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old tube radio - impedance issue

Started by gtangas, May 03, 2013, 11:27:09 AM

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gtangas

Hi Guys

I bought an old Phillips radio... 10 Tubes including a EM80... The front glass is broken but i will make a new one with photoshop...

but this model as no speakers on it! The price was 25$ so i couldn't complaint right!!!

The output impedance on this thing is 800 Ohm... OMG...

Now I'm on a quest to find how to plug this thing to a normal speaker!!

I've done search on the web but no conclusive results! Some guys use a impedance matching transformer but I can't find one with this value!

Any ideas on how to adapt to normal speakers?




stecykmi

you're unlikely to find an 800ohm speaker, so i think your best bet would be finding a 10:1 transformer and hooking it up to a far more common 8ohm speaker.

gtangas

#2
finding a 800 Ohm speaker is a never ending quest!!!

The transformer is the way!

can you point me to one? My knowledge is very poor on this things! especially in transformers....  ??? ???  

smething like this?

http://www.ebay.com/itm/1K-ohm-Centre-Tapped-8-ohm-Output-Transformer-/310402823312  

http://www.ebay.com/itm/2x-EI-14-Audio-Output-Transformer-1K-8-to-32-ohm-e-/151024517937?pt=LH_DefaultDomain_0&hash=item2329c34331

frankie5fingers

There are two places I can think of that might have the parts and the experise, to help.
http://www.fairradio.com
http://www.oselectronics.com/index.htm

stecykmi

in the best case, you'll need a 800ohm : 8 ohm transformer, with a 20Hz to 20kHz bandwidth (somewhat less should be okay, like 50Hz to 15kHz) that is rated for at least the output power of the radio (should be listed on the back somewhere). then you'll need two of them, 1 for each channel.

I have no idea where to find such a thing, however.