[UntilThen]

Very nice! Shuguang Black Treasure and Psvane KT88T2 (similar with mine). I am really curious about what you will say about these. I love my Psvanes but read nice things about the Black Treasures.

I bought them off a friend who chose Auris Nirvana over his Bigger Ben. So these tubes (drivers and power tubes) have been slightly burn in with not many hours of usage and sold to me quite cheaply. A good friend indeed.

Things have been just right for me lately. Destiny the 300b amp will be ready for collection on Sat morning. LCD4 arrives on Friday.

 

[UntilThen]

I might pull the trigger on a cheap pair of RFT EL34.

I've heard it and use it on the Elekit TU-8200 when it was still alive, the sound is tight and leaner than the Philips Miniwatt 6CA7 (EL34). For the price it's worthwhile getting a pair. The Mullard EL34 NOS or Philips Miniwatt 6CA7 is still better.

 

[OctavianH]

I am currently investigating the situation of the EL34. I have to admit I have ignored them until now. From what I see on Ebay and also on different websites, the cheapest NOS are RFT (some rebranded Siemens or other name). The Mullard EL34 is much more expenssive, I've seen also some Valvo, some Tesla or Telefunken, all of them more expenssive. Honestly I have no idea what to choose or if to choose something. I will continue to read, any advice is welcomed.

Interesting to read is this link.

And a book!

Later edit: Ah, these are cheap, I'll take them. LOL

 

[hpamdr]

About EL34, You can get sometimes Mullard EL34 or Tesla EL34 rebranded by Haltron or Ultron but as those also rebrand many tube not as good you have to be careful if you want to get the right ones. With the book, you can have a closer look to the construction and get the right tube for the right price.
The metal base are very expensive and not easy to find as a reallly matched pair unless you know someone changing amplifier with tubes keep the tube, re-sell the amp !
Quality of EL34 vary a lot, it is like comparing GEC 6AS7G brown curved base with 6H5C.
I personally got a pair of Ultron in fact old Tesla Production, i prefer 10 times more EL39 !

 

[OctavianH]

From Tesla EL34 and RFT EL34 what you advise to choose? I've seen some Tesla brown base double halo getter at around 25-50EUR (depending on quality) and RFT EL34 black base single ring getter at around 25-30 EUR if you search a little bit. Mullard EL34 xf* are very expensive, hard to find a matched pair and so on...

Later edit: Mullard metal base:

 

[triod750]

I am currently investigating the situation of the EL34. I have to admit I have ignored them until now. From what I see on Ebay and also on different websites, the cheapest NOS are RFT (some rebranded Siemens or other name). The Mullard EL34 is much more expenssive, I've seen also some Valvo, some Tesla or Telefunken, all of them more expenssive. Honestly I have no idea what to choose or if to choose something. I will continue to read, any advice is welcomed.

Interesting to read is this link.

And a book!

Later edit: Ah, these are cheap, I'll take them. LOL

It's funny when they translate 'valve' to 'ventil'.

 

[OctavianH]

It's funny when they translate 'valve' to 'ventil'.

Yes, first time I've seen that I was thinking about the wheel of a bike.

 

[UntilThen]

You buy EL34 for it’s lushness and ‘romantic’ tone. You buy KT88 if you want slam, punch and a hard hitting tone. The contrast cannot be greater here. KT77 falls somewhere in between and KT66 leans more towards EL34. EL12 spez is a EL34 on steroids.

It’s generally agreed that the best EL34 in terms of smoothness and fluidity are the Mullard EL34 (xf2 would be nice) of which the Philips Miniwatt 6CA7 is similar. Even within Philips Miniwatts 6CA7, you have different constructions. Those in the know claim that the double 'O' rings getters are better than the single 'O' ring and that the double 'D getters are the best, aside from the metal base. Telefunkens and other East German brands generally have a different tone - leaner and tighter with better dynamics. Which is better depends on your preference.

When you have an amp like Eternity, you can loose sight of why you got an amp in the first place. That is to find an amp that fits into your system and that synergises with the rest of your gear. Tube amp rolling is part of the fun and the reason we do that is to fine tune our system. However you can get too caught up in this and miss the joy of discovering new songs. Instead you repeat all your favourite songs and marvel how wonderful and slightly different how each song sound with each new tube change. There's no right and wrong here. A person chooses how they use their finance and their time. If tube rolling serves as part of your enjoyment so be it. However from my past experience and from many others, there will come a time when you'll settle on a tube combination, settle back and just enjoy the music. Then you'll look at your pile of tubes sitting in boxes and wonder how you got this point. and you start to sell them off... and the next buyer repeat the process. It's the circle of life.

Just take care of the tube sockets. They wear out over time with repeated and frequent tube changes. Socket savers help but they just create another unnecessary layer that will not aid SQ.

My advise is to buy a pair of Mullard or Philips EL34 when you have the means and be done with it unless you're UntilThen. I wouldn't roll 300b tubes though because they are too cheap and tube rolling in them cause migraine and heart palpitations.

 

[OctavianH]

Wise words. Well, the tone of KT77 was never exactly what I preferred. This romantic and lush presentation is not matching my type of music. But I want to try a pair of EL34 just to see if the tone is the same as expected in Eternity. So I went to a pair of Tesla brown base overlapping double-O getter rebranded Edicron. From what I read the 70-80s Tesla made in Czehoslovakia are quite good, having a better high frequency extension and better dynamics than the Mullard, which of course has other qualities, being more romantic and rich in tone. In my case I guess it was the best choice, if not we will search for others. As you can see I already settled to KT66/KT88, this amplifier was built for KT66 in my case, and tube rolling is ocasionally just for fun. I have not rolled anything for 3 days.

 

[UntilThen]

GEC KT66 was one of my favourite when I was rolling in Elekit TU-8200. Only piped by the EL12 spez IMO. The Philips Miniwatt 6CA7 is third.

I need to explore KT88 again. Pretty sure I will try KT150 just for the fun of it. EL156 looks tempting. Thereafter I will roll drivers followed by rectifiers.

The combination I am looking forward to is EL11 and EL12 spez.

 

[OctavianH]

I need to explore KT88 again. Pretty sure I will try KT150 just for the fun of it. EL156 looks tempting. Thereafter I will roll drivers followed by rectifiers.

When the KT* mania started on the F.A. amps I bought new russian production of Tung Sol 7581A, Gold Lions KT66/77/88. From all of these KT66 was my preference but KT77 had a nice tone, warmer, good to use in those amps as driver. Many used KT88 driven by KT77 or 6L6 and considered a very good combination. The reissue of KT88 sounded for me harsh, somehow towards solid state and I renounced on them fast. A similar, but better tube was, for me, 6550A (KT88 equivalent). Now a long time ago I had the chance to buy at a very good price (50EUR/tube) a pair of Psvane KT88T2 (similar to what you have posted yesterday, orange base grey glass) and these sounded incredible to me even on Elise. But from what I remember (cannot compare now, my russian Gold Lions KT88 are sold for many months already) these sound very different from what I knew about KT88, very clean, full and articulated, without that harshness and even that solid state feeling is much attenuated. Even the bias values are strange for me, since these Psvane I have are biasing similar with my KT66 (not sure if a general problem or specific to my pair). I cannot say how these compare to GEC KT88, I never heard them, let's hope I will be lucky enough to find a pair at a good price sometimes.

 

[UntilThen]

Surprise that those power tubes works well as drivers in FA amps. Practically almost all amp builders will not agree with that.

I have only use Gold Lion KT88 in TU- 8200 and Primaluna KT88 in the Primaluna Dialogue Premium HP amp. In both instances, the tone is leaning towards solid state tightness and hard hitting. I need to use this LCD4 with that. Should be very interesting.

Several well known tube amps uses 6SL7 as drivers. Such as Bigger Ben and Mogwai Se. As well as Eddie Current Zana Deus. 6SL7 will also be use as drivers in Odyssey as well as 6SN7. I have 2 good 12au7 and 12at7. Odyssey will be very versatile and will have tremendous power. Even more powerful than my 300b amp.

 

[hpamdr]

Surprise that those power tubes works well as drivers in FA amps. Practically almost all amp builders will not agree with that.

I have only use Gold Lion KT88 in TU- 8200 and Primaluna KT88 in the Primaluna Dialogue Premium HP amp. In both instances, the tone is leaning towards solid state tightness and hard hitting. I need to use this LCD4 with that. Should be very interesting.

Several well known tube amps uses 6SL7 as drivers. Such as Bigger Ben and Mogwai Se. As well as Eddie Current Zana Deus. 6SL7 will also be use as drivers in Odyssey as well as 6SN7. I have 2 good 12au7 and 12at7. Odyssey will be very versatile and will have tremendous power. Even more powerful than my 300b amp.

I was in contact with Henryk long time ago about tube adapter.... He gave me some hint on F.A. tolerance he was OK for having EL/KT tube as output but was not ready to promote those in driver position. In fact he finally decided to not promote none of the "Exotic" combination you can find in F.A. thread. The special auto-bias and the capacitor used makes the amp very versatile. Euforia sound good with a lot of tube combination and with many headphone. Even if it is not the best for every combination it is most of the time in good position !

I also use 6H9S as driver with EL39 on EuForia, I can say that this is a very special combination that emphasis details and soundstage but still with a warm/romantic overall tone. I plan to also use 12SL7 on Eternity and 12SC7 almost same characteristics as 6SL7 but more powerful and easier to bias I will personally keep Euforia to play and enjoy with with tube rolling. Eternity will be used to find good combination and enjoy music. Excatly as you said, tube rolling and music listening are not exactly the same hobby.

 

[OctavianH]

This morning I had a surprise when trying the GEC KT66 with one of the tubes I never enjoyed and liked, actually I always considered it one of my worse acquisitions. The Philips 6SN7WGTA:

I tried these on Littledot MK2, at that time with some adapters in the power position (if I remember correctly), then with Elise as drivers. All the time I was considering these dull sounding. Well, today just for fun, since the tube was already in the position, I switched the input from single -> double triode and started the amplifier.
I was prepared to stop it fast and put a "decent" driver but the sound I heard was extremely clean, clear and towards neutral. A lot of micro details, these taming a little bit the KT66 sweetness. I have to admit that I prefer a little bit more of a full bodied sound, but honestly these were a surprise. I wonder how such clean neutral drivers would complement a lush and romantic EL34. I think I have to try this! So, surprise. I know that this tube is not well respected in the community, many consider it, like I was, a dull sounding 6SN7.

 

[OctavianH]

And yes, brutal times, it had to be done. KT150 on Eternity! I've checked the grid bias twice, -25V to be sure.

I've tried to sweeten them a little bit with the GEC L63, still quite dry sounding. A lot of bass, power and good clarity. What to say, I prefer KT88 or KT66, but had to try these.
KT150 on a small headphone only amplifier. Next KT170 when they release them.

And, to have an idea about the size difference:

The currents started with delay to rise on KT150. The inputs were already at 4mA when the outputs started, slowly, to rise. They got also quite hot, I had to wait a few minutes to be able to remove them.