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EL84 amplifier
#1
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Hi all,

Some weeks ago I got this new baby... it is an amplifier that I got from an "old radio console" that was damaged very badly. I added some pics, it uses the following tubes 1-EL84, 1-EZ80 and 1-EBC81 as you cna see this amplifier already have the transformer and IN and OUT. Capacitors looks good not damaged nor leaks, Do you recommend me to replace them ? 

I want to build a stereo amplifier with this, I already have 2-EL84, 1-EZ80 but I need one ECB81.

I am not sure if I can use the same transformer that I already have. I am not looking for a strong amplifier just want to hear the nice sound of music thru tubes.

Thanks for your comments and advices.

[Image: http://www.casamadriddev.com/philco/nonphilco1.jpg]
[Image: http://www.casamadriddev.com/philco/nonphilco2.jpg]

Frank Tovar
#2

ECC81 is a 12AT7, a common tube. If you have a 12AU7, it'll work fine in this set. I'd replace the filter capacitor can with up to date discrete components that will easily fit under the chassis.
#3

Thanks a lot for your recommendation, do you think that I should use the same transformer or shall I buy a new one ?

Frank Tovar
#4

I'm not certain about what you are asking, if you are asking whether you can convert this single ended amplifier and power supply into a stereo amp then the answer is maybe. The question is whether there was anything else attached to this unit, if it had a tuner chassis plugged into, and powered off of it then you might be able to use that transformer to power a duplicate amplifier for the other stereo channel. However if this was just a single ended amp from a phonograph unit then it's really just a guess as to whether the power supply would be enough. Where was the EZ80 tube located, I see two tubes in two sockets, and a third in the end with nothing in it? Where are the controls, like the power switch, volume control, etc? Do you have a schematic for this unit?
Regards
Arran
#5

Arran,

Sorry, you are right I didn't asked properly, Here is some background about the module. I got the module from a device that had a tuner and phonograph, I will call it "the console". It was made in 1959 and it was stereo, the module in pics was placed and configured to be outside the main module and one channel of the phonograph was connected to this module thru an RCA connector, I also have the phonograph with all its original components (I will post a pic later). "the console" main module was really damaged, at inside all capacitors and resistors were gnawed by a mouse so the values and resistor colors were not there, I searched for schematics but there was not any available in internet worst the builder company is AUDIOVOX (mexican company) doesn't exists anymore so it will be really difficult to get the schematics and make it work, so I decided to just get the phonograph, speakers and this module that was assembled outside the main module, the idea was to sell the tubes but I noticed that the module was an amplifier then the idea came to my mind and I said "why not bring the phonograph back to live?" so I am now on this just evaluating if I can do it...

In regards the missing tube, yes I have it (EBC81), it is not shown in pics because it has to be mounted horizontally but it will have a risk to get it broken if it is not handled properly so I removed (I will update the pics later).

I also have the speakers in a very nice shape and they provide very clear and nice sound.

In order to make this project success I was thinking to build a tube pre-amp with stereo volume control (the phonograph is stereo).

** by mistake my parents dropped the main module to the garbage there is no way to get the power supply and all other stuff back.

*** my big concern is that all these tubes use high voltages and I don't want to suffer an accident I must be very careful with all these old components when I test them.

Thanks again for your replies.

Frank Tovar




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