June 5, 201511 yr by the way fully balanced version coming. lots of parts! 100% differential 100% complementary http://gilmore.chem.northwestern.edu/cfa3production.pdf not sure why it took me years to come up with this NO FEEDBACK of any kind thd <.005% and absolutely flat over the 10hz to 200khz frequency response +0, -3db .017hz to 4.43 MHz So, is it end of the game SS dynamic amp??? What's your opinion?
June 6, 201511 yr Author don't know yet. with the he1000 coming out, all this power is unnecessary and the ssdynalo works great. the no feedback part is sweet however. Edited June 6, 201511 yr by kevin gilmore
June 6, 201511 yr Looks like I need to save the attenuator boards for this and not the T2 what's wrong with SMD in this case, the packages are large enough to do by hand, not to mention still available at mouser Edited June 6, 201511 yr by nopants
June 6, 201511 yr Power is still necessary Looks like I need to save the attenuator boards for this and not the T2 what's wrong with SMD in this case, the packages are large enough to do by hand, not to mention still available at mouser Harder to match them. Anyway, there are just 4 of them per board. It's OK.
June 7, 201511 yr Hi Kevin, I have read several times on other forums that the higher voltage 15034 & 15035 parts sound better than the 15031 and 15030. Is it worth trying both parts you think? probably not cheap though.
June 7, 201511 yr Author I have never tried it. not available in plastic insulated tab, so you would have to make sure the insulation is right. at least its low voltage
June 8, 201511 yr OK, so your not working on MJE package, i didn't pick that up, either way its probably easy to try. I actually have a few of the mje15035 & 15035. You mention Ayre in this thread, is this your inspiration for this amp? I believe all their amplifiers are zfb designs, maybe the codex is too, should see some reviews on this product soon.
June 8, 201511 yr Try Toshiba 2SC5171/2SA1930. They are available at Bdet (2SC5171/2SA1930) and Mouser (2SA1930). Grab them!
June 8, 201511 yr Nice tip, they are same pinout as onsemi parts, but you need to buy 500 of them from mouser or digikey.
June 8, 201511 yr Minimum quantity from Mouser is 1 pcs (2SA1930). Same from BDent (2SC5171). Ah yes, 2SA1930 is in stock in Digikey. Minimum quantity is 1 pcs. too.
June 9, 201511 yr where I live I gotta get a one stop shop. Last quote I got from Future Electronics was 70 dollars shipping. for 40 dollars worth of semis. I live in NZ, its far, but it aint the moon:-)
January 20, 201610 yr Running my CFA2 at +/- 24V rails currently, but thinking about testing something a bit higher, given that the Transconductance Amp seems to benefit from slightly higher rails. Is this thinking about it backwards? and if not, what is the highest voltage possible in stock configuration (given adequate heatsinking)?
January 20, 201610 yr Author the opamp blows up at +/-40V would have to check the other parts, but +/-30V should absolutely work speaking of power... unbalanced/balanced/cast to balanced input block for all sorts of things, but mainly the uberamp, just need to find a way to get it into the box will probably involve splitting off the driver section. Uses GR power supply +/-30V for the front end and another GR power supply +/-40V to run the regulated output voltages to the output amp. If i add zeners to the servo amp, can easily go to +/-50V and as shown, its 100 watts of pure class A, and something north of 225 watts A/B front end NO feedback of any kind, .0025% thd at 20khz, 2nd harmonic. 3rd harmonic not measurable. output amps are current feedback. i think i have created a monster
January 20, 201610 yr You read my mind. I was looking for a project like this I'm at the early stages, but I'm planning on building some exotic speakers. More on that later.
January 20, 201610 yr The design of this has absolutely nothing to do with me having Quad ESL57's and a new big living room...
January 21, 201610 yr 8 hours ago, spritzer said: The design of this has absolutely nothing to do with me having Quad ESL57's and a new big living room... Welcome to the Quad side! I've had mine since the early 1980s.
January 21, 201610 yr Is this why Birgir is building something other than electrostatic amps..? From Mjolnir Audio on 17-01-2016 in the News section:- "Stay tuned soon for some crazy news such as me finally building some dynamic amplifiers and other madness… "
January 21, 201610 yr Gotta do some dynamic amps as well. Show people how they should be done as there is an awful amount of crap out there. 7 hours ago, n3rdling said: Quad 57 club checking in Birgir, when did you get yours? Late last year. There was a local set for sale that I tried to avoid but I finally broke down when the owner called me out of the blue. Apparently it is known here now that I like electrostatics... They are just sitting unused for now but I'll probably ship them out to be completely refurbed.
January 21, 201610 yr Are they not working properly? I've heard from several Quad owners out here that their refurbed units never sounded the same, and that's with the popular restorers.
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