Washed Out Reverb Issue

General discussion area for tube amps.

Moderators: pompeiisneaks, Colossal

User avatar
dorrisant
Posts: 2613
Joined: Tue Sep 21, 2010 1:27 pm
Location: Somewhere between a river and a cornfield
Contact:

Re: Washed Out Reverb Issue

Post by dorrisant »

Yes sir... did that twice just to confirm...
"Education is what you're left with after you have forgotten what you have learned" - Enzo
tubeswell
Posts: 2337
Joined: Thu Mar 27, 2008 6:42 am
Location: Wellington. NZ

Re: Washed Out Reverb Issue

Post by tubeswell »

Have you done a VAC test on the reverb transformer? - could have a partially shorted turn. Unhook all the RT leads. Then hook the secondary leads (one end each) up to each side of the heater winding in your amp. Switch the PT on and measure the VAC across the primary side of the RT. You should get quite a large VAC on the primary C/f the ~6.3V on the secondary. Measure both the secondary winding VAC and the primary winding VAC simultaneously to get an accurate Pr:Sec VAC ratio. Make sure none of the leads touch or short to anything else when you do this test. Use insulated gator clips. Fender type RT Impedance Ratios vary from manufacturers to manufacturers, and they can be designed to deliver anything between about 18k to 27k (with an 8R pan input transducer). So that's a Pr:Sec VAC ratio anywhere between 47:1 and 58:1 (which could be anywhere between 298VAC to 365VAC across the primary with a 6.3VAC source across the secondary, which is why you don't want the leads touching anything else).
He who dies with the most tubes... wins
User avatar
dorrisant
Posts: 2613
Joined: Tue Sep 21, 2010 1:27 pm
Location: Somewhere between a river and a cornfield
Contact:

Re: Washed Out Reverb Issue

Post by dorrisant »

Thanks Tubeswell, I tried a brand new reverb TX... Same thing.
"Education is what you're left with after you have forgotten what you have learned" - Enzo
Stevem
Posts: 4551
Joined: Fri Jan 24, 2014 3:01 pm
Location: 1/3rd the way out one of the arms of the Milkyway.

Re: Washed Out Reverb Issue

Post by Stevem »

You need to pin down which side of the thing has the issue, the drive side , or the recovery!


Get a RCA to 1/4" adapter and feed the output of the pan drive back into the normal channel of the amp , or into another amp , does it sound good?
If so take the output of the pan and do the same thing.

I am starting to think you have a conductive oil board, but these 2 test will pin that down I think!
When I die, I want to go like my Grandfather did, peacefully in his sleep.
Not screaming like the passengers in his car!😊

Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
User avatar
dorrisant
Posts: 2613
Joined: Tue Sep 21, 2010 1:27 pm
Location: Somewhere between a river and a cornfield
Contact:

Re: Washed Out Reverb Issue

Post by dorrisant »

I just made the board a while back...

Customer demoed the amp when he picked it up... Was actually very happy with the reverb as it was... Maybe I'm too picky. Happy customer wins out.
"Education is what you're left with after you have forgotten what you have learned" - Enzo
Post Reply