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EL156 SE



 
 
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  #1  
Old January 26th 12, 07:51 AM posted to rec.audio.tubes
King Kong
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Posts: 8
Default EL156 SE

Who has built a EL156 SE? I guess it needs feedback due to the nature
of pentode, right?

Please advice. Just bought few Chinese made Valve Art EL156 (octal
base).
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  #2  
Old January 27th 12, 01:09 PM posted to rec.audio.tubes
Patrick Turner
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Posts: 3,964
Default EL156 SE

On Jan 26, 5:51*pm, King Kong > wrote:
> Who has built a EL156 SE? I guess it needs feedback due to the nature
> of pentode, right?
>
> Please advice. Just bought few Chinese made Valve Art EL156 (octal
> base).


If you search the rec.audio.tubes archives then probably you will find
ppl who used EL156 during the last 10 years.
In pure pentode mode, you will need a total of 20dB of NFB, and the
sound will be "pure pentode with NFB" and that won't be as good as
using say 2 tubes in parallel SE in triode for about the same PO, but
with much less NFB. I don't know why anyone would buy such tubes
without understanding what they have to do to make an amp work. To
understand, you have to work from the tube data curves, if you can
find a set , then establish Ea, Ek and the Q point for Ia, and EG2,
and then work out a load so you know just what OPT you will need.

Patrick Turner.

  #3  
Old January 27th 12, 01:19 PM posted to rec.audio.tubes
Patrick Turner
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Posts: 3,964
Default EL156 SE

On Jan 27, 11:09*pm, Patrick Turner > wrote:
> On Jan 26, 5:51*pm, King Kong > wrote:
>
> > Who has built a EL156 SE? I guess it needs feedback due to the nature
> > of pentode, right?


Plenty of stuff on EL156 if you Google EL156 SE amp.
for example, http://www.single-ended.com/images4/EL156-SRPP-2bs.png

This uses a 6U8A triode pentode in SRPP for fairly high gain for V1
stage to drive the EL156 grid. EL156 is set up for SE Ultralinear mode
with screen tap on the anode winding, probably at 40% of primary
turns.
And yes, it has global NFB.

Patrick Turner.
  #4  
Old January 27th 12, 10:25 PM
John L Stewart John L Stewart is offline
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First recorded activity by AudioBanter: Jan 2011
Location: Toronto
Posts: 301
Smile

Quote:
Originally Posted by King Kong View Post
Who has built a EL156 SE? I guess it needs feedback due to the nature
of pentode, right?

Please advice. Just bought few Chinese made Valve Art EL156 (octal
base).
The EL156 appears to be a rather high powered TV Horizontal Sweep tube. But the specs given on the data sheet while in PP pentode operation look quite good. The same in PP Triode mode.

About 10 years ago I built a couple of experimental SE amplifiers using TV Sweep tubes. The 6LU8 is a combined pentode/ high mu triode. In SET & SEUL the performance was quite good. In SET it compared well with a 2A3 at a fraction of the cost.

But in SE Pentode operation it was fairly terrible. Not recommended at all.

Anyone wants the dope on the experimental amps contact me direct at-

johnnhelen4 at gmail dot com

Cheers, John
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  #5  
Old January 28th 12, 02:49 AM posted to rec.audio.tubes
[email protected]
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Posts: 138
Default EL156 SE

On Jan 27, 3:25*pm, John L Stewart <John.L.Stewart.
> wrote:
> King Kong;951098 Wrote:
>
> > Who has built a EL156 SE? I guess it needs feedback due to the nature
> > of pentode, right?

>
> > Please advice. Just bought few Chinese made Valve Art EL156 (octal
> > base).

>
> The EL156 appears to be a rather high powered TV Horizontal Sweep tube.
> But the specs given on the data sheet while in PP pentode operation look
> quite good. The same in PP Triode mode.



It is most certainly not a sweep tube: it was developed specifically
for audio applications and in particular the Neumann cutting lathe
head amplifiers. It has an unusual ten pin base.

An "octal EL156" is a ******* tube and an unnecessary one since the
correct socket can be had for a few dollars.
  #6  
Old January 28th 12, 11:10 AM posted to rec.audio.tubes
King Kong
external usenet poster
 
Posts: 8
Default EL156 SE

On Jan 28, 5:25*am, John L Stewart <John.L.Stewart.
> wrote:
> King Kong;951098 Wrote:
>
> > Who has built a EL156 SE? I guess it needs feedback due to the nature
> > of pentode, right?

>
> > Please advice. Just bought few Chinese made Valve Art EL156 (octal
> > base).

>
> The EL156 appears to be a rather high powered TV Horizontal Sweep tube.
> But the specs given on the data sheet while in PP pentode operation look
> quite good. The same in PP Triode mode.
>
> About 10 years ago I built a couple of experimental SE amplifiers using
> TV Sweep tubes. The 6LU8 is a combined pentode/ high mu triode. In SET &
> SEUL the performance was quite good. In SET it compared well with a 2A3
> at a fraction of the cost.
>
> But in SE Pentode operation it was fairly terrible. Not recommended at
> all.
>
> Anyone wants the dope on the experimental amps contact me direct at-
>
> johnnhelen4 at gmail dot com
>
> Cheers, John
>
> +-------------------------------------------------------------------+
> |Filename: 6LU8 SEUL Amp 100.jpg * * * * * * * * * * * * * * * * * *|
> |Download:http://www.audiobanter.com/attachment.php?attachmentid=259|
> +-------------------------------------------------------------------+
>
> --
> John L Stewart


Japanese has highest praised on EL156 for SE application other than
300B.

I listened to an amplifier with this pair of EL156 in pentode with
regulated SG, sounds very very good!!
  #7  
Old January 28th 12, 02:17 PM posted to rec.audio.tubes
NX211
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Posts: 11
Default EL156 SE

I've got a pair of them in PP and they sound great. They require much
less bias on them then say a KT88 or 6550 so they might not work well
in those amplifier. I'm not sure why more people don't use them.
  #8  
Old January 28th 12, 05:07 PM posted to rec.audio.tubes
King Kong
external usenet poster
 
Posts: 8
Default EL156 SE

On Jan 28, 9:17*pm, NX211 > wrote:
> I've got a pair of them in PP and they sound great. *They require much
> less bias on them then say a KT88 or 6550 so they might not work well
> in those amplifier. *I'm not sure why more people don't use them.


Years ago, I bought a pair of Tango X5P for PP project with Curcio
driver. But didn't go ahead due to family matters. The catalog said
that the Tango transformer I bought is highly recommended for EL156
usage.
  #9  
Old January 29th 12, 05:01 PM
John L Stewart John L Stewart is offline
Senior Member
 
First recorded activity by AudioBanter: Jan 2011
Location: Toronto
Posts: 301
Smile

Quote:
Originally Posted by View Post
On Jan 27, 3:25*pm, John L Stewart <John.L.Stewart.
> wrote:
> King Kong;951098 Wrote:
>
> > Who has built a EL156 SE? I guess it needs feedback due to the nature
> > of pentode, right?

>
> > Please advice. Just bought few Chinese made Valve Art EL156 (octal
> > base).

>
> The EL156 appears to be a rather high powered TV Horizontal Sweep tube.
> But the specs given on the data sheet while in PP pentode operation look
> quite good. The same in PP Triode mode.



It is most certainly not a sweep tube: it was developed specifically
for audio applications and in particular the Neumann cutting lathe
head amplifiers. It has an unusual ten pin base.

An "octal EL156" is a ******* tube and an unnecessary one since the
correct socket can be had for a few dollars.
Still make a damn good sweep tube, just as the 807 & 6L6 did in the early daze of analogue TV. And safer for HV operation on that strange base than on octal.

However, unlike most sweep tubes the mug1g2 is high at 15 like the EL34. So doesn't need much signal to drive it to full power.

Would I build an amp with EL156? Not too likely. I like things that may still be available down the line a bit. But all looks interesting just the same.

My 2, anyway. Cheers, John
  #10  
Old January 30th 12, 03:11 AM posted to rec.audio.tubes
[email protected]
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Posts: 138
Default EL156 SE


> > >-
> > > > Please advice. Just bought few Chinese made Valve Art EL156 (octal
> > > > base).-

>
> > > The EL156 appears to be a rather high powered TV Horizontal Sweep

> > tube.
> > > But the specs given on the data sheet while in PP pentode operation

> > look
> > > quite good. The same in PP Triode mode.-

>
> > It is most certainly not a sweep tube: it was developed specifically
> > for audio applications and in particular the Neumann cutting lathe
> > head amplifiers. It has an unusual ten pin base.

>
> > An "octal EL156" is a ******* tube and an unnecessary one since the
> > correct socket can be had for a few dollars.

>
> Still make a damn good sweep tube, just as the 807 & 6L6 did in the
> early daze of analogue TV. And safer for HV operation on that strange
> base than on octal.
>
> However, unlike most sweep tubes the mug1g2 is high at 15 like the EL34.
> So doesn't need much signal to drive it to full power.


WOULD it make a good sweep tube? I dunno. To come to that conclusion
we would need to build a tube TV around it. Not much of that going on
anymore.

Although....I've heard a lot of sea stories about the superb contrast
and detail some homebrew monochrome sets in the 50s obtained by
determined hot rodder builders. Most of them used mercury or xenon
vapor HV rectified EHV from scope-like HV supplies, deadly if one
weren't careless, and big round military CRTs. And tuners salvaged
from the earliest postwar TVs.

>
> Would I build an amp with EL156? Not too likely. I like things that may
> still be available down the line a bit. But all looks interesting just
> the same.


They're still cutting vinyl with those amps so the supply may
continue.
 




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