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2 watt amplifier

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I have just won two speakers with output transformers attached. They are 2 watt speakers and the transformers have 3K primaries.
If I wanted to make single ended amplifiers for them, what valve (tube) would be suitable for these.
Can I use a 6V6 for example as I have some of these?

Tony.
 
Well, are your transformers designated for single-ended operation? if you do not know, you can check how they are stacked (if you can see the laminations of course).

Also 3K for 6V6 = low load, higher distortion, lower allowed HT=lower output power. Better with EL34 or KT77 or 6L6.
 
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Mmmh ?
Loudspeakers with attached transformers was usually designed to be attached on a 70 or 100 volts distribution system.
Transformers has no gap nor center tap so they can't be used in classical SE no more than in PP configuration.
However some totem pole arrangements like SRPP or SEPP could do the job.

Yves.

Many of the old vintage German speakers used to have attached SE transformers. It was not that uncommon.

Shoog
 
The transformers have the py & sy impedences marked 3K & 3.2 ohms. I dont know what they were originally out of or what valve would drive them possibly a ECL82/86? The speakers are marked Victor P D loudspeaker. In English.
 
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The transformers have the py & sy impedences marked 3K & 3.2 ohms. I dont know what they were originally out of or what valve would drive them possibly a ECL82/86? The speakers are marked Victor P D loudspeaker. In English.

You mean ECL82/86. Yes that would probably do nicely. ECL82's are very common and cheap, ECL86 are unobtainable.

Try this for size;
Single Tube amplifier

Most speakers of that vintage were 4ohm, but most modern speakers are 8ohm. If you put an 8ohm speaker on your transformer you would get 6K impedance which is about right for that circuit.

Shoog
 
Having thought about this - the ECL82 wont hack it because you already have the speakers so are restricted to 3K.

The EL86 only needs 2.5K plate load so would do nicely. An even cheaper version can be made by using the PL84 which is a 15V heater version of the EL86. These are very cheap and plentiful since they were primarily used in colour TV's, and the heater voltage is easier to source with a range of cheap salvaged transformers.

Take a look at the datasheet;

http://www.r-type.org/pdfs/el86.pdf

The EL86 is a very sweet sounding valve.

Shoog
 
Hi
A 2W output for 3 ohm load is 2.4V. With a 1000:1 impedance drop (3k:3) that works out at 75V. I suspect Yvesm is right, post 6, but it could also be that 75V rms can be powered by a 250V SE stage. DId you check how the laminations were stacked? That should tell you what your transformers are.

John
 
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