Tube Rolling w/Crack

[Paul Joppa]

"If it sounds good, it IS good" remains true, and I can't argue with it.

But drawing conclusions is a different issue. For example, a 12AT7 will have a higher plate voltage, driving the 6AS7 to a higher cathode voltage, and (without the Speedball) higher current. Our experiments have shown that increasing the current in the 6AS7 improves the sound - so ascribing the improvement to the 12AT7 by itself would be inappropriate. (With Speedball the current is constant so this effect is less significant.)

The same arrangement would increase the dissipation of the cathode resistor beyond the design condition. With the Speedball, it's the transistor dissipation that would increase. Either way, the components may have a shorter lifetime.

Both of the above are caused by the direct coupled design - sounds good but it's just less robust than cap-coupled topologies.

 

[Laudanum]

The WE 421 is/is not a Tung-Sol 5998 debate will always rage on amongst very small groups of hobbyists.  Do a google search,  you will find tidbits of info from both sides of the debate.  I dont have a WE and have no plans to spend the money on one.  I'll just have to slum it with the 5998 and two spares that I do have.  By the way, from everything I have found, all of the 5998's are Tung-sol made, no matter what they are branded.  That's not the straight glass 5998A's (which are generally considered a lesser tube, sonically).  I dont know if the A's were made by more than one manufacturer, but the ST shaped 5998 was only made by Tung-sol ... again, as far as I know. 

 

[Dr. Toobz]

For what it's worth, I did put a 12AT7 in the driver socket one time, just out of curiosity, as I was trying to wrap my mind around the electrical workings of a direct-coupled circuit. I don't have the voltages I measured handy, but I recall the plate voltage being definitely higher than usual, and that was with the standard LED biasing the cathode. I have the Speedball installed, so that probably put the brakes on any large changes. Needless to say, the resulting combination sounded like poo - very low volume and an anemic sound. I take it that the Speedball was doing its job by preventing large shifts in the circuit - so who knows what would happen with the standard resistive arrangement? However, I can't help but feel sticking a totally different tube in there isn't ideal. The furthest I've gone from the standard 12AU7 is an E80cc, and now a 12BH7, both of which are much closer in terms of plate impedance and mu when compared to something like a 12AT7 or 6922. I'm not even sure how the latter would work in this circuit! Wouldn't the high transconductance and low plate impedance result in altered behavior at the grid of the 6AS7?

 

[nick-seattle]

I have the basic version of Crack (no upgrades whatsoever). 12at7 works and sounds on the level of 12au7 (with Sylvania 12at7wa, it killed the majority of 12au7s except maybe for Mazda - I couldn't hear any sonic differences between these two tubes), but with much more volume. I know it's not suppressed to sound good - but it does (in Crack, in McIntosh, in SET 300b) - and I have experience in what a good sound is supposed to be - I tried all major brands of 12at7, 12au7 & 12ax7 - from Telefunkens selects - at $200 a tube to GE gray plates at $1 a tube)

Not sure about voltages anywhere, but it's a tube, if it works - it will continue working - compared to transistors. I don't see myself upgrading to anything that would involve transistors in Crack - I understand that they might make things better, but it's a transistor I love my Creack - pure!

Tube rolling wise, here are my favorites in Crack: Mazda 12au7, Sylvania 12at7wa, RCA 5962 (red base), Sulvania JHS 5814, Amperex 12at7 france, Amperex 7062, Westinghouse 12au7, Amperex 12au7, Westinghouse 6gu7. Some produce incredible clarity and sound stage, some produce superb warmth - depending on the mood

 

[Beefy]

I don't see myself upgrading to anything that would involve transistors in Crack - I understand that they might make things better, but it's a transistor I love my Creack - pure!

I could not disagree more with this position. Tubes must have a load and in the vast majority of cases, including the Crack, a CCS provides a *much* better load on the tube than a simple resistor. You get better PSRR, lower distortion, higher gain...... and from every single report I have read (plus my own experience) the Speedball just plain sounds better.

How is it pure to ignore these benefits? Does it make you a "better" tube guy to forego better sound quality by deliberately avoiding transistors?

 

[nick-seattle]

How is it pure to ignore these benefits? Does it make you a "better" tube guy to forego better sound quality by deliberately avoiding transistors?

This is absolutely just an OPINION I have. I have a hybrid headphone amp and it does sound very good - so I'm not a complete purist, but I have more PERSONAL fun by rolling tubes and discovering incredible sound than changing amp circuitry - to each its own. However, I do believe that tube amps without transistors sound perfectly . I went through many amps and still have to find something that sounds better than McIntosh 275 with Vienna Acoustics Beethoven (plus Genesys sub - so there are transistors involved ) - at least to MY ears, this is a sonic paradise - with the right tubes.

No how about rolling one of these tubes in Crack?
http://www.stereomojo.com/KR%20Audio%20Kronzilla%20SX1%20Mk%20II%20Review/KRAudioKronzillaSX1MkIIAmplifierReview.htm

 

[nick-seattle]

So I've been rolling today I tried to put 6sn7 (RCA 5692 Red Base) against 12bh7 (Sylvania gray round plates) against 12au7 (Mazda). I would say these are the best of the best in each family.

Here are my findings:
6sn7 - great bass, good details, very well developed mid-range - very forward, not much air - it's all kind there in the music, but doesn't wrap you up in it.
12bh7 - great bass, great details, more air than 6sn7. mid-range is not as developed. Much more feeling of being there.
12au7 - bass is not as good as previous two, phenomenal air, superb mid-range. With this tube there is a spooky feeling of being there. It's like seating on a stage with the artist.

Did blind testing with my wife - the only thing she knows about tubes is that they take a lot of money and a lot of my time Out of the 3, she stated that she loved Mazda again because of the "being there" feeling.

One of the best performances for this are: Patric Bruel - L'appart - Seul Ou Presque.

Disclaimer: This is my personal OPINION. Your results may vary. 12bh7 is a great tube

 

[BNAL]

Nick,

You got my attention with your posts and switched out my personal favorites, CBS 5814A and 5998 for the Mazda 12AU7 and RCA 6AS7G. Listening to the later combo now and loving it. I'm not going to say witch I thinks is better, because I really don't know but really enjoying this combo.

 

[Paul Joppa]

In spite of my technical remarks in this thread, I love it. Reminds me of the early days of the Foreplay, when people stuck pretty much anything with 9 pins into the sockets just to see what happens - hey, it's cheap fun and even if something blows up you can fix it, there aren't many parts and they are not expensive. I can gas on all day about optimal operating points, distortion, headroom, etc - but none of us would be here if it wasn't also FUN!

 

[nick-seattle]

In spite of my technical remarks in this thread, I love it. Reminds me of the early days of the Foreplay, when people stuck pretty much anything with 9 pins into the sockets just to see what happens - hey, it's cheap fun and even if something blows up you can fix it, there aren't many parts and they are not expensive. I can gas on all day about optimal operating points, distortion, headroom, etc - but none of us would be here if it wasn't also FUN!

Exactly!!! If you stick it and love it - "roll" with it!!!

 

[nick-seattle]

Nick,

You got my attention with your posts and switched out my personal favorites, CBS 5814A and 5998 for the Mazda 12AU7 and RCA 6AS7G. Listening to the later combo now and loving it. I'm not going to say witch I thinks is better, because I really don't know but really enjoying this combo.

I would love to hear your thoughts on the combo of Mazda and 5998. I was thinking about pulling the plug on 5998, but hesitate a bit. The darn thing sounds so good right now that I can't even imagine it sounding better Try Svetlana, it costs very little to try (compared to 5998), it adds a bit of air compared to RCA.

Lately, I've been in love with with Mazda. Everything I try - starting from 12ax7 with silver plates (not in Crack) to 12at7 to 12au7 is absolutely phenomenal. I was impressed by the air that telefunkens can create, but telefunkens are not match to Mazda. I got a huge deal today on ebay. $100 for 5 Mazda 12au7 marked with GE brand!!! They guy wanted much more for it, but Ebay is like any other market - you can negotiate. This one is with the slit in the plate - that's the one I have right now - absolutely phenomenal. I couldn't understand what soundstage was to it's full extent until I got Mazda - I have no idea what French put in it, but darn  - C'est si bon. Oh no, I've been listening to french tubes tooooo long. Now I'm waiting for another set of 4 Mazda - this time it's military Cifte with a round hole in the plate. I will post my impressions as soon as I get them. Ebay is a gold mine if you are willing to negotiate I would love to compare this to the SELECT Telefunkens that I have, these bustards sell for $225 a tube, I got it with my McIntosh, but 12au7s perform poorly in MC (Yes I did put them in MC even if the spec said that I only should put 12ax7 - whatever).               

 

[BNAL]

Nick,

I think what you like about the Mazda and what makes it different from the rest of the tubes is that it has a cleaner sound and not the traditional tubie sound. That is one of the reasons I believe in your comparison a few post back that you found it did not have as much base as the other tubes.

The 6AS7G is a great tube and no brianer recommendation. The 5998 I believe takes you to that next level, but that is my opinion. From what you discribe about what you like with the sound I found that the 5998 did it for me.

 

[Laudanum]

Nick,

I think what you like about the Mazda and what makes it different from the rest of the tubes is that it has a cleaner sound and not the traditional tubie sound. That is one of the reasons I believe in your comparison a few post back that you found it did not have as much base as the other tubes.

The 6AS7G is a great tube and no brianer recommendation. The 5998 I believe takes you to that next level, but that is my opinion. From what you discribe about what you like with the sound I found that the 5998 did it for me.

Agreed, that what it sounds like to me as well.  I dont have a Mazda tube but Im catching a "drift" here so to speak.   Nick,  I think it would be worth trying the 5998 but you may need to again be prepared to roll the driver.   Also, dont completely dismiss the Speedball.  I believe it will give you exactly what you are trying to achieve with tube rolling.  You arent breaking any "rules" with it.  I was a bit resistant as well.  Take advantage of what technology has to offer.  You may save some money on buying all them tubes 

 

[nick-seattle]

I just got two 5998 on Ebay today for $30  . They are weak but in working condition as the seller claims - we will see - I hope they are at least not DOA.

I'm quite sure that I will try Speedball sometime in the future. Yesterday I added Triad Choke and quite impressed with absolute silence that the amp produces. I still hear hiss, but only at extreme volume levels - I can't use the amp at that level (with Mazda for example, which is superbly quiet, I have to max the amp out to hear a hiss) - I usually push the volume up on my PC and can reduce the amp volume to a fairly low level.

I also got recently Xonar Essence STX audio card for my PC and very impressed. No more interference from PC and absolute silence during pause. The card has -124 db SNR! Very impressive. It also has a built in headphone amp - not very impressive. A standard SS sound (although a good one) - good bass, but not much air, no feeling of presence - boring. But based on specs it kills Crack

 

[nick-seattle]

I broke up and change Crack to accept 12ax7 Now the amp works with 12au7, 12ax7 and 6sn7 families. What can I say - I love it. The sound is superb. It's not possible to find in 12au7, which has its own stars, tubes that sound like Sylvania GB 5751 or Raytheon 5751 Windmill.

Paul, thanks for you help in making the mod. The diode & resistor did the trick.

 

[nick-seattle]

BTW, I got Bellari HA540 today to roll 12ax7 tubes... 30 minutes later I printed return shipment label and sent it on its happy way back to where it came from. Crack Rules!!! I don't even want to compare the two.

 

[Paul Joppa]

Here's an old story about 12AX7s that you might not have heard - it goes back to the second (?) VSAC, somewhere in the late 90s (?).

My late friend Tim Lollar (brother of the excellent boutique guitar pickup maker Jason Lollar) built a preamp with sockets for something like ten different tubes, switch selectable. All of them were on all the time to eliminate warmup effect, and each was operated at its own optimal current, giving identical normalized operating points. So we could pretty much count on technically identical operation, leaving only tube and gain differences. We adjusted the gain for identical outputs.

We did a mass listening comparison at the show with a crowd of about 35 people, each filling out their own rating sheet. The tubes were not identified until the session was over, and I as speaker did not know in what order Time was switching them. As close to a double-blind comparison as we could manage. No discussion was permitted until we had gone through all the tubes - of course, a pretty lively discussion followed (and carried over to the bar after)!

The interesting thing was, in the discussion nobody liked the 12AX7, and hardly anyone even mentioned it. IIRC, 6SN7s and 01A's were highly regarded, with a smattering of several others. Several months later, I tried to make statistical sense of the ratings. First place was all over the map. BUT ... for a clear majority, the 12AX7 was their second-favorite. I guess it was a little too politically-incorrect among audiophiles at the time, probably because it's a guitar tube. But in blind listening, it was very popular. I never found any other statistically-meaningful result from the test, and we never published the results. But I do tell the story now and then...  :^)

 

[nick-seattle]

Here's an old story about 12AX7s that you might not have heard - it goes back to the second (?) VSAC, somewhere in the late 90s (?).

My late friend Tim Lollar (brother of the excellent boutique guitar pickup maker Jason Lollar) built a preamp with sockets for something like ten different tubes, switch selectable. All of them were on all the time to eliminate warmup effect, and each was operated at its own optimal current, giving identical normalized operating points. So we could pretty much count on technically identical operation, leaving only tube and gain differences. We adjusted the gain for identical outputs.

We did a mass listening comparison at the show with a crowd of about 35 people, each filling out their own rating sheet. The tubes were not identified until the session was over, and I as speaker did not know in what order Time was switching them. As close to a double-blind comparison as we could manage. No discussion was permitted until we had gone through all the tubes - of course, a pretty lively discussion followed (and carried over to the bar after)!

The interesting thing was, in the discussion nobody liked the 12AX7, and hardly anyone even mentioned it. IIRC, 6SN7s and 01A's were highly regarded, with a smattering of several others. Several months later, I tried to make statistical sense of the ratings. First place was all over the map. BUT ... for a clear majority, the 12AX7 was their second-favorite. I guess it was a little too politically-incorrect among audiophiles at the time, probably because it's a guitar tube. But in blind listening, it was very popular. I never found any other statistically-meaningful result from the test, and we never published the results. But I do tell the story now and then...  :^)

That is hilarious I love 12ax7 no matter what people are saying about them - they provide tremendous dynamic impact and superb clarity. Since it's one of the most popular tubes, I bet a lot of funds were invested in developing it. For some reason, I actually prefer the rare dark gray (kind of hazy) color 12ax7 tubes. I found them among Westinghouse and RCA brands - I bet other ones made them as well - so many tubes to try If I understand correctly these were created during the transition in from Black to Gray material.

To be honest, the goal of the transition was to convert the amp to support 5751 tubes. To my ears, these are one of the most incredible tubes created. I mean Sylvania 5814 GB is awesome, but the 5751 gray plates (not a big fan of black plates 5751) with 3 mica is magical. So now I have two favorites: 1) Sylvania 5751 GB - when I want to listen to something very personal - think Melody Gardot; 2) Mazda 12ax7 or 12au7 - when I'm listening to concerts or classical music.

 

[Noskipallwd]

This is for anyone with experience using the 12AX7. Any preferred brands? NOS or Current production? Just purchased a used Jolida FX tube Dac that I am modifying and is slated for my bedroom system. It uses 12AX7s in the output.

Cheers,
Shawn

 

[Beefy]

This is for anyone with experience using the 12AX7. Any preferred brands? NOS or Current production? Just purchased a used Jolida FX tube Dac that I am modifying and is slated for my bedroom system. It uses 12AX7s in the output.

I know that the electrostatic headphone technophiles like the new production JJ. They have the very low noise and microphonics required for high gain applications.