O-Ring sizes for Tube Dampers

[sbelyo]

Does anyone know what size O-Rings are used for dampers?

Like for 6922, 6sn7

[wa2ise]

The O rings that come with car headlight light bulbs make for good tube dampers. That rubber material can handle the heat.

[sbelyo]

They're made from silicone... Those rings are available in a myriad of places. I just was wondering what size people use like : Inner Dia. XX for 12AU7 etc...

[vinylkid58]

I just measured two 12AX7's. 0.850" dia. at the top, tapering slightly to 0.875" at the bottom. The closest 3/32" cross section o-ring from the chart is 0.799". Not sure if this helps as I have never tried it.

Jeff

[sbelyo]

That's pretty close... I'll see if I can find them here

[NickC]

Yes you can it works

There are two types of o-rings normal temp and the high heat type. THe high heat type are often red in color and the black in color is standard. Red type is the silicon rubber type
Standard is 3x cheaper but wear and harden up after a year(+- on the heat of the tube).
There are many o-rings diameter in the market. I get them at hardware shops or industrial shops. Just bring in your tube and they should have them
The rings work but can cause hardness in the sound. With it the sound is tighter and more focus. Without the rings the sound is abit loosey, more airer but more fluidity.
I do not use them as i find them to be hard.
I will say its system dependable

Cheers
NIcholas

[Majestic]

Too much damping on the wrong kind of tube (eg a "dull" sounding modern produced 6DJ8 for eample) can definately result in less appealing sonics.

On the other hand, my own experiences are that a little damping cam improve things markedly. The nice thing about this "tweak" is that they're painless to try, and reversable if you happened to think I was wrong.

This page claims the best rings are actually the cheaper (ie "non-audiophile") industrial ones. Accordingly, I believe for 12AX7 sized widths, his advice thus references this product.

Alternatively, there are obviously many audio-speciifc companies who will charge you $10 per silicone ring.

This is also this gentleman on eBay who's offerings look reasonable and interesting.

Hope some of that helps you out.

[sbelyo]

I was looking at that place but wondered if the material was too hard. I'll try and scout some out this weekend

[Majestic]

Originally posted by sbelyo
I was looking at that place but wondered if the material was too hard. I'll try and scout some out this weekend

There definately needs to be some rubbery elasticity there. Sorbothane rings would be ideal for damping, but unfortunately it can't, as a substance, stand much above 200 degrees before melting. Most tubes will be close to this edge, and others will be definately over it. Silicone then, seems the safest way to go.

Having said that bit about elasticity, the HAL-O (funny, eh? ) rings, have a slightly different approach, but also seem to garner great reviews. I've not tried them myself yet however so I'm not in a position to help you compare.