[triod750]

This is wildly OT… I was smitten by the audiophile bug while I was in college in the early 90s. Went to a high end dealer and heard actual imaging from speakers and it blew my mind. First job out of college was selling audio gear. Mostly sold Denon but also Parasound, Rotel, and McIntosh. I got to go to a lot of people’s houses and hear a lot of different systems. I had always been enamored by tubes since I was a kid. We had a really old DuMont TV that used tubes. Watched dad fix it by yanking tubes, going to the hardware store, using the tube tester, and getting replacement tubes. Heard my first tube system at the job. Customer had a McIntosh 240 and a pair of Spendor speakers. It was love at first listen.

Later on I moved near Washington DC and discovered a dealer that only sold tube gear. No home theater, no TVs anywhere. He had all sorts of amps, speakers, you name it. Here’s a picture I took 6 or 7 years ago.


That’s a pair of Atmosphere OTL amps driving a pair of Omni directional speakers. Probably about 30k worth of a system. Some random Conrad Johnson amp and Italian gear on the back table. Check out all the albums to test out gear! There were another 3 rooms like that filled with LPs. Turning to my left I saw


That’s a custom line preamp using top cap tubes, several vintage amps, a field coil speaker from the 40s I think. Oh, and a 2 chassis Jadis preamp that probably costs upwards of 20k just sitting there. There are 9 or 10 different listening rooms there just stuffed to the gills with gear. It’s a real wonderland for tube lovers. Here’s a shot from some years before that:



That’s an actual Western Electric Voice of the Theater horn with a vintage WE amp. Oh, and some custom made amps strewn around. It’s just absurd what he gets through there.

I hung out there regularly for multiple years listening to all sorts of amps and speakers. Also got to go listen to some of the custom systems he had made for clients.

At the same time I started reading Audio Asylum religiously. Years later I hung out on DIYaudio absorbing more technical information. Was able to connect some dots and figure out what I liked and what probably caused what I liked. It was quite the education and tons of fun of course. I drifted away from audio for a while when I moved overseas but came back to it with a vengeance over the past 4 years. I’m still learning about the technicalities about amp design but I known just enough to be dangerous lol.

Now back to our usual tube rolling…

Pretty good background, you are through the basics by now .

 

[OctavianH]

At the same time I started reading Audio Asylum religiously. Years later I hung out on DIYaudio absorbing more technical information. Was able to connect some dots and figure out what I liked and what probably caused what I liked. It was quite the education and tons of fun of course. I drifted away from audio for a while when I moved overseas but came back to it with a vengeance over the past 4 years. I’m still learning about the technicalities about amp design but I known just enough to be dangerous lol.

That's why I also try all these. Not to find a good pair, to understand why I like what I like and how I can somehow link that with the design of my equipment and the tube parameters I choose. I am unsure if I'll fully understand this, but I can say that I started to have an idea about it. A long road ahead.

I have a killer idea for an amp, but I do not have someone to build it for me at the quality level I would like to. So read your books, we have stuff to do.

 

[OctavianH]

I am quite busy during the week so I had to go for something which will sound good without any doubt. My ITT Lorenz E88CC with my Philips 4654K are one of my favourite combos. A technical combo, but which still sounds harshless and very good.

Soon I'll try the Tesla 4654 and then a bunch of EL41. EL41 is a leftover which I wanted to try nearby EL42 but things went sideways. No problem, we return to EL41 and maybe make a recap on EL42. I loved it at the time I tried it and for sure needs more attention. Then I'll try some 6K6 because some folks told me that it sounds good and found a box of them somewhere. Let's hope it arrives safely to me. I would try also 6W6 and 6F6 but prices are not tempting me and I am unsure if those are interesting enough.

I said that EL50 is the end and I was not joking. EL50 redefined for me the sound somehow. But from time to time I want to focus on a special tube, something rare or interesting which can bring value to my experiments. Not what people use, what people forgot about. I have a few ideas and luckily when people forget, those sell incredibly cheap. So I bought a few rare and unknown tubes. I am looking forward.

Until then, an evening with E88CC and 4654K is always a success. I could live with this combo, but I will not because I have 100 amps in one and I can exchange them whenever I want.

 

[OctavianH]

So I said I'll do it and I'll do it. The final chapter of the 4654 saga, Tesla 4654. After this I stop exploring this part because things start to be clear from my point of view.
So this is it: Tesla 4654 on Eternity near Fivre 6SL7. I wanted to put this one because I used it extensively with Philips 4654 (EL50) and I had a clue about the sound. So I think I am able to compare.

What's interesting is that we have 2 types of getters in these tubes.

And:

And if I'll tell you that I have a thind one which is different from these both you'll say I'm crazy. Anyway soundwise these are identical. I tried to find out when these were manufactured and found (if this table is correct):
CU = June 1961
RS = November 1959

Soundwise these are different than the Philips "red base" and Valvo "grey base" I tried in the past. If I said that Valvo and Philips were close, these are different from both, going more to a thinner presentation, less bass and more neutral. Detail retrieval is good, maybe better than on the Philips but this might be a consequence of the more neutral signature. Overall, it's a nice and decently smooth sound but nowhere as holographic and liquid as the Philips "red base" ones. I think I can put these near the more technical sound of 4654 and 4689 tubular versions (metal base). For the price? Exceptional sound. Better than Philips EL50? Not, but this does not mean these are not very good sounding. Being more neutral and technical, sound quite fine on rock music. I like what I hear and I'll definitely use these often. These surpass many other tubes I have, but just do not reach the level of richness and soundstage of EL50.

These are, of course, preliminary conclusions, but I think what I say will remain valid after more and more listening hours.

 

[Isaacc7]

I have been cycling through input tubes for the 12av5. Ecc31, Raytheon 6f8g, and Tung Sol BGRP. The first 2 didn't work very well for a variety of reasons. The TS gave a very round, smooth sound that had a lot of appeal. Ran those for several nights. Have since switched to the c3m and I am once again very impressed by what I am hearing. They are doing their disappearing act, it's like there's no tube there at all. It sounds like the output tubes but with more drive. Open, transparent, and very neutral. Bass and mid bass are thunderous. All of the tube combos with the 12av5 in triode have had great clarity and naturalness through the midrange but with the c3m the 12av5 is just... it's best self I guess.

I think the overall sound is clear but a bit on the romantic side with amazing bass and pure tones. Compared to the c3m with the vt60a the 12av5 is just a little more colorful while the vt60a gives me a more transparent view into the recording. Not bad for $5 tubes! even the regular 6v version can be gotten for under $20 a tube.

 

[OctavianH]

Not bad for $5 tubes! even the regular 6v version can be gotten for under $20 a tube.

The real audio journey starts when you buy tubes under $5 per piece. I buy usually boxes used and not tested. 90% of them measure better than the one NOS NIB bought in the past from reputable sellers. And unknown tube types usually sound better than what majority uses, but you need to dig a little bit in the datasheets for equivalents and pinout and parameters.

I made a photo of Tesla 4654 glow, very nice looking during evening or night listening sessions.

 

[OctavianH]

Tesla 4654 is addicting even if it does not match the Philips versions. So I guess I can also live with it without loosing too much. It's clean, sharp, detailed and also an idea sterile compared to the others. I miss somehow what Philips EL50 adds, that richness and holographic sound, but in the end also this one is a very fine version. It surpasses a lot of other much more expensive tubes. I wasn't able to read too much about it because not many are using it, but in my view is excellent.

 

[OctavianH]

Almost 3 days of Tesla 4654. We need something new and as I said, I'll focus on more intersting tube types. So let's welcome Philips PE06/40-N. Yep, I know, many would say "What is that?". I was always confused about these naming conventions of Philips, for example I have some Mullard 807 tubes which are branded Philips QE06/50. And now these PE06/40-N which also look like 807. The base and pinout is the same, but is this one an 807? I tried to make some photos:

And on the base we have "KL/DUF", which some links to Valvo, Hamburg. I am unsure if they are right or not.

But are these 807? Well according to bias not. They are older than many 807 I think (on the paper in which they were packed was written November 1952), a kind of Philips version with the same pinout but which bias a lot lower. I went around -29V grid voltage to keep these at 200V/20mA. An 807 or 6L6 goes around -19V for the same operating point. And then I put these on the amp.

The previous photos are not making them justice, these are very beautiful tubes so I tried to make some detailed ones.

And:

But how these sound? Well, not like any 807 I heard. These are incredibly dynamic and sharp. Fast bass, very articulated and punchy. Clean and sharp. This is how I would rate these. I need time for them, but I think these pentodes surpass any 807 I heard. Of course, these are not as rich as EL50 but are damn good sounding. One of the forgotten tubes nobody most probably cares about. I've seen 3 types of it, even with that P8A socket and I think those work in my EL50 adapters. These ones work in 807 adapters without problems.

Are these the 807 killers? I would not call them like this, 807 remains a very good sounding tube and for the price it's a steal. But these are better, more detail and natural timbre. Of course, they are also much more rare. I will store all my 807 and keep these in my 807 adapters.

Later edit:
My remark that these are older than 807 is not quite true. While I have here a lot of 807, majority of the RCA ones being dated in the 60s or 70s, I also have some WW2 ones marked as VT-100. Those have some dating on the boxes around 40s. So they are some Philips equivalent or european version of 807? I have not idea yet. This is a pentode while those are beam tetrodes. Who knows more let me know.

 

[Isaacc7]

Almost 3 days of Tesla 4654. We need something new and as I said, I'll focus on more intersting tube types. So let's welcome Philips PE06/40-N. Yep, I know, many would say "What is that?". I was always confused about these naming conventions of Philips, for example I have some Mullard 807 tubes which are branded Philips QE06/50. And now these PE06/40-N which also look like 807. The base and pinout is the same, but is this one an 807? I tried to make some photos:



And on the base we have "KL/DUF", which some links to Valvo, Hamburg. I am unsure if they are right or not.



But are these 807? Well according to bias not. They are older than many 807 I think (on the paper in which they were packed was written November 1952), a kind of Philips version with the same pinout but which bias a lot lower. I went around -29V grid voltage to keep these at 200V/20mA. An 807 or 6L6 goes around -19V for the same operating point. And then I put these on the amp.



The previous photos are not making them justice, these are very beautiful tubes so I tried to make some detailed ones.



And:



But how these sound? Well, not like any 807 I heard. These are incredibly dynamic and sharp. Fast bass, very articulated and punchy. Clean and sharp. This is how I would rate these. I need time for them, but I think these pentodes surpass any 807 I heard. Of course, these are not as rich as EL50 but are damn good sounding. One of the forgotten tubes nobody most probably cares about. I've seen 3 types of it, even with that P8A socket and I think those work in my EL50 adapters. These ones work in 807 adapters without problems.

Are these the 807 killers? I would not call them like this, 807 remains a very good sounding tube and for the price it's a steal. But these are better, more detail and natural timbre. Of course, they are also much more rare. I will store all my 807 and keep these in my 807 adapters.

Later edit:
My remark that these are older than 807 is not quite true. While I have here a lot of 807, majority of the RCA ones being dated in the 60s or 70s, I also have some WW2 ones marked as VT-100. Those have some dating on the boxes around 40s. So they are some Philips equivalent or european version of 807? I have not idea yet. This is a pentode while those are beam tetrodes. Who knows more let me know.

Your description of the sound reminds me of what I hear with the vt-60a. I thought that RCA made the 6l6 first, created the 807 with top cap for higher voltages, and then everyone else tried to copy that. That’s the lore I remember at least.

 

[triod750]

Mesh above top mica?

 

[OctavianH]

Your description of the sound reminds me of what I hear with the vt-60a. I thought that RCA made the 6l6 first, created the 807 with top cap for higher voltages, and then everyone else tried to copy that. That’s the lore I remember at least.

The sound was sharp and fast, while 807 is smooth sounding with more bass. I will need time to compare these, but for sure, impressive tube. While RCA 807 is warmer and more rounded, this one is more extended on highs, and the bass is slimmer but incredibly punchy and fast. It remembers me on the EL86 (that one brighter than this one but same style of bass). Sounds very dynamic, but gain is similar with EL50 (same volume position with 6SL7 on input). I will say more about these in time.

Mesh above top mica?

Seems so. Here is a link on some french site where you can find a picture of this one near the SFR P17C. I'll post it here because I mentioned the source.

If you look at these, I think there are some similarities in internal construction.

 

[triod750]

Interesting. And in that SFR tube you see digits stamped into the rim of the bottom mica 'tray'.
You need to find P. 17 C at a reasonable price!!

 

[OctavianH]

Interesting. And in that SFR tube you see digits stamped into the rim of the bottom mica 'tray'.
You need to find P. 17 C at a reasonable price!!

I have enough tubes. I've seen that some SFR P17C look like this and there are some SFR P17W similar with 5933 tubes.
Some more info here.

 

[triod750]

All I can say is that the socket colour is attractive!

 

[triod750]

And that we all know that mesh in a tube makes it the holy grail and any mesh should be called mesh plate. Am I right?