RI fender reverb unit >> eyelet board re-wire

[jbennett]

Kazoo. I'm really happy with the conversion. The reissue was great but it got very tinny and harsh in a bad way with the tone above 4. All the controls are now more usuable and subtle.

[Kazooman]

Did you just swap tanks between the two units or did you allow one unit to drive the tank and recovery circuit in the other unit? You would have to drive both units in parallel and select the output to feed the amp. That would narrow it down as to whether the mojo is on the drive side or the recovery side.

I never tried driving the pan with one unit and feeding that signal in to the recovery side of the other. That would be an interesting experiment. You are correct that I would need to drive both units so that there would be dry signal to blend with the signal from the tank. Perhaps I should run both outputs into separate amps and play in stereo

[loudthud]

Did you just swap tanks between the two units or did you allow one unit to drive the tank and recovery circuit in the other unit? You would have to drive both units in parallel and select the output to feed the amp. That would narrow it down as to whether the mojo is on the drive side or the recovery side.

[Kazooman]

Wow!! That looks great!

I am really interested to hear how you like the results of your reverb. My guess is that you are very happy with the sound from your build. I have an original Fender reverb from the '60s and I recently built as close a clone as possible. They sound different. I can cross the leads to the reverb pans and that does not change the difference in the sound. Swapping tubes has no effect. There is still a difference in the sound of the original and the clone played through the same amp (1961 Fender Bandmaster - blonde on oxblood cloth with 12" speaker and tone-ring). I have grown up with the sound of the original for 40+ years and that certainly introduces a major league bias in my listening.

I would love to be able to create the original sound to share with everyone, but there is some sort of "mojo" about the old parts.

For what it's worth (probably not a lot!!!) my 40+ year old gear sounds the same to me today as it did way back in the good old days when I was a budding rock and roll star. The "exact" clone does not have the same sound.

Also for what it's worth, I am not chasing some elusive sound from a legendary player on a specific track. I am making an A versus B comparison and with NO changes in the components in the circuit there is a major difference in the sound.

[jbennett]

So. I finished my project.



I ended up replacing the aerovox caps with some Mallorys from watts tube audio. But I re-wrapped them in a retro design I cooked up since new mallorys look so boring.



Here are all the photos of my rebuild process. Thanks for looking and for your help along the way.

Only one issue left to deal with. The Dwell knob seems to be faulty, or fried. When I turn the dwell to zero I get a sustained BUZZ. Otherwise it sounds really great without any unwanted noise.

[jbennett]

Okay... well I walked to home depot on my lunch break. Bought a pair of snips and a sheet of zinc. measured, clipped, and folded it (using my desk drawer at the office) in 10 minutes.





Cost less than any available "doghouse" and I get to keep the snips!

[jbennett]

Well, they were "NOS" and should be okay. I'll test them out with a power supply soon and see where they fall. I have new .1 caps to drop in if they are no good.

[Kazooman]

Looks good thus far. Those two Aerovox caps do appear a bit suspect. Any reason not to replace them?

[jbennett]

Some new photos.

Rectifier:






Main board:






Electrolytics:

[jbennett]

I'm using the MOD replacement for the 4AB3C1B pan.

[Gtr_tech]

Reverb pans come in all sorts of varieties....some with grounded inputs and/or outputs (to the pan). It can make a difference depending on your drive/return circuitry.

[jbennett]

[jbennett]

Got started.

Also, went to Leeds Radio on my lunch break. WOW! Anyone in NYC must check that place out sometime.
What a treasure. Picked up some straggling components.

[jbennett]

Thanks for the links. Hopefully I won't encounter the hum, but if I do it seems like there are a few good methods to try and quiet things.

I don't want to have any occasional shocks... not a fan of that.

[loudthud]

Here's a link to the thread I was refering to: http://music-electronics-forum.com/t12432/

Probably others that you should read. I searched "Reverb ground loop" and got 84 hits. Not all were about reverb units.

A two wire line cord will give you problems too. Like the occasional shock when touching the chassis. Here's a link to the thread on the way to break the ground loop: http://music-electronics-forum.com/t28243/