Tube Rolling: Does it Make a Difference?

[the_brunx]

What about frequency response measurements?

 

[DanielT]

That depends. I've seen a LOT of incompetent high distortion cathode follower circuits. Two common mistakes: assuming low output impedance means low loads are driveable (so yeah, let's use a 12AX7!), and biasing (with the grid at 0V, just take the signal off the 1k cathode resistor!).

This DIY tube pre amp seems to have been decent with low distortion, or? Tube pre amp with tube ECC88

Index of /Morello/Tube-preamp

faktiskt.io • Visa tråd - GDS-projekt: rörförsteg - LEVERANS!!

 

[DanielT]

MMmmm... ale.. nom nom.. This a fine ale at just above freezing temps otherwise it gets a bit tangy. I've been known to drink a dozen or so at a time.
View attachment 168974

Not chilled. That is not enough. Vaccum tubes should be frozen, you know that?

These are Cryogenically Treated Vacuum Tubes. They are matched tubes and burned in for 24 hrs with treatment. Guarantee the best quality hand picked.

McIntosh MC-275 Audio Research PrimaLuna Genalex Gold Lion KT88 Cryo Treated Set | eBay

Up for sale is a SET of (8 pcs Matched Cryo KT88) Russian re-issue of the Legendar Genalex KT88. They've been working great in all applications and haven't had a single complaint. Read web forums and you'll see tons of praise for this tube.

www.ebay.com

Apart from snake oil waffle, how do you know they have really been cryo-treated? He he.

 

[Doodski]

Not chilled. That is not enough. Vaccum tubes should be frozen, you know that?

These are Cryogenically Treated Vacuum Tubes. They are matched tubes and burned in for 24 hrs with treatment. Guarantee the best quality hand picked.

McIntosh MC-275 Audio Research PrimaLuna Genalex Gold Lion KT88 Cryo Treated Set | eBay

Up for sale is a SET of (8 pcs Matched Cryo KT88) Russian re-issue of the Legendar Genalex KT88. They've been working great in all applications and haven't had a single complaint. Read web forums and you'll see tons of praise for this tube.

www.ebay.com

Apart from snake oil waffle, how do you know they have really been cryo-treated? He he.

Hehe. That's cheap for those big fat output tubes. I was looking at 300B's the other day and they are>
Matched Pair $1499 • Single Tube $699 • Matched Quad $3099

 

[Jimbob54]

Thanks for measuring this. Something I've always been a bit skeptical of.

Also interesting to see that this tube amp has loudspeaker like distortion numbers .

If only this were an amp. Its a DAC!

 

[Veri]

This DIY tube pre amp seems to have been decent with low distortion

I believe @JohnYang1997 once engineered a tube circuit with very low distortion numbers (I guess for fun), maybe it ever sees the light of day in a future product release.

 

[JSmith]

Surely there are better things to be rolling than tubes...

If only this were an amp. Its a DAC!

Yeah I don't want tubes anywhere near my DAC... or amps for that matter.


JSmith

 

[Jimbob54]

Surely there are better things to be rolling than tubes...

Yeah I don't want tubes anywhere near my DAC... or amps for that matter.


JSmith

Agreed. What would be interesting is where in the chain can you put (EDIT- SWAP) tubes for maximum impact. Doesnt appear to be in the DAC and I dont believe tube pre-amps do much either.

Not that I personally want any of it, but you'd be annoyed to buy into tubes then find that the really expensive ones you bought do nothing whatsoever.

 

[DanielT]

I believe @JohnYang1997 once engineered a tube circuit with very low distortion numbers (I guess for fun), maybe it ever sees the light of day in a future product release.

Same as Morello, that DIY. He has done this as a fun "try on" winter project. He competes with himself to try to bring down the distortion. Actually he hates he tube amps. He usually manufactures class AB transistor-based amplifiers.

By the way, thanks for the measurement Amir, it was interesting. Not too unexpected but it was good that you researched it.

 

[Gorgonzola]

What surprised me, perhaps, was how similarly the different tubes measured. I not surprise, though, that overall performance is blamed on the circuit rather than the particular tubes.

Purely subjective impression of course, but my Sonic Frontiers preamp sounds distinctly different from my Glassware Aikido preamp with the same tubes.

 

[ZolaIII]

Well that second chenel difference to average of 37 dB is 17.5% with WE 396A. But its probably just a glitch. That DAC pre amp looks as hazard with catastrophi awaiting to happen. Arguably if it whosent a glitch or defective lamp on some deacent design with mid 50's SINAD that 17.5% would maka a whole lot of the difference.

 

[Holmz]

I never understand why it's called "rolling tubes" as opposed to "changing tubes". It seems to imply some inherent skill involved in the process.

May be this:

https://www.cheechandchong.com/wp-content/uploads/2016/08/slide1.jpg

 

[L0rdGwyn]

Looks like the circuit isn't a simple cathode follower. The measurements would be a lot better this way and thus less 'tube goodness'.
So it looks like the tube stage amplifies the signal and that's why measurements are poor and 'tube sound' is maximized.

Would have been interesting to see distortion profile at say -10 and - 20dB

Here is a DIY NOS R2R "tube DAC" I made using an older BB chip, PCM56, it uses a common cathode gain stage on the output, however the distortion is significantly lower, around 0.0093% with a -6dBFS signal, around 2Vrms.

NOS Burr-Brown PCM56 DAC with Tubes!!!

Hey ASR, Showing another DIY project of mine, I said I wasn't going to post anymore but I am proud of my monstrosities :D I designed a NOS DAC based on the vintage Burr-Brown PCM56. It's a 16-bit chip. This is my foray into digital design, so I thought simple is best. I know the NOS R2R...

www.audiosciencereview.com

I'm not sure why the distortion is so high on the Pagoda, it would be interesting to see a schematic.

 

[TabCam]

I never understand why it's called "rolling tubes" as opposed to "changing tubes". It seems to imply some inherent skill involved in the process.

Changing tubes could just mean replacing an old one for new tube while "tune rolling" over time also took the meaning of changing to a different type/kind of tube like with "OpAmp rolling" which just are changed with an up-down motion.

 

[Schollaudio]

Indeed, CF would be better, but they are proud of producing even 3 V at the output of this DAC - so probably tube amplifies signal.
I cannot understand why and how they decided "this is it, let's sell it" ?
I have made many tube amplifiers for myself, some were really bad, but I would never think of them "that is great" - just mistake.
Simply integrated sound-card from PC would tell them that there is something wrong with this device.
Did they deny to make any measurements? Magic brand.

As you know, it's easy to make a small signal tube sound good and measure well. Possibly tuned by ear to sound the way they liked it.

 

[Svperstar]

I owned an MHDT Paradisea+ back in the day when NOS DACs were the rage and it is the worst piece of audio gear I have ever owned.

 

[Peacemaker]

MMmmm... ale.. nom nom.. This a fine ale at just above freezing temps otherwise it gets a bit tangy. I've been known to drink a dozen or so at a time.
View attachment 168974

Made me think of this one...

 

[Spkrdctr]

Personally even if I signed up for a tube product, I would not waste time "rolling tubes." You are likely to suffer more from "rolling placebo" by your brain than any variation in such tubes.

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I immediately thought of DAC placebo effect. Just the way my mind thinks............ Well, my wife has said numerous times, "You are not right in the head!"

 

[Spkrdctr]

MMmmm... ale.. nom nom.. This a fine ale at just above freezing temps otherwise it gets a bit tangy. I've been known to drink a dozen or so at a time.
View attachment 168974

Did you bring enough to share?

 

[Doodski]

Made me think of this one...

View attachment 169042

I googled that Kootenay 120 amp. It's a top shelf tube amp from what I gathered. My pic shows it off better.