Pentode or tetrode

[ajkimba]

Can someone tell me if this tube is a pentode or tetrode?

Also any good for subsitute for EL84's.

[rjgtr]

Based on the markings it is a Pentode like the EL84. The E84L designation means that it is an upgraded version of the normal tube, with possibly more power output.

[ajkimba]

Thanks, Richard, that's exactly what I wanted to hear.

[T-bones]

Nice quad there. I believe those are RFT's. Bad boys of the EL-84 family no doubt. I've never heard a better sounding EL-84 in a guitar amp period. My supply of these are getting low and there hard to find new anyways. I think the sarge is in agreement on these also from what I remember. They were made in Germany on the east side, although they were also produced in western Germany and Poland. I've used them all and never found them to differ from one another in any way what so ever. The prejudice thing still exists today on this German and Japanese tube thing, whatever you want to call it. Thats a shame. Dont get me wrong I like Mullard and Amperex types also but as far as the overall volume and tone goes those are very hard to beat. You can run them nice pink plates and man they just smoke. Great clean and great overdrive, best of both worlds, I guess thats why I like them. If you don't like them them you can send them over to my house. I would like to say how many NIB Mullard EL-84's that I have had over the years that shorted compared to the RFT's you would be amazed. I've had better luck with the Holland and Siemens produced EL-84's which are pretty much the same tube with manufacturing agreements when they were made. Telefunken go home your way over rated. T-bones.

[DutchMarco]

Looking at the image title, you got them for free. Lucky you!

You can't tell from the outside if a tube's a pentode or tetrode, you have to look inside. Or the markings on the tube should give it away. In fact, that's the preferred method because it conserves the vacuum!

Maybe if there's an opening in the plate, you could count the grids and maybe even see the beam-forming elements (like a 6V6s). But without knowing the tube type, it's useless. You don't know the specs, even the pinout would be hard to make out. So you have no idea even of the required filament voltage, never mind about max anode voltage etc.

Having said that, you suffer from none of those problems because those are clearly marked.

E = 6.3V (G = 5V) heater
L = power tetrode or pentode (Z = full-wave rectifier)
8 = 9-pin miniature (3 = 8-pin regular size)
4 = sequence number.

(compare to GZ34)

Swapping the type designation (L, or CC for instance) with the socket designation and sequence number was a common way to denote Special Quality or SQ (higher ratings or cherry picked) tubes. Hence E84L, E83CC, etc. Or the current JJ E34L.

[billv]

AJ,

Did you manage to pick those up this weekend?

[Easto]

They went for $170.00

[ajkimba]

No way I'd spend $170 for 5 EL84's, unless they were made with gold

[allynmey]

Telams are some of the best sounding EL-84's out there. I've got 4 NOS and won't part with them for anything. Well....maybe two of 'em for Jessica Simpson naked on a shag rug purrin' like a kitten!

Allynmey