I'm pleased to report that Extreme_Boky's suggestion led to resolution of the gain issue. I had in fact placed the wrong resistors in R1, R3 and R4. I guess I didn't pay sufficient attention to the designations "221K" vs "22K1". In any event, all is sorted now and the Aleph J is performing beautifully.
I'd like to express my gratitude to Extreme_Boky, Dennis Hui and Zen Mod for taking the time to respond to my post, and sharing your understanding of electronics and the Aleph J circuitry. While I'm at it, thanks also to 6L6 and flohmann for the excellent build guides. And of course to Nelson Pass for making these designs available to the DIY community.
Nice!
My recently completed 300B monoblock project sure ate up lots of space on the rack.
Sorry for the OT, but what 300b monoblocks did you build?
Put the 7's together and the 9's in the other channel, will work great.
Idss (what they are matched for) has essentially nothing to do with gain or volume. And anyway, the front end has a constant current source, the matching is required only so one side of the pair doesn't hog the current.
P.S.
<--- The white dog that's my avatar was named Zoe.
Idss (what they are matched for) has essentially nothing to do with gain or volume. And anyway, the front end has a constant current source, the matching is required only so one side of the pair doesn't hog the current.
P.S.
<--- The white dog that's my avatar was named Zoe.
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i built Aleph J few weeks back
both channel worked, biased well, nice stable zero on output, except no led light on one channel
later I discovered that instead of 4k7 resistor for led voltage drop, I used 4M7
crazy thing is I took all those 4k7 resistors from the same bag, must have been some mixed up bag
both channel worked, biased well, nice stable zero on output, except no led light on one channel
later I discovered that instead of 4k7 resistor for led voltage drop, I used 4M7
crazy thing is I took all those 4k7 resistors from the same bag, must have been some mixed up bag
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... I discovered that instead of 4k7 resistor for led voltage drop, I used 4M7 crazy thing is I took all those 4k7 resistors from the same bag, must have been some mixed up bag
On more than one occasion, I have received 220K resistors in a bag labelled 220R. Since I made this discovery, NOTHING goes into a PCB without being measured first.
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