not found documentation about the Blackhole on "Stax mafia circuit boards", only references to the dark/dork star. Report
October 25, 20187 yr Author comment_797080 that was ray's darkstar amp. the blackhole is something different. the blackhole uses a national semiconductor driver chip lme49830 and a pair of alf16P/alf16N semisouth fets for the outputs. You can probably substitute something else for those parts, including bipolars, as the board has options for that too, but I never tested that way. the darkstar sounds absolutely miserable, and these days has stupidly large voltage swings guaranteed to set just about anything on fire. the blackhole is suitable as a small speaker amp. Edited October 25, 20187 yr by kevin gilmore Report
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