[leftside]

I just took a look on eBay. Most of the GEC KT88 on there are pretty burnt out, but Langrex has a nice pair. Expensive I know, but good luck finding a genuine NIB/NOS for cheaper:
https://www.ebay.co.uk/itm/274978443831?hash=item4005fe1237:g:I3YAAOSwCC1hYC~O

Like the metal base GZ34 these things last for ages. And like the metal base GZ34 they will typically test quite high forever, and then suddenly one day fail. That's why you should always look at the side getter flashings on the GEC KT88's. Bigger/more silver = better. Smaller/more brown = worse. Honestly some of those expensive KT88 on eBay are on their last legs.

 

[OctavianH]

I will not invest now in any KT88 since I am sold to Tesla EL34 which cost less than 50EUR/piece if you look carefully. Of course these sound differently. But I wanted to warn the community against that seller, it is the second time he lists such a pair. I was not fully convinced I am right so I asked around and you confirmed me. Thanks!

Now, the Tesla I am talking about:

These are from time to time listed on Ebay as "Edicron EL34" (rebranded). Brown "sparkle" base with dual overlapping angled O-getters. These are manufactured by Tesla, but I have no idea in which year. The date codes on them are strange and I could not decypher them (E9LP8 or G9LP8). Only by assumption I expect that "G9" or "E9" is the actual date code and "LP8" might be the tube type or a factory code. It does not really matter to me, I like them a lot regardless the manufacturing date. From time to time these appear as Marshall EL34 like here or here. I know about variations like EL34L or EL34M but I never spent time to decypher. Some of them are designed for higher plate voltage which might matter in guitar amps but for me, because my amplifier keeps these at 200V, it is not relevant. These are different (at least the angled getters) by 33 or 37 Tesla which are selling around 100 EUR/piece but I doubt they sound differently and since I like them so much I never wanted to spend money on the others. If I will do I will report back about differences in sound. And if you can believe me, for me at least, these are on the same level as Mullard xf2, but these solve a problem I have with those soundwise (here everything is subjective): those have recessed highs and too polite mids. These have the same nice bass, but are more airy and a little bit harsh on mids. But oh boy, how the electrical guitar sounds on top of that harshness, these are for me the best for rock music and, in general, distorted electric guitar. xf2 are perfect for blues or maybe jazz music. I have almost all types of EL34 (except metal base) and even if others sound more "audiophile" (like Telefunken or Philips xf5) for me xf2 and these are my favourites. And if we start to discuss about price/performance ratio, well...

 

[Magol79]

I have an offer from a seller for a quad of Tungsram EL34 made in 1970. Does anyone know who made their tubes? The seller thinks the are made by Tesla, but I have also seen people say that Mullard made the Tungsram EL34s.

 

[OctavianH]

I have an offer from a seller for a quad of Tungsram EL34 made in 1970. Does anyone know who made their tubes? The seller thinks the are made by Tesla, but I have also seen people say that Mullard made the Tungsram EL34s.

I think you can find Tungsram made by Mullard/Tesla/RFT. If you can show some pictures maybe I recognize them. I have all these types here near me.

 

[Magol79]

I think you can find Tungsram made by Mullard/Tesla/RFT. If you can show some pictures maybe I recognize them. I have all these types here near me.

 

[OctavianH]

These seem to be Tesla. Yes. But let's see what others say.

Later edit: Let's see a picture with my Tesla EL34 near a Mullard EL34 xf2:

The 2 round holes on the spacer and those "dents" on the lower one made me think it is Tesla. Brown base, welded plates. I think Mullard xf1 had those dents on it but xf2 and xf5 and others I've seen are round. Let's see what others think.

Here some Philips xf5 near some RFT:

Many RFTs I've seen have stappled plates and black base. But there are things which are not seen in your pictures like getters, here for example Philips has double-D and RFT has single ring but there are many possible combinations. Then the base where Philips has a hole in the guiding key, while RFT does not and also here there are several combinations. But from what I was able to see in your pictures, I guess those are Tesla NOS.

 

[Magol79]

These seem to be Tesla. Yes. But let's see what others say.

Later edit: Let's see a picture with my Tesla EL34 near a Mullard EL34 xf2:

The 2 round holes on the spacer and those "dents" on the lower one made me think it is Tesla. Brown base, welded plates. I think Mullard xf1 had those dents on it but xf2 and xf5 and others I've seen are round. Let's see what others think.

Here some Philips xf5 near some RFT:

Many RFTs I've seen have stappled plates and black base. But there are things which are not seen in your pictures like getters, here for example Philips has double-D and RFT has single ring but there are many possible combinations. Then the base where Philips has a hole in the guiding key, while RFT does not and also here there are several combinations. But from what I was able to see in your pictures, I guess those are Tesla NOS.

@OctavianH, I would just like to thank you for your dedicated service:

 

[OctavianH]

@OctavianH, I would just like to thank you for your dedicated service

It was my pleasure, please let us know what you think of them when you receive them. My advice is to avoid paying too much for these and try instead some cheaper ones as I posted before, for around 50 EUR/piece. There are still good stocks of EL34 and you can find good deals. But things might change since people start to move from 6SN7/6AS7 to 6J5 and KT66/77/88/EL34 so in the future prices will increase for these categories.

 

[mordy]

It was my pleasure, please let us know what you think of them when you receive them. My advice is to avoid paying too much for these and try instead some cheaper ones as I posted before, for around 50 EUR/piece. There are still good stocks of EL34 and you can find good deals. But things might change since people start to move from 6SN7/6AS7 to 6J5 and KT66/77/88/EL34 so in the future prices will increase for these categories.

Yes, there are sellers who are lurking on these pages and watching what is being written - sometimes when somebody discovers a good inexpensive item suddenly many are listed for sale and the price goes up...

 

[Galapac]

Yes, there are sellers who are lurking on these pages and watching what is being written - sometimes when somebody discovers a good inexpensive item suddenly many are listed for sale and the price goes up...

If that’s the case then all GE tubes are awesome!

That is why I tend not to discuss the tubes I really like too much…I have had similar feelings about that myself.
Like when someone talks up a tube…all of a sudden there are bidding wars on the bay.
Sellers are doing that too.

 

[mordy]

If that’s the case then all GE tubes are awesome!

That is why I tend not to discuss the tubes I really like too much…I have had similar feelings about that myself.
Like when someone talks up a tube…all of a sudden there are bidding wars on the bay.
Sellers are doing that too.

Not to mention GE tubes described as GEC tubes...
Why not, doesn't it say General Electric Corporation?

 

[OctavianH]

That is why I tend not to discuss the tubes I really like too much…I have had similar feelings about that myself.

I know this, but in the end, we loose the purpose of these threads. Let them be greedy, I can live 10 lives with the collection I already own.

Now, since we spoke about GEC KT88 labeled as Gold Lion I remembered why I associate GEC with Gold Lion and since it is relevant for this thread I will post here.

I am a quite big fan of KT77. This is a tube where the NOS pairs are not quite easy to find for normal money. But I was able, during the time, to obtain a pair of GEC KT77 and a pair of Genalex KT77. Because both pairs are very electrically unmatched (my amplifier needs to keep current in both channels in a range because of MOSFETS and stuff so I need decently matched pairs), I am forced to use them mixed. This means, one GEC and one Genalex as a stronger pair and the rest as the weaker. And honestly, I never heard any difference from these. For me these are a kind of ultimate EL34, same sound but with the creamy richness of the GEC tubes. Since good pictures with these are not easy to find, I will post here a few made for comparison. As you will see these are not perfectly identical, however the differences are small and irrelevant.

PS. Yes, I was the one bidding on Ebay for a pair of Genalex KT77 from Italy but I have stopped. To let you know about the price these sell today:

No problem, when KT77 are selling so high we use EL34. If someone of you sells a pair, let me know.

 

[whirlwind]

I just took a look on eBay. Most of the GEC KT88 on there are pretty burnt out, but Langrex has a nice pair. Expensive I know, but good luck finding a genuine NIB/NOS for cheaper:
https://www.ebay.co.uk/itm/274978443831?hash=item4005fe1237:g:I3YAAOSwCC1hYC~O

Like the metal base GZ34 these things last for ages. And like the metal base GZ34 they will typically test quite high forever, and then suddenly one day fail. That's why you should always look at the side getter flashings on the GEC KT88's. Bigger/more silver = better. Smaller/more brown = worse. Honestly some of those expensive KT88 on eBay are on their last legs.

Yeah, those brownish getter flashings are showing the tubes life span for sure.

 

[Isaacc7]

Man, you guys are way out of my price range! How about some great bang for the buck tubes? First up are some 6v6 versions. Here's a Sylvania 7c5, a loctal 6v6.

These are plenty cheap and equivalent to the Sylvania 6v6. I also have about 30 of the 12v versions, the 14c5. Pretty sure they, like so many loctals were all made by sylvania regardless of the branding on the tube. Next up is an example of late stage tube manufacturing where contracts had to be fulfilled and as long as the measured values were within spitting distance of what was asked for you could put whatever you wanted in a tube. This is a Sylvania labeled 6ez5 but I am 90% sure that it is just a GE greyplate 6v6. It certainly has the GE markings.

These actually sound a little warmer in my amp than the sylvania 6v6. GE doesn't have the best reputation for sonics but these sound really good, especially for $5 they usually go for!

 

[Isaacc7]

One of my favorite tubes in the 6l6 family is the Tungsol 6ar6. Built incredibly well and general consensus is that they are similar to the legendary Tungsol 5881. These things are still plenty cheap. Yes, you need an adapter but they sound amazing!

Big, beefy plates! It is also a squat tube, even with the adapter it is a compact package.