Author Topic: Fender Rhodes Peterson 80W Suitcase Preamp Restoration (Image Heavy)  (Read 1372 times)

Offline Tim Hodges

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I figured you might be interested in seeing the progress I made on restoring a preamp I purchased as broken a long time ago.

Here it was before any work was done on it. It was missing it's 100k volume pot, the RCA cable had been cut off and the case was corroded.



Inside was just as bad, someone had attempted to repair it with new caps and had used pretty cheap ones, some caps were missing and one was broken and had it's leg re-soldered to fix it.





There was lots of trace missing, pads had been lifted off and there were cold solder joints all over the place:





I began by fixing the missing trace and re-flowing it with new solder:





The original diodes were replaced with modern versions:



All the cheap radial caps were replaced with high quality Nichicon Japanese axial caps, I used their MUSE series for the bi-polar caps (10uf and 1uf).



A lot of the transistors needed replacing so I matched a load and used them in the board (the vibrato ones were fine.)

Christian from Electric Keys provided me with a replacement 100k volume pot and the later concentric knobs.





I took the case to Avon Electro Plating here in the South West and they cleaned up the case and gave it a new zinc with yellow passivate finish just like the original, only cost £17 too.





Replaced the black preamp cable with a Van Damme XKE high quality cable in grey just to finish it off.

Only thing I need to do now is to add the effects loop see here and also find 3 3/8" C Clips in the yellow zinc finish like the original. Unfortunately I can't seem to get them over in the UK. Is anyone able to help with those?

Bristol Electric Piano
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Offline sookwinder

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Re: Fender Rhodes Peterson 80W Suitcase Preamp Restoration (Image Heavy)
« Reply #1 on: March 28, 2017, 07:22:26 PM »
Great to see this.
Always love seeing high quality photos of restoration/build projects.
Have you any idea what would have caused the lifting/failing of the circuit tracks?  I have experienced this in a fender Hotrod deluxe , but that can be put down to the "over heating" of the amp when running it at "11".  I would not have thought there was that much heat generated in a preamp like this.


Another question..  why did you choose Japanese caps  as replacements.... given there is a vast array of USA made caps that many boutique amp builders use.... some are sometimes snake oil ... but there are high quality local (for you guys) caps available that I would have used... Or was it based upon available real-estate space on the board or reputation/performance criteria ?

David
Late 60s Pianet N - Late 70s Pianet T - Ensoniq ESQ1 - Hammond XK2 - Wurli 206A converted to a 200A - 1973 Rhodes Stage 73 - Roland RD150 - Vintage Vibe 64 EP - s**t load of guitars, basses & amps

Offline Tim Hodges

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Re: Fender Rhodes Peterson 80W Suitcase Preamp Restoration (Image Heavy)
« Reply #2 on: March 29, 2017, 03:47:42 AM »
Great to see this.
Always love seeing high quality photos of restoration/build projects.
Have you any idea what would have caused the lifting/failing of the circuit tracks?  I have experienced this in a fender Hotrod deluxe , but that can be put down to the "over heating" of the amp when running it at "11".  I would not have thought there was that much heat generated in a preamp like this.


Thanks David!

I believe it's most likely down to someone applying too much heat whilst de-soldering components, the pads are quite fragile and any heat for a duration will melt the adhesive.


Another question..  why did you choose Japanese caps  as replacements.... given there is a vast array of USA made caps that many boutique amp builders use.... some are sometimes snake oil ... but there are high quality local (for you guys) caps available that I would have used... Or was it based upon available real-estate space on the board or reputation/performance criteria ?

David

Good question, mainly because of reputation. I've used Nichicon before and I've always found them to be excellent quality and also reasonably priced. Also the supplier I use has a lot of their stock so that works in my favour (I'm based in the UK)

I'm definitely not adverse to using US caps, I'm currently re-building a late Wurlitzer 200 amp with Kemet capacitors for the power supply but they're not as easy for me to get.

On a separate note I think some people can go overboard with trying to get expensive capacitors to get that "vintage mojo tone", it's certainly more prevalent in the guitar community. In my opinion a well regulated and voiced Rhodes is much more important for tone then say some of these modern vintage style capacitors. What is important to me is that it is well manufactured, reliable, fits and doesn't detract from the amp. I can only guess but when they produced this amp back in the first few weeks of 1970 they were putting in Mallory capacitors because they were either available or economically feasible but probably not due to the tone.
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Offline sookwinder

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Re: Fender Rhodes Peterson 80W Suitcase Preamp Restoration (Image Heavy)
« Reply #3 on: March 29, 2017, 08:06:44 PM »
Yeah Fender amps have the white Mallory caps from the late 60s and 70s, the blue molded "tone" caps from the early 60s and then the blue blob and brown turd looking caps that replaced them.  I have heard Fender amps with all versions and many sound awesome.

There is certainly a lot of snake oil out there  ;D

I have a new (old) Stage 73 EP winging its way across the Pacific Ocean to me and so I have decided to build/design my own preamp for it. I am currently in the middle of the building process, it is based on the Twin reverb (and Princeton) with variable (adjustable) overdrive capability (full use of valves), and with trem.  When I have completed it I'll put up a thread about it.

David
Late 60s Pianet N - Late 70s Pianet T - Ensoniq ESQ1 - Hammond XK2 - Wurli 206A converted to a 200A - 1973 Rhodes Stage 73 - Roland RD150 - Vintage Vibe 64 EP - s**t load of guitars, basses & amps

Offline pnoboy

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Re: Fender Rhodes Peterson 80W Suitcase Preamp Restoration (Image Heavy)
« Reply #4 on: April 01, 2017, 04:28:05 PM »
Great to see this.
Always love seeing high quality photos of restoration/build projects.
Have you any idea what would have caused the lifting/failing of the circuit tracks?  I have experienced this in a fender Hotrod deluxe , but that can be put down to the "over heating" of the amp when running it at "11".  I would not have thought there was that much heat generated in a preamp like this.


Thanks David!

There's an area of the board in which the overheating is obviously caused by hot components.  There are 2 higher wattage large resistors in that area.  Mounting them up off the board will help.  Also, cheap single-sided PC boards like these are easy to injure when soldering/desoldering.

I believe it's most likely down to someone applying too much heat whilst de-soldering components, the pads are quite fragile and any heat for a duration will melt the adhesive.


Another question..  why did you choose Japanese caps  as replacements.... given there is a vast array of USA made caps that many boutique amp builders use.... some are sometimes snake oil ... but there are high quality local (for you guys) caps available that I would have used... Or was it based upon available real-estate space on the board or reputation/performance criteria ?

David

Good question, mainly because of reputation. I've used Nichicon before and I've always found them to be excellent quality and also reasonably priced. Also the supplier I use has a lot of their stock so that works in my favour (I'm based in the UK)

I'm definitely not adverse to using US caps, I'm currently re-building a late Wurlitzer 200 amp with Kemet capacitors for the power supply but they're not as easy for me to get.

On a separate note I think some people can go overboard with trying to get expensive capacitors to get that "vintage mojo tone", it's certainly more prevalent in the guitar community. In my opinion a well regulated and voiced Rhodes is much more important for tone then say some of these modern vintage style capacitors. What is important to me is that it is well manufactured, reliable, fits and doesn't detract from the amp. I can only guess but when they produced this amp back in the first few weeks of 1970 they were putting in Mallory capacitors because they were either available or economically feasible but probably not due to the tone.

Offline Ben Bove

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Re: Fender Rhodes Peterson 80W Suitcase Preamp Restoration (Image Heavy)
« Reply #5 on: April 03, 2017, 01:39:41 PM »
Great clean up and restoration on that preamp
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