• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
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    the safety precautions around high voltages.

R-Core OPT

I have had a pair of the RW-20's for over 10 years and are presently in a Tubelab SE amplifier with 300B's. I am happy with them. They are also very versatile.

The ones you linked to are even more versatile with 2 separate Cathode windings and I too have been looking at them (RW-40's) for another project.
 
Has anyone tried an R-Core output transformer on their SET amp?

Have been looking at these and would be interested in hearing anyone's opinion about r-core opts.

Softone RW-40-5 Single-Ended Audio Output Transformer

Thanks

Softone are good transformers. The PP ones are fine, SE and IT transformers are lacking a bit of primary inductance but for the rest they are good and they are best used with low plate resistance tubes.

The IT transformer is one of the very few affordable SE😛P transformers with excellent phase splitting balance and it's also very versatile.

That specific SE model is fine with 300B or 2A3 working at 60 mA.
 
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Good question. No idea, just suspicion they are manufactured already with a gap and this is not cut later. Also winding coils around 1 piece core is not that straightforward.
 
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It is pretty straightforward. The two bobbins are freely rotating around the core, and each has a little gear to engage with winding rotator. R-core technology allows simple winding technique for a gapless core, without complications of winding toroids.
 
5,000 ohm tap= 127 DCR 2,700 ohm tap= 94 DCR

Mine had a crappy little spot welds holding the vertical trans mounting plate to the base. I made a little brace to join the two more securely out of scrap pieces of 3/8" aluminum. See pictures.
 

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Has anyone tried an R-Core output transformer on their SET amp?

Have been looking at these and would be interested in hearing anyone's opinion about r-core opts.

Softone RW-40-5 Single-Ended Audio Output Transformer

Thanks
I have used the Softone RX-30-8 and RW-20 output transformers, and the RC-20 interstage. I agree with 45, these are good transformers that perform just as Softone advertise.
 
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