Cryogenics

[PoorMan]

Anyone experimented with it?

[copperheadroads]

have been pretty damm cold at times working ,during winter working up north in the frozen tundra -55 degrees celsius

[David Schwab]

I've been using that big tank of liquid nitrogen I have to chill my martinis.

[Rick Turner]

I started doing strings in 1984, and when I worked for Gibson, circa 1988-'89 I had an entire F-5 mandolin and a number of MasterTone banjo tone rings done. Didn't get around to pickups.

So much time, so little to do...

[Bruce Johnson]

Hello Rick;

It's good to see your name again! I learned a lot from you back in the mid '90's when I was getting started. I'm still at it, building my Scroll Basses. I hope all is well with you?

[Joe Gwinn]

I've been using that big tank of liquid nitrogen I have to chill my martinis.

I thought the tank was for the preservation of aging rockers.

[David Schwab]

Hey Rick! Great to have you here.

I thought the tank was for the preservation of aging rockers.

I may need that soon!

[Ronsonic]

I thought the tank was for the preservation of aging rockers.

It's the only way to keep the ponytail and white shoes intact without discoloration.

[Plucky]

have been pretty damm cold at times working ,during winter working up north in the frozen tundra -55 degrees celsius

I grew up in Northern Alberta, and I remember many a winter going to school in -55 Celsius. Frostbite in 15-20 seconds...

I started doing strings in 1984, and when I worked for Gibson, circa 1988-'89 I had an entire F-5 mandolin and a number of MasterTone banjo tone rings done. Didn't get around to pickups.

Save yourself the time and just get your ears done. Catch-all.

By the way, hi Rick...

[RedHouse]

Anyone experimented with it?

Well not really cryogenics, but a psuedo-cry thing.

I've been experimenting with poping the pickup into the freezer for about 5-30 minutes after winding, then removing the pickup and letting it come up to room temperature before testing the parameters of the pickup. This seems to work well to get the core heat out of the coil to get a better assesment after winding.

It also (for reasons I can't explaing ..yet) seems to do something to the copper wire, perhaps causes it a "set" in-place which seems it is slightly less likely to get microphonic, not as eviddent as light potting but seems to have some effect and hard to A/B for any proof so consider this as hear-say/bs at this point.

[Rick Turner]

For testing DCR, I think you might be better off simply letting a batch of coils sit overnight and then measure them. I do this with my humbucker coils so I can match them to within + or - 2% DCR with an exact match on turns, and when I can I get them to within 1% + -. This yields very, very good hum canceling performance. Generally the coils are all within about + or - 4% DCR, and so it's easy to match up coils in batches of 10 per polarity.

The only effect I can think of that chilling might do is to make the coils contract...shrink a bit, and then expand back. Not sure what the coefficient of thermal expansion is for copper, but it must be moving a bit.

[Rick Turner]

Well, here you go: Coefficients of Linear Expansion

From this it would appear that you'd want to freeze a pickup before potting or risk breaking wire...especially if you wanted to go full minus 320 or lower cryo.

[Rick Turner]

And hi to old friends here...

[Arthur Dent]

Rick: did you say you had an entire F-5 mandolin cryogenically treated?! What was the effect?

[Rick Turner]

Yeah, in the white, strings on! Hey, it's a nice sounding mandolin, but it sure didn't like the cold very much! It developed a few cracks, and the celluloid binding came out much the worse for it, but I finally did a 'burst on it and a friend of mine in Tasmania has it now.

I have no idea what the effect of the cold was tonally, I did it on a lark. However, I also did Mastertone banjo tonerings, and that's now become a fairly standard thing for high end banjos.