Can cap replacement AO29

[geldo79]

Hi,

I'd like to put new capacitors into my AO29. Especially the caps in the black can and the silver can. Is it possible to get the old caps out of the can and install new ones inside? Did anyone try this? Otherwise i would have to find some place where i can install the new ones and disconnect the can caps.

greetings
Christian

[David Anderson]

This is tube amp 101. Some people do restuff the cans with new discrete modern capacitors and have been doing it for decades. Google "restuff can capacitors." There are plenty of web pages describing how to do it.

You can also install new discrete caps on terminal strips under the chassis. This has the benefit of making them more serviceable in the future.

I'm not going to get into which is the "best" way. It depends on your priorities.

[muckelroy]

CE Distribution manufactures identical replacement cans. Your milage may vary with those, though. I have had some fail in the field, but I think they have improved their quality control issues in recent years. Tonewheel General Hospital includes those cans as part of their recap kit.

[Jyvoipabo]

-FTcap (Germany) and JJ Tesla (Former Czechoslovakia) manufacture quality multisection capacitors. But it will be necessary to enlarge the hole and drill to install the fixing collar. These capacitor are very easy to find in Germany. (https://www.tube-town.net/ttstore/ba...kondensatoren/ and many others)

Now, would like to give you some advice from my own experience.
-I have always been surprised to find that these capacitors age very well. I advise you to measure them.
-Replacing the capacitors does not necessarily solve all the problems. All the other electrical and mechanical components must be cheked. In the end I more often found resistors which had drifted than capacitors (except paper capacitors).
But if the amp has already been overhauled you can forget this advices.

JP

[geldo79]

Thanks for your hints. On that website I do not find the special values needed for my AO29. But i'll see if i find them somewhere else. My organ produces lots of hum. I thought it would make sense to replace the electrolytic filter caps. Maybe i should also replace the 5u4 tube.

[David Anderson]

The 5U4 tube is not going to be a source of hum. You replace them when they wear out.

[Jyvoipabo]

At JJ You can find almost what you need (TC series)
https://www.jjtubes.eu/image/data/tcte.pdf
You can also add axial or even radial caps in the chassis.
We can increase the values a little except filter head (C62 50µF)

The idea of replacing the 5U4 may not be bad. But if you have the possibility checking all the tubes with a tube tester it is still better.

JP

[geldo79]

Thanks. I'll check that out. Unfortunately i don't have tube tester. But...another question concerning hum: can the leslie kit induce hum? I am asking because i installed a 8010 leslie kit. Before, i was using a line out and a leslie clone and did not have problems with hum.

Christian

[Jyvoipabo]

I do not know your installation.
There may be cable or transformer problems or something like that....
But anyway, you have to start by taking care of electrical safety.

The organ and the Leslie must be earthed.
Organ : Installation of an IEC socket seems appropriate. This also allows you to get rid of the wire attached to the organ.
If your organ haven't a fuse you must have to install one.

Leslie : As the Leslie is powered by the organ and ground connected together by amphenol pin 3, there is no need to ground it.
But, you must remove C1 and C2 (between 2,4 and 3) which have no use.

May be the source of your hum?
JP

[geldo79]

The organ is earth grounded. And as i mentioned, the hum is audible since i installed the kit. Think i will just disconnect the kit and see what happens. First I thought it could not be the source if hum because i can hear it through the internal speaker in the 'main' setting of the MEE switch as well.....and i thought the leslie kit is not involved in the signal path then. Although the signal is going into the kit and the is sent to the internal speaker. Maybe hum is induced to the signal there?

The mod in the Leslie concerning c1 and c2.....can you explain it? At the moment i can't say if they are still inside my leslie amp.

[tpappano]

Temporarily disconnecting the adapter kit would be a reasonable troubleshooting procedure. It would be good to verify whether the organ sounds clean and proper by itself. C1 and C2 would pose a shock hazard if they should fail and because of their age, that could easily happen. It's true they serve no useful purpose and should simply be removed.