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and now for something completely different part 3


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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?

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Close to finish casing my balanced CFP amp. Waiting for a 4-pin XLR socket. This one runs on 26VDC rails and 220mA bias current.  I am posting an unfinished amp because I want to report that

So when I got my case I got pretty upset with the looks of the power switch: So I search around the house for what could be used to improve this and found and unused aluminum kitchen drawer

Another CFA is alive and well. Sorted out the issue with the bias when using the SS/ZF switch by doing the following (board rev 1.2): - Remove the 4 ZF jumpers near the 600pF - Increase R44/

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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 by nopants
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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.

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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.

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  • 7 months later...

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)?

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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 :lol:

ubalbalcast.jpg

uberamp2.jpg

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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...  ;D 

Welcome to the Quad side!  I've had mine since the early 1980s.

HQ Subwoofer.JPG

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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…  :-)"

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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 :D  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...  ;D  They are just sitting unused for now but I'll probably ship them out to be completely refurbed. 

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