Notes on Useful Modifications to a Fender RI (Re-Issue) Standalone Reverb
*Note: If you are not trained in basic electronics, please do not attempt these changes on your own. Most technicians will be glad to help you.
Reduce Hiss and Possible Microphonics (Noise) with a Replacement V1 Tube:
Reduce noise by using a 12AT7WA tube. The 12AT7WA is a low noise tube with extra mica wafers to reduce microphonics. Since one tube may cost $15 or more, I suggest ordering a specific low noise type, not just a name brand. The stock Groove Tube 12AT7 is in the first position (1st tube on the right when looking at the back of the reverb cabinet). See a good description here at 12AT7 Description at VacuumTubes.com. Both these tubes are plug-in replacements with 9 pins and only one way to insert into the socket. Obviously, there are other low noise 12AT7 type tubes available.
Noise Reduction when the RI Foot switch is connected:
The metal footswitch pedal that came with my Fender RI Reverb was not electrically grounded to the Reverb chassis. Fender footswitches from the sixties have a soldered ground connection to the inside of the metal body via the shielded cable side of the SPST stomp switch. On both switches, when the switch is OFF, the HOT side of the cable connects directly to the Ground of the shielded cable and added noise will not be an issue. Without this ground connection providing body shielding, when the RI Reverb is ON, the SPST switch connection is ‘open’ and the HOT side of the cable acts like an antenna for noise and hum.
To Ground the Foot switch body:
Rather than grinding a bare spot and soldering to the inside of the foot switch (FS) body, I unscrewed the stomp switch from the FS. Then, I took a piece of bare wire and wrapped it once around the stem of the switch on top of the second nut. I brought the wire to the shielded cable side of the SPST stomp switch and soldered it. I re-attached the stomp switch back into the footswitch body. Obviously, several inches of wire is used and completely stripped of insulation at both ends. You would definitely NOT want to solder or wrap the wire to the HOT side of the switch (the insulated center wire connection), since this would turn the Reverb OFF all the time (whenever the footswitch is in use).
Notice that I also placed a sheet of aluminum foil in the bottom of the plastic cover, along with some paper to isolate the foil from the switch connections.
Shielding the Reverb Springs:
Dave Wronski posted a shielding tip on Surf Guitar 101 (search Nov 2003) about applying shielding material and grounding it. This reduces the noise picked up by the reverb tank springs from the electronic noise generators (like fluorescent lights).
Dave is right and this is probably a good thing to do on all Fender Standalone Reverbs. However, I had to use a specific approach with my Fender RI.
The RI has a chassis Ground, but the inputs and reverb tank are isolated several Ohms above Chassis Ground. This type of design reduces ground loops. In any case, you cannot add a grounded shield and allow this connection to touch the actual reverb tank (via the suspension springs) or you are making an unintentional circuit change.
I took off the front panel, applied aluminum foil-backed card stock paper to the inner side, carefully cut out holes for the four corner spring studs, and connected the foil to Chassis Ground. Then, I checked and double-checked with a multi-meter that the reverb tank and the shield had several ohms of resistance between them (both before I re-assembled and after). The aluminum side of the paper is face down on the front panel. It was tricky to get this grounded shield setup isolated from the tank, but I used electrical tape and neat work to get the job done. This mod seemed to reduce overall noise even before turning the reverb unit to different certain angles to find the quietest spot (just like an AM radio might pick up a station better/worse if you turn it).
Two different reverb sounds:
When I had the reverb tank off to glue the shielding paper on the backside of the front panel, I saw the foam pad which damps the springs when engaging the reverb lock. This reminded me of a comment that Gerald Weber made in one of his books. He explained how to obtain two different sounds - the reverb tank flat against the front panel or floating via the four little springs attached to the studs. Of course, the foam pad cannot be used if the tank is against the panel. The foam pad protects the springs (holds them immobile) with the lock engaged.
Wanting to try out these sounds, I removed the pad. Previously, I had applied a tiny drop of epoxy glue to each spring end, including the connections in the middle of the two springs. After re-assembly, I now have two distinct reverb sounds: One with the lock engaged (similar to having the tank screwed to the front panel) and one without the lock engaged. I like it, but you have to decide if you want to risk the damage to the reverb springs.
Update on ‘Two different reverb sounds’:
Using the “locked down” position, I initially experienced some feedback problems, usually at higher volumes. It does work well at home/studio settings. (See below)
Gerald Weber Mods
One of the tweaks Gerald recommends is adjusting/treating the small transformers at either end of the reverb tank. I did this, too. It seemed to help with the feedback problems mentioned above.
My settings for Dwell and Mix decreased to about ‘3’ with Tone remaining close to full up (7-10). Basically, my RI now has a wider range of useful reverb settings.