Rhodes Peterson amp module rebuild kit?

Tech Questions Regarding Fender Rhodes Pianos

Rhodes Peterson amp module rebuild kit?

Postby gmg on Thu Sep 02, 2010 1:30 pm

I am currently installing a "Fender Rhodes Peterson amp module rebuild kit" . I have exchanged all the components exactly as the white paper diagram but the amps have low distorted ouput. I noticed on the white paper diagram that the 3405 transistor is there but i did not recieve a replacement for this in my kits? Should that be replaced in the silicon conversion kit? There was some resistors missing in the kits i recieved so maybe the 3405 replacements were forgotten? I have not changed the 3405 so the original is still in there. If it is not to be replaced why is it shown on the white paper diagram?. I have checked EVERYTHING twice so it is not pre amp, power supply, speakers etc...

Could somebody please confirm if the original 3405 needs to be exchanged for the silicon conversion kit to work.


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Joined: Thu Sep 02, 2010 1:12 pm

Re: Rhodes Peterson amp module rebuild kit?

Postby vintagevibe on Sat Sep 11, 2010 7:19 pm

hi Mike,

No the 3405 is not supposed to be in the kit, it rarely goes bad, we do sell it as an extra if needed. What may be happening is cross over distortion. Try placing a 10K 2 watt resistor over the 820 ohm 2 watt resistors. This may cure the problem. If you do not have these resistors ask us and we can hook you up with them.
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Joined: Sat Sep 11, 2010 6:06 pm

Re: Rhodes Peterson amp module rebuild kit?

Postby crosswick on Sun Jan 02, 2011 11:31 am

I've been having this same problem, with a slight twist: right after adding the 10k resistors in parallel to the 820k ones, the crossover distortion is gone. After a while though, the crunchyness comes back... any idea what might be causing this?

At first I thought it was due to the resistors from the kit not being 2W, but after fitting 2W 10k resistors the problem is still the same. I have one pair of 10k 2W resistors left.

Thanks for your help!
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Joined: Wed Nov 24, 2010 10:08 am

Re: Rhodes Peterson amp module rebuild kit?

Postby fizze on Wed Jul 06, 2011 3:14 pm

I've got a Mk1 suitcase 73 with the 100W Peterson power amp. Now one of the transistors has gone bad.
In anticipation, I've got a peterson amp rebuild kit, with the transistors only.
The bag contains a few resistors, and the two transistors. I'm pretty sure the transistor is the only thing thats bad. So far it's just distorting the signal, and the B-E on-voltage has risen to 0.8V.

According to the text, only one pair of resistors needs to be changed. The schematic isn't exactly helpful there.
Which one is it? I assume that the 2.7 Ohm resistors have to be swapped out with 12 Ohm models?
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Joined: Wed Jul 06, 2011 1:27 pm

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