[mordy]

Good times are coming. I was able to get a cheap bundle of used 6SN7 of various brands and this is the perfect pretext for me to return to the "infamous" 6SN7 and see if I will like them more than on Elise, where, honestly, I have not quite used them. At those times I tried several unicorns but never really got into them. The Psvane CV181T2 with Tung Sol 5998 was my favourite combo until I discovered KT66 with 6V6. And from that point I never or rarely changed something for short periods of time. When I sold Elise I sold mostly all my 6SN7 / 6AS7 collection to switch to EL34 or 807 and what I currently use. I had matched pairs and did not made sense to keep them. When I received Eternity I tried a few of the remaining ones and preferred 6SL7, 6N7, 6J5 and later 12A*7 or 6C4. So 6SN7 was never a big love of mine. However, I read periodically the dedicated thread and felt that I need to spend more time and learn more from these, the only problem was the price I was not willing to pay for them. But luckily I got this bunch of tubes, cheap and used, and now after I measure I'll try some of them on Eternity. I like used tubes, I do not need NOS values and I am able to check them so all has to be fine.



A nice surprise was that many of these measure much better than expected at 180V / 4mA and this shows that a tube measured in datasheet conditions is not always reflecting its measurement at your amp operating point. I am sure these have plenty of life left.

And another thing I'll try is a pair of GEC KT61 in both input/output positions.



I have to be careful to pair these with some higher gain outputs, because I expect these on input will need to turn up a lot the volume knob.

Ok, we have a plan, now let's find energy to follow it. Hardest part is to remove GEC KT77 from them amp because every time I decide to do that I just realize it sounds perfect and I postpone my actions.

Be careful! Sometimes after you remove that “perfect“ tube and then put it back after some time, it may not sound the same to you.
Don’t know why this happens to me, but I have noticed it several times. - Maybe the brain needs to adjust, or whatever, but this is a fact to me.

 

[Isaacc7]

Good times are coming. I was able to get a cheap bundle of used 6SN7 of various brands and this is the perfect pretext for me to return to the "infamous" 6SN7 and see if I will like them more than on Elise, where, honestly, I have not quite used them. At those times I tried several unicorns but never really got into them. The Psvane CV181T2 with Tung Sol 5998 was my favourite combo until I discovered KT66 with 6V6. And from that point I never or rarely changed something for short periods of time. When I sold Elise I sold mostly all my 6SN7 / 6AS7 collection to switch to EL34 or 807 and what I currently use. I had matched pairs and did not made sense to keep them. When I received Eternity I tried a few of the remaining ones and preferred 6SL7, 6N7, 6J5 and later 12A*7 or 6C4. So 6SN7 was never a big love of mine. However, I read periodically the dedicated thread and felt that I need to spend more time and learn more from these, the only problem was the price I was not willing to pay for them. But luckily I got this bunch of tubes, cheap and used, and now after I measure I'll try some of them on Eternity. I like used tubes, I do not need NOS values and I am able to check them so all has to be fine.



A nice surprise was that many of these measure much better than expected at 180V / 4mA and this shows that a tube measured in datasheet conditions is not always reflecting its measurement at your amp operating point. I am sure these have plenty of life left.

And another thing I'll try is a pair of GEC KT61 in both input/output positions.



I have to be careful to pair these with some higher gain outputs, because I expect these on input will need to turn up a lot the volume knob.

Ok, we have a plan, now let's find energy to follow it. Hardest part is to remove GEC KT77 from them amp because every time I decide to do that I just realize it sounds perfect and I postpone my actions.

I have been fascinated with the kt61 for a while. I have the loctal version kt81 and the 12v version n34. GEC warns that they should always be used in an auto bias circuit so I won’t be able to use them in my new amp. I briefly tried them in my SE amp and they sounded lovely. Just like aI thought they would. Unfortunately my SE amp runs them over spec so I didn’t want to put too many hours on them and age them prematurely. I’m scheming on ways to use these tubes and others with similar specs, especially the older 4v tubes.

 

[OctavianH]

Be careful! Sometimes after you remove that “perfect“ tube and then put it back after some time, it may not sound the same to you.
Don’t know why this happens to me, but I have noticed it several times. - Maybe the brain needs to adjust, or whatever, but this is a fact to me.

It also happens to me often. I like to think we have several "best of" combinations and those are dependant on the mood. But besides that, perception changes to me often depending on the level of stress or how tired I am. But even in these conditions, for me KT77 always remained on top of the other output tubes I tried.

In the next period I want to play with these 6SN7 I spoke earlier about. But I also want to identify and make some research about some of them which are unknown to me. As a glimpse of what's to come:

But the plan is to make pictures in good light and research a little bit about all of them. For example on the first row the first 2 from left are branded as "Haltron" but they are most probabily rebrands. They can be a good starting point for me.

Later edit:

While the green painted one looks similar with one RCA:

The one with red logo is still a mistery to me. No problem, we have time to find out about that one.

 

[mordy]

It also happens to me often. I like to think we have several "best of" combinations and those are dependant on the mood. But besides that, perception changes to me often depending on the level of stress or how tired I am. But even in these conditions, for me KT77 always remained on top of the other output tubes I tried.

In the next period I want to play with these 6SN7 I spoke earlier about. But I also want to identify and make some research about some of them are unknown to me. For example 2 Haltron ones which I expect are rebrands.

As a glimpse of what's to come:



But the plan is to make pictures in good light and research a little bit about all of them. For example on the first row the first 2 from left are branded as "Haltron" but they are most probabily rebrands. They can be a good starting point for me.



Later edit:

While the green painted one looks similar with one RCA:



The one with red logo is still a mistery to me. No problem, we have time to find out about that one.

The red on could be a BRIMAR which is selling for a good price:

 

[gibosi]

It also happens to me often. I like to think we have several "best of" combinations and those are dependant on the mood. But besides that, perception changes to me often depending on the level of stress or how tired I am. But even in these conditions, for me KT77 always remained on top of the other output tubes I tried.

In the next period I want to play with these 6SN7 I spoke earlier about. But I also want to identify and make some research about some of them which are unknown to me. As a glimpse of what's to come:



But the plan is to make pictures in good light and research a little bit about all of them. For example on the first row the first 2 from left are branded as "Haltron" but they are most probabily rebrands. They can be a good starting point for me.



Later edit:

While the green painted one looks similar with one RCA:



The one with red logo is still a mistery to me. No problem, we have time to find out about that one.

And I agree, the one with the red logo looks like a Brimar.

 

[OctavianH]

The red on could be a BRIMAR which is selling for a good price:

Good catch, I was searching in the same direction reading here.

 

[triod750]

I like to think we have several "best of" combinations and those are dependant on the mood.

Agree!

 

[triod750]

The Haltron/Brimar looks exactly as my Brimar so I don't know what it is

 

[OctavianH]

I managed to get the GEC KT77 off the amp. It was hard. So I thought about a "reference" tube for output to be able to understand what is happening with these new toys.
And the best solution was GEC KT88, it is a little bit sweet in tone but, in rest, close to what many call "reference". And my pair is heavily used, so no problem to stress it a little bit, I do not care about it too much.

First try, KenRad 6N7 with GEC KT88. I put them in the 6J5 slot, so both triodes wired in parallel. And as expected, a very warm and relaxed sound, I like it. 6N7 is a good option to make the KT88 more musical and add some bass here and there. Now I need a glass of whiskey.

 

[OctavianH]

I started on big horses with the 6SN7 but in the end remained on these Ken-Rad 6N7.

In combination with GEC KT66 which I find incredible on acoustical instruments, they add some warmness and weight and make everything more fluid. Exceptional combination for piano or vocals. This combo is a keeper and another proof that 6N7 is for me a very important type. Unfortunately I still cannot find myself comfortable with the 6SN7 and I will, of course, continue to check them and see where this goes.

 

[UntilThen]

I love my GEC KT66.

 

[OctavianH]

And a small new chapter in Eternity's life: GEC KT61. Incredibly good sounding, above expectations. A 6V6 with GEC flavour or more? I'll have to decide this in the following days.

Bias was around -4V for 20mA @ 200V.

 

[Isaacc7]

And a small new chapter in Eternity's life: GEC KT61. Incredibly good sounding, above expectations. A 6V6 with GEC flavour or more? I'll have to decide this in the following days.



Bias was around -4V for 20mA @ 200V.

Yup. That is exactly how I was expecting them to sound. The kt61 and el33 have the reputation of being amazing tubes as long as you don’t need a lot of power. I’m thinking of having an amp made specifically to use tubes in that power range.

 

[OctavianH]

Yup. That is exactly how I was expecting them to sound. The kt61 and el33 have the reputation of being amazing tubes as long as you don’t need a lot of power. I’m thinking of having an amp made specifically to use tubes in that power range.

They sound very good, at first I would say these are close to 6V6 but with that british aristocratic sound and somehow more powerful. I am impressed.

Later edit: I had to make another picture of these beauties.

 

[OctavianH]

Indeed, these GEC KT61 pair very well with 6J5. For example with GEC CV1067 L63.

This was an important milestone in Eternity's life, the KT61. I was not expecting that I would be so pleased about these, and soon I'll try them on input. I am curious about the gain in that case, I guess I'll pair them with some EL34 or higher gain outputs.