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Just grabbed a Bogen AP-60 from estate sale. What next?

H

herkyhawki

New Member
Just grabbed a Bogen AP-60 in the original Bogen cardboard box from an estate sale.
The "kids" said Dad still used it up until 2016, but it was mothballed when he passed away. As far as I can tell, it is complete and in very good, used condition. I have not applied power. Any suggestions how to proceed?
I trained in electronics in early 80's but never worked on tubes. I know just enough about it to not leave it at the estate sale.
 
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herkyhawki said:
Just grabbed a Bogen AP-60 ... As far as I can tell, it is complete and in very good, used condition. I have not applied power. Any suggestions how to proceed?
I trained in electronics in early 80's but never worked on tubes.
Click to expand...

If you have access to a Variac that would be my first suggestion this way you can bring it up slowly and get a better idea of whats working or not. I would then track down a Schematic

Some info here if you haven't already seen it schematic is free if you join that site which is a legit site which a lot of folks here at AK utilize for info etc

https://www.radiomuseum.org/r/bogenpr_amplifier_ap_60.html

Welcome to AK and congrats on your acquistion, as @wlgrant6 mentioned pics please, we like our pics here also curious as to what brand tubes are in the unit.
 
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I'm guessing the capacitor closest to the back has been replaced. It has a screw in it while others are rivetted. It is also just a hair too tall and hits the edge of the wooden case when pulling out the chassis.
 
Before firing it up I recommend cleaning all the tube sockets and pins, deoxit the controls, switches and pots.

It appears to have a solid state rectifier so it will begin generating HT (high tension aka DC voltage) with the least bit of wall voltage applied. This can come in handy if you want to try to gradually reform the filter caps. A variac enables this, and you can go as slowly as you want (5 more volts each hour, for instance.)

You could also monitor the current draw by clipping an ammeter in place of the fuse, to get an idea if excess current is being drawn (indicating a problem). A dim bulb tester can help you here, as well.
 
Can't really tell if the capacitor towards the back has been replaced. It looks original to me. The output tubes are 7355's. The guy put a makeshift shield between the output transformers and the tubes to help the output transformers stay cooler. If there is any concern, a metal tube shield might work better.
 
That diaper on the OPT's isn't original, is it? The material looks a bit like some asbestos gloves I saw once.
 
was thinking it may be some asbestos heat shield as well. Be careful if it is, the fibers are absolutely not good to breathe in.

Bogen made highly competent stuff. Sometimes the engineering was a wee bit unusual but it was actually well thought out. They had (and still do) have lots of professional sound experience and some of that build quality did seem to make it over into their home hifi gear.
 
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