Vintage EHX Small Clone MINI-CHORUS SAD1024 Help please

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Fuzzlefty77
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Post by Fuzzlefty77 »

Scruffie wrote:
29 Jul 2020, 14:28
Well seeing as the 2N5087 collector should be grounded, I'd say there's still a mistake :)
:oops: :lol: Jeez, thats so glaringly obvious. Doh!

Fuzzlefty77
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Post by Fuzzlefty77 »

WORKING! :D

After fixing the glaring Collector to ground mistake on the 2N5087. Still nowt.......
Then here comes the really dumb mistake (no the above wasn't the worst), I'd soldered the 12k resistor in the wrong place :oops:
I'd skipped across a position so no wonder it didn't do much:
Doh.jpg
But still nothing..........built myself an audio probe and started poking around. Everything sounded identical except the 2N4340 metal can JFET made some horrible farty noises then dumb thing number 3 became apparent.
I use a handy little tester board (from Fuzzdog FX) for testing my boards, BUT thats a Full Bypass board and obviously the Small Clone wasn't designed for that. Removed the 2n4340 JFET and jumped the Drain and Source making it always on and bingo.
IMG_20200730_143200685.jpg

She's chorusing like a good 'un.

My hopefully final questions:
I guess when I box it all back up the 2N4340 needs to be back in there with the original switching?
If (big if) the 2N430 is bad would that have effected the SAD1024 giving low output voltages?

Scruffie
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Post by Scruffie »

Fuzzlefty77 wrote:
30 Jul 2020, 13:59
My hopefully final questions:
I guess when I box it all back up the 2N4340 needs to be back in there with the original switching?
If (big if) the 2N430 is bad would that have effected the SAD1024 giving low output voltages?
Scruffie wrote:
10 Jul 2020, 10:07
lift one leg of the 10k coming from the same place to make sure nothing further down is dragging it down and if that doesn't change, it's dead.
Glad you got it working :thumbsup

As you can see, as long as you followed my advice there, you should have already ruled that out as a possibility as I did consider it. That being the case though, it's still a possibility that half the chip still works which happens in which case it's not totally useless (you could build a mistress with it) so don't bin it.

And yes, you will want the 2N4302 if you're sticking with the original switching.

Fuzzlefty77
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Post by Fuzzlefty77 »

Yeah this one has taught me a few hard lessons.

Thanks for all your help Scruffie!

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