tube experts please help

[JeffGT]

Appologies if this is in the wrong section, wasn't sure if this should be in the technical info or not. A friend at work had a couple old tube caddies that had a few interesting tubes. One is a set of RCA EL34's that say Made in Germany. Here's a couple pics:





They have a hole in the guidepin if that helps any.


The second are 4 of these:


They say SPL 719930
and below that BG 193

?????????????

I can't find much on them except they may be a version of a 6V6.


Thanks for any help

[hogy]

First one's not Made in Germany, but even better, it's a double getter Mullard EL34.

Second one is a 7199 octal preamp tube, very desirable as it was used in certain Ampeg and Dynaco amps among many others. This one looks like a beefed up version like a Red Bank/Bendix, made to withstand g-forces in airplanes and missiles.

Nice find.

[rockon1]

Intersting. I know a lot more about pre amp tubes than power. That said it looks like a Blackburn Mullard code at the base! Hmmm. Check out this pic of a Mullard ... Bob


http://www.tube-classics.de/TC/Tubes...EL34/EL342.htm

[rockon1]

Beat me by a minute...one fingered typing blues.... lol!

[DEMENTED]

Yeah, the EL34's are Mullards for sure, double getter XF2...probably early 60's....NICE!

[JeffGT]

Thanks guys, much appreciated

[JeffGT]

OK, more mystery here. I checked some 7199 tubes and the 719930 tubes I have appear to be bigger, like 6v6's....one of them was in a 6v6gta box. So I checked around and found this: http://www.kcanostubes.com/products/...tched-Pair.htm

It looks just like this. I put the 4 of them BRIEFLY in a 4-6v6 amp and they powered up and worked....so I assume they are power tubes as they made sound....sounded good but I only wanted to leave them on for a few seconds. They look exactly like the 5992 and have a blue glow as was described on another site.
I hope Hogy stops back for an opinion.

[hogy]

Hey Jeff, what markings can you find on the tubes (not the boxes)? The Bendix 6V6 version is the 5992. Any etched numbers or complete printings on the bases?

[JeffGT]

Absolutely nothing etched in the glass. The only numbers on the base are 719930 on top and below is a BG # that is different for each one...BG 193, BG 201, BG 025 and BG 026. I'll take some more pics...my camera battery went dead and I have to re-charge.
Probably won't help, but the boxes say:

3370-286000-7266
TUBE
AF-33-604-9908
DATE PKD. SEPT. 1956
III
MFRS. PT#719930
REINSPECTION REQUIRED IF IN STORAGE AFTER JUNE 1959
SPERRY GYROSCOPE COMPANY

slso stamped on the box is 5960-296-4141

[bosstone]

I have four matched Mullards 6CA7s, NOS NIB that are labeled National. I haven't been able to bring myself to putting them in my Canadian Marshall 2204 or Ampeg VL 502 yet.

[mbetter]

Originally Posted by JeffGT

Absolutely nothing etched in the glass. The only numbers on the base are 719930 on top and below is a BG # that is different for each one...BG 193, BG 201, BG 025 and BG 026. I'll take some more pics...my camera battery went dead and I have to re-charge.
Probably won't help, but the boxes say:

3370-286000-7266
TUBE
AF-33-604-9908
DATE PKD. SEPT. 1956
III
MFRS. PT#719930
REINSPECTION REQUIRED IF IN STORAGE AFTER JUNE 1959
SPERRY GYROSCOPE COMPANY

slso stamped on the box is 5960-296-4141

Might as well throw them out, they expired nearly fifty years ago.

[JeffGT]

Here's a couple more pics if it helps....just trying to find out what they are. Thanks for any help.

[slider313]

Those are not 7199's. A 7199 is a 9 pin miniature and wasn't offered in 1956 and never came in octogal form. They do look like Bendix 5992's and may have a special part number,for Sperry, with no other markings.

[hogy]

Slider is right, I had a brain fart with the 7199s. Your tubes do indeed look like Bendix 5992s, I just looked at some I have here, they look the same. I don't know why the number doesn't match up, but the 5992 is a specialty substitute for the 6V6. It is designed for maximum mechanical stability for use in warheads, airplanes, etc.
That doesn't mean it's the greatest SOUNDING 6V6 ever, but it is certainly a desirable tube.

Hit me up if you want to sell them.

Here's an interesting article about Bendix/Red Bank that also discusses the 5992:

http://www.vacuumtube.com/issue5.htm

[Blue Strat]

Originally Posted by hogy

Slider is right, I had a brain fart with the 7199s. Your tubes do indeed look like Bendix 5992s, I just looked at some I have here, they look the same. I don't know why the number doesn't match up, but the 5992 is a specialty substitute for the 6V6. It is designed for maximum mechanical stability for use in warheads, airplanes, etc.
That doesn't mean it's the greatest SOUNDING 6V6 ever, but it is certainly a desirable tube.

Hit me up if you want to sell them.

They do look alike, but so do a lot of tubes. My 5992s are clearly marked as such.