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Old 8th May 2007, 12:43 AM   #541
Magura is offline Magura  Denmark
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It's a great trick that I have seen implemented before, to build a chimp amp into a class A amp chassis as well. Then you will be able to have background music that dosn't require 300W+

Magura
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Old 8th May 2007, 04:48 AM   #542
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That's a cool idea, Magura. BTW how's the amp coming?

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Old 8th May 2007, 10:06 AM   #543
h_a is offline h_a  Europe
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@Veteran

sorry to hijack this thread, but you don't seem to reply to emails and neither respond to the Zen#9 group buy thread, where people would be very much interested in another group buy!

Is any planned? If not, could you please say so? Otherwise people are just waiting and hoping...it's here:

PC Boards for v9?

In case you're not doing another run, could I maybe have the gerber files? It's such a nice pcb artwork!

Thanks a lot!

Cheers, Hannes
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Old 8th May 2007, 11:54 AM   #544
Magura is offline Magura  Denmark
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Quote:
Originally posted by carpenter
That's a cool idea, Magura. BTW how's the amp coming?


I'm not too happy to admit this....

I got around to testing the inductor theory IRL last week, it seems that I get about 50% extra inductivity by winding parallel air cores the bifilar way.

As for the amps...ouch, not good....there is a woman that have been taking up an awful big part of my spare time latly. I have made the PCB's but I havn't gotten around to testing them. Things are though not at a complete halt, but just moving real slow

Magura
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Old 8th May 2007, 03:06 PM   #545
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Some things move slow, but other things move real fast? Isn't love grand?!

Tell me more about the parallel, bifilar cores. You can go to my ZV7-T thread if you don't want to be accused of hijacking.

John
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Old 8th May 2007, 04:10 PM   #546
jleaman is offline jleaman  Belgium
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I hope this is not a stupid question, but does the F4 have to have 3 IRFP9240's and 3 IRFP240's ?

Can it be all the same of one or can they all be the same ?
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Old 8th May 2007, 04:24 PM   #547
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You can still delete that question and I think it's better if you do
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Old 8th May 2007, 04:48 PM   #548
jleaman is offline jleaman  Belgium
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Quote:
Originally posted by Peter Daniel
You can still delete that question and I think it's better if you do
Or you can answer it
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Old 8th May 2007, 05:02 PM   #549
massimo is offline massimo  Italy
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Quote:
Originally posted by jleaman
Can it be all the same of one or can they all be the same ?
NO, they cannot.

Think about the P.S.: it's dual, it has a + and - rail. Thus you need N channel and P channel devices. It's mandatory for a push-pull circuit!
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Old 8th May 2007, 05:03 PM   #550
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Quote:
Originally posted by twitchie
I got my F4 (original circuit) wired up last night and just as with CVILLER's first attempt, my heatsinks are cold. Please forgive the newbie questions, but can anyone please let me know some points to measure/check?

I was able to adjust DC offset properly, and measured 6.97V across D1 and D2 (zeners). I used all the exact values from the original PDF, except for 2N4736 zeners, where I used 1N4736 (someone said the 2N was a typo and should actually be a 1N).

I also have to admit I got lazy/anxious to get this powered up, so I have 1 channel with a dead 2SJ74 after running +- 26V through that channel (when toshiba says 25V max, they mean 25V max). Currently, I'm holding the voltage down to 22V with a small variac in front of the PSU (400VA capacity variac).

Thanks,

Stephen
Update: Actually, it turns out the problem wasn't with running 26V through the amp - the JFETS are fine (so far) with this voltage, it was a incomplete etch in the source resistor and output device that caused one of the source resistors to overheat (it turned red and discoloured). With both amp boards connected, I measured the PSU output at around 23V on both + and - sides.
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