Shunt Reg Using a 13E1 as Shunt Element

Paul Barker · Post by **Paul Barker** » Sat Dec 24, 2011 10:53 am

Might just fall into place. I think Steve has some 12e1's, if not I can send some.

One consideration of the SP 211 amp is the use of 211 to return ac. We so often neglect to realise that the other (b+) side of the opt in a se amp has as much influence on Sound . Same valve as output valve makes sense.

Cressy Snr · Post by **Cressy Snr** » Sat Dec 24, 2011 10:59 am

Paul Barker wrote:Might just fall into place. I think Steve has some 12e1's, if not I can send some.

Hi Paul/Laurence

I used to have a couple of 12E1s but the top caps came off unfortunately.
However I do have some 12E14s, which I think are 12E1s in a 6080 style straight bottle and no top cap.

I'll have a look at the specs of both valves. IIRC they are identical but there are no curves for the 12E14 on its datasheet. That could be because the 12E1 curves fit it, so STC did not publish them twice.

Be back soon.

Cressy Snr · Post by **Cressy Snr** » Sat Dec 24, 2011 11:12 am

OK here are the specs for the 12E1 and 12E14

The ratings look identical to me.

Steve

Laurence · Post by **Laurence** » Sat Dec 24, 2011 11:20 am

It has to be the same doesn't it?

Cressy Snr · Post by **Cressy Snr** » Sat Dec 24, 2011 11:34 am

Well I would have thought so.

Extrapolating the curves I reckon that with a 75C1 on the cathode I would get around 40mA, which will do for me.
B+ might be down to 350V but that's not worth worrying about.

Post by **Nick** » Sat Dec 24, 2011 1:08 pm

In fact I think it was the 12E1 that I used.

Paul Barker · Post by **Paul Barker** » Sat Dec 24, 2011 2:18 pm

Oh bum.

Cressy Snr · Post by **Cressy Snr** » Sat Dec 24, 2011 2:26 pm

Tell you what!

Shall we abandon this?

OO-ER....I've just had a horrible thought.

At the moment with the series regulator in place, I've isolated the driver stage and output stages from each other by placing the
400 odd Volt driver stage supply take-off behind the regulator pass tube feeding the output stage.

This ain't gonna be possible with shunt regulation is it? Not without a completely separate supply to the drivers.
This is getting complex but incredibly interesting in terms of learning stuff.

The driver stage draws 51mA...
35 for the 12HG7 and 16 for the 150V gas tube on the screen grid.

Paul Barker · Post by **Paul Barker** » Sat Dec 24, 2011 2:42 pm

You could leave that regulator in position. Pop the 12e14 and 75c1 in place adjust the series pass reg to provide the output stage B+ you require and just take whatever the 12e14 does as a bonus. Report back what it does and if it improves the sound.

I can send you a 75c1.

Cressy Snr · Post by **Cressy Snr** » Sat Dec 24, 2011 2:44 pm

Paul Barker wrote:You could leave that regulator in position.

Now why didn't I think of that?

Paul Barker · Post by **Paul Barker** » Sat Dec 24, 2011 2:45 pm

see my edit.

Paul Barker · Post by **Paul Barker** » Sat Dec 24, 2011 2:48 pm

You see Steve the beauty is that the shunt section will try to pull down the voltage but you have the series section to adjust the voltage back up. Once you have your desired voltage the shunt section will assist the series section in holding it tight.

Cressy Snr · Post by **Cressy Snr** » Sat Dec 24, 2011 2:51 pm

Paul You have a PM

Paul Barker · Post by **Paul Barker** » Sat Dec 24, 2011 2:59 pm

I wish it wasn't so blinking cold on the top floor of my house or I would go up there and breadboard the shunt element to let you know what current it pulls from a 360v B+. i am just really worn out after working away long time doing 12 hr days and am at last home body has gone into a metabolic rate plunge dive.

oh what the heck I'll wrap up warm and get back to you all in a few days. Doesn't seem much point in just breadboarding the shunt valve, might aswell build a monoblock with both series and shunt elements.

Cressy Snr · Post by **Cressy Snr** » Sat Dec 24, 2011 3:05 pm

No worries Paul, don't mess about on my account

Still...it's nice when things get interesting.

I'm almost sure Broskie combines a shunt and a series reg, way back
but he might have used transistors.

audio-talk

Shunt Reg Using a 13E1 as Shunt Element

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