Starting another PRS Sonzera 20 post as the symptoms are different than the title of the last thread that I started.
If amp has low distorted volume and even injecting a signal directly into the return jack isn't good.
The two mosfets Q1 and Q2 are the culprits. Even just plain weird issues like the reverb pot on channel 2 acts like a second volume pot for that channel can be these two mosfets. Both #IRF820. I used 844-IRF820APBF from Mouser. They're very inexpensive. Under $2.00ea.
Since there is no full schematic for this little bugger nad it was pretty difficult to draw just this section to determine that these two mosfets actually pass signal.
I originally thought they were some kind of voltage regulators as they both have very high voltages on their Drains and voltages around 6 - 10V on the Source & Gate.
Here are the nominal normal voltages these guys should have (all dc of course):
Q1: G-12.66v D:290.00V S:9.66v
Q2: G:2.8v D:176.00v S:6.1v
They are situated around the send return jacks in the schematic so that's probably why I couldn't inject a signal into the return jack and bypass them.
Just a few tidbits for these PRS amps. glen
If amp has low distorted volume and even injecting a signal directly into the return jack isn't good.
The two mosfets Q1 and Q2 are the culprits. Even just plain weird issues like the reverb pot on channel 2 acts like a second volume pot for that channel can be these two mosfets. Both #IRF820. I used 844-IRF820APBF from Mouser. They're very inexpensive. Under $2.00ea.
Since there is no full schematic for this little bugger nad it was pretty difficult to draw just this section to determine that these two mosfets actually pass signal.
I originally thought they were some kind of voltage regulators as they both have very high voltages on their Drains and voltages around 6 - 10V on the Source & Gate.
Here are the nominal normal voltages these guys should have (all dc of course):
Q1: G-12.66v D:290.00V S:9.66v
Q2: G:2.8v D:176.00v S:6.1v
They are situated around the send return jacks in the schematic so that's probably why I couldn't inject a signal into the return jack and bypass them.
Just a few tidbits for these PRS amps. glen
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