From tremolu–(at)–ol.com Sat Jul 27 15:11:07 CDT 1996
Article: 12530 of rec.audio.tubes
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From: tremolu–(at)–ol.com (Tremolux)
Newsgroups: rec.audio.tubes
Subject: Re: Fender RI reverb tweaks?
Date: 27 Jul 1996 14:07:27 -0400
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>>>One thing that has me puzzled is that other than the 6V6, isn’t
the reissue the identical circuit as the original ? If so, why
would you want to change component values and why would that
make the reverb sound more like an original ?

>>>(I admit that having had an original and a reissue, the reissue
does not sound nearly as good)

Simple Jack. The originals have close to 30 years use on them, so the
components have aged and their values shifted a bit. You seem to be an
avid tweaker and modifier, this seems like it would be right up your
alley. I spoke in depth with Terry Buddingh who wrote the article in GP
mag expalining his proposed tweak. He proposes changing the 250 pf
coupling cap to a 390 pf. This does improve the sound, since it lets more
reverb signal through, particularly at lower frequencies.

I have a reissue, and I have taken the process a bit further than Terry.
Instead of 390 pf, I used 470 pf, which gives an even bigger sound.
Additionally, I loaded down the reverb pan return by soldering a 47k
resistor directly across the socket where the return signal plugs in.
This further improved fidelity and “bigness” of sound. Lastly, I
incorporated a bit of Ampeg engineering. Refer to the schematic for an
old Reverberocket. Notice Ampeg put a low pass filter consisting of a 10k
resistor and a cap between the recovery tube’s grid and cathode. Put that
in the Fender reissue and it gets rid of some of the brittleness the
reissues have. End result is a Fender reissue reverb that sounds
significantly better than stock, IMO.

Regards.