Hey Guys!

I am looking for some advice on a Fender Princeton Reverb that I am building.

I am building it on a Elk Stageman 30 which is a FPR knockoff from Japan made in the 60s as far as I know.

Okay two questions:
1. The big cans, most Fender amps has 4 22 uF 500V tin can caps in the power supply. It seems in the schematic from Fender that 450V caps was specified in this position and as I understand these caps are able to take a bit more since they are in parralel with the 1 ohm balancing resistor in between.


Source:
http://www.amparchives.com/Amp%20Archives/Fender/Schematics/Fender%20Princeton%20Reverb%20Schematic.gif


So I have found 22uF 450V caps at Communica:
http://www.communica.co.za/Catalog/Details/P1425839557

So my question is, can I use 4 of these capacitors replacing the 4 500V cans? And, will it affect anything? I know that the Power Amp section is very sensitive to changes in filter caps. I have done a search and a guy said that he used similar caps and the bottom end improved, I don't know.

And also is there response wise a difference between the Aluminium big cans and these small electrolytics or is it all about the Big cans looking cool and original?


2.
The caps that came with the Stageman:

I am building a new turret board replacing all the resistors and oil filled capacitors in the circuit with new carbon film (mostly) resistors and new electrolytics since those oil filled ones are failing as I read. I am wondering about the poly caps in there they are brown square ones and look quite decent, I do not want to replace them If they are of good quality and sound good. Does anybody have some experience on the stock Elk poly caps?

Here is an image of the guts I got from the web. You can see the rectangular brown caps I am referring to in the pic.



Thanks guys!
It is really great to have a forum in South Africa where we can get some great advice from knowledgeable people.

JGP wrote: Once you have the amp working it will be time to replace the "Chinese" speakers if it is going to sound anything like the original

Yeah Ill have to rob a bank for the alnico blues, might settle for some greenbacks. ?

lapdawg wrote:

psyx wrote: Hey man!

The tubes look a little rough too... I think that would also be a good start to change them.

Be wary of replacing old valves. New valves generally do not compare to the old ones. Replace them only if you are sure they need to be replaced.

Thanx Lapdawg you are right, I will first see if they work hope they do.

I found the right caps online at justradios.com. I think I will attempt to ship it here untracked since it is so expensive for the proper insured/tracked shipping.

They have the right 25mm diameter dual caps which is nice since it will fit nicely in the clamps.

If someone wants something from justradios.com drop me a line.

Thank you very much for the reply Psyx.

I am based in Pretoria and love playing guitar, very recently I have taken an interest in recording so I have yet to complete my first track. I like anything bluesy. I wil have to update my profile soon :-[.

Yes those Sovteks are veterans, I will be replacing them soon.

I actually opened the bottom now, the one end of the 16uF/16uF can shoots right through and has been replaced with a single 32uF cap. The other side is still in tact but I suspect that it is toast. It explains the overheating choke since it shorts can short.

I am going to try and source that cap and see what happens. I see mr valve has some caps on their website.

Hi Everyone,

This is my first post on GF (quite a long one). I am looking for some help with regards to an amp I bought.

I have bought a 60`s AC30 off gumtree and is totally thrilled. The amp is broken however. It is the AC30/6 top boost, it looks like it has most of its original components. Woden trannies and the tolex looks original but in bad shape (doesn't bother me in the least). The front grill was swapped for a black cloth, and the original speakers was replaced with Chinese speakers, the handles is also removed. Electronic wise the signal caps look original except for the vib/trem that was removed and a solid state rectifier was installed.

A bit of background I have studied Electronic engineering but have no solid knowledge of valve amplifiers whatsoever.

I have switched it on and there is a faint hiss, as I understand this indicates that the output transformer is fine, or am O incorect?

When I switched the amp on after I while I smelled something hot. It is the choke that is so hot. Is it possible that the choke should run hot, or can it be that something down the line is shorting? Perhaps the 16uF/16uF cap next to it?

Also in your opinion should I replace the electrolytics now or at a later stage?

I read that the SS rectifier is a bad thing, should I swap it back to original?

Sorry for the long post, any advice or knowledge on the matter will be appreciated. I wanted to test it with you before I warm up my soldering iron.


The Amp:


Internals:


Transformers:


Suspect cap: