Tube Rolling w/Crack

[Aeolus Kratos]

Kratos,

My GEC tube sounds like a very refined, premium, noise free 6080.  In terms of comparing sonics, through my setup w/ hd800's, 5998's sound slightly brighter, livelier and more holographic.  The GEC and 6080's are slightly more laid back and have a bit more mid-bass - particularly around 100hz where the hd800's have a significant spike in their impedance curve.  This all makes sense given that 5998's/7236's lower your output impedance (considered a good thing by many) but also raise the gain, which may or may not be a good thing in your setup.  (See also page 2 of http://www.pmillett.com/Wheatfield/rolling.pdf - similarly describing the sonic differences between these tubes.) 

At approximately equal volume, if I throw on bass heavy tracks (e.g. 2pac's "u can't see me"), I perceive that the bass hits harder and fuller if I'm running my GEC 6as7g (or, for that matter, my other 6080's), when compared to any of my handful of 5998's.  In the 6as7 thread on head-fi, folks with different amps and headphones have claimed just the opposite - that 5998's have more bass, which may be the case with the headphones they are using.  As I understand it, the impedance curve of the headphone is going to impact the effect of the change in output impedance.  Check out, for example, this thread on hd800's and high output impedance amps: http://www.changstar.com/index.php?topic=90.0. 

All in all, I certainly would not drop the 2 bills ebay sellers are currently charging for GEC tubes.  I paid $100 for mine, and I doubt I would be inclined to pay that much again.  I like the tube, but I would say that I find myself reaching for my 5998's just as often. If I manage to take my own good advice, I'll stop collecting surplus tubes and save my pennies for the bh dac. 

My favorite a-socket tube is still a tung sol 12bh7.

Hi dubiousmike,

First of all, thank you very much for your superb detailed and helpful advice!

As far as I know and thanks to what you said, I assume that the HD650's ( or 'dark', slow and 'veiled' headphones ) are more suitable to the 5998's as their sound is bright, fast and detailed; whereas the GEC 6AS7G's are for the bright, fast, detailed headphones like the HD800's to give them more mid-bass and 'tubey' sound. Am I right?

And yes, I would definitely save my money for the coming BH DAC. I bet it is gonna be great when paired with the Cracks

All the best,
Kratos.

 

[adamct]

Honestly, just don't worry about tubes. I don't know how much more plainly to say it.

 

[Aeolus Kratos]

I pretty much agree with everything dubiousmike wrote below (except that I paid waaaaaaaaaay more than he did for my GEC 6AS7Gs). A few further notes:

1. I like my GEC because it is quiet, not because it sounds better.
2. The GECs are not the only quiet tubes out there. In particular, I find the 6080s of all brands and prices tend to be quite quiet.
3. I don't notice any differences in bass compared to my 5998s one way or the other, but I frankly haven't tried to compare that and don't plan to. Any differences much be tiny, so I'm not surprised that people fall on both sides of that fence.
4. I wouldn't bother replacing the output tube unless it is somehow broken. Every tube I've tried sounds good... Well, except for the first tube I got, which went kablooey the first time I fired up my Crack (the tube was bad, the amp was fine).
5. I'm using a Mullard 12BH7, but just about every driver tube I've tried has sounded good, too.

Tube rolling just doesn't seem like a wise use of money to me. If you want to tweak the sound of your rig, your money is much, much better spent on headphones (Sennheisers in particular are outstanding with the Crack).

Regards,
Adam

Hi Adam,

Haha, sorry to hear about what you paid for your GEC 6AS7Gs, they have been crazy expensive these day

Now I think I would stop collecting premium tubes and wait for the BH DAC, do you know when it will be released and its expected price?

Best,
Kratos.

 

[adamct]

Nope. Nobody does. But I expect it to be at least 2 months away from availability, and probably longer. The design of the digital section isn't finalized. Then Doc needs to handle the analog sections. Then they need to finalize parts. Then write the manual and take pictures. Then they need to source parts and receive them. Then they need to pack and ship. They are working on it, but this won't be done in the next week or four.

I'm sure the Bottlehead team will jump in if I am disseminating misinformation.

 

[w0lfd0g]

Honestly, just don't worry about tubes. I don't know how much more plainly to say it.

:'(

If only I had heard these words from Adam two months ago.  But, fwiw, I can hear a difference between output tubes in my system.  There is just a disproportionate relationship between the money spent to experience the difference and the magnitude of the differences. 

 

[Doc B]

I think our design philosophy has probably not been discussed as much as it should lately. Basically, we feel that the sonic impact of the circuit design itself outweighs all of the parts swapping. So the tube rolling and cap swapping that seems to positively consume some builders, while it does certainly have a sonic impact, is just the final tuning step and not a thing that "fixes" a problem. Changing a tube is more like your short brunette girlfriend changed her hairstyle than like you got a new tall blonde one. Some of us wouldn't even notice if Norah Jones got a haircut, but no one is gonna miss the difference between Norah Jones and Charlize Theron.

Everyone should pursue a hobby in such a manner that it gives them maximum satisfaction. I imagine that if some tube and cap rollers spent an equal amount of energy learning as much as possible about how the circuits that they are rolling parts thru work they would find the hobby even more rewarding.

 

[adamct]

I think our design philosophy has probably not been discussed as much as it should lately. Basically, we feel that the sonic impact of the circuit design itself outweighs all of the parts swapping. So the tube rolling and cap swapping that seems to positively consume some builders, while it does certainly have a sonic impact, is just the final tuning step and not a thing that "fixes" a problem. Changing a tube is more like your short brunette girlfriend changed her hairstyle than like you got a new tall blonde one. Some of us wouldn't even notice if Norah Jones got a haircut, but no one is gonna miss the difference between Norah Jones and Charlize Theron.

Everyone should pursue a hobby in such a manner that it gives them maximum satisfaction. I imagine that if some tube and cap rollers spent an equal amount of energy learning as much as possible about how the circuits that they are rolling parts thru work they would find the hobby even more rewarding.

I am, admittedly, a frequent offender. That said, this should be added as a sticky in every product forum.

 

[earwaxxer]

There ideally should be some sort of 'zen' about the whole process. That, of course, is ideal in most, if not all, situations in life, depending one ones philosophy etc. Doc makes some good points. Mindless lust for "better" sound is a "fools errand"... (god I love that pirate shit!) - but what CAN be a positive is getting to know these various parts, relative to how they sound in kit "A" vs speaker crossover "B", vs. whatever. Parts definitely make a "difference". Rolling tubes makes a difference. Its all part of the game. We only have so many years on this earth. Thats why people spend thousands of buccaneers on caps/tubes/yourcurrentobsession

 

[Mike B]

I always roll.  With Bottlehead gear I roll before the stuff even gets here.  Lead time ya know.

I like it, I call it the "research" period.

For Crack, I have a couple of Solen 100 uf poly films 'cause everyone knows that anything is better than electrolytic for coupling caps.

And I got some Sylvania triple mica 6080's and some RCA side getter clear tops.

Why?  Cause Doc said that was what he was going to put in with the first 6 "special deal" orders and I knew I was not in the "6"

Yeah, you talk about how good stock is, but then you ply us with "special" tube offers.

The only valve gear I have that I never rolled tubes in is the K12G kit that started me down this glass path.  It still has the original 10GV8's in it.

 

[John EH]

I have built two of these Crack's with Speedball now.  Both amps SHINE with Mullard Box Plate CV4003's.  Best tube in my amps far and above anything else and I have them all I think.

John

 

[Mike B]

I bought one on your rec.

I'm done.  I am getting close to the line.

Never spend more on accessories than you spent on the item to be accessorized.

 

[w0lfd0g]

Never spend more on accessories than you spent on the item to be accessorized.

Spend to whatever level you like, provided:

1. It is within your means
2. It brings you enjoyment

The line is different for everyone, gentlemen. 

 

[Mike B]

Oh, I don't care what anybody else spends, just me.

I figure if I spent more on accessories that I did on the original item, I would have been better off just buying something better in the first place.

 

[w0lfd0g]

That sounds logical to me! 

I'm just very happy with the amp I have and its fit with the rest of my system.  I don't mind spending a bit more on optimising it!

 

[earwaxxer]

I think Nathan has expressed a "truism"  that hits us modders in the gut. We are much more inclined to experiment with kit that was affordable to obtain. I felt that way with the Quickie and my Maggie MMG's. I just went crazy on them. Why not? A great experience that I would have never had with high priced kit. IMO.....

 

[palmfish]

I got home from a business trip today and my new tubes were waiting for me! CBS 6AS7G and CBS 5814A. I can't tell any difference in sound quality from the stock tubes, but microphonics are much improved. And they look so good!

 

[Pepper]

I ordered a Tung Sol 5998 tube, and so I'm hoping to try that out soon. I hear there is a very noticeable improvement, especially because it is a different design (or something?).

However, I am wondering if replacing the small tube makes a big difference. If so, what type of tubes could I be looking at if I'm going to be working with a Tung Sol 5998 for the big tube?

Thanks!

 

[adamct]

Read through the last couple of pages in this thread. As far as I'm concerned, the benefits of rolling either tube are quite limited, particularly if you have installed the Speedball. And if you haven't installed the Speedball, then you are far better off installing the Speedball than spending money on tubes. None of the tubes I have tried has been a reliable, significant and cost-effective improvement over the stock tubes, which could very well wind up being less microphonic and noisy than whatever you replace them with, regardless of cost. And note that I say that without evening knowing what stock tubes you received. Why? Because it ultimately doesn't matter what you got with your kit.

Still, some people enjoy rolling tubes, so you won't get any arguments here if you decide to try for yourself. But if you are on the fence and money is tight, you can be secure that you aren't missing out on anything at all. And if you do decide to roll tubes, don't set your expectations too high, or you are likely to be disappointed.

Best regards,
Adam

 

[w0lfd0g]

Read through the last couple of pages in this thread. As far as I'm concerned, the benefits of rolling either tube are quite limited, particularly if you have installed the Speedball. And if you haven't installed the Speedball, then you are far better off installing the Speedball than spending money on tubes. None of the tubes I have tried has been a reliable, significant and cost-effective improvement over the stock tubes, which could very well wind up being less microphonic and noisy than whatever you replace them with, regardless of cost. And note that I say that without evening knowing what stock tubes you received. Why? Because it ultimately doesn't matter what you got with your kit.

Still, some people enjoy rolling tubes, so you won't get any arguments here if you decide to try for yourself. But if you are on the fence and money is tight, you can be secure that you aren't missing out on anything at all. And if you do decide to roll tubes, don't set your expectations too high, or you are likely to be disappointed.

Best regards,
Adam

+1

 

[Pepper]

Hey guys,

I've done some research, and there's glowing praise for the 12BH7A as a replacement for the 12AU7 in the Bottlehead Crack. I read one post which said there had to be a circuit modification.

Can anyone confirm if the 12BH7A needs any sort of circuit modification to work in the Bottlehead Crack + Speedball upgrade?

Also, having a 12BH7A and a Tung Sol 5998 would work, right? Or is there some circuitry/electronics reason why the two might not work together?

Thank you so much.