[Renderman]

The Feliks Audio Elise headphone amplifier is becoming quite popular amongst forum members and I thought it would be a good idea to start a thread to concentrate on the different tube options for the Elise.
 
A very nice budget option might be: 1960's RCA 6080 with Foton 6H8C, should render a nice soundstage with good depth and bass extension and smooth highs, might be slightly diffuse but is still hard to beat for the price!
 
Tubes found to be compatible with the Feliks Audio Elise are:
 

Power Tubes:
 
5998
6080

Spoiler: RCA 6080

Bought a matched, well-tested pair of RCA 6080 from a trusted seller for the crushing sum of $14 to my door. Though the sound lacks the large scale of 6AS7G, the tube is very smooth on top, relatively transparent, sweet mids with a good projection of depth and space around the instruments, slightly loose bass without the [ultimate] extension of the Chathams, somewhat laid back overall and dead-quiet. A very nice sounding tube. - Shaffer

6080WA
6080WB
6080WC
6AS7G/CV2523

Spoiler: GEC 6AS7G/CV2523

Although I may have hinted previously that the GECs didn't seem to be bringing a GREAT deal more to the table, with further listening I'm beginning to change my mind. As I am able to turn up the volume almost with impunity on these tubes (short of destroying my eardrums!), by doing so changes the ball game quite dramatically. The slight 'politeness' I mentioned takes on the full dynamism of the Russian tubes, and adds greater 3- dimensionality plus micro-detail to die for (not that the Russians were lacking in any way at all, lol!). Plus something that really got my head spinning - the male vocal lead in Genesis's 'Behind the Lines' has always been well-placed in the recording (with decent equipment) but had a very slight 'aloofness' to his voice. With the GECs in situ, he suddenly appeared as if surrounded by a protective 'cushion' of sound, from which he would occasionally almost float upwards into the air and then gradually descend once again. I almost thought I was hallucinating! I have NEVER experienced anything like this before in music production (apart that is from the soaring voices of a Church choir, but that's more obviously the ensuing tremendous echo/reflection - this was different), or REproduction...totally amazing, not to say weird (and no, I hadn't been hitting the bottle or smoking something exotic!). So from now on, most of my listening is going to be with these beauties in the hot seat. - Hypnos1

Spoiler: Shuguang 6AS7G

On first listen, the 6AS7Gs sounded just like the driver tubes - lean and mean. 50 hours of burn in did nothing. Gave them another 24 hours; nothing changed. These tubes sound like crap. I guess I'll keep them for a spare pair. Not even worth the $20, as for the same money one can have a decent pair of 6080s. - Shaffer

Spoiler: 6n13H (Elise Stock tubes)

[size=1em]The Russian tubes are decent; I'm listening to them right now with 7N7 drivers. They're slightly less resolving than the Chathams, but it's not a night and day difference. Compared to my Chinese tubes, they sound quite smooth, very extended, good sense of body, admirable dynamics, and a pretty rockin' low-end. I like them, albeit, not as much as the RCA 6080 and the Chatham 6AS7G, but a lot more than, say, Sylvania 6080WC - Shaffer[/size]

 
Driver Tubes:
 

Spoiler: Shuguang 6SN7

On first listen, the 6SN7s sounded lean and mean. Talk about sibilance! OMG. One could slice bread with the sound. ~100 hours of burn in, and the highs mellowed considerably, the mids became sweeter and slightly more transparent, and the bass stayed just as lean. I'm going to give them another 100 hours in hopes of the tubes becoming more transparent and the bass being more fleshed out. There's definitely some promise here. - Shaffer

6SN7-GT
6SN7-GTA

Spoiler: Sylvania 6SN7GTA

Initial impressions after, maybe, 20 hours of listening paint the tube as very smooth on top, yet extended, grainless, detailed mids, and relatively weak bass. Less weight than a 7N7, but without its definition and articulation. - Shaffer

6SN7-GTB
6SN7WGT

Spoiler: Foton 6H8C/6N8S

'60s NOS. Everything is there, but no magic. Unexciting. The system doesn't beckon one to listen to music. Edit: coupled with early/mid-50s Sylvania 6AS7G (possibly made by RCA), the sound is no longer dull and uninvolving. Dynamics are more fleshed out. There's a sense of life. Male vocals gain more body. It's as if there's an actual full-size human singing, rather than a voice stemming from dead space. - Shaffer

Spoiler: PsVane CV181-TII

Everytime i put back in the PSVANE CV181-Tii, can't help but notice the deeper tinier details coming thru. This is my favorite tube, no doubt. - Lorspeaker

ECC32
ECC33
ECC35
 
Driver Tubes with adapters:
 
C3g (Commercial adapters not available)
7N7

Spoiler: RCA 7N7

RCA made Delcos. After a bit more than 100 hours of burn in, the tube finally came into its own: it sounds wonderfully clear - and I mean clear - very detailed, no grain, a vivid presentation and bass that deserves its own mention. While the bass lacks the weight of some of the other drivers, it's beautifully articulated. No overhang, just a detailed portrayal of the bass. Nothing missing. It's the non-Rap-loving audiophile's low-end dream. - Shaffer

Spoiler: RCA 7N7

I'm totally loving the 7N7s. I don't know whether the amp broke in, or the tubes benefited from an extra 100 hours of burnin, but these things are brutally clear sounding. Every note starts and stops in time - no overhang. They sound fast and highly articulated. The issue I had with bass weight is highly diminished to the point of almost being a non-starter. So far, they're my favorite drivers with the stock 6AS7Gs and the Chathams, followed by Sylvania 6SN7GTA and CBS 6SN7GTB. - Shaffer

ECC31
ECC40
E88CC

Spoiler: Sylvania 6A6

However, even though the Sylvania 6A6 had only 6 hours of burn-in, last night, I decided to chill out and just listen, and was very pleasantly surprised. This is a very musical tube with holographic imaging and a wide and deep soundstage. The bass isn't up to the ECC31, but in that regard, the ECC31 is in a class of its own. Still, the Sylvania 6A6 is a very nice tube. And given that it was actually designed for use in audio, unlike 6SN7 and 6DJ8, maybe this shouldn't be a surprise. - gibosi

 
 
This list is in no way complete but we can add to it as we discover more compatible tubes. Along with some impressions of the different types of tubes.
 
If you would like to share your experience with a certain set of tubes on the Elise please feel free to do so, your input will be appreciated!

 

[Renderman]

reserved

 

[Shaffer]

I've been auditioning various driver tubes, including 7N7, and will post some impressions in a few weeks. The 7N7 is an interesting tube, performance-wise.

Oh, what the hell, I'll talk about the 7N7 now. I bought a NOS pair of RCA-made Delcos. Figured, as the tubes were meant for GM's car radios, they were already kinda screened for audio. Plugged the 7N7s into the Elise and heard and overly bright, very sibilant, no-bass sound. Thankfully, I don't have to use the Elise to burn in tubes; my LDIII with octal adapters does a fine job, so I let them cook. After 50 hours most of the sibilance was gone and some bass appeared.

After a bit more than 100 hours of burn in, the tube finally came into its own: it sounds wonderfully clear - and I mean clear - very detailed, no grain, a vivid presentation and bass that deserves its own mention. While the bass lacks the weight of some of the other drivers, it's beautifully articulated. No overhang, just a detailed portrayal of the bass. Nothing missing. It's the non-Rap-loving audiophile's low-end dream.

 

[Renderman]

Thank you for this early addition to this thread Shaffer! I've added an excerpt to the opening post.

 

[Shaffer]

Thank you for this early addition to this thread Shaffer! I've added an excerpt to the opening post.

My pleasure.

Perhaps we should also add a 6SN7GTA to the list. FWIW, I actually have a pair of GTA Sylvanias.

 

[Renderman]

Done and done! What do you think of the Sylvania 6SN7GTA, is it a good tube?

 

[Shaffer]

Done and done! What do you think of the Sylvania 6SN7GTA, is it a good tube?

I haven't listened to it enough to form a firm opinion. Initial impressions after, maybe, 20 hours of listening paint the tube as very smooth on top, yet extended, grainless, detailed mids, and relatively weak bass. Less weight than a 7N7, but without its definition and articulation. I need more time....

 

[hypnos1]

I've been auditioning various driver tubes, including 7N7, and will post some impressions in a few weeks. The 7N7 is an interesting tube, performance-wise.

Oh, what the hell, I'll talk about the 7N7 now. I bought a NOS pair of RCA-made Delcos. Figured, as the tubes were meant for GM's car radios, they were already kinda screened for audio. Plugged the 7N7s into the Elise and heard and overly bright, very sibilant, no-bass sound. Thankfully, I don't have to use the Elise to burn in tubes; my LDIII with octal adapters does a fine job, so I let them cook. After 50 hours most of the sibilance was gone and some bass appeared.

After a bit more than 100 hours of burn in, the tube finally came into its own: it sounds wonderfully clear - and I mean clear - very detailed, no grain, a vivid presentation and bass that deserves its own mention. While the bass lacks the weight of some of the other drivers, it's beautifully articulated. No overhang, just a detailed portrayal of the bass. Nothing missing. It's the non-Rap-loving audiophile's low-end dream.

 
Hi S.
 
I was very impressed with my 'Sylvania' full 'chrome dome' 7N7s - a worthy addition to anyone's collection of 6SN7s to be sure...(must give them another try soon, to remind me of how they compare to my reference C3gSs).
 
Keep up the good work with continued rolling...a great help to fellow (and future) Elise owners.

 

[hypnos1]

Hi R.
 
Nice to see things moving on your thread - I'm sure there will soon be loads more informative feedback from other fortunate Elise owners...
 
For your driver list there is also of course the PsVane CV181 TII (identical substitute for the 6SN7) - a beautiful tube and one of the better newer offerings. Like the 7N7 I shall be revisiting these soon...it should prove interesting!

 

[Renderman]

Thanks Hypnos1, of course the PsVane should be on the list! I have already added it, would you like your impression of it added to the OP?

 

[Shaffer]

"Vacuum tubes are just that, a glass envelope ( usually) in a vacuum. The better the vacuum the better the performance: you get extended highs and much more detail.

However all vacuum tubes will start to out gas. Molecular air will be dissolved in the metal work and the very glass itself. As the tube goes through heating cycles this molecular gas will eventually enter the glass envelop. The Getter flash (chromed coating on the inside of the tube) is supposed to absorb this stray gas and retain the vacuum. In fact the vacuum pumps used to evacuate the tube in assembly can not get the vacuum low enough and the getter is flashed after assembly in order to lower the vacuum.

However with use and the out gassing products, the gasses emitted will be become ionized by the voltages in the tube elements and the getter can not accomplish its stated purpose. Often times you will see that blue glow developing on the glass envelop.

It is possible to activate the Getter and lower the vacuum within the tube.. It is relatively easy to do. I place the tubes in a toaster oven and turn it on at the lowest setting. Every 30 minutes , I raise the temperature by 50 degrees to a maximum of about 300 degrees and simply allow the tubes to bake for as long as I feel comfortable ( sometimes overnight).

Once the baking process is over I simply unplug the oven. I try not to open the door as the colder air can cause heat stress and fracture the glass. Allow the tubes to cool to room temperature before removing, and replacing in your unit.

The getters are activated by heat, but since the voltages are applied during play, the ionized air tends to gravitate to the respective anode and cathode. This a lot of the air can not actually reach the getter. Its a good idea to label the tubes, especially power tubes so that you don't have readjust the bias ( if you mix them up).

If your tubes were glowing blue, you will notice the glow will have disappeared or significantly diminished. The top end will become pristine again as the tubes sounded when they were brand new.

This process will not restore old tubes, but will give you better sound from an older set.

It is our belief that one reason why NOS (New Old Stock ) tubes sound very good is that many were built in the Cold War era. The military sponsored a lot of research to better the performance of the tubes. They employed hydrogen bake outs for critical tubes, baking out the tube elements in a pure hydrogen atmosphere ( highly explosive) which made it easier for the vacuum pumps to excavate the very light hydrogen molecules. In addition, many of the glass envelopes were acid washed to remove a surface layer of hydroxides.

In the modern era, I doubt if many of the Chinese tubes undergo such procedures. That being said, modern production is constantly increasing in quality. The era when Chinese tubes were considered to be firecrackers is largely over. However, their prices have been increasing dramatically. The new PSVane tubes are almost as expensive as an NOS tube that they are trying to emulate. ADL still feels at those prices, the NOS types are a proven thing and probably worth the price when viewed as a long term investment."

Thoughts?

 

[hypnos1]

  Thanks Hypnos1, of course the PsVane should be on the list! I have already added it, would you like your impression of it added to the OP?

 
Yes indeed R, any of my previous impressions that you might find helpful may perhaps be of some use to someone, lol! 

 

"Vacuum tubes are just that, a glass envelope ( usually) in a vacuum. The better the vacuum the better the performance: you get extended highs and much more detail.

However all vacuum tubes will start to out gas. Molecular air will be dissolved in the metal work and the very glass itself. As the tube goes through heating cycles this molecular gas will eventually enter the glass envelop. The Getter flash (chromed coating on the inside of the tube) is supposed to absorb this stray gas and retain the vacuum. In fact the vacuum pumps used to evacuate the tube in assembly can not get the vacuum low enough and the getter is flashed after assembly in order to lower the vacuum.

However with use and the out gassing products, the gasses emitted will be become ionized by the voltages in the tube elements and the getter can not accomplish its stated purpose. Often times you will see that blue glow developing on the glass envelop.

It is possible to activate the Getter and lower the vacuum within the tube.. It is relatively easy to do. I place the tubes in a toaster oven and turn it on at the lowest setting. Every 30 minutes , I raise the temperature by 50 degrees to a maximum of about 300 degrees and simply allow the tubes to bake for as long as I feel comfortable ( sometimes overnight).

Once the baking process is over I simply unplug the oven. I try not to open the door as the colder air can cause heat stress and fracture the glass. Allow the tubes to cool to room temperature before removing, and replacing in your unit.

The getters are activated by heat, but since the voltages are applied during play, the ionized air tends to gravitate to the respective anode and cathode. This a lot of the air can not actually reach the getter. Its a good idea to label the tubes, especially power tubes so that you don't have readjust the bias ( if you mix them up).

If your tubes were glowing blue, you will notice the glow will have disappeared or significantly diminished. The top end will become pristine again as the tubes sounded when they were brand new.

This process will not restore old tubes, but will give you better sound from an older set.

It is our belief that one reason why NOS (New Old Stock ) tubes sound very good is that many were built in the Cold War era. The military sponsored a lot of research to better the performance of the tubes. They employed hydrogen bake outs for critical tubes, baking out the tube elements in a pure hydrogen atmosphere ( highly explosive) which made it easier for the vacuum pumps to excavate the very light hydrogen molecules. In addition, many of the glass envelopes were acid washed to remove a surface layer of hydroxides.

In the modern era, I doubt if many of the Chinese tubes undergo such procedures. That being said, modern production is constantly increasing in quality. The era when Chinese tubes were considered to be firecrackers is largely over. However, their prices have been increasing dramatically. The new PSVane tubes are almost as expensive as an NOS tube that they are trying to emulate. ADL still feels at those prices, the NOS types are a proven thing and probably worth the price when viewed as a long term investment."

Thoughts?

 
Interesting S...and would certainly go a good way to explaining the general preference for older NOS tubes...when was this article written BTW? - the prices of the better NOS tubes now appear to be getting ASTRONOMICAL and not just a little more expensive than the PsVanes (CV181 TII).
 
I suppose the moral of the tale is to try - if one can! - to find good, strong, reliable(?) used older tubes from a (hopefully) trusted, reliable source at a more reasonable price...which I suspect will be  harder and harder to accomplish as time goes by...but then I am a confirmed pessimist/cynic in my increasingly old age!!...

 

[Shaffer]

Interesting S...and would certainly go a good way to explaining the general preference for older NOS tubes...when was this article written BTW? - the prices of the better NOS tubes now appear to be getting ASTRONOMICAL and not just a little more expensive than the PsVanes (CV181 TII).

I imagine it's at least a few years old.

I suppose the moral of the tale is to try - if one can! - to find good, strong, reliable(?) used older tubes from a (hopefully) trusted, reliable source at a more reasonable price...which I suspect will be  harder and harder to accomplish as time goes by...but then I am a confirmed pessimist/cynic in my increasingly old age!!...

You and me, both.

Here's a recent experience: I came across a seller with two pairs of JAN Chatham 6AS7Gs. One pair was NOS ($45) and the other was used ($35). I bought the NOS pair. Looked at his site today, and the used pair is now ~$48. Three weeks passed.

 

[Shaffer]

Bought a matched, well-tested pair of RCA 6080 from a trusted seller for the crushing sum of $14 to my door. Though the sound lacks the large scale of 6AS7G, the tube is very smooth on top, relatively transparent, sweet mids with a good projection of depth and space around the instruments, slightly loose bass without the [ultimate] extension of the Chathams, somewhat laid back overall and dead-quiet. A very nice sounding tube.

 

[Lorspeaker]

this should get the vacuum recharged fast...
 

...on some russian candlesticks.