EL34 SE

[Paul Barker]

So the amp I listen to is EL34 SE. The Variac has become unreliable.

So Ive made it 117v permanently. Through the power supply that gives 317v b+ which draws 21v bias. Running hotter current 82mA. B+ 300v.

This isnt a bad compromise . For this amp it becomes 3 watts, but its cleaner lower distortion. Unsurprising. More punch (greater current flow) yet it’s loud enough.

The beauty is all those other octal Mullard EL36’s will be about max at 300v. 3 to 4 watts. So as soon as the first arrive, amp is already set up. Top cap and base changes only. Then just listening pleasure on European/British made valves. Should be a step up.

Then the push pull EL821/2 ampfilier signal section is best at 250v b+ I could shunt reg 50 volts that down to 250. Bit of extra work. Or just introduce the big blue variac.

So only the new output stage to build.

[Nick]

Or just introduce the big blue variac.

Or just make a fixed stepdown autoformer out of a toroid.

[Paul Barker]

A lot simpler I already bought a 50 watt 20v secondary. 2.7v change per primary volt a 20v additional primary will deduct 54 volts from the supply on the safer side that’ll do. If I needed a bias supply Ive got one on the other secondary. In this case I am using so little voltage its not necessary. EL821 will be 8mA -4 v bias 500 ohm rk output pair EL822 is ccs bias with a current balance pot to try and keep valves balanced.

[Paul Barker]

Took delivery of boxed nos EL36

Featured at Triode Fest 2006 5.7 watts SE Triode Connected. This will become the first valve change in the EL34 Amplifier. Quite excited.

[Paul Barker]

I get downstairs to find Steve’s four Mazda arrived. Thank you Steve?

[Paul Barker]

I think Mazda would have been made in Japan. So they ought to be quality.

[Cressy Snr]

Glad they got to you in one piece.