[OctavianH]

But like in every war we loose some battles and won others. EL30 was a disappointment for me. At first I wanted those for output but lack of into never made me think I would be at the limit (it's true I never tried the output trimmer for grid bias at minimum, usually on input you go so close to 0V). Then on input they are not what they should be. I start to think this is a general problem for RT or Cifte house sound, because all their tube quite bore on input (even ECC40 which is one of my favourites). So I'll not try something from these on input from now on.

But let's move forward because we left something unfinished here. STC 5B/254M. I bet @Isaacc7 will like this. He was one of the promoters of this tube.

And indeed, he was right. Very good sound from this tube. I can say even that I like this an idea more than the RT 4654, but well I will not jump into these kind of statements at the moment. I will only say that even if some claim these are 807 equivalents, on my amp these bias stronger, needing -20.5V for 200V/20mA. The normal 807 is around -18.5V on the same situation. So, well, equivalent or not, these sound excellent from the start, good tube.

My first try (and the photo) was made with the RT EL30 still on the input position, but I switched lately fast to Fivre 6SL7. Much better, EL30 was the problem before and even with those these sounded good. With Fivre 6SL7 are sweet and the bass is nice, a very musical tube. STC are in general an idea sweeter sounding because I remember also my STC 12E1 I tried in the past.

I would pair this with something sharper, so maybe next I'll go with some Tung Sol 6SL7 or why not some Telefunken 12AT7. I do not think you need something like Fivre for these and you can easily go towards a more neutral input.

Good tube, like A2293 this was a victory. EL30 was a defeat. No problem, we move forward.

 

[Fonranion191]

Good tube, like A2293 this was a victory. EL30 was a defeat. No problem, we move forward.

I love your optimism, keep going, you don't need to win every battle to win the war

 

[OctavianH]

I love your optimism, keep going, you don't need to win every battle to win the war

A battle lost for me might be a victory for others. We are one step forward regarding EL30 because we tried it, measured it and know we know more about it. I always make risk assessment and when something has potential to be a disappointment I always lower a lot my pricing standards. If it's cheap enough I'll try it and then at least know more. I will not lie that I am also interested to dig more and more into french tubes so this was a part of the decision to see what Philips France made and how it sounds.

Some OCD, when listening to these 5B/254M I observed that one had a darker plate and the one a grey one. LOL So from the 4 pieces, 3 have double square getters on top, one has double ring getters on top. Now I've seen that the plate color is not identical. OCD in motion, I had to change it to have both identical and replaced the grey one with another one from the quad. Of course, no difference in sound but, why not do it, since I had it. Now the bias went even lower around -21.4 for both (the one replaced being weaker than this one I had also to swich places to have the stronger one on my left channel where I set the mA meter to monitor).

So now both look the same. I put also some socket savers because the adapters got quite hot.

 

[OctavianH]

Ok, enough with experiments. We need to listen to serious stuff because it is Friday evening. Today I have received from Deyan a very nice pair of adapters for EL50, so now I can move the RT 4654 to them and use the adapters with longer wire for their own purpose: Philips EL51 Heerlen. This tube is a monster, bigger than the photo. LOL

In order to show a little bit more of this very beautiful and imposant tube, I made a photo with the family.

You would say that 4654 is a small tube looking in the left at the RT mesh anode pair or in the right at the Tesla pair. And because I plan to put Philips EL51 Herleen on Eternity I definitely need to pair it properly. You cannot go with mid-fi here because this is one of the most beautiful and loved tube from my collection. So I went directly to the top with some Philips ECC40 Sittard, a rich and aristocratic tube to match the noble sound of the mighty EL51.

And the result is fabulous. The richness of Sittard ECC40 matches the solid and energetic sound of the EL51. It's energetic, emotional and full bodied. So it needs an album of the same level and my choice for this evening will be Hamferð – Men Guðs hond er sterk from Faroe Islands.

Now I can enjoy a good Augustiner beer. My job is done for today. We had EL30, 5B/254M and ended in style with EL51. What one can want more? There is nothing above this and I do hope I will be lucky to obtain a pair of Tesla EL51 to put here on comparison. At the moment only pieces at crazy prices and I have no reason to buy them.

 

[OctavianH]

And since we are here, some detailed photos of EL51. Construction is incredible, you rarely see something like this.

This is of course overkill on my small low power amplifier but it sounds spectacular on it. I will, of course, make justice to this tube and all my old european pentodes one day asking someone to build me a proper amplifier for them. I researched months and months and built a concept. One day, EL51 will have a proper place to shine. Until then I am enjoying it now more than ever.

 

[OctavianH]

The evening was perfect until I had a crazy idea. To put EL38 on input to pair with EL51. Crazy setup isn't it? Well, let's do it.

I had to put my EL38->6V6 adapters on top of 6V6-6J5 but no problem, we can do that. Power pentodes on input sound wider and smoother for me but this isn't necessarily a quality. With EL51 on output the EL38 sounds good. Not as rich and good as ECC40 but it has a good tone. I'll keep these for a while, while I will still claim that rimlock is the missing link between old pentodes and the new world of tubes and EL38 is just a british decent tube. But of course, here it is saved by the king.

 

[OctavianH]

Beautiful view on top of these.

And a glow shot:

 

[OctavianH]

But EL38 was just an impulse. When possibilities are infinite like on this amp you tend to make also crazy choices. EL38 was veiled, as every british tube. So I had to return to the old Philips sound to make justice to the Philips EL51. This time I made a small change, went to ECC40 Eindhoven from the Sittard and this helped a bit to tame the sound. Even if Sittard is one of my favourites (also for EL42) I prefer from time to time Eindhoven, I feel my guitars sound right on it.

 

[OctavianH]

And a small post about tube families and how I see things are similar in different families. This is for people listening to many types of tubes, others might not find this relevant. I think about EL51 and EL50. Higher gain and lower gain, all in all same type of sound. Then I think about EL84 and EL81. Somehow the same. Then I think about EL41 and EL42. There is always a more energetic musical one and a more equilibrated one. Tube families have always similarities. While all are different, also all share some of the same attributes. And on top of that the house sounds, those things making them sound as the others from the same factory sound. I know this post might be abstract, for many, but for me it makes sense. LOL

 

[Isaacc7]

But like in every war we loose some battles and won others. EL30 was a disappointment for me. At first I wanted those for output but lack of into never made me think I would be at the limit (it's true I never tried the output trimmer for grid bias at minimum, usually on input you go so close to 0V). Then on input they are not what they should be. I start to think this is a general problem for RT or Cifte house sound, because all their tube quite bore on input (even ECC40 which is one of my favourites). So I'll not try something from these on input from now on.

But let's move forward because we left something unfinished here. STC 5B/254M. I bet @Isaacc7 will like this. He was one of the promoters of this tube.



And indeed, he was right. Very good sound from this tube. I can say even that I like this an idea more than the RT 4654, but well I will not jump into these kind of statements at the moment. I will only say that even if some claim these are 807 equivalents, on my amp these bias stronger, needing -20.5V for 200V/20mA. The normal 807 is around -18.5V on the same situation. So, well, equivalent or not, these sound excellent from the start, good tube.

My first try (and the photo) was made with the RT EL30 still on the input position, but I switched lately fast to Fivre 6SL7. Much better, EL30 was the problem before and even with those these sounded good. With Fivre 6SL7 are sweet and the bass is nice, a very musical tube. STC are in general an idea sweeter sounding because I remember also my STC 12E1 I tried in the past.

I would pair this with something sharper, so maybe next I'll go with some Tung Sol 6SL7 or why not some Telefunken 12AT7. I do not think you need something like Fivre for these and you can easily go towards a more neutral input.

Good tube, like A2293 this was a victory. EL30 was a defeat. No problem, we move forward.

Glad you were able to try out the 5b/254m! It is really lovely though I’m not sure if you’ll be getting its best at 200v. I am currently running the Sylvania 6bg6ga at 400v 60ma and getting lovely sound. I will try the 5b/254m at the same ratings to compare in a few days. I will be trying several different input tubes first though.

I don’t know if you saw my post in the 6j5 thread but I figured out why the ktz41 sounded so much different than expected. I had heard that they were essentially a 4v version of an ef37/6j7. I couldn’t find any real info about them so took their word for it. I finally stumbled across some info and they very very different. They draw so much juice that they could have damaged my amp long term. Oh well, at least I can use the 8d2 with the same adapter. Except when I tried putting them in I heard a loud crack from the adapter when I made sure they were making good contact. I’m afraid to use it now. I think that ends my experiments with British 7 pin tubes.

I’m now using a pair of tall black glass 14n7 as inputs. These are tubes I’ve been trying to get good sounds out of for a while. Sound good enough now. Will let them burn in for a few days and see how they go.

 

[OctavianH]

Glad you were able to try out the 5b/254m! It is really lovely though I’m not sure if you’ll be getting its best at 200v. I am currently running the Sylvania 6bg6ga at 400v 60ma and getting lovely sound. I will try the 5b/254m at the same ratings to compare in a few days. I will be trying several different input tubes first though.

That would be cool. Please let me know how you find them at ratings closer to what I have here. I know it might not be optimal what I do, but even like this I can say these are nice tubes.

I don’t know if you saw my post in the 6j5 thread but I figured out why the ktz41 sounded so much different than expected. I had heard that they were essentially a 4v version of an ef37/6j7. I couldn’t find any real info about them so took their word for it. I finally stumbled across some info and they very very different. They draw so much juice that they could have damaged my amp long term. Oh well, at least I can use the 8d2 with the same adapter. Except when I tried putting them in I heard a loud crack from the adapter when I made sure they were making good contact. I’m afraid to use it now. I think that ends my experiments with British 7 pin tubes.

I am looking from time to time there but without too much focus, I do not like 6J5 / 6SN7 so it's not quite my thread to read. Good that you found that, strange indeed.

 

[OctavianH]

ITT Lorenz E88CC put in front of the king. I spoke in the past about this tube and I consider it very special.

This is a tube I always return to. It's a Siemens tube, or Lorenz if you want to call this way. I do not remember what those A6/61 codes mean or if I ever understood them. One thing I know for sure is that I like this one. E88CC or E188CC are interesting tubes, like 6922. Unfortunately I was late to the party and they got expensive before I had a chance to try more. Too bad, who knows, maybe one day I'll experiment more in this area.

Starting to think about these small noval tubes, I find the 12AU7 the weakest of them all and this is one of the most famous ones which everyone pays for more than for the others. I just find it boring. 12AT7 are better, even 12AX7 and 6922 or E88CC are I think the best. I also liked E80CC in the past. But my main experience is on 12AT7. Ah, I have some 6CG7 somewhere but I never understood those, I think about them as the 6SN7 of the noval nation. Good that at least pinout is the same as with 6922 and I can reuse the adapter for something better.

 

[OctavianH]

When people are bored they look at the pinouts of the side contact era. I have no idea what happened on octal era but for sure, on that one you need 100 adapters to make something working. Here with 2 types of adapters you have them all. Also loctal era is much better. Octal era is the worse, in short.

Basically with EL2 adapters you can use all these. Even the heptode section of an ECH3. Damn, I need to build the Tribute amp, too many things align. Who used a heptode section of ECH3 in input stage? Most probably nobody, maybe some took the triode in it like these guys digging into ECL/ECH families. Well, no problem, I'll dig into ECH3 or EBC3 because we know that "the older, the better". And EBC3 is a triode with side contact base. We want a triode on input stage with the rest of the bunch right? Maybe I'll check the rp as mr. Lobal advised but on my amp rp makes sense only on output.

It's funny that the most anti-rolling socket ever invented is the best for tube rolling and adapters rolling. LOL

 

[OctavianH]

EL51. A fascinating tube.

 

[OctavianH]

E188CC dated ◿8D5. I've always neglected this tube. I have no idea why, I was blinded by 12AT7. Pairing with EL51 is very special, I wonder if EL51 sounds good with mostly all these small tubes or if there is something special around. For sure, I have to dig more into this area.

Luckily for me there is a lot of information in this area, with the downside that I'll never buy more tubes at current prices.