Cryo treating tubes

[Torpedo]

I think we all know what sir KG would have to say about Cryo anything and audio. I tend to agree with him...

I don't know what KG has to say, but I've had the chance to carry a DBT at my place using cryoed and uncryoed tubes on my speaker amp, and I spotted them with 0 errors . This doesn't mean the cryoed were better. They weren't. Cryoing was clearly an awful thing on power tubes.

On caps I also noticed clear differences, but for obvious reasons it was impossible to carry a proper DBT. Probably some parts change more undergoing cryoing than others. Not sure the plastic sheet on an electrostatic HP would change a wee bit.

[spritzer]

I think we all know what sir KG would have to say about Cryo anything and audio. I tend to agree with him...

I'm not a great believer in cryo but I had a SR-SC1 and a SR-404 here side by side and the SC1 doesn't suck. The 404 was a few months old but the SC1 I bought used but installed new pads when they arrived so that eliminates the pads out of the equation.

[grawk]

That doesn't mean cryoing hurt those tubes, it just means those tubes sucked

[Anders]

80kYen is a bit excessive when the SR-007 is around 100k. The SR-SC1 is indeed much better then the SR-404 but my unit was used so it could be a production variation or that cryo actually works on very thin sheets of plastic.

I am also skeptical of cryo treatment but now remember something I have read about it. It is an accepted method to increase the strength of metal but of course this is not the same as better sound. Another use of cryo treatment is to increase the durability of thin synthetic materials. According to the article, some women leave expensive brand stocking for cryo treatment because they last 2 - 3 times longer after treatment. So treating electrostatic film could possibly be an advantage.

[Torpedo]

the DBT is kinda invalidated by the inherent variation and fragility of tubes, unless you are very careful with how you set it up. how many did you use?

We used tubes from the same manufacturer, which were measured by the amp's manufacturer before being sent for cryoing, and also after treatment. The power tubes were matched as quartets. They were JJ 6922 and JJ E34L.

For sound and measurements, it's as though cryoing had aged the tubes. The DBT was carried quite seriously, the manufacturer of the amp was really into knowing if the cryo treatment was worth the expense and the hassle.

Using the same procedure, but without being able to DBT, is how the cryoed and uncryoed caps were used. Two identical amps measuring the same, using the very same tubes, one with cryoed caps and the other with normal ones. We made it twice, one in my place and the other at one of my friend's. Despite the non-DBT I think the results were consistent.

[deepak]

Moved the cryo treatment discussion to its own thread.

[kevin gilmore]

I finished cryo treating a bunch of stuff for a guy over on head-fi.

I expect his reports in the next few weeks.

1 day to cool down, 7 days in Liquid N2, 1 day to warm up.

[Torpedo]

but how many tubes did you use?

This was a long "experiment" and we worked on 4 different scenarios:

- Cryoed input 6922 using non-cryoed power EL34

- Cryoed input and cryoed power tubes.

- Normal input tube and cryoed EL-34

The reference for the DBT was a set of normal tubes and we carried it only to compare the cryoed 6922 + normal EL34, because it was this combination the only one that offered small and not so clear differences. All the other combinations involving cryoed power tubes sounded so different for everyone attending the test, that we decided it wasn't necessary spending much time on a DBT.

We had two sets of cryoed tubes and two sets of normal tubes, but only needed one set of each, all measured by the amp designer-manufacturer and matching within 99.5% before the cryo treatment. We had two amps, one used just to keep the tubes warm driving a resistive load and the other for the listening. The trickiest part was swapping tubes while they were hot

Obviously the test wasn't strictly double blind since the pal swapping tubes knew which ones he was plugging, and it wasn't immediate A/B, but none of the listeners knew if the cryoed or un-cryoed 6922 was on until the end. We were 4 listeners, plus the manufacturer who was swapping the tubes. I'm not sure now how many trials we made, something between 6 and 8. Two of us spotted the tubes used right in all of them.

I've made other blind tests using tubes, but none as thorough as this one and none invoving cryoed tubes.

Rgrds

[Torpedo]

No, not easy at all, specially in the first assessments when the cryoed and un-cryoed very hot EL34 had to be swapped. The guy used the gloves to take hot trays off the oven. We were afraid of the tubes being damaged for hot swapping, but they stood well.

[kevin gilmore]

What you need to do now, is burn in the cryo'd tubes for say 10 hours, then

put them aside for a day. Then listen again and see if you can hear the differences.

In my tests, the cryo'd tubes return to normal (pre cryo) after a day or two of use.

[justin]

If all you were doing is guessing if the tube is cryo or non-cryo, 6 to 8 trial isn't nearly enough. What if every trial was actually the same tube? How would you have done then?

[Torpedo]

What you need to do now, is burn in the cryo'd tubes for say 10 hours, then

put them aside for a day. Then listen again and see if you can hear the differences.

In my tests, the cryo'd tubes return to normal (pre cryo) after a day or two of use.

We had already done that. The tubes after cryoing (the power tubes) not only sounded different, but also measured different after treatment. Measurements were taken -the manufacturer told us and I have to believe him- right after the tubes got to him, then he burnt them for about 24 hours and repeated measurements. I don't recall the exact figure, the manufacturer told us that they had lost some power delivery which hadn't recovered after that burn-in. In our experiment the tubes were used already burnt-in by the manufacturer.

This was less significative on the small signal tubes (6922) and while the sound was different, it really wasn't "that" different.

Justin, I won't get into the statistics discussion about how many trials give significance to a test, nor how to make a proper DBT, please consider that I'm a MD involved in clinical research. We made this more than two years ago just to help the manufacturer to decide if it was worth cryoing the tubes he included with his amps. We didn't pretend to make a scientifically 100% valid test, nor I'm claiming this is even close to "true science". IMHO the test is good enough, and as far as I was involved in the listening, I'm pretty sure the tubes sounded different, especially the cryoed power ones.

Rgrds

[cclragnarok]

I'm not a big believer in cryo treating tubes, but are you sure the cryo treatment is done right?

Maybe the tubes were somehow damaged by improper cryo treatment (sudden changes in temperature, etc).

[Torpedo]

I'm not a big believer in cryo treating tubes, but are you sure the cryo treatment is done right?

Maybe the tubes were somehow damaged by improper cryo treatment (sudden changes in temperature, etc).

The cryo treatment was performed by a company that does that for Hovland and other electronic parts manufacturers using cryo treated components. I don't know if they know their bussiness, but I'm prone to believe they do.

[kevin gilmore]

Here is how i do it. The controller can do .25 degree C per minute up or down

http://gilmore.chem.northwestern.edu/jordan1.jpg

and the stuff i did for the guy over there

http://gilmore.chem.northwestern.edu/jordan2.jpg

Now you got me interested in the power tubes thing again. So i'm going

to accumulate a batch of el34's i don't care about and do it again. Although

i'm going to stick them into an electrostatic amp, so its not really the same thing.

The power tubes you did the experiment with could have been absolute crap...

[Torpedo]

JJ tubes were produced upon the factory that Tesla tubes once were made, and had a very good quality, for built and for sound quality, but as long as their sales have been increasing, it's said they moved to a bigger facility. Maybe they outsourced production of some parts to China, who knows.

The fact is that their quality has been going down with time. In the last two years I haven't had a E34L quartet that lasted for more than 1200 hours. Most of them fail for one of the pins losing connection to the inner wires, and can't be fixed by filling the pin with soldering. Once one of the tubes fails, you need to change all four in my amp for its fixed bias design.

Maybe using other brand tubes for this experiment yields different results. In my experience, cryoing JJ E34L is not a good idea. The ones that the manufacturer sent for cryoing were some from an old batch, probably made in the late 90s or early 2000, and were compared to tubes of that same batch. It hadn't been smart comparing "better made" tubes cryoed to some of recent production ones, which we knew had lower quality.

[Icarium]

Ha ha what? Dude is having you cryo some cds?

[lostonetr]

Didn't know those things could be cryo'ed. Thought ppl cryo the bare wire, then put all the pretty stuff on it, does it not really matter for order?

and KG's got a really lucky # for post count.

[penger]

I finished cryo treating a bunch of stuff for a guy over on head-fi.

I expect his reports in the next few weeks.

1 day to cool down, 7 days in Liquid N2, 1 day to warm up.

You should try some liquid helium.

[Beefy]

You should try some liquid helium.

Ooooooh, superfluids. The weirdest shit I ever did see......

[penger]

Expensive too.

[kevin gilmore]

You should try some liquid helium.

We now recycle 95% of our helium. It still is not cheap. The 50kpsi pump that

makes the helium gets a new piston and seals every 8 weeks. Pain in the fucking ass.

I very much doubt that the wide mouth dewar can withstand liquid helium

temperatures. One of these days i will try.

Yes that was a bob dylan sacd. Don't remember what the other 2 were, but

i think they were also sacd's. They survived just fine (only listened to them

a few seconds) One of the plastic cases however had a crack in it, and it

turns out that plastic baggies evidently don't like liquid N2 they get and stay

ultra brittle.

[penger]

We run a MEG and don't get to recycle our helium... it just kind of dissipates and needs to be refilled once a week.

[kevin gilmore]

Once a WEEK.... OUCH. How many litres. My magnets hold for anywhere between

3 and 6 months. And my biggest magnet is 21 tesla. Whats the field on that thing,

someting between 2 and 5 tesla... No wonder health care costs are so high.