[jamato8]

7193 went wonky after a while. Mids pushed forward and a little too much hard detail, but then they are new, NOS, and after more hours of burn in the tubes are settling down. The sound is more full now, slightly warmer and natural. So the positives are coming back with a huge sound stage but not unnaturally so. And a sweet tone when is seems like it should be.

Not microphonic at all, though I like just a little bit of microphonics for the sound. But these still have a vibrancy to the sound. These are one of the most natural sounding tubes I have heard. Odd that I never tried them before but then not too much into grid cap tubes, let alone grid cap and plate cap but it is all good.

I assume the wires used for the caps are copper but may replace them with my dead soft high purity silver with teflon, or not but some nice 22 gauge silver in dead soft has never had a downside in my experience over the years.

The nice thing abut have the tube divided up like this, you can really match the tubes for plate current and other characteristics. Unlike a 6SN7, which may be close, I have enough that I can get the two halves super close. Not that it always matters.

 

[jamato8]

Hello head-fi experts,

I am building a new system for a new apartment. Sources are the Innuos ZEN Mk3 going into the dCS Bartók. Eyeing the Cayin HA-300MK2 to replace a HeadAmp GS-X mk2 to get more of the tube goodness. I use a Riviera AIC-10 to drive the DCA Stealth in another rig. That amp / headphone combo works beautifully.

Stealth is my preferred headphone. Personally enjoy it more than the Abyss 1266 Phi TC or the Susvara. Is anybody driving the Stealth with the Cayin? Does it deliver enough juice to make the Stealth sing - as it requires a lot of it? What is your listening experience with that combo?

Second question I own a ZMF Verité Closed but it gets little use. Love the experience with the Stealth too much. Would a ZMF Caldera be a lovely combination for the proposed chain? The Bartók is a capable source and provides deep insight into the music.

I forgot my TC are balanced. I normally use them balanced but will have to try them in the 300BMK2. I use the ibasso SR3 most of the time, they are that good.

 

[DMITRIY R]

Hello head-fi experts,

I am building a new system for a new apartment. Sources are the Innuos ZEN Mk3 going into the dCS Bartók. Eyeing the Cayin HA-300MK2 to replace a HeadAmp GS-X mk2 to get more of the tube goodness. I use a Riviera AIC-10 to drive the DCA Stealth in another rig. That amp / headphone combo works beautifully.

Stealth is my preferred headphone. Personally enjoy it more than the Abyss 1266 Phi TC or the Susvara. Is anybody driving the Stealth with the Cayin? Does it deliver enough juice to make the Stealth sing - as it requires a lot of it? What is your listening experience with that combo?

Second question I own a ZMF Verité Closed but it gets little use. Love the experience with the Stealth too much. Would a ZMF Caldera be a lovely combination for the proposed chain? The Bartók is a capable source and provides deep insight into the music.

Cayin HA-300MK2 pairs well with DСA Stealth. Even on the default tubes, excellent speed, deep bass, delicious tube tones. When setting different resistances on the amplifier, DСA Stealth plays a little differently, but always good. The amplifier also works well with the Abyss 1266 TC.
When using any of the headphones listed above, the power of the amplifier is more than enough. The volume control even on the quietest recordings does not exceed the 2 o'clock position.

 

[jambaj0e]

Much thanks to @Wes S for helping me identify which RFT I want, they definitely have an unique construction, It took months to get a pair (that isn't ebay levels of prices), but it was all worth it. I have been enjoying them since last week, it is a fantastic experience

I figured some of the MELZ 1578 guys might wanna know the difference between both, here are some summary notes of my opinions using them with the Elrog :

- If you have heard of the Kenrad VT231 and Telefunken ECC82 smooth plates, IMO these are the perfect cross between both, it has a nice blend of smoothness and impactful bass, but most importantly on the Elrog, the bass do not reach the muddy levels that the kenrads can get to sometimes.
- MELZ 1578 and the RFT have different sound profiles, I don't think they are really comparable directly. RFT sounds faster with harder hitting bass, whilst the MELZ is more towards the sparkly brighter side of things, it has a wider stage and more defined instrument separation
- I consider both RFT and MELZ to be well balanced in tonality, you will not go wrong with either for everyday general usage, but I found them different enough to warrant to get both. I do not think the MELZ lacks bass, the same way I do not think the RFT lacks treble presence - but long story short, go RFT if you want bass, go MELZ if you want treble
- I must stress that the RFT bass is really good, its a well controlled kenrad IMO!!
- Noise floor wise, maybe I have lucked out, but testing with my Focal Utopia, both the Melz and RFT are quiet - I think it is possible to get low noise units of both. But I am sure you can visit the 6SN7 thread for tips on soldering pins if necessary


I guess I am a fan of German tubes now, Elrog, Telefunken and RFT all have been a hit for me

Which model & year are the RFT? first time I've ever heard of those

 

[jamato8]

Can I ask where you found a matched quad of these?! I had been keeping on eye on eBay but gave up.

Here are 5 NOS for sale. I would bet they are pretty close. Not a bad price and I would test and check them for match for you. And these are Ken-Rad, the best sounding, IMO.

https://www.ebay.com/itm/185740419286?hash=item2b3efde0d6:gaMAAOSwTqFjxakR&amdata=enc:AQAIAAAAwFstFLIJkvgRmLs8jzcZwwhttgRXDjSOK3v+a+QRsE/wfYcHyYXNtfM+dit4VhVrPbAgAkRiNleYhB/JEOf5ne97bMbOuMu6x4Qzljr9fHI5iJGX9iXLXNwrukEBqgGn8S7BQHNjDlRi02piJV05WHATtQqGDqRVEG7mQ5AQHtepXndyPOx2C3wQGY0ku8c8XtzqNqJH56VgilJJWNvyXm5chKwqXeeOczY1ZVtwo3nXGq1FWM1cSblb8bk+ymAbvA==|tkp:Bk9SR5qUoOjwYQ

 

[jamato8]

Cayin HA-300MK2 pairs well with DСA Stealth. Even on the default tubes, excellent speed, deep bass, delicious tube tones. When setting different resistances on the amplifier, DСA Stealth plays a little differently, but always good. The amplifier also works well with the Abyss 1266 TC.
When using any of the headphones listed above, the power of the amplifier is more than enough. The volume control even on the quietest recordings does not exceed the 2 o'clock position.

Yes, it drives the Abyss without issue.

 

[DMITRIY R]

Does anyone use active cooling of the amplifier? For example, an ordinary household fan that blows around the amplifier and power supply.
If you do, can you hear the difference in sound with and without cooling?

 

[jamato8]

Does anyone use active cooling of the amplifier? For example, an ordinary household fan that blows around the amplifier and power supply.
If you do, can you hear the difference in sound with and without cooling?

I use a small fan that runs off of a USB C during the summer. Longer life of tubes and components.

 

[ARCXENOS]

Which model & year are the RFT? first time I've ever heard of those

Ceramic Spacers with Welded Plates is what they are referred to frequently, this particular variant should be made in the 50s (and maybe early 60s)

There is a later variant with yellow markings and stapled plates, those have a different construction, and apparently don't have the same sound.


@Wes S could probably give us all a better history lesson

 

[JazzVinyl]

Does anyone use active cooling of the amplifier? For example, an ordinary household fan that blows around the amplifier and power supply.
If you do, can you hear the difference in sound with and without cooling?

Yes, I use a 12v computer case fan to move air across the top of my amp, to keep heat at bay. Not detrimental to sound quality imho.

 

[DMITRIY R]

I use a small fan that runs off of a USB C during the summer. Longer life of tubes and components.

I also installed a fan to blow the amplifier. I wanted him to drive air in the rack where the system components are.
As soon as I started using the fan, the tubes practically stopped cracking after turning off the amplifier. Protective housings of transformers, when blown, are barely warm.
The sound of the amplifier has become more pure, devoid of the background characteristic of the tubes.
To be honest, I did not expect such an effect. I wanted to know if anyone else hears sound improvements when using active cooling?

 

[alvin sawdust]

These blow away any 6F8G (and I have many NOS), 6SN7 (Many NoS and some of the best) and other types. The 7193, just has it all. Extremely open sounding, dynamic and layered. Quite surprising at the difference. Each 7193 is one half of a 6SN7 and has a Grid cap and Plate cap, which must be part of the secret.

The speed the delivery is startling. Adapters from China that work very well.

Also, these 1942 Kenrad tubes are extremely quiet. Also, they match super close. All the 7193 I have checked are very close in plate current draw and mutual conductance. No problem matching them to quads.

After reading your post I decided to revisit the 7193 in my UltraSonic 300b amp, replacing a very good quad of Osram L63 with a mixed quad of Ken-Rad and NU 7193. They have the sweetest, airiest highs I have ever heard, thunderous bass and beautiful open mids, very intoxicating.

 

[Wes S]

Which model & year are the RFT? first time I've ever heard of those

There are several versions, and I have been comparing 3 of them over the past couple of weeks.

Version 1 from 54' - This is the earliest and warmest of the bunch with huge bass, and huge depth and holographic staging, excellent detail in the mids while staying euphonic and smooth and decently extended highs. This tube is incredible and if you like bass and a very natural sound with super deep holographic staging this is your tube. Notice the welded plates and ceramic spacers with dual foil getters.

Version 2 from 55' - Second version and notice the metal clips are gone from the first version and now we have mica bumpers at the top of the plates, and everything else is the same. This version is a bit more neutral although still leans a bit warm/natural and has a bit better balance top to bottom compared to version 1, yet still has slamming tight bass. This version has more intimate staging, and a bit less bloom in the mids compared to version 1. Detail is on par with tube 1. So, this version is just a bit more balanced, but still sounds super fun with a bit of warmth.

Version 3 from 57' This is where things get interesting and the plates are not welded anymore and are stapled instead, and the dual foil getter is gone as well and has been replaced with a single foil getter. This tube is much more linear and transparent with a more open sound, and is tighter sounding top to bottom. This tube makes it seem as if the musicians are in your room, with it's extreme transparency and detail and huge open staging with incredible top end extension. The speed and dynamics are also through the roof with this one, and it's a fun ride. Detail is greater than the first two, at the expense of some organic warmth and note weight. The treble extension and air in the mids with incredible dynamics and detail is where this tube shines.

I am happy to own all 3 versions and they each have their strengths. What I have learned from this is there are two kinds of presentations and they are both awesome. The first 2 versions make you feel like you are where the music is being played live in some other venue. The last version makes it seem like the music is being performed live right where you stand. I don't think either scenario is bad, and it just comes down to preference. From what I have learned here and read from others, I imagine version 3 could give the Melz's top end and staging a run for the money. . .

Happy Hunting!

 

[Wes S]

Does anyone use active cooling of the amplifier? For example, an ordinary household fan that blows around the amplifier and power supply.
If you do, can you hear the difference in sound with and without cooling?

I use a ceiling fan on high, of which is pretty much directly over my amp. Living in Texas, heat is always a concern, and a little extra air moving around the tubes definitely extends their life. I don't hear a difference in performance with or without the fan, but knowing it extends their life by running cooler is enough for me.

I say use whatever type of fan you can get away with, that does not interfere with the sound. I have found that some of the smaller computer fans are actually louder than my ceiling fan, so I don't bother with them.

 

[ARCXENOS]

smooth and decently extended highs

Even after swapping 22DE4s and 300b, I found my pair very agreeable in any setup I use them on

I would definitely try to pick up version 3 when I found one that is not ebay prices most definitely.