Need four 6GW8/ECL86 tubes

[LooseChange]

Got a HH Scott stereo amp and I need four of those.
Any ideas? Any subs? Sources?
Thanks!

[Ed_Chambley]

PCL86 and a voltage doubler might work.  I'll check when I get home and see if I have some.  I am thinking I have 2, but not sure may have more.  They are $40 at Tube Depot.  Guild used them in some of their amps and there was a portable Italian organ (cant think of the name) that used a lot of them.  I did a pull on the organ but have not tested the tubes.  I know Hammond organs used them as well.

Is this for your stereo or a repair?

[HotBluePlates]

Supposedly the 6BM8 is equivalent with a different pinout.

Other forums also mention 6HC8 and 6HZ8 as close substitutes, again requiring socket rewiring. However, when I check the ready source of odd tubes, Antique Electronic Supply, they are sold out of all these variants.

[kagliostro]

If you are fine to use 6BM8/ECL82

http://thetubestore.com/ehx6bm8.html

but $ 18.95 isn't very cheap .......

6HZ8 is cheaper

http://thetubestore.com/nos-6hz8.html

$ 5.95

K

[DummyLoad]

is 6BM8 really a good sub for 6GW8? seems to me you'd have to hack too much such as change Rk, move pins 2,3,7 & 8, and you'd lose around 4W of output power per channel. 6HC8 is a very rare tube - i've only been able to hunt down a pair for quite some time. 6HZ8 is more common, with 6GW8/ECL86/PCL86 even more so, but costlier. richard and i experimented with the 6HZ8 and found that it would break into oscillation very easily and really didn't seem suitable for use with audio - there is a thread about our follies with that tube, long buried now - IRRC, it was the AZ-BZ-DZ thread.

sent you a PM.

respectfully,

--DL

[Heinz]

The 6BM8/ECL82 is not really a substitute for the ECL86. The triode has less gain and the pentode has less power, as Richard said. However, the PCL86 is available on Ebay at a decent price (some starting at $6 per tube). That doesn't seem too bad. It is equivalent to the ECL86 but has a 13V/300mA heater. An extra 12V transformer with 1.2A would do the trick. Maybe you could re-use an old halogen lamp transformer.

richard and i experimented with the 6HZ8 and found that it would break into oscillation very easily and really didn't seem suitable for use with audio

I had the same problem with the ECL86 in some applications, but then I found an old article (unfortunately I didn't save or bookmark it) stating that the ECL86 should always be used with a socket that has a shielded base. I tried it with a preamp socket (with the top removed) and it actually worked.

[HotBluePlates]

is 6BM8 really a good sub for 6GW8? seems to me you'd have to hack too much such as change Rk, move pins 2,3,7 & 8, and you'd lose around 4W of output power per channel.

I don't personally know anything about any of these tubes. Just repeating some odds & ends, but at least one source was the Antique Radio Forum, and I'd trust those guys have a good handle on usable subs.

They did mention some of the same things you did. That is, pinout is different, Rk would need changing and gain is lower. They also noted that you'll lose a little output power. My take (and theirs) is if the "right tube" is so cost prohibitive as to be undesirable, then similar but slightly less power seems an acceptable alternative.

But then, if you have time on your side, wait and get the exact tube. I wouldn't be surprised if we found that the 6GW8 was one of those tweaky tubes made towards the end of tube manufacture, for which there is no exact substitute (excepting the Euro designation for the same tube).

[Geezer]

I've purchased a bunch of tubes from these guys ( http://www.thetubecenter.com/vacuumtubes_tubelist_tubes_6d4-6jz8.html ), so I know they're on the up&up, but $18 a pop ain't cheap! Those must really be getting scarce.....

G

[zendragon63]

LC, I have bought several smaller pentodes from these guys (MDB Ventures); reasonable but still not cheap. Just another possible resource...

http://www.fourwater.com/audio/audio_au26.htm#6GW8/ECL86

Regards

dennis