2. amps-preamps
  3. 191157-18279

DC Offset Issue in Don Sachs Preamp

I have a nice Don Sachs preamp.  It's making an incredibly loud popping sound on power off.  Obviously, it's always good to power preamps first then amps and reverse the order for power down. But, I'm still concerned about potential damage to my loudspeakers. 

Would this be do to a leaky coupling cap at the output stage?  Or not enough uF/capacitance to take out all the DC? 

I could email Don but I bought the amp used and I got the sense he may have retired. 

 

Any insight is very welcome. Thank you.

128x128jbhiller
bigkidz
3,381 posts
 

lynn nailed it

 

 

mickeyb
573 posts
 

It’s the rectifier tube. Don will tell you tot always power amp down first than preamp. 
I know because I had the same thing happen on his preamp and he told me it’s completely normal. Pre on first, wait 1 minute, then amp on. Amp off first, then pre. 
This is normal, no worries. 

wsrrsw's avatar
wsrrsw
1,016 posts
 

Yes. Amps on/off first per Don. (For the Raven/Blackbirds) My one word review of the Raven/Blackbirds would be. Get. 

jbhiller's avatar
jbhiller OP
1,403 posts
 

Thank you everyone!  Lynn, you are the man! 
 

don’t tempt me on those new models! 

rajugsw
215 posts
 

Don is awesome people and one day I aspire to have enough saved up to buy his great products (And Lynn Olsen too for that matter).

Here’s proof that Don is "Alive & Kicking". Another awesome fellow Canuck (for a West Coaster anyways) smiley

https://youtu.be/iUk0vc9FyXY?si=KtsNDt2KD1ze8jlS

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