Copper Gherkins (KT150s)

[The Black Adder]

Yes, they sorted it all out fine. They write the readings on each box. All the readings measure the same so they simply plug in.

[Marco]

Ok, mate. Cool... Just wanted to check before I order some!

Marco.

[Ali Tait]

Hotrox are good and give reliable service in my experience. Use with confidence.

[Marco]

Yup, mate, so I've heard. I'm just deciding on where to get the 150s from, there or from my usual source in the States, where they also Cryo-treat the valves. That's where I got my KT-120s from.

Here, in fact: http://www.upscaleaudio.com/tung-sol-kt-150/

The cryo treatment, in my experience, makes a notable difference to how they sound.

Marco.

[User211]

I was told by a metallurgy expert the obvious. That cryo is likely to do a lot more harm than good.

Any tonal changes are likely to be a result of damage e.g. loss of vacuum etc...

He is also seriously into hi-fi.

[User211]

To elucidate what he said was the expansion/contraction of glass versus metal is very likely to matter at such low temperatures and cause leaks. The same is true for any differing material types inside the valve e.g. carbon versus metal etc.

I had and still have 4 cryo'd Mullard E88CC equivs and they are all, without exception, microphonic. They came with my current preamp wot I got off ebay.

[Marco]

Hi Justin,

I can't really argue against that, as I'm no expert; merely comment on my experience to date (having had numerous cryo'd valves and compared them with the same types, non-cryo'd), and the former always, without exception, sounded better - and measured better too, in Anthony's valve tester!

He's taken a set of valves (KT88s in this instance), measured them beforehand (noting down their various parameters), then sent them off to Frozen Solid to have them cryo'd, and measured them again when they came back. The aforementioned parameters always change for the better on return. Plus the valves always perform better, sonically.

Therefore, on that basis, when possible, I'll be sticking with using cryo-treated valves

Marco.

[walpurgis]

To elucidate what he said was the expansion/contraction of glass versus metal is very likely to matter at such low temperatures and cause leaks. The same is true for any differing material types inside the valve e.g. carbon versus metal etc.

I agree. That has to be the case. Also the physical stresses involved are considerable. Expanding and contracting solids can produce an amazing amount of force.

[Marco]

Well...... See my above post!

Also, I would add, any cryo-treated valves I've used have never 'leaked', and to boot, have lasted LONGER than non-cryo'd ones.

Marco.

[User211]

It's hi-fi. Go with your hunches!