• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Vintage Tube Amp kit - Can it be refurbished?

neo004

Member
2016-02-16 10:33 am
Hey all,



I've recently started getting into the diy audio scene with some speaker building and looking to make an amp soon.



I was chatting tonight to my dad about this and he pulled out an old amp he made when he was 16, which would have been 1968.



The amp has Playmaster Stereophonic on the front. Its a tube amp. Built from a kit purchased from Electronics Australia.
https://en.wikipedia.org/wiki/Electronics_Australia


I realise this isnt strictly an australian forum, but someone might have seen it before.



Now i havent got too many more details as yet, he thinks he may even still have the circuit diagram somewhere.

I haven't really looked through the circuit board for any model numbers or anything as i dont really want to touch its internal until i know some more about it.



What im wondering is if its considered a good amp? And if its worth cleaning up and restoring?



If anyone has any ideas, it would be a huge help.



I've attached some pics.
 

kevinkr

Administrator
Paid Member
playmasterunit2.gif
 

neo004

Member
2016-02-16 10:33 am
Ah sorry, it didnt seem to accept the pics when i posted it originally.

hope this works
 

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It's related to the Playmaster 106 with tuner (Dec 1963) - pm me if you can't locate the article. The fascia is a little different from the magazine article photo, and includes a tuning indicator.

There is a Playmaster tuner from Pt2 in Nov 65. Perhaps that is the tuner, coupled with the No.4 (May 62) 6GW8 UL amp circuit that was used in the later 118.

Nice amp - well worth restoring to original condition. It's not the highest of hi-fi, but would likely exceed your requirements for many years. There is a lot to learn to restore it, so it would make a good project. If you haven't done any valve electronics, then best to find a buddy/mentor due to safety.

For local forums, there is also http://www.guitargear.net.au/ and yahoo groups Oz-Wireless.
 
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As was mentioned,the electrolytics and coupling caps should be changed.

First thing I would do is clean the rust and oxidation off the unit.take some 100 grit sand paper around the transformer especially because those particles cause all of issues and then spray inside the tube sockets with deoxit D5 or some other equivalent type cleaner.
The electrolytics you could go 2.5 times the original value and then use Schotky diodes or UF4007s in the doubler. You probably contact Jim McShane and he can put together a complete kit for you but most of the resistors I would leave alone if they are the German Rodersteins.