I had a stromberg carlson stereo power amplifier that used a couple of
these.. Driver stage was a 7199 per channel.. Used a hefty power
transformer, produced about 20Wrms out per channel and sounded quite nice
actually.. I have never seen another, seemed like an ideal amp for a
smaller system.. Nicely put together, high quality parts. Sold it
unfortunately ages ago, did not recognize its rarity at the time - and I
have never seen another.

Kevin

"Fred Nachbaur" wrote in message
...


JKoning wrote:
"Fred Nachbaur" schreef in bericht
...

[...]

The specs show it capable of a respectable output power in Class AB1,
but at a low B+ voltage, as would be expected in line-operated designs.
However, its filament voltage/ current doesn't lend itself very well to
such designs. (A variant that used the same heater power at the 0.15A
current used in series-string radios would have had to be 64 volts, i.e.
64DZ7).


Does your book explicitly list 6DZ7 for (110ac) line-operated designs?
Typical operation values in the GE data sheet are at 250V plate.
So I guess it's useable for line operation, but not intended.
Also, as you said, filament V/I suggests tranny operation.

No, my comments were based on the figured given in the (hopelessly
abbreviated) "typical characteristics" in the single-line listing at the
back of the book. But looking again with a magnifying glass, I see that
I'd misread them. The recommended values are 400/300 volts B+, for -11v
fixed bias and 120 ohm cathode bias respectively, screen 250 volts for
both. Total plate current 100/80 mA.

I haven't seen any distortion specs (or even curves), but I'd suspect,
given the low plate voltage for which it was designed, that it would be
nothing to write home about.


Data sheet, including distortion curves, at :
http://www.mif.pg.gda.pl/homepages/f...093/6/6DZ7.pdf

Of course! Good old Frank... Thanks!

I almost get the sense that this was an abandoned experiment, perhaps a
foray into higher-powered audio for television sets -- which never took
hold and was dropped.


Maybe another abandoned experiment?
http://www.mif.pg.gda.pl/homepages/f...24/e/ELL80.pdf
Non interconnected g2's make PP-UL possible.

That does look interesting. Wonder how many of them are out there? They
seem to go for about $10 on ebay ($20 per pair).

Seems there's an American equivalent also, 6HU8.

Any other theories, opinions, or perhaps even facts about this odd tube?


A 1960 GE publication about 6DZ7 among others:
http://www.triodeel.com/ham1.gif
http://www.triodeel.com/ham2.gif
Would be interesting to hook up 2x 6DZ7 in PP-UL.
Given Ra-a ~4.5K for 2x 6DZ7 penthode PP, how does one calculate
optimum
Ra-a for PP-UL?

I've never seen or heard of a rigorous treatment, or way of calculating
optimum Ra-a. I've personally just gone by recommendation of the
transformer manufacturer (Hammond), and have noted that the values are
comparable to normal pentode operation, perhaps 10-25% lower.

Seal your lips, prevent the 6DZ7 frenzy at the Bay!

Haha, yes indeed! Interestingly, a search shows none listed at this
time, or in recent completed auctions.

Cheers
Fred
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