[UntilThen]

The 807 internal structure is exactly the same as the 6L6GC. It's no wonder it gets so much love.

 

[UntilThen]

RCA ceramic based 807 sounds divine, a bit bright with 5A/152M

ITT tubes have flashed across my eyes so much these few days. Made by International Telephone and Telegraph in England for the Armed Forces. I wouldn't pull the trigger on these cousins of c3g because I have already 2 pairs of c3gs but I'm curious to listen to the ITT 5B/254M, the next of kin to 807.

 

[VanHai]

ITT tubes have flashed across my eyes so much these few days. Made by International Telephone and Telegraph in England for the Armed Forces. I wouldn't pull the trigger on these cousins of c3g because I have already 2 pairs of c3gs but I'm curious to listen to the ITT 5B/254M, the next of kin to 807.

Since you already have 2 pairs of C3Gs, you do not need 5A/152M. Only for people who do not want to pay extra money for C3Gs. I also have a pair of 5A/152M made by ITT, looking forward to hearing your impressions on ITT 5B/254M.

 

[UntilThen]

looking forward to hearing your impressions on ITT 5B/254M

@OctavianH said good tube indeed. He has the 5B/254M. Sweeter than the rest of 807, more powerful, that's what he said.
I will compare it with GEC 807 ATS25.

Some are branded STC 5B/254M. Standard Telephones and Cables Pty Ltd.
https://www.ebay.com.au/itm/393694055201?

 

[UntilThen]

Received this pair of Tung Sol 7236 (IBM) as a gift from @mordy. Thanks very much. Very well preserved tubes in great condition.

Inserted into gEm amp and power it up. With no music playing and volume to the max, there is no noise at all. How impressive on gEm and the 7236 tube.

I had a pair of IBM 7236 and also a pair of Cetron 7236 before but I sold them all after I sold off GOTL. I am listening to it now. Lovely, lovely tone, like a leaner version of 5998.

7236 is an old series pass tube for power supplies. Very old computers like Univac used them. They are not drop in replacements for the 6080. Higher amplification factor than the 6080 but less than the 5998.

Pin out is the same for all 3.

6080 - mu = 2 - transcond. 7000 umhos

7236 - mu = 4.8 - transcond. 12,500 umohs

5998 - mu = 5.4 - transcond. 15,500 umohs

By now, you could tell that I love this gEm amp.

 

[Deleeh]

@UntilThen, yes, you're right, this month I've hit the ground running as far as that's concerned, but I have to say that a lot of things are the cream of the crop.
And it actually goes up another notch, if not two.

About KT63 :
Langerex is being accommodating again and I've written to them and told them what's going on.
And I would try again with the KT63 if they can guarantee that this tube will work.
Since only one of the 2nd set worked, they wrote to me today and said that they would send me another pair that should fit and work.
The only thing is that there should be a small difference in height with the 3rd pair.


6BQ7A : Unfortunately there were small logistical problems and I won't receive them until tomorrow.

RCA 6550 :
These arrived undamaged from Denmark today.
The price for this pair was again a small theft, but I can live with it, the pair is brand new and unused.
My wife lent me 215€ to get them, that was the price for this beautiful pair including shipping.
After cleaning they look like this and are plugged into the Ultimate and run flawlessly.
@UntilThen maybe you can tell me which version these are from the photos.
There are 2 O getters on the side of the discs and another one on top.

A big thank you goes to @David A Silva ,without his valuable tip I would not have this beautiful pair.
When I researched further I was able to find more details on how to get a pair of indirect TS 6550s without breaking the bank.

I have paired it with Vcap EZ80 Haltron,TS 6SL7 GT as an experiment.
Soundwise they are still a bit sharp at the top, probably because they are still new.
Midrange is very good, nice and forward, bass could be a bit better.
But as always, there is still room for improvement with driver tubes and playing time.
The instruments are great, I already like it when the drums or double bass are thumping away.
The sound seems a bit bright for the first time, hence the sharpness in the first hour
The TS6SL7 isn't played in yet either, and as is typical for TS I think they come out better after 100 hours.
But otherwise very happy with it for now.

Untilthen was right that Kt's, 6550 and EL 34 are not comparable, each genre sounds different, but different in its own way.
Time will tell which I prefer.
Is it worth it? For now yes, the EL34 SED are really the best value for money so far, even if they are still in the burn in phase I like them.
I haven't heard much KT88 Svetlana from St.Petersburg but I'm also very happy with them.
6550 Rca will show it, but the first impression is very good.
And all worth the money.

 

[UntilThen]

@Deleeh your TS 6550 (RCA) is from 63 onwards but should still sound great as the others. They are the ones that are still available today.

-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

Through the 1950s to the 1960s there are at least 4 versions of Tung Sol 6550. Black plates are more desirable than grey plates.

With the black plates there are 4 versions.
Version 1 had a single top square getter only (1950s). Version 2 had 2 top D getters. Version 3 had three getters (single top D getter and 2 side D getters). Mine is version 4 black plates with a single top O getter and 2 side O getters introduced in the 1960 for about 9 months before they transferred the exact same internal construction design across to solid grey plates until the end of 1962. From 1963 onwards you have the 3 hole perforated grey plate version.

Regardless of which version you have they all sound totally awesome. Some are rebranded RCA and GE but Tung Sol are more coveted.

 

[UntilThen]

I have paired it with Vcap EZ80 Haltron,TS 6SL7 GT as an experiment.
Soundwise they are still a bit sharp at the top, probably because they are still new.
Midrange is very good, nice and forward, bass could be a bit better.
But as always, there is still room for improvement with driver tubes and playing time.
The instruments are great, I already like it when the drums or double bass are thumping away.
The sound seems a bit bright for the first time, hence the sharpness in the first hour
The TS6SL7 isn't played in yet either, and as is typical for TS I think they come out better after 100 hours.
But otherwise very happy with it for now.

Tung Sol 6550 is revealing at the top. Midrange is front and centre and engaging. Bass is not overly voluptuous but it is controlled and thumping. For a more relaxing top end, try the GEC 807.

Untilthen was right that Kt's, 6550 and EL 34 are not comparable, each genre sounds different, but different in its own way.
Time will tell which I prefer.

Whatever you do, don't rush to get all the tubes. It will take time unless you're a millionaire. It took me a while and I am still buying selectively. It's terrible when you're inflicted with this love for lovely tubes.

All those tubes are unique in their own way and when you have a chance to compare them, you will find that they are gems in their own way. Perhaps love them all?

 

[UntilThen]

Still listening with Ultimate using 6S3P and GEC 807. Using Susvara and volume at 11am. I have to say that Ultimate with a high gain driver, drives Susvara very well. I'm very satisfied. I prefer listening to Susvara through Ultimate directly than using Ultimate as preamp into my Redgum integrated amp.

Through Ultimate directly, the tube tone is incredibly intoxicating. Hearing is one of the 5 senses and what I am hearing now is like a daily sugar drip. It's hard to leave the chair.

 

[AnyDave]

@Deleeh your TS 6550 (RCA) is from 63 onwards but should still sound great as the others. They are the ones that are still available today.

-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

Through the 1950s to the 1960s there are at least 4 versions of Tung Sol 6550. Black plates are more desirable than grey plates.

With the black plates there are 4 versions.
Version 1 had a single top square getter only (1950s). Version 2 had 2 top D getters. Version 3 had three getters (single top D getter and 2 side D getters). Mine is version 4 black plates with a single top O getter and 2 side O getters introduced in the 1960 for about 9 months before they transferred the exact same internal construction design across to solid grey plates until the end of 1962. From 1963 onwards you have the 3 hole perforated grey plate version.

Regardless of which version you have they all sound totally awesome. Some are rebranded RCA and GE but Tung Sol are more coveted.

I really like the TS 6550s. I've got a couple of pairs of the 3 hole, but I slightly prefer the black plate version with the 2 side D getters that I have:

 

[UntilThen]

I really like the TS 6550s. I've got a couple of pairs of the 3 hole, but I slightly prefer the black plate version with the 2 side D getters that I have:

Your D getters are a rarity now. Good find !

 

[VanHai]

The UltimatE has opened up finally and sounds tremendous with Sakuma style, 5A/152Ms as driver and power tubes. Spotless, super clear and super crispy, the bass hits very hard. Properly the best sounds on the Ultimate so far.

 

[UntilThen]

The UltimatE has opened up finally and sounds tremendous with Sakuma style, 5A/152Ms as driver and power tubes. Spotless, super clear and super crispy, the bass hits very hard. Properly the best sounds on the Ultimate so far.

That’s the feeling I get using c3g as both drivers and power tubes.

I need to get that back into rotation again but I’m still enjoying the GEC 807.

 

[VanHai]

That’s the feeling I get using c3g as both drivers and power tubes.

I need to get that back into rotation again but I’m still enjoying the GEC 807.

Tremendous vocals and clarity, just like you listen to a live concert. If I get isolated on an island with the UltimatE, the only thing I need is 2 pairs of 5A/152M or C3G.

 

[UntilThen]

Tremendous vocals and clarity, just like you listen to a live concert. If I get isolated on an island with the UltimatE, the only thing I need is 2 pairs of 5A/152M or C3G.

When I talk about c3g driving c3g sometime ago, no one took any notice. Glad it’s your desert island combination.

As far as I know, Ultimate is the only amp that allows you to do this.

This combination is particularly good with Susvara.