Gentlemen,

I am searching for extended data / specs on
the EL38 / 6CN6 tube. I did look already at
the usual suspect sites like the one from
Frank Philipse, but the data sheets for that
tube to be found there are very short and
compact.

Especially I am looking for load/Po and
load/distortion graphs for SE (and maybe
PP) pentode mode (reg'd screens).

I am aware that EL38 data seems to be quite
close to EL34 in many respects, but first
experiments on the breadboard seem to tell
quite a different story regarding for
example load/Po figures.

Any help would be appreciated!

Tom.

--
Life: All in all a bad game, but graphics are really good.

"Tom Schlangen" wrote in message
...
Gentlemen,

I am searching for extended data / specs on
the EL38 / 6CN6 tube. I did look already at
the usual suspect sites like the one from
Frank Philipse, but the data sheets for that
tube to be found there are very short and
compact.

Especially I am looking for load/Po and
load/distortion graphs for SE (and maybe
PP) pentode mode (reg'd screens).

I am aware that EL38 data seems to be quite
close to EL34 in many respects, but first
experiments on the breadboard seem to tell
quite a different story regarding for
example load/Po figures.

Any help would be appreciated!

Tom.

Try this site:
http://www.mif.pg.gda.pl/homepages/f...030/e/EL38.pdf

Jim


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Hi Jim,

like the one from Frank Philipse [...]

http://www.mif.pg.gda.pl/homepages/f...030/e/EL38.pdf

Thank you, but that is (a mirror of) Frank's site ;-)

Tom

--
A gleekzorp without a tornpee is like
a quap without a fertsneet (sort of).

Hi Tom !
Another project coming up ??!!

I've no more info bout this toobs that you certainly already found at
Frank's.
It's an horizontal sweep output penthode and as such would prefer to be
operated
at some lo voltage (250 V ?) an hi current (say 100mA to satisfy the 25W
Pd).
Of course, I've no idea about linearity, but 've another rule of thumb to
approximate load for
an SE penthode: (VB+) / (I idle) : 250 / 0.1 = 2500 Ohms ... and you fall
within 20% off the ideal ;-)
(Not so bad if you consider the usual variations of a loudspeaker accros the
audio band !)

Have fun,
Yves.

"Tom Schlangen" wrote in message
...
Gentlemen,

I am searching for extended data / specs on
the EL38 / 6CN6 tube. I did look already at
the usual suspect sites like the one from
Frank Philipse, but the data sheets for that
tube to be found there are very short and
compact.

Especially I am looking for load/Po and
load/distortion graphs for SE (and maybe
PP) pentode mode (reg'd screens).

I am aware that EL38 data seems to be quite
close to EL34 in many respects, but first
experiments on the breadboard seem to tell
quite a different story regarding for
example load/Po figures.

Any help would be appreciated!

Tom.

--
Life: All in all a bad game, but graphics are really good.

Hi Yves,

Another project coming up ??!!

Well, since I have all parts at hand to make
a copy of the EL34SET amp I built last
year, I was thinking of a "coke bottle" version
of it for a change: 5U4 rect, and EL38 output
tubes. Or maybe 807/QE06/50 ...

It's an horizontal sweep output penthode and
as such would prefer to be operated
at some lo voltage (250 V ?) an hi
current (say 100mA to satisfy the 25W
Pd).

I thought so. The cathode area is quite impressive
(oval shaped) and surely is good for lots of space
charge and continuous high plate currents.

Problem is, I would like to use high B+ instead
of high current ... because the OPTs are good
for 70mA at most. (In the original amp the
EL34 run at 425V and 50-55mA).

but 've another rule of thumb to
approximate load for an SE penthode:
(VB+) / (I idle) : 250 / 0.1 = 2500 Ohms ...
and you fall within 20% off the ideal ;-)

Great! Hey, I think we should start a list
of these "rules of thumb" we've collected
already.

Surely would make interesting stuff for
discussons here :-)

Tom

--
All the true gurus I've met never claimed
they were one, and always pointed to someone
better. -- Bill Vermillion

Hi Tom ,

Just guessing , but your EL38 might be closer to the EL50 .

Ronald .

"Tom Schlangen" schreef in bericht
...
Gentlemen,

I am searching for extended data / specs on
the EL38 / 6CN6 tube. I did look already at
the usual suspect sites like the one from
Frank Philipse, but the data sheets for that
tube to be found there are very short and
compact.

Especially I am looking for load/Po and
load/distortion graphs for SE (and maybe
PP) pentode mode (reg'd screens).

I am aware that EL38 data seems to be quite
close to EL34 in many respects, but first
experiments on the breadboard seem to tell
quite a different story regarding for
example load/Po figures.

Any help would be appreciated!

Tom.

--
Life: All in all a bad game, but graphics are really good.

Hi:

Read someplace that an EL38 is essentially an EL37 w/plate cap for HV use.
They even look just like EL37s too in epay auctions where I've seen lots of
EL38s not make reserve/opening bid. Could be wrong too. What do you
think???

__

Steve

Hey Steve ,

I think your guess is better than mine ......

Ronald .

"Steve O'Neill" schreef in bericht
...
Hi:

Read someplace that an EL38 is essentially an EL37 w/plate cap for HV use.
They even look just like EL37s too in epay auctions where I've seen lots
of
EL38s not make reserve/opening bid. Could be wrong too. What do you
think???

__

Steve

In case Mr. Crittle isn't looking in, read these.
http://groups.google.com/groups?ie=I...q=crittle+el38

Tom Schlangen wrote in message ...
Gentlemen,

I am searching for extended data / specs on
the EL38 / 6CN6 tube

Dear Tom

here are the audio specs for EL38. Some of my customers have used
these as replacements for EL34 in ST-70 amps. You may need more bias
than normal for optimum results. I have found wide variations when
testing EL38 valves, so to get a matched pair or quad you may need a
larger batch of valves to test and select.

One point to note: the pinout of EL34 and EL38 is very similar, the
only difference being the anode connection. For EL34 it is pin 3, for
EL38 it is a top cap. So to use in an existing EL34 amp the only mod
required is to mount a small banana socket connected to pin 3. The
anode connection is made via a short lead with banana plug on one end
and top cap connector on the other. EL34 and EL38 can then be used,
with appropriate bias adjustment.

EL38 specs

Heater: 6.3 volts 1.4 amps

Typical characteristics:
Plate: 275 volts
Screen: 275 volts
Plate current: 91 mA
Screen current: 11 mA
grid one: -ve 9 volts
gm: 14 mA/v
rp: 20 K

Maximum Ratings:
Plate: 800 volts, 25 watt
Screen: 400 volts, 8 watts
Cathode current: 200 mA
Heater-cathode voltage: 100 volts

Operating conditions: two valves in push pull
-----------------------------------------------
Condition 1 cathode bias

Plate and screen: 350 volts
Cathode resistor: 100 ohms
Plate current (each valve) 71 ma (zero signal) 83 mA (max signal)
Screen current (each valve) 8.8 ma (zero signal) 23.5 mA (max signal)
Load plate-plate 5 K ohms
volts in (grid-to-grid) 29.4 volts rms
Power output 38 watts
-----------------------------------------------
Condition 2 cathode bias

Plate and screen: 375 volts
Cathode resistor: 122 ohms
Plate current (each valve) 67 ma (zero signal) 75 mA (max signal)
Screen current (each valve) 8.8 ma (zero signal) 24.5 mA (max signal)
Load plate-plate 6 K ohms
volts in (grid-to-grid) 30 volts
Power output 37.5 watts

-----------------------------------------------
Condition 3 cathode bias

Plate and screen: 400 volts
Cathode resistor: 145 ohms
Plate current (each valve) 63 ma (zero signal) 69 mA (max signal)
Screen current (each valve) 8.3 ma (zero signal) 24 mA (max signal)
Load plate-plate 7 K ohms
volts in (grid-to-grid) 31 volts rms
Power output 37 watts

-----------------------------------------------
Condition 4 fixed bias

Plate and screen: 400 volts
Grid one -ve 23 volts
Plate current (each valve) 40 ma (zero signal) 110 mA (max signal)
Screen current (each valve) 5.2 ma (zero signal) 26.8 mA (max signal)
Load plate-plate 4 K ohms
volts in (grid-to-grid) 31.4 volts rms
Power output 55 watts

-----------------------------------------------
Condition 5 fixed bias

Plate 600 volts
Screen: 400 volts
Grid one -ve 25.2 volts
Plate current (each valve) 30 ma (zero signal) 103 mA (max signal)
Screen current (each valve) 3.4 ma (zero signal) 28.5 mA (max signal)
Load plate-plate 7.5 K ohms
volts in (grid-to-grid) 34.6 volts rms
Power output 84 watts

-----------------------------------------------
Condition 6 fixed bias

Plate 800 volts
Screen: 400 volts
Grid one -ve 26 volts
Plate current (each valve) 30 ma (zero signal) 107 mA (max signal)
Screen current (each valve) 3.1 ma (zero signal) 28.5 mA (max signal)
Load plate-plate 10 K ohms
volts in (grid-to-grid) 36 volts rms
Power output 102 watts

-----------------------------------------------

David Crittle
http://www.retrovox.com.au

Thank you all very much! I will try to
very the data given by Mr. Crittle and
have look for EL37 data, too.

Tnx2u again,

Tom

--
Life: All in all a bad game, but graphics are really good.