How odd, my B1 has died, both channels at the same time.
To recollect, this build uses the PSU (SALAS Shunt Reg) from the DCB1 but uses a clone of the original B1 for the buffer.
It was working flawlessly and had been for several years.
I've just completed a Pearl 2 project which works perfectly directly driving my Aleph 4 - so no problems there.
I decided to add the B1 as a volume control and it's died.
I've tried the original CD source and the B1 is definitely the culprit.
I just can't believe that it's coincidence that the B1 has been killed by the Pearl 2.
This post isn't about "What is wrong", it's more about "Why"
To recollect, this build uses the PSU (SALAS Shunt Reg) from the DCB1 but uses a clone of the original B1 for the buffer.
It was working flawlessly and had been for several years.
I've just completed a Pearl 2 project which works perfectly directly driving my Aleph 4 - so no problems there.
I decided to add the B1 as a volume control and it's died.
I've tried the original CD source and the B1 is definitely the culprit.
I just can't believe that it's coincidence that the B1 has been killed by the Pearl 2.
This post isn't about "What is wrong", it's more about "Why"
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Just for reference, a mosfet will be instantly destroyed of you apply 28 V gate voltage. For JFET's I have no personal experience to destroy.
The reason why I know about mosfets is that datasheets only say max ± 20 V but when do I break the fet and what kind of failures do I get? More than 26 V = no mercy.
The reason why I know about mosfets is that datasheets only say max ± 20 V but when do I break the fet and what kind of failures do I get? More than 26 V = no mercy.
Yeah, and at least one member has encountered a large turn-on thump:
http://www.diyaudio.com/forums/pass-labs/156397-pearl-two-130.html#post2828745
Perhaps the OP can try measuring and see if that might be an issue.
Dennis
It's quite possible to blow the Gates with a spike.
Could the Pearl 2 generate such spikes ?
Jfets are a little more resistant than Mosfets, but you can still take them
out. All the cases I have seen have to do with Tube sources, usually
the turn on/off transient of somebody's tube preamp.
It can only have been a spike on the inputs, as it is both channels it must be the Pearl 2.
I can't see how the lower two JFETs could possibly be destroyed as their gates are tied to ground.
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Pass DIY Addict
Joined 2000
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Hard to believe Pearl having that much swing. Are you using Gate resistors
on the Jfets, or are they seeing the input directly?
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