Jun 14, 2023 at 6:12 PM Post #2,521 of 5,799
C Change symbol. The intention of this is not clear but it may have been a symbol that was to be
changed for each batch produced. In the ‘old’ code there was no year but the change symbol
sequence was replaced in three year cycles such that this, taken together with the month
symbol, would be a unique combination for any particular year. For example: Month W with
change T would be unique to May 1955. The change sequence was as follows:
Batch: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 20
1948-1950 0 1 2 3 4 5 6 7 8 9 P K % t I C T
1951-1953 A B C D E F H K L M S > d r Y N
1954-1956 N P R S T U W X Y Z + k M m [ L
In the ‘new’ code this was just a sequence of symbols which appear to have no purpose other
than perhaps provide batch traceability. Evidence indicates that this aspect of the code may not
have been applied too rigorously at some locations. It is found to be missing on examined
valves of Australian Philips manufacture for example. It was not applied to bought in valves.
The sequence to be applied was:
0 1 2 3 4 5 6 7 8 9 A B C D E F H K L M N P R S T U V W X Y Z d f m r t
Presumably this sequence was then repeated if necessary

The first tube seems to have five digits, hence old code, while the second has six digits which means new code. That's my guess anyway.
But this wasn't your topic, was it?
 
Jun 15, 2023 at 2:24 AM Post #2,522 of 5,799
The first tube seems to have five digits, hence old code, while the second has six digits which means new code. That's my guess anyway.
But this wasn't your topic, was it?
You make a very interesting point here, because I looked in the manual and did not saw that. I was trying to place in time these EL42. I chose these 2 pairs with D-getters and date codes:
1) M5P DZ (both)
2) M51 D6C
3) M51 D6H

So we have:

TTC FYM
M5P D Z
M51 D6C
M51 D6H

M5 = EL42.
P and 1 are revisions.
D= Valvo, Hamburg.

This was the easy part.

Now. M5P old code, Z appears only once, Aug 1959/52/55 and I guess is 1955.

1686809905481.png


Now, for the new code, we have 6C and 6H, which means 1956, C=March and H=Aug according to here:

1686810016893.png


So if I decyphered correctly:

1) M5P DZ (both) = Aug 1955
2) M51 D6C = Mar 1956
3) M51 D6H = Aug 1956

All similar soundwise and the same internals. But there are other interesting things on the 2) and 3) :

ValvoEL42.jpg


One of the has on top marked "Ade" and an "A" on the bottom. I have seen these numbers and type of markings usually on Telefunken. And date code orientation is reversed, one towards the middle the other towards exterior. In rest, identical. Sound? All 4 identical.
 
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Jun 15, 2023 at 8:05 AM Post #2,523 of 5,799
M5P - P is the second batch in 1954, 1955 and 1956.

DZ - Z is August in either 1949, 1952 or 1955.

So 1955 is the only year where P and Z correlates. You don't have to guess with 'old code'. New code is more difficult. @gibosi tells me that older is better and I always have to agree with him. He is older than me so he has the added knowledge to understand 'new code' better.
 
Jun 15, 2023 at 8:55 AM Post #2,524 of 5,799
I took a small break from EL42 to make something which I am sure @Isaacc7 will like. He likes those Cossor with similar plates to what I will show here. A pair of Ediswan 12E1 in some original huge boxes. To have an idea:

Ediswan12E1_box.jpg


Small tubes isn't it? Well, on the amp look bigger.

Ediswan12E1_SittardECC40.jpg


These have similar plates as my STC 12E1C I have somewhere in my storage, but look nicer with brown bases. Very solid tubes, I am at around -47.5V grid to keep these at 20mA. I was warned that these might go into thermal throttling with fixed bias, well here all goes well. Or at least it seems so. Valvo EL42 looks hilarious near these.

I am not very aware of who manufactured these Ediswan/AEI tubes. I guess I'll have to research a little bit. These have a very powerful sound with a lot of bass, so
 
Jun 15, 2023 at 10:28 AM Post #2,525 of 5,799
I took a small break from EL42 to make something which I am sure @Isaacc7 will like. He likes those Cossor with similar plates to what I will show here. A pair of Ediswan 12E1 in some original huge boxes. To have an idea:

Ediswan12E1_box.jpg

Small tubes isn't it? Well, on the amp look bigger.

Ediswan12E1_SittardECC40.jpg

These have similar plates as my STC 12E1C I have somewhere in my storage, but look nicer with brown bases. Very solid tubes, I am at around -47.5V grid to keep these at 20mA. I was warned that these might go into thermal throttling with fixed bias, well here all goes well. Or at least it seems so. Valvo EL42 looks hilarious near these.

I am not very aware of who manufactured these Ediswan/AEI tubes. I guess I'll have to research a little bit. These have a very powerful sound with a lot of bass, so
I have been intrigued by the 12e1 but scared by the tales of thermal runaway with fixed bias. I’m sitting on a fair number of kt61 analogs (n34 And kt81) that I haven’t run because of similar worries. By all accounts they are lovely sounding tubes but I don’t have the right kind of amp to run them safely.
 
Jun 15, 2023 at 10:30 AM Post #2,526 of 5,799
I have been intrigued by the 12e1 but scared by the tales of thermal runaway with fixed bias. I’m sitting on a fair number of kt61 analogs (n34 And kt81) that I haven’t run because of similar worries. By all accounts they are lovely sounding tubes but I don’t have the right kind of amp to run them safely.
Well, I tried here KT61 and did not had problems. I still do not really understand what's all about thermal runaway. EL42 goes quite hot, 12E1 does not really seem to care 20mA. We will see how things are going.
 
Jun 15, 2023 at 11:23 AM Post #2,527 of 5,799
I finally managed to make decent pictures for my tube database. I consider these as some of the most beautiful tubes I've seen. But well, you know, beauty is in the eye of the beholder. I use them in some EL39 -> 6V6 adapters, work perfectly, so you do not really need special adapters for them, pinout is very close. Gain is lower than for 807 (mu=5 vs 8) or the usual suspects, so you need to pair with some 6SL7 or at least 6N7 to be at a decent level with the volume knob.

This is the Ediswan:

1686842534297.png


This is the GEC:

1686842549783.png


These are some metal base STC:

1686842568803.png


All look incredible, are quite rare but not incredibly expensive due to the fact that basically nobody listens to these or at least I was not able to read anything on these forums. Soundwise, a lot of bass, a very strong sounding tube, I was comparing it with 807, but all with some british flavour. I will return to my EL42 but this was a well deserved break.

Later edit:
Here someone used a quad identical with these Ediswan in some audio amp. -40V for 260V/120mA. Quite something.
And here Thomas Mayer has some ITT marked as KB/FE looking close to mine.
 
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Jun 15, 2023 at 5:00 PM Post #2,528 of 5,799
Well, I tried here KT61 and did not had problems. I still do not really understand what's all about thermal runaway. EL42 goes quite hot, 12E1 does not really seem to care 20mA. We will see how things are going.
The problem is that with such a high mutual conductance, a small amount of drift as the tube ages can equate to a much greater current draw very suddenly.
 
Jun 16, 2023 at 12:23 AM Post #2,529 of 5,799
When I first approached Tomas about my amp I was really only interested in a 6v6/6f6/6k6 output section. He recommended that I could use higher power tubes with just a bit of a change to the design and so I did it. And while I have really enjoyed the various 807(ish) tubes I was disappointed that I couldn’t get a sound I liked out of the 6v6(ish) tubes that I had. Decided to revisit them since I have, ahem, a few more driver tubes to pick from than I did when I first got the amp.

I really like the JAN 7c5 in the Dennis Had amp so I have been wanting to figure out how to run them at their best. Happened across a site that says that in triode they should be run at 280v 35ma into an 8k load. That’s what my transformers are, hooray! On a whim I decided to try the Mullard 12j5(ish) tubes because I was also disappointed in not getting good sound with them so far. It’s a great combo! I’m getting a classic tube amp sound, more Dynaco than old Mac, or maybe it’s a new Mac instead of a classic one lol. Fairly neutral, good extension on both frequency extremes, not the last word in detail and doesn’t have the bloom or sweetness or whatever romantic description but it is honest from a timbre standpoint and not fatiguing.

Going to let these cook for a week or so. Might try rolling in some different input tubes since this is the first combo I’ve tried but that can wait a bit while I enjoy these.
 
Jun 16, 2023 at 2:08 AM Post #2,530 of 5,799
I really like the JAN 7c5 in the Dennis Had amp so I have been wanting to figure out how to run them at their best.
These are followers of 6V6 as far as I see:

1686895616747.png


6V6 sounded an idea weak on my amp, I wanted more bass and power like sound. Not bad but I preferred 6L6 or 807. I sold many of those I had, but I still have 1 pair of Sylvania 6V6 to play from time to time.
 
Jun 16, 2023 at 11:57 AM Post #2,531 of 5,799
What do we have here? A trip to the other side. Violectric V200 and Ultrasone Signature Pro meet my existing setup.

V200_Final.jpg


V200_Ultrasone.jpg


Why? Well I was bored so I traded my T1.2 for these. I was not using them for a long time and they do not pair well with Eternity. And I've done that to be able to play a little bit with this small Violectric amp many praise here. A small break from the tube rolling, but some well deserved tests and a little bit of introspection. There are some big questions we need to ask ourselves from time to time:
- How far am I from a mid-fi setup?
- How does sound a simple sistem without any power filtering or other tricks?
- How does Final D8000 Pro scale on V200? I never tried it with a dedicated headphone amp except Eternity.
- How does a small travel headphone as Ultrasone Signature Pro sound on V200 and then on Eternity?
- Do I need all these expensive gadgets or I was happy with much less?
The final question, the most important. Let's see where this goes.

I will not touch my main system, the DAC will be my audio-gd NFB11.32 which also has an integrated amp. So another question:
- How does V200 sound compared to this integrated amp? Do I need it or it does not make sense?

And in the end some playground with several pairs of interconnects. Interesting times. I never tried my interconnects on different gear so I'm curious.

Before starting, I have to say that Violectric V200 looks quite nice, sturdy and the volume pot is a pleasure to operate. Excellent build quality.
Ultrasone Signature pro are also very nice built, but I am not very much into the closed back/travel equipment. However, leather headband and leather earpads are a plus.
The included cables are also very flexible, 6.3mm Neutrik plug. So both are nice in my book.

I have a lot of questions to ask myself today, and a lot of things to experiment. All I need is a cold beer. :)
 
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Jun 16, 2023 at 1:23 PM Post #2,534 of 5,799
By the way, quite nice the 2 x 6.3mm on V200. I listen in parallel with Final D8000 Pro and Ultrasone Signature Pro. The only thing I have to take care is to lower the volume when switching because of different impedances and sensitivities. As expected Ultrasone Signature Pro sounds louder. In rest, no chance against D8000 Pro. It kills the soundstage, less resolving, less separation between frequency bands, what to say, I was not expecting something different, I am not a fan of closed backs and here I guess we discuss about different price ranges. I avoid to say that the comfort is close because this is debatable, you know, many complain D8000 Pro is heavy, for me it stays fix on my head when working and the earpads are quite comfortable. But there is only one thing I liked more on Ultrasone, which I guess is common for all closed backs with decent bass, more visceral in isolated passages. And Signature Pro has more bass than D8000 Pro. Here I have to admit I liked it, but it was, well, 1 case on 3 tracks. LOL

Ultrasone_Final.jpg


But I guess that Ultrasone Signature Pro works well for EDM and people listening to electronic music. In my case with rock, well, this kind of "in your face" sound does not really appeal. Is the difference between them 3x (like the original price when launched)? Of course not, I would say 20% but Final is less sharp, wider, more natural, does things much better.

But the difference between headphones is not so important. Today I realized how much of my preferred sound signature are the interconnects. I started connecting the audio-gd NFB11.32 to V200 via some DH Labs Air Matrix (1m, RCA-RCA). All sounded shouty, veiled, same feeling as my Valvo EL42. Not necesarily bad, at first I thought that well, this is the SS area and its limits. But later I put the same interconnects I use on TT2 -> Eternity: some custom made Neotech NEI-2001 I use for many years. These are made by a local professional, but have very good quality and he used also very good connectors. And damn, magic was back, my SS smaller system started to sound similar (but not at that level) with my main rig. Of course, there are differences and limitation, but WOW what a difference some good interconnects make. I have 2 pairs of interconnects made by the same person from the same NEI-2001 (one RCA and one XLS terminated) so I will use the same type on both systems from now on. And now the Cable Inquisition will come and explain me that a 5 USD cable from Amazon is the same if properly soldered. Come on guys.

I will compare these for days, but a few words about the amp comparison, starting with 2 words about V200 vs Eternity:
- Eternity is, as expected, the best. Same speed or even faster as V200, but wider and more organic sounding. Everything is more 3D, you feel more about the placement, an idea more resolving (here we have TT2 + M Scaler against a mid-fi DAC, I was expecting more, honestly). But Eternity is not with its best tubes on it, I use some Sylvania 6L6 with Tung Sol 6SL7 (7/10 if you ask me, compared to what I can do with Eternity, but the other amps, well, they are like they are, this is the beauty of tube rolling and flexible amps). Eternity can go up with better combos, SS amps will sound the same in every situation.
- I wondered sometimes if D8000 Pro would benefit from an SS amp, or if Eternity is not bringing out of them the maximum, well, I do not feel that V200 provides more. Of course, there are its bigger brothers V281 or newer models (I do not remember their names) but what I hear here is not more from what Eternity provides in terms of impact, bass. The only difference is that Eternity sounds smoother, this is the tube magic, less digital, but not slower nor less impactful. If you like or not this kind of sound is your personal preferrence.

And now some more stuff between Audio-gd NFB11.32 vs 200, when using Final D8000 Pro:
- V200 sounds smoother and more realistic, it's a more organic sound compared to the integrated amp of my DAC (nothing I would not expect). So the question if V200 makes a difference is YES. I quite like it. It's not about the level of detail, it's about the presentation, more natural, organic. It has more bass, better separation.
- audio-gd NFB11.32 sound more "digital" to me, I guess more sibilant and flat.

From memory I can say that V200 sounds better that TT2's integrated amplifier. And this is happening when connecting this small amp to a mid-fi DAC. It would be nice to try it with TT2 but I do not want to touch the main system.

In short, what I tried to say is that V200 is the best solid state amp I had the chance to listen (I had not many, but I think I like it more than A2 for example, because of its clean and organic presentation). Neotech NEI-2001 are killing other interconnects and are a big part of my favourite sound, more than I was expecting. Final D8000 Pro is in another league than Ultrasone Signature Pro, but closed back headphones with decent bass have a visceral presentation, which from time to time, is nice. And last but not least, I was expecting a lot more of a difference between TT2 + M Scaler vs audio-gd NFB11.32. But maybe these differences will come in time. Or maybe the tracks I've chosen are not as relevant. We will see. (Do not understand me wrong, there is a difference, just that I was expecting to be bigger).

And now I really deserve my beer.

beer.jpg


PS. I'm limited to D8000 Pro stock cable because my FAW Noir Hybrid has XLR connector. So that's it, I'll have to use this one.
 
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Jun 16, 2023 at 3:08 PM Post #2,535 of 5,799
Ok, back to serious things guys. Tung Sol 6SL7GT and Sylvania 6L6GAY. I need to explore more in 6L6 area because these are nice and it is a territory I never dwelled enough. In the end 807 is a kind of 6L6. This is an intermediary step for me between going back to EL42, but today after all my fun with several amps I wanted simplicity. No adapters, just music and some tubes which work natively.

Tung Sol 6SL7 - Sylvania 6L6.jpg


The most realistic presentation of all. Fast, impactful, smooth but not excesive. Definitely better that the other. However, V200 kept its place with decency. It earned my respect and Violectric confirmed for me that it is a hard working brand we need to support. We need more people like them in our hobby.
 

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