[mchuckp]

Yea, having check those prices I decided they simply went beyond my red line (which I’ve been known to stretch unreasonable before, but not here with this alternative)

Would be super curious how you find those would compare. Probably the only who could tell us…. no pressure…

Thanks for sharing. Curious if the Tung Sol 6550 new production is worth checking out. Seems they are around $180ish for a matched pair. I’m sure not as good as a quality NOS pair but might be good. So far, I don’t dislike any new production tubes I’ve tried. Really enjoying the Gold Lion KT77.

 

[mattiastomas]

I've just rolledw in Tung-Sol made RCA 6550 tubes and, boy, are they awesome!

I've ended up putting a longer post on the Tungesten thread in reply to those headphones, but the impressiosn may be worth sharing, so cross-posting

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original post: https://www.head-fi.org/threads/mod...-and-discussion.968835/page-165#post-18021096



well, I've just rolled some new output tubes on my DIY Aegies, replacing my beloved EL37 with Tung-Sol made RCA 6550 (this amp is particularly great for tube rolling, and most responsive in sound signature to the choice of output tubes).

Listening now with the Tungsten (ds; ultra perf pads). These tubes defintely extracst a much deeper and tighter bass (not surprsiing, as they were the US version of the European KT88 and of similar DNA).

The bass is awesome! Now, for those that look for "bassy headphones", I found that means that they often love headphones that are tuned with a real bass shelf. The Tungsten isn't, it's tuned naturally without any artifical coloration of FR tilt. But, when bunch is called for, it's just awesome - natural, not exaggerated, right quanity and well textured.

I just put on the track "OK" by Kirk Franklin, a gospel song with some real earth-shattering sub-bass and mid banss (an awesome testing track btw, and so much fun regardless). The Tungsten capture the sub-bass rumbel (e.g. min 1:03 to 1:20); doesn't physically shake you (for that, see Atrium Closed; or perhaps 1266 for those who can live with that device), but it renders is very well without exaggeration. And lower/mid bass is super physical, lush, and impactful. These headphones are just f$%^-ing awesome!

Also, they render bass with a very satisfyting attack with sufficeint decay to make the notes both impactful and organic sounding. I've now switched to this jazz/classic fusion piece by Jacques Loussier that has tons of hard-hirring fast drums, as well as highly percussive piano. I'm just having a blast!

Now, as for ease of amplification...

With the new release of the commrecial version of the Aegis this past weekend for $3.2k release price if I recall (will be $3.5k later I think) -- there is now a very accessible TC tube-amp option that is mid-priced (realizing this will be too expensive for many, so using this adjective in relation to a very wide spectrum of amps).

The Aegis has a very (very) broad selection of tubes rolls that allow for very signifciant tuning to taste. At this moment, the 6550 are proving to be a bass-lover delight, while retaining great reoslution and clarity.

I'd imagine the Caldera's would sound great with the 6550s too.

time to scour ebay lol.

 

[Kdot]

I’ve only had like an hour with them, so caveat emptor and all..

But they do feel like a great and differentiated flavor. I’m certain the EL37 will remain for many moods and genres, but I think this may be the 6550 may end up being first pair that will go into active alternating rolling duty when looking for that lush bass. I do like that the dynamics aren’t resulting in any immediately observable trade off in the mids like I experienced with the EL38 (still another pair to demo there).

So ethereal, refined, expansive soundstage (EL37) vs. tight deep bass, dynamics, and more center focused (6550) is my initial impression.

To be evolved…

I'm already scouring ebay lol. They sound like a fun tube to compliment the EL37, thanks for sharing! You are also not the first person to suggest Tung-Sol 6550 to me recently so I am just taking that as a sign.

 

[L0rdGwyn]

Another tube from the KT88 / 6550 family I have been interested in trying is the KT90, originally made by Ei, but new production available from Electroharmonix.

 

[mattiastomas]

Another tube from the KT88 / 6550 family I have been interested in trying is the KT90, originally made by Ei, but new production available from Electroharmonix.

Those look interesting.

The description from viva tubes says:

"This tube has a bit more power than a KT88 but with the classic warm, bass-drenched sound of an EL34. The tube really is the best of both worlds. These are drop-in substitutes for a 6550 or KT88 amplifier but will need some re-biasing."


Would we have to worry about re-biasing?

 

[L0rdGwyn]

Those look interesting.

The description from viva tubes says:

"This tube has a bit more power than a KT88 but with the classic warm, bass-drenched sound of an EL34. The tube really is the best of both worlds. These are drop-in substitutes for a 6550 or KT88 amplifier but will need some re-biasing."


Would we have to worry about re-biasing?

It should work as a drop in. Could measure the bias current to make sure it is in the 60-70mA range at most. If it's higher (with GZ34), using a high Vdrop rectifier like 5R4 should drop the current down. But if KT88 and 6550 are working fine, it should too.

 

[goldwerger]

Well, it has been a few month since my last acquisition

Thanks for sharing. Curious if the Tung Sol 6550 new production is worth checking out.

I tried a pair of Sovtek 6550 a while back and didn’t fidn them worth keeping in the sockets. But time, memory, mood.. I’ll revisit, test fresh, compare and report..

I'd imagine the Caldera's would sound great with the 6550s. too.

I have a hunch you are right. Will also test that and report..

 

[khaine1711]

Thanks for sharing. Curious if the Tung Sol 6550 new production is worth checking out. Seems they are around $180ish for a matched pair. I’m sure not as good as a quality NOS pair but might be good. So far, I don’t dislike any new production tubes I’ve tried. Really enjoying the Gold Lion KT77.

Nothing like the nos 6550 (especially the tungsol solid plate); If you want to try 6550, among the new production the Svetlana winged c 6550 is quite ok, a tad bit warm though.

I have fond memories of the nos 6550, used to run a quad of them in my old Kt88 push pull amp for the He6. The price has gone up a lot though, certainly crossing my threshold for comfortable price. But then I cave in for the El156, maybe I should just get a pair of 6550 (and gec kt88, and 6l6gc) for peace of mind ...

 

[goldwerger]

ok tried the Caldera with the NOS 6550s (Tung-Sol mad RCA, coke bottle shape with 3 holes in plate)

I think this is a combination may people here will love.

I'm comparing it with my referecne for the Caldera, a Decware combo (ZMF OTL into Taboo).

In comparison, the Aegis with the 6550s is definitely more bassy (which it wasn't with the EL37). There is a very nice bass extension with a touch of elevation, tastefully done. Resolution remains great across the FR with very nice warmth and texture.

The LE37 provide a great soundstage (perhaps the best I've experienced) but it's beyond what most people expect, and the Aegis with the 6550 has what I would call a more normal soundstage one expects from a good amp. The EL37 presents a more delicate and refined presentation, and the 6550 ia a bit thicker, warmer, and grabbier.

In short, they are both excellent, and offer a true contrast. I would choose one of these based on your music preferences and taste.

And, if you can, I'd recommend both. With the EL37 and Tung-Sol made NOS 6550 you have the best of both worlds.

 

[Toonartist]

@goldwerger great review / summary. That's exactly how I see it with the EL37 & KT88. The Aegis is just a crazy amp that can take so many different tubes which results in a completely different sound or presentation. It's great to be able to swap these around depending on mood or genre. Like having multiple amps in one.

I love the soundstage of the EL37... fantastic for classical but also Psytrance when sounds are coming from all over the place. So dynamic. But, if I was listening to double bass or cello solo, the KT88 or, another favourite, EL39 provides more bass depth and lush sound.

With the EL37 (and other tubes) when paired with the Brimar KB/FE CV717 5R4GY rectifier, it adds a bit of warmth back in which can help the EL37. After I compared the Brimar 5R4GY with the Elrog 274b, it felt like the resonance or reverb from stringed and percussion instruments was being cut short. The 274b seems to reveal more of the sound that follows the leading edge while still being very detailed. I found this creates a lovely level of realism to the music, especially with live music. You get a better feel of the venue. It creates a very deep soundstage with fast dynamic sound with great bass extension. It was this rectifier that really made me love the EL39... great combo.

While I would like to pickup a pair of the Tung Sol 6550s (and most likely will at some point), I have a feeling the GEC KT88 are probably quite similar... so, I think I may still make the KT150 or KT170 my next try. New production tubes but they do get great reviews as well.

 

[mattiastomas]

ok tried the Caldera with the NOS 6550s (Tung-Sol mad RCA, coke bottle shape with 3 holes in plate)

I think this is a combination may people here with love.

I'm comparing it with my referecne for the Caldera, a Decware combo (ZMF OTL into Taboo).

In comparison, the Aegis with the 6550s is definitely more bassy (which it wasn't with the EL37). There is a very nice bass extension with a touch of elevation, tastefully done. Resolution remains great across the FR with very nice warmth and texture.

The LE37 provide a great soundstage (perhaps the best I've experienced) but it's beyond what most people expect, and the Aegis with the 6550 have what I would call more noraml soundstage one expects from a good amp. The EL37 presents a more delicate and refined presentation, and the 6550 are a bit thicker, warmer, and grabbier.

In short, they are both excellent, and offer a true contrast. I would choose one of these based on your music preferences and taste.

And, if you can, I'd recommend both. with the EL37 and Tung-Sol made NOS 6550 you have the best of both worlds.

Thanks for the update. Definitely keen on trying 6550s. When you get a chance could you upload a picture of what your pair looks like? Am seeing a few different looking ones online

 

[goldwerger]

Thanks for the update. Definitely keen on trying 6550s. When you get a chance could you upload a picture of what your pair looks like? Am seeing a few different looking ones online

Will do..

 

[goldwerger]

The 274b seems to reveal more of the sound that follows the leading edge while still being very detailed. I found this creates a lovely level of realism to the music, especially with live music. You get a better feel of the venue. It creates a very deep soundstage with fast dynamic sound with great bass extension.

I have a 274b of some unknown brand. Will try it..

 

[Toonartist]

I have a 274b of some unknown brand. Will try it..

I've only tried the Elrog which is a bit different from the normal 274b design. I believe they use a Thoriated Tungsten Filament... which is why they glow so brightly. I'd like to try another 274b but not sure which one to go for... maybe Takatsuki but not sure of the best source in the UK.

 

[goldwerger]

Thanks for the update. Definitely keen on trying 6550s. When you get a chance could you upload a picture of what your pair looks like? Am seeing a few different looking ones online

Here you go: