Weber ReVibe Reverb Unit

by Laird Bedore · 2013/03/03

The idea behind the Revibe is brilliant: Take a standalone reverb unit and add the two-phase “harmonic vibrato” found in the 6G12 Concert.

I first built this Revibe in 2010. I bought the fiberboard and power transformer from Weber, and used my own components for everything else. I modified the layout to fit a narrower chassis by relocating the power filtration section to a ‘doghouse’, but all the fundamental orientations remained the same as stock.

This is a really freakin’ cool effect to have, especially the two-phase tremolo! But there are a few adjustments that can really improve this project:

I made some layout improvements. The position of the input and output jacks was reversed… I don’t know why they were ever recommended to be criss-crossed with unnecessary long connecting wires – putting the input at the edge of the chassis and the output directly next to its output connections is common sense. I also used Cliff jacks to guarantee chassis isolation and allow the sensitive connections to ground when the jacks are unplugged.
I added an isolation network between the circuit and chassis/safety ground, like in Jeff Gehring’s Revibe V2 schematic. I never used the “brass plate” grounding scheme from the Weber layout – merging chassis and circuit grounds is a really bad idea when it comes to anything that will be subject to high gain (like a pre-preamp Revibe!) In order to complete the separation of circuit ground from the chassis I moved the reverb return’s 220K resistor (R17) to the fiberboard, next to the 1.5K/250uf cathode connection on V1A.
The stock ReVibe gave me less than unity gain. To resolve I added a bypass capacitor to the cathode of V1B, parallel to R26. Another way to accomlish this is to change the values of R25 and R51 – making them both 47k or 51k would also increase the gain.
Because I am using a “hot” 6V6 to drive the reverb tank, i was getting crashing during heavy input. As a cheap and dirty solution I lifted the cathode bypass cap, problem solved. Trialing less aggressive tubes or switching to a 6K6 would be a better solution. If you’re the type that uses a lot of boosting pedals and runs into this problem often you could try changing the balues of R7 and R8 to reduce the input gain.
The tremolo stability needed some improvement. I removed C28 because it doesn’t appear to be necessary and it reduced the tremolo intensity. I moved the tremolo footswitch connection to the first lug of the Intensity pot. This greatly improved stability and switch-in delay when a footswitch is used.
I moved the reverb footswitch connection to the first lug of the tone pot. This plus the grounding improvements substantially reduces the amount of noise and reverb attenuation introduced when using a footswitch.

With all of the “experiences” I have had with this Revibe unit, I would not build it again. As I learned with my junkpile 6T9 “Revibe” project, this effect can be built much simpler, smaller and quieter with less effort and less cost. I hope to come up with my own original “Revibe” design soon leveraging a 12FQ8 for asymmetric tremolo, a pentode/triode combo for reverb and at most one more tube.

Audio Clips

ReVibe Sample 1: