[leftside]

Here's some more tubes to talk about - Mick's/Supratek latest creation"
https://supratekaudio.blogspot.com/2023/07/supratek-merlin.html

 

[triod750]

Here's some more tubes to talk about - Mick's/Supratek latest creation"
https://supratekaudio.blogspot.com/2023/07/supratek-merlin.html

I really like this kind of madness. Why not?

 

[Isaacc7]

Here's some more tubes to talk about - Mick's/Supratek latest creation"
https://supratekaudio.blogspot.com/2023/07/supratek-merlin.html

I think it’s a bit crazy to use such rare tubes. It only takes one oops moment to damage either the tube or the amp itself. I wonder if the amp could be easily modified to use different tubes In case something happens. There are a variety of transmitting tubes that can take those kinds of voltages but I don’t know if they can use similar transformers. I get the appeal of a super powerful single ended amp but the high voltages mean that the price of everything goes up dramatically. On a practical level I don’t think I want something using that much juice in my front room!

 

[Isaacc7]

I’ve been listening to the Sylvania 12av5 for a few weeks now and I am really impressed. Comparisons to the 2a3 are reasonable I think although these are capable of more power. My particular listening impressions probably aren’t all that useful here on head-fi but I’ll post them here in case anyone finds them by googling. Nobody needs a push pull amp with these kinds of tubes for headphones but all of the reports that got me interested in this tube talked about running them single ended. Check out http://tubelab.com/articles/tube-testing/6av5-sweep-tube/ for details.

I’m running them in push pull at 300v 40ma with an 8k transformer (monolithic Magnetics) In both triode and ultralinear. In triode mode they have a very pleasing presentation, slightly soft but gorgeous midrange and voices. Great bass, slightly subdued highs. But that midrange… When I flip them to ultralinear I am reminded of 2a3 based systems I have heard before. The softness of the triode mode is gone and there is now a great sense of clarity. The midrange doesn’t have that softness to it anymore but in return I now have a lot of presence or something like that. Things just sound so… there, I dunno how to describe it. It is the kind of sound I attribute to triode amps (300b, 2a3, etc.) that have more modern designs. They don’t have the lushness or “bloom” that old school 300b amps give you but instead lean into the inherent linearity of the tubes. I will say I am getting better bass out of this than any single ended amp I have ever heard when I run them in ultralinear. There are advantages to push pull Some people like tube equipment to give them a “warm” sound, I prefer tubes because they sound timbreally correct to me. That’s what newer triode amps give you and that’s what I’m getting out of these. My favorite drivers in triode mode are the 5a/152m as triodes and in ultralinear I really like either the Fivre 6c5 or the ktz41 run as a triode. Only truly mad people use the ktz41 though, the heater requirements are nuts.

So yeah, highly recommended. But there are a few gotchas. First, it isn’t clear that any *av5 will work as well as these at these voltages. Apparently the tubes I have are actually 6fw5 or close to it. They can handle more juice than actual *av5 tubes can. I have yet to try other *av5 tubes. If I do I will have to pay close attention to the voltage used. George says that they can go into runaway quickly. The other thing to look out for is that lots of people complain about oscillations when using these tubes. I haven’t had any problems with that but I’ve heard it enough that it’s something to look out for.

There is a Canadian company that makes a push pull amp using the Sylvania 6av5 but I’m not aware of any other recent commercial amps that do so they tend to be pretty reasonably priced. The 12 and 17 volt versions are just straight up cheap. You’ll need adapters to use them in your typical el34 6l6 etc. amp but even with that figured in they are cheap.

 

[Xcalibur255]

You definitely need grid stoppers to use 6AV5 family tubes in a triode application without oscillation issues. It should be possible to implement adapters for them that way. I remember reading once along time ago that at the very end of 6B4G production they were actually just substituting 6AV5 guts wired as triodes into the larger glass envelopes and labeling/selling them as 6B4G.

 

[Isaacc7]

You definitely need grid stoppers to use 6AV5 family tubes in a triode application without oscillation issues. It should be possible to implement adapters for them that way. I remember reading once along time ago that at the very end of 6B4G production they were actually just substituting 6AV5 guts wired as triodes into the larger glass envelopes and labeling/selling them as 6B4G.

When my amp was being built I had asked Tomas to put in grid stoppers because I knew I wanted to use this tube and I knew about its reputation. He was dismissive and said that his amps didn’t need them. I assume he didn’t put them in. Maybe @Deyan put them in the adapters? In any case I have not had any oscillation problems and I don’t think that there are any grid stoppers in my system. Having said that I don’t know what the risks are with tube amps oscillating. Maybe it‘s not a good idea to take the risk.

 

[ARCXENOS]

Christmas came in early for me

I know there are probably cheaper alternatives that sound similar with adapters, but dammit, I really wanted them for sometime and a good deal for a new testing lightly-used set popped up, I had to go for it

I hold GEC valves to a high standard, and these are no exception. They proved they are the Kings of the KT88/6550/EL34/6L6GC family for me, because :

- Instrumental separation and staging perception is extremely wide relative to 6550/EL34/6L6GC
- Microdetails are rendered so clearly and in a non-fatiguing manner, it is truly superlative.
- Rich mids presence and vocals with the liquid smoothness that you know and expect from plenty of UK valves? Its there.
- Deep bass that is not overwhelming, it is firm and tight, just the right amount for me

The last time I felt such a close connection to a pair of glass was when I first used the Mullard ECC32 and the Elrog ER300b... I absolutely adore the GEC KT88

Current setup used are the RFT 6H8C and Raytheon 5U4G to ZMF Verite Open and Aeolus, I will explore further combinations during the weekends

The above is probably old news to you veteran rollers, but dam do I love GEC

 

[crakers7]

Christmas came in early for me

I know there are probably cheaper alternatives that sound similar with adapters, but dammit, I really wanted them for sometime and a good deal for a new testing lightly-used set popped up, I had to go for it

I hold GEC valves to a high standard, and these are no exception. They proved they are the Kings of the KT88/6550/EL34/6L6GC family for me, because :

- Instrumental separation and staging perception is extremely wide relative to 6550/EL34/6L6GC
- Microdetails are rendered so clearly and in a non-fatiguing manner, it is truly superlative.
- Rich mids presence and vocals with the liquid smoothness that you know and expect from plenty of UK valves? Its there.
- Deep bass that is not overwhelming, it is firm and tight, just the right amount for me

The last time I felt such a close connection to a pair of glass was when I first used the Mullard ECC32 and the Elrog ER300b... I absolutely adore the GEC KT88

Current setup used are the RFT 6H8C and Raytheon 5U4G to ZMF Verite Open and Aeolus, I will explore further combinations during the weekends

The above is probably old news to you veteran rollers, but dam do I love GEC

Those G.E.C KT88's are at the top of my list , I recently missed out on some G.E.C 6550 (10 of them for $880 aud ) . Do the GEC KT88 sound better than the 6550 ?

 

[ARCXENOS]

Those G.E.C KT88's are at the top of my list , I recently missed out on some G.E.C 6550 (10 of them for $880 aud ) . Do the GEC KT88 sound better than the 6550 ?

Did you mean GE 6550s, I don't remember GEC making 6550s as its an American designation I think

For 6550s I currently have :
- Tungsol Gen3
- Sylvania
- GE
- Svetlana Winged C, St Petersburg factory
- Shuguang 98

I do enjoy all of them time to time depending on the driver, I think if I have to pick based on the last 3 drivers I have used with the GEC (Tesla 6CC10, TS BGRP VT-231, RFT 6H8C), I personally will shell out for the KT88 first knowing what I now know. 2nd in my list will be the Tungsol 6550 for some bass cannon fun, but the GEC has more refined quality (for my taste and music choice) IMO

But with that said, you can probably find the 6550s for cheaper, and I do enjoy them all (even the Shuguang and GE!). I could not go wrong with any of the 6550s on any day - if budget allows, and if you can get a deal for them (I have seen 300-400 USD for pairs of Sylvanias and GEs, I DID NOT PAY THAT!!), they are still fun to listen to.

 

[crakers7]

Did you mean GE 6550s, I don't remember GEC making 6550s as its an American designation I think

For 6550s I currently have :
- Tungsol Gen3
- Sylvania
- GE
- Svetlana Winged C, St Petersburg factory
- Shuguang 98

I do enjoy all of them time to time depending on the driver, I think if I have to pick based on the last 3 drivers I have used with the GEC (Tesla 6CC10, TS BGRP VT-231, RFT 6H8C), I personally will shell out for the KT88 first knowing what I now know. 2nd in my list will be the Tungsol 6550 for some bass cannon fun, but the GEC has more refined quality (for my taste and music choice) IMO

But with that said, you can probably find the 6550s for cheaper, and I do enjoy them all (even the Shuguang and GE!). I could not go wrong with any of the 6550s on any day - if budget allows, and if you can get a deal for them (I have seen 300-400 USD for pairs of Sylvanias and GEs, I DID NOT PAY THAT!!), they are still fun to listen to.

Yep , my bad they were GE not GEC (see photo)
I also have the Svetlana winged C 6550 and KT88 which sound wonderful but am keen to get the GEC KT88

 

[Toonartist]

Christmas came in early for me

I know there are probably cheaper alternatives that sound similar with adapters, but dammit, I really wanted them for sometime and a good deal for a new testing lightly-used set popped up, I had to go for it

I hold GEC valves to a high standard, and these are no exception. They proved they are the Kings of the KT88/6550/EL34/6L6GC family for me, because :

- Instrumental separation and staging perception is extremely wide relative to 6550/EL34/6L6GC
- Microdetails are rendered so clearly and in a non-fatiguing manner, it is truly superlative.
- Rich mids presence and vocals with the liquid smoothness that you know and expect from plenty of UK valves? Its there.
- Deep bass that is not overwhelming, it is firm and tight, just the right amount for me

The last time I felt such a close connection to a pair of glass was when I first used the Mullard ECC32 and the Elrog ER300b... I absolutely adore the GEC KT88

Current setup used are the RFT 6H8C and Raytheon 5U4G to ZMF Verite Open and Aeolus, I will explore further combinations during the weekends

The above is probably old news to you veteran rollers, but dam do I love GEC

Congrats… they’re beautiful tubes!

I picked up a NOS pair earlier in the year and I’m fairly stingy with them but, I’ve managed to pick up one near new spare and I’ll add another if the opportunity arises! Enjoy… they really do aound amazing

 

[ARCXENOS]

Yep , my bad they were GE not GEC (see photo)
I also have the Svetlana winged C 6550 and KT88 which sound wonderful but am keen to get the GEC KT88

I did read they were similar but you have to use an adapter, I had my eye on these but I really wanted the KT88. I am not sure when another pair of the above will popup, but thats a choice. For me, I will just tell my past self to DO IT. YMMV maybe someone else have another close substitute suggestion. Its definitely more of a want than a need, but its a hobby

Congrats… they’re beautiful tubes!

I picked up a NOS pair earlier in the year and I’m fairly stingy with them but, I’ve managed to pick up one near new spare and I’ll add another if the opportunity arises! Enjoy… they really do aound amazing

Thank you! The set I bought was actually a quad, so I could use it a little bit more freely unlike my Mullards, those only get used when I can commit to 4-6 hours of listening with no distractions! And I agree, they are really amazing

 

[leftside]

I did read they were similar but you have to use an adapter, I had my eye on these but I really wanted the KT88. I am not sure when another pair of the above will popup, but thats a choice. For me, I will just tell my past self to DO IT. YMMV maybe someone else have another close substitute suggestion. Its definitely more of a want than a need, but its a hobby


Thank you! The set I bought was actually a quad, so I could use it a little bit more freely unlike my Mullards, those only get used when I can commit to 4-6 hours of listening with no distractions! And I agree, they are really amazing

Exactly the same as a GEC KT88. Just have the extra top cap. Recommended

Looks like the bottom has fallen out of the tube market. The TT21 used to sell for a lot more.

 

[Toonartist]

I also spotted GEC TT22 on the bay... are they the same? They're marked as KT88 as well

 

[Isaacc7]

I also spotted GEC TT22 on the bay... are they the same. They're marked as KT88 as well?

Tt22 is a 12v tube but otherwise the same as the tt21.