EL34 SE

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Paul Barker
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#1 EL34 SE

Post by 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.
"Two things are infinite, the universe and human stupidity, and I am not yet completely sure about the universe." – Albert Einstein
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Nick
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#2 Re: EL34 SE

Post by Nick »

Or just introduce the big blue variac.
Or just make a fixed stepdown autoformer out of a toroid.
Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.
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Paul Barker
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#3 Re: EL34 SE

Post by 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.
"Two things are infinite, the universe and human stupidity, and I am not yet completely sure about the universe." – Albert Einstein
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Paul Barker
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#4 Re: EL34 SE

Post by 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.
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"Two things are infinite, the universe and human stupidity, and I am not yet completely sure about the universe." – Albert Einstein
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Paul Barker
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#5 Re: EL34 SE

Post by Paul Barker »

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

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"Two things are infinite, the universe and human stupidity, and I am not yet completely sure about the universe." – Albert Einstein
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Paul Barker
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#6 Re: EL34 SE

Post by Paul Barker »

I think Mazda would have been made in Japan. So they ought to be quality.
"Two things are infinite, the universe and human stupidity, and I am not yet completely sure about the universe." – Albert Einstein
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Cressy Snr
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#7 Re: EL34 SE

Post by Cressy Snr »

Glad they got to you in one piece. :D
Sgt. Baker started talkin’ with a Bullhorn in his hand.
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