[boead]

I have a Transcendence Seven SLR Preamplifier.

I have spent some time tube rolling and have some impressions to share.
Line Tubes:

Telefunken ECC81, short gray ribbed plates, Germany (60’s)
- Most neutral sounding, almost bland and a bit unfocused. Good for some system, not for mine. Tubes were somewhat microphonic when touching them hot.

Mullard 12AT7WA CV4024’s, Great Britain (early 80’s)
- Less neutral then the Telefunkens in that they had a fuller bass. Midrange vocals were neutral, maybe a one row back. Highend was also fairly neutral but somewhat unfocused. Soundstage was deep and neutral wide. I’m quite familiar with Mullard tubes, these late model variants are not typical of the classic Mullard sound but still are quite nice and if you’re looking for a neutral to slightly laidback sound these would work nicely. Not microphonic at all.

RCA 12AT7WA, Triple Mica, Black Plate, USA (mid 60’s)
- Extended, tight bass that’s less full then the Mullards. Midrange is pronounced and upfront with good strong tone. Highend was strong to somewhat bright but nicely controlled and focused. A little edgy at times but had loads of apparent detail. Soundstage was wide and forward. I found them to be a little too fatiguing at times and a little raspy depending on the material.

Amperex E81CC ‘PQ’ gold pin, gray plate, West Germany (mid 60’s)
- Extended, tight bass. Midrange is VERY pronounced and upfront but was somewhat congested in my system. Highend was tight and nicely controlled and focused. Soundstage was less wide then most. Loads of detail, a bit bright and way too congested in the midrange, I tried hard to like these tubes but I just can’t! Maybe someone else can.

Sylvania 12AT7WA, Triple Mica, Grey Plate, USA (60’s)
- Good tight bass, nicely extended. Midrange is very well balanced with wonderful tonality. A little upfront and present but not at all congested. Highend was lively, detailed and well focused. Soundstage was wide, airy and deep. Very quiet, no microphonics. By far my favorite tube for the T7. I was told that if I liked this tube, I may really like the triple mica black plate version made by Sylvania with the gold labels, they are hard to find!

I also tried some RCA and Sylvania double mica gray plate 12AT7’s and was quite disappointed. Overly bright and lack vocal tonality, focus and bass.

I am looking to try a Holland made Amperex Bugle Boy 12AT7. They are really hard to come by. I’d told they are nothing like the German PQ’s (which are made by Siemens) or the British made Amperex (which are made by Mullard). I’ve always been a fan of Amperex Bugle Boy tubes.


As for the Phono Section:

Telefunken 12AX7 long smooth plates, West Germany (50’s)
Again, neutral and bland. Good overall sound for many, I understand. The tubes used are computer grade and worth nearly $100 each! I just don’t like them allthout they sound nice in my DAC.

RCA triple mica, black plate, USA (60’s)
- good tight bass, nice midrange, a little unfocused. Highend was a little dull and occasionally piercing. Not very well balanced. Nicer then the stock JJ’s.

Amperex 12AX7 Bugle Boy, Long Smooth Gray Plates Holland (early 50’)
These tubes are Expensive!! $150/pair is common.
- extended bass, tight and rich. Midrange is wonderfully balanced and lush! High end is lively and is well focused. Strong sparkly on the top end at times but its overall presentation of vinyl is superb. Very musical and never fatiguing. Worth every dollar!


I power a Decware Zen Select SET amp. My sources include a vintage Sony TTS-3000A turntable with an AR tonearm and a Grado Red cartridge. My digital sources are a Denon DVD-2900 SACD player and a California Audio Labs Sigma-II 24/96 DAC. I use MIT S3 IC’s and a pair of DIY Litz type-2 copper speaker cables. My speakers are custom made Parker Audio Model 95 signatures (full range drivers run in a 2 ohm load, with a ribbon tweeter buffed with a single cap) efficiency is 95db 1w/1m. I also use a KRK V12S sub.


Some other tubes I use:

California Audio Labs DAC:
RCA 12AX7 triple Mica, black plate, USA (late 50’s)
Best sounding 12AX7 I have heard in my DAC. My second favorite is the Amperex 12AX7 Bugle Boy I mentioned above.

Zen Select SET amp:
Mullard EL84 power tubes are my favorite, second ar the EI Elite EL84EG’s made in the early 90’s.
Mullard GZ32 Rectifier is my favorite. I also like RCA 5U4GB.
My favorite input tube is a Amperex 6922 white label PQ, gold pin made in the USA. Second favorite is the common Amperex 6DJ8 Bugle Boy Holland made in the 60’s.

Oh and I use mostly Harmonic Tech and Virtual Dynamic power cords.
I hate power conditioners for anything but digital sources, the wall outlet is best.

And the single most important thing to do is tweak your room! Listening room acoustics should always come first!!

Enjoy!

[Keith F.]

Boead,

Thanks for sharing Your experiences with different tubes with the T-7 Preamp. I also 'role' quite frequently. I will have to try those Sylvania's.
I have tried the same type of Mullards You did and can attest to Your results. I don't like the sound of those in My system either and it's to bad, I think because I beleive they are about the best structurally, with no microphonics at all.

The tube I like best in the line section is the Telefunken ECC801s. They really are transparent especially in the midrange. If a system is capable of reproducing high resolution, these tubes, I have found really shine.
The down side of these tubes is they are quite microphonic, or mechanically noisy. Still, so far, I like them the best in the line section of the T-7.

What does suprise Me though, is that in the power amp (I have the AVA Fet Valve 550EXR5), They do not have the same effect. I have some RCA square black plate 6201's that seem to be the best in there.

[aln]

I too, would like to try to Sylvania tubes in my T7. I noticed you wrote about the 12AX7-what are your experiences with the line stage using the 12AT7?  I currently use Telefunkin.

[boead]

LOL, my mistake which I just fixed.

The Sylvania I’m using in the line-stage is a 12AT7WA (3 mica, gray plate JAN tube).

I wouldn’t use a 12AX7 in the line-stage. I love the Bugle Boy 12AX7’s in the phono stage.

Sorry for the confusion.

[skrivis]

Given that the circuit was designed to use a specific tube... of what value is swapping in a bunch of tubes with random characteristics?

It seems diametrically opposed to AVA's stated principles.

Am I missing something here?

[avahifi]

Actually our tube and hybrid products are not designed to use a specific tube brand.

We require high gain, low noise, low microphonics, reliability, availability, and a rational price for the production units.

In general, low open loop gain tubes reduce feedback, increase harmonic distortion, and present a warmer more "tuby" sound with poorer bass control.  Very high open loop gain tubes increase feedback, reduce harmonic distortion, and sound less "tuby" and more controllled.

Lots more factors enter into this of course, some not well understood.  For example one brand of tubes we tried in the Fet Valve amplifiers caused an interaction between the output of the tube and the gate of the associated mos-fet that we have absolutely no clue as to why that was happening.  Other brands did not.  This is one of several reasons for the Rev5 upgrade; to revise the circuit a bit to make sure no tube could cause this kind of interaction.

We are aware that no two brands of tubes of the same kind are identical sounding, even if their measured characteristics are nearly the same.  Thus "tube rolling" is possibly of value to some of you that enjoy that.

It would have useful if Boerd had also given his subjective impressions of the stock JJ Electronic (Tesla) tubes we are suppying at this time in most of the equipment.

One word of caution, making a large change in tube characteristics in the Fet Valve amplifiers can affect the bias adjustment and that is not an easy do-it-yourself issue to deal with.

Frank Van Alstine

[boead]

It would have useful if Boead had also given his subjective impressions of the stock JJ Electronic (Tesla) tubes we are suppying at this time in most of the equipment.

Hi Frank,

I bought the T7 SLR used. He never used the stock tubes and shipped it to me with Mullards. I don’t care for Mullards most of the time. I had a pair of JJ 12AX7’s (phone section) and I did try them, I thought they were edgy and bright and lacked focus. I replaced them with Amperex Bugle Boy 12AX7's and in my opinion; I am hearing a significant improvement in the preamps musicality.  

I don’t have a pair of JJ 12AT7’s. I like the Sylvania’s I’m using right now. They sound great! I’m sure the stock JJ’s are fine. I’m have listened to dozens and dozens of different brand and model tubes and they all sound different. I have heard JJ’s many times before and I just don’t think they are all that good. Most newly made tubes are not to my liking. Just my taste.

BTW: Conrad Johnson ships one of their newest preamps with NOS tubes made in the early 70’s. They said they have thousands in stock and only sell to preamp owners with a valid serial number. A number of other manufacturers do the same thing. BAT tells you outright that the stock tube that ship with their preamp should be replaced with better tubes and will discuss the type of music you listen too, your tastes and then recommend brands and models that you may like. They don’t sell them.

[skrivis]

Actually our tube and hybrid products are not designed to use a specific tube brand.

We require high gain, low noise, low microphonics, reliability, availability, and a rational price for the production units.

In general, low open loop gain tubes reduce feedback, increase harmonic distortion, and present a warmer more "tuby" sound with poorer bass control.  Very high open loop gain tubes increase feedback, reduce harmonic distortion, and sound less "tuby" and more controllled.

Lots more factors ent ...

I stand corrected... sort of. I was thinking of the amps and assumed that the line-level circuits also required adjustment when tubes are changed.

For tube rolling to be of any worth, you would need to know which tubes match or better the stock tubes in gain, noise, and microphonics. Then you have to match your tubes channel to channel.

I suppose you could rely on Vendor X to sell you select, matched pairs... but I know of one tube vendor where the "selection and matching" consists of slapping some labels on. Kind of, "We selected 2 tubes, so it's Select Grade. We made sure they're both the same kind, so it's a matched pair."

What chance do I, as a consumer without fancy test equipment, have of getting tubes of equal or better quality than stock?

[dave1010]

WOW-You have tried all the tubes in the T7 that I have not tried! A valuable thread for 12AT7 tubes is in audioasylum under best 12at7. I have a pair of the Bugleboy France, and 1 pair from Holland. They are botrh excellent, but the Holland tubes are better. Just like an Amperex, soft, detailed with a very full midrange. I just purchased new Aurum Cantus Music Godess speakers, and the BB tubes were too full for the midrange. Since I have 6 PQ Amperex U.S. tubes in my BAT cd player, the sound was too full for my speakers. The TFK 801s is best for older stuff, or any Mccintosh pre-amp. The 6201 PQ Amperex is a Valvo tube, and I like it, but it worked well in the Paradigm speakers, not my new chinese speakers. I found the G.E. tubes to be horrible, no decay whatsoever. Just a note, and then it was gone.....The Mullards are horrible, I had the bass playing thru the midrange speaker of my paradigm's. The Sylvania tubes are very lush, especially the triple mica Gold Brand's.I have 8 Gold Brand 6922 tubes from 1959, and they sound very similar. I saw a pair(12AT7 Sylvania+) on e-bay for 10.00 including shipping last week. I like them, but my latest favorite is the common Siemens. It is what other tube rollers refer to as a solid state sound. I can tell you that they made a huge difference in the sound of my system. I have found that  Siemens in the pre-amp with Amperex's in the cd player sound amazing! The other way around with siemens in the cd and Bugle Boys sounds good, but the Siemens are better tubes (12at7 specifically) than the bugle boys. My opinion of course! Amperex just was not that great at the 12at7. The difference in clarity between the siemens and the BB greatly favors the siemens. The siemens offer heavy bass with transparency on par with the 801s telefunken.The sound is very similar either way. The Bass is truly deep in the Siemens, and the linear personality of their 12at7 works well with ribbon tweeters. I should also mention that some people seem afraid to roll tubes. Or they think they are too expensive...The TFK 801s is expensive 70-90 bucks a pair. But everything else I have purchased has averaged 15 bucks a pair. I just bought 14 new Amperex tubes 6922 for 275$. Inlcuding PQ's,1968 USN (better than white label PQ's), and RCA made in Holland tubes. I have purchased over 700$ worth of tubes on e-bay, and have only had positive experiences. One guy sold me the wrong tube, and sent me 3 new Siemens NOS tubes from the 60's for free, just to be nice! Just check the feedback. Nos tubes can make a tremendous difference, and 12at7 tubes are cheap!

[tubepudz]

Dave,

How do you like the Music Godess speakers.  I am in China working and trying to find Hi Fi shops in Beijing to listen to Chinese equipment.

[skrivis]

Dave,

How do you like the Music Godess speakers.  I am in China working and trying to find Hi Fi shops in Beijing to listen to Chinese equipment.

They _look_ nice anyway. I would never have thought of yellow poplar as a desirable wood, but the pic I saw of these on the Aurum Cantus site looked good.

I also thought it was interesting that they translated to: "The outside finish of Music Goddess wholly uses light yellow poplar tumor." I think they meant burl instead of tumor.

I wonder about the state of Hi FI in China. Are there a lot of shops selling Chinese audio gear, or is it mainly for export? I guess I'm wondering whether the audio industry in China is mainly driven by the Chinese market or by the US market.

[TheChairGuy]

I wonder about the state of Hi FI in China. Are there a lot of shops selling Chinese audio gear, or is it mainly for export? I guess I'm wondering whether the audio industry in China is mainly driven by the Chinese market or by the US market.

Tho there is a growing middle class in China, most everything they do today is export related and driven. I think the per capita yearly wage just peaked over $1000.00 there recently...there are still many hundredsof millions of poor in P.R. China.  But, due to the enormous size of the population there, their middle calss numbers may actually exceed US in a few short years.

Not much market for $1000 amps and $2000 speakers (re: HiFi)  for that reason.

[skrivis]

Tho there is a growing middle class in China, most everything they do today is export related and driven. I think the per capita yearly wage just peaked over $1000.00 there recently...there are still many hundredsof millions of poor in P.R. China.  But, due to the enormous size of the population there, their middle calss numbers may actually exceed US in a few short years.

Not much market for $1000 amps and $2000 speakers (re: HiFi)  for that reason.

That's about what I expected.

It would (and will) be interesting to see what kinds of audio products they'll design for domestic consumption.

[ricmon]

Here is a cool tube site.  It appears to hove so good info.

http://www.tubefreak.com/tubesadvice.htm

[dave1010]

I will make this quick as this subjuct is getting off track, I hope I answered the question about the Aurum Cantus in my private message. For an eye opening view of the future, try www.anycities.com/andyhifi/ on the site is says Home Audio Hi-Fi stores t-Hit this and go to the last paragraph about OEM manufacturers. "The Chinese Way I want to know "and the amazing Busmans Holiday a trip to China.  

[Rocket]

Hi Dave,

I presume this is what you mean?

CHINESE: Chinese hi-fi companies are now starting to enter the world market on their own. For years Japanese companies such as Denon sold rebadged OEM products by Shanling and Shengya, and Rotel and Mark Levinson's Red Rose Music sells rebadged OEM products by Korsun. Carrying on his successful story of Korsun, Mr. Zou Yuan Yuan, president and chief designer, founded Dussun. aaa-audio.com and Ming-Da products are targeting the high end, definitely not "cheap" electronics. Affordable Valve Company and PrimaLuna are getting popular in Europe. Many speaker brands including Klipsch, Velodyne, Infinity, Tannoy and Athena import speakers from China. A lot of hifi equipment and cables are actually rebadged imported OEM'd electronics from China with huge price markups. Maybe finally the world hifi market deserves a "wake up call" to start selling their products at reasonable affordable prices. The decline in sales of hifi hardware is directly attributable to the insatiable greed of hifi companies who've raised their prices to insane tiers. This article "The Chinese way: I want to know" lists Chinese brands that are OEM'ed and rebadged by more expensive brands. This article "Busman's Holiday, China Style" shows that hifi is more popular in China than anywhere else in the world, probably, next to Japan. Hifi dealer Sekei, listed below, sells Chinese hifi in their native brands.

and this?

http://audio-nirvana.fortunecity.net/pag_eng/chinawayg.htm

Regards

Rod

[skrivis]

Here is a cool tube site.  It appears to hove so good info.

http://www.tubefreak.com/tubesadvice.htm

It's interesting, but I'm not sure how well it applies to hi-fi use. Most of the things that a modern guitar amp does are _not_ characteristics you'd want in a hi-fi preamp.

You actually _want_ distortion in a lot of cases with a guitar amp. It's easy to push the preamp tubes, and they don't go up in flames as soon as abused output tubes do. So much of the gain and distortion in a modern tube amp is achieved in the preamp.

Those preamp tubes are therefore not operating much like the tubes in a hi-fi preamp at all. That's why I'm not sure you can apply observations from one to the other.

Most guitar amps are much more sensitive to a microphonic tube than hi-fi preamps are since the speaker is often mounted in the same box as the amp chassis. (Although I bet there are people who like microphonic tubes because they give a sound something like a cheap reverb tank. hehe)

The info given on that site about microphonics might be useful, but I suspect that there are tubes that would not work in a guitar amp and would work fine in a hi-fi preamp.

The comments on that site about the sound or tone of each tube are probably worthless unless you use the same guitar amp as they do.



When other people are recommending tubes for hi-fi use, their comments about microphonics are useful. Their comments about how the tube "sounds" are not at all useful unless they own the same preamp or amp as you do. Even then you have to take it with a grain of salt.

So don't go out and spend big bucks on some NOS tubes that a guitar player thinks are wonderful, and then expect them to do wonderful things for your AVA preamp.

[boead]

WOW-You have tried all the tubes in the T7 that I have not tried! A valuable thread for 12AT7 tubes is in audioasylum under best 12at7. I have a pair of the Bugleboy France, and 1 pair from Holland. They are botrh excellent, but the Holland tubes are better. Just like an Amperex, soft, detailed with a very full midrange. I just purchased new Aurum Cantus Music Godess speakers, and the BB tubes were too full for the midrange. Since I have 6 PQ Amperex U.S. tubes in my BAT cd player, the sound was too full fo ...

Nice Dave!

My amp, a Decware SET, and speakers need a little richening up in the midbass and low end.

I’ve wanted to try the Siemens, can you suggest any particular variant?

[dave1010]

I just have the older 1960's-12AT7/ECC81,nothing special. I know they also have a e81CC version, like the Telefunken ecc801s version. They last forever ,(I hear) but I have not heard them in my system. The E81CC version is more expensive however. I have heard they sound similar to TFK's, and I do not need complete transparency....although the term sure sounds nice. I look at the Amperex and Siemens as being head and shoulders above the rest, to me, so far.....