Good morning!
I'm trying to tame a very obnoxious issue with an old Gibson Falcon amp. The arrangement of the reverb circuit is inherently noisy; with the effect turned on we are applying 100% of the recovery circuit into the preamp. Can anyone shed any light on the idea of moving the reverb volume control from the input of the reverb system to the output, just before the 680K grid stopper of the preamp? Looks more like a deluxe reverb that way.
Thanks!
I'm trying to tame a very obnoxious issue with an old Gibson Falcon amp. The arrangement of the reverb circuit is inherently noisy; with the effect turned on we are applying 100% of the recovery circuit into the preamp. Can anyone shed any light on the idea of moving the reverb volume control from the input of the reverb system to the output, just before the 680K grid stopper of the preamp? Looks more like a deluxe reverb that way.
Thanks!
Shed any light? What do you want to know. Obviously it works, the other brands do it that way. This is just a guitar amp, not some precision circuit. You want to replace the drive side control with a resistor? Go ahead. Want to replace the return side resistor with a control? Go ahead.
It returns to the power amp voltage-gain stage, at higher signal level (about 0.9V) than "preamp".
What is "different" is putting the reverb path gain control at the path input instead of the path output. Compare with Fender. There are some advantages to how Gibson did it, though it is the road less traveled.
Gross hiss would be V2 or resistors around V2.
What is "different" is putting the reverb path gain control at the path input instead of the path output. Compare with Fender. There are some advantages to how Gibson did it, though it is the road less traveled.
Gross hiss would be V2 or resistors around V2.
DUDE! what exactly did you do for this modification????? I have been trying to get rid of the hiss for months!!! (i.e the forum I started about a year ago lol https://www.diyaudio.com/community/threads/gibson-ga19-rtv-falcon-reverb-modification.363441/)
I am running the same schematic that you have attached above.
What changes did you make? My god, if this solves my problem I will be sooooo freakin happy!
My initial thoughts are taking the output terminal of R2 and connecting it between R41 and C23 as per the schematic that you shared since that is the one I am working on. That's how I read it, but I may be incorrect as I am a novice in training lol.
Thanks in advance!
Last edited:
https://www.thegearpage.net/board/i...falcon-ga-19-rvt.2196760/page-6#post-33726199
Sorry that was my original forum. I copied and pasted yours by accident
Sorry that was my original forum. I copied and pasted yours by accident
I’m interested in the solution to this noise issue as well. Was it ever shared? I’m dealing with a noisy reverb circuit in the same amp too.
I would take the signal off of the volume control wiper and go to the grid on pin 8 (grid). Then I would use a mosfet as a source follower off of the V2 recovery, then try the vibro Champ tremolo with the addition of the 47R resistor.
https://fenderguru.com/wp-content/uploads/2015/04/vibrochamp-schematic.jpg
I have not done this with tubes but with some naughty SS devices. I never spent enough time to dial it in but just proved the concept.
https://fenderguru.com/wp-content/uploads/2015/04/vibrochamp-schematic.jpg
I have not done this with tubes but with some naughty SS devices. I never spent enough time to dial it in but just proved the concept.
Sorry for the CRUDE image.
Not at home, all I have here is CRUMMY POS Windows Paint (ugh!)
As mentioned above, but "an image is worth 1000 words", you remove the Reverb pot from the drive side and reconnect it on the "return" side.
You´ll need to make a little wiring, no big deal.
Not at home, all I have here is CRUMMY POS Windows Paint (ugh!)
As mentioned above, but "an image is worth 1000 words", you remove the Reverb pot from the drive side and reconnect it on the "return" side.
You´ll need to make a little wiring, no big deal.