[ketchup]

I have some Herbies UltraSonic Rx-9 dampers, and the rubber o-rings have started to dry rot and fall apart.  Does anyone have a source for replacements that are easy to get?

These are the ones I have:
https://herbiesaudiolab.com/collections/tube-dampers/products/ultrasonic-rx-damping-instrument?variant=12645125849143

[richidoo]

You can obtain replacement o-rings from amzn or industrial supplier.
https://www.amazon.com/s?k=silicone+o-ring

You want silicone o-rings to match the (specified) heat resistance of the originals, which they state is 250C, (450F) which is silicone. 250C is slightly above the heat rating for standard silicone, but if you find a source then you can replace them as often as needed for low cost. Also, signal tubes usually operate far cooler than 250C. A meat thermometer probe can give you rough idea of the operating temp. If they are dried up I would doubt they are silicone. Maybe the current version is silicone, but yours are probably nitrile (Buna-N). Silicone is softer than nitrile, so you might get a little more vibration damping with silicone.
https://websealinc.com/technical-info/o-ring-temperature-guide/

They look to me like standard thickness o-rings, aka standard "cross section."
https://www.marcorubber.com/o-ring-size-chart-as568.htm
https://www.marcorubber.com/downloads/marco-o-ring-size-chart-as568.pdf

If the old o-rings are too far gone to remove for measurement without damage, then just measure the diameter of the teflon plastic wheel groove that holds the o-ring. You can use a caliper to measure accurately, https://www.amazon.com/dp/B01C6WHQ92, but a ruler should be close enough to narrow it down to the 2-3 standard o-ring sizes to try.

The replacement o-ring needs to be slightly stretched to remain in position, so choose ID that is ~0.030" - 0.050" smaller diameter than the teflon wheel groove diameter.
https://www.amazon.com/s?k=silicone+o-ring
https://www.rocketseals.com/o-r-s-n-silicone/

Maybe something like this (in size 011:) https://www.marcorubber.com/product/S1036-011
But you might need larger size than 011

Silicone o-rings are easier to find in red color: https://www.amazon.com/s?k=silicone+o-ring+size+011
again, this is just size 011, you may need bigger size.

They are so cheap you can just buy a few different size packs and experiment to find what fits best.
Good luck!

[ketchup]

You can obtain replacement o-rings from amzn or industrial supplier.
https://www.amazon.com/s?k=silicone+o-ring

You want silicone o-rings to match the (specified) heat resistance of the originals, which they state is 250C, (450F) which is silicone. 250C is slightly above the heat rating for standard silicone, but if you find a source then you can replace them as often as needed for low cost. Also, signal tubes usually operate far cooler than 250C. A meat thermometer probe can give you rough idea of the operating temp. If they are dried up I would doubt they are silicone. Maybe the current version is silicone, but yours are probably nitrile (Buna-N). Silicone is softer than nitrile, so you might get a little more vibration damping with silicone.
https://websealinc.com/technical-info/o-ring-temperature-guide/

They look to me like standard thickness o-rings, aka standard "cross section."
https://www.marcorubber.com/o-ring-size-chart-as568.htm
https://www.marcorubber.com/downloads/marco-o-ring-size-chart-as568.pdf

If the old o-rings are too far gone to remove for measurement without damage, then just measure the diameter of the teflon plastic wheel groove that holds the o-ring. You can use a caliper to measure accurately, https://www.amazon.com/dp/B01C6WHQ92, but a ruler should be close enough to narrow it down to the 2-3 standard o-ring sizes to try.

The replacement o-ring needs to be slightly stretched to remain in position, so choose ID that is ~0.030" - 0.050" smaller diameter than the teflon wheel groove diameter.
https://www.amazon.com/s?k=silicone+o-ring
https://www.rocketseals.com/o-r-s-n-silicone/

Maybe something like this (in size 011:) https://www.marcorubber.com/product/S1036-011
But you might need larger size than 011

Silicone o-rings are easier to find in red color: https://www.amazon.com/s?k=silicone+o-ring+size+011
again, this is just size 011, you may need bigger size.

They are so cheap you can just buy a few different size packs and experiment to find what fits best.
Good luck!

I did say "easy to get"  haha.  I know that I can buy an assortment or measure mine and buy a few different sizes and hope one fits perfectly, but I was really hoping that someone might know an exact replacement part number.  Thank for the help, though!

The reason I'm asking here is because Herbies won't get back to me for some reason.  Maybe they're just slow to respond.  I don't know.  I have never dealt with them before.  Didn't they used to have a circle here?  What happened to that?

[FullRangeMan]

I did say "easy to get"  haha.  I know that I can buy an assortment or measure mine and buy a few different sizes and hope one fits perfectly, but I was really hoping that someone might know an exact replacement part number.  Thank for the help, though!

The reason I'm asking here is because Herbies won't get back to me for some reason.  Maybe they're just slow to respond.  I don't know.  I have never dealt with them before.  Didn't they used to have a circle here?  What happened to that?

Herbie retired and the sales are now run by his son while supplies last.
They are a one man small bussines.

[ketchup]

Herbie retired and the sales are now run by his son while supplies last.
They are a one man small bussines.

Oh darn, that stinks.  These items show out of stock, so I guess I'm out of luck on getting genuine Herbies o-rings.  Oh well, I'll find something.  Thanks for the heads up!

[FullRangeMan]

Oh darn, that stinks.  These items show out of stock, so I guess I'm out of luck on getting genuine Herbies o-rings.  Oh well, I'll find something.  Thanks for the heads up!

No prob for now there is a lot of useful info in Richidoo post.

[Escott1377]

I purchased my tube dampers from seller sandysphotos on EBay.  They work well for their intended purpose.  I read an article about a year back that said tubes are not meant to have dampers so I no longer use them.  But as always, use what you like.

FYI - I have never used these on power tubes bit I did put them on 300B’s and I thought it degraded the sound.

[FullRangeMan]

I purchased my tube dampers from seller sandysphotos on EBay.  They work well for their intended purpose.  I read an article about a year back that said tubes are not meant to have dampers so I no longer use them.  But as always, use what you like.

FYI - I have never used these on power tubes bit I did put them on 300B’s and I thought it degraded the sound

Tube dampers are not snake oil as IEC power connectors, they are recommended when the tube is microphonic, but if the valve is not microphonic the use may not bring improvement.

These rubber O rings heat up the valve and should not be used:


These ''dampers'' below are even worse and will greatly increase the valve temperature reducing valve useful life, but they are fancy and will amaze the friends.

[ketchup]

These ''dampers'' below are even worse and will greatly increase the valve temperature reducing valve useful life, but they are fancy and will amaze the friends.

My phonostage came with dampers like these on its tubes, but you can't even see them because they're in the chassis.  The manufacturer must think that they work.

[Tom Bombadil]

Tube dampers are not snake oil as IEC power connectors, they are recommended when the tube is microphonic, but if the valve is not microphonic the use may not bring improvement.

+1 to all that FRM wrote.

[kernelbob]

I have some Herbies UltraSonic Rx-9 dampers, and the rubber o-rings have started to dry rot and fall apart.  Does anyone have a source for replacements that are easy to get?

These are the ones I have:
https://herbiesaudiolab.com/collections/tube-dampers/products/ultrasonic-rx-damping-instrument?variant=12645125849143

Years ago, I called Herbies and discussed third party replacement rings.  He explained that they evaluated a variety of damping o-rings and that the ones supplied by them perform sound the best.  I'm certainly not recommending that you not follow their advice to only use their o-rings when replacements are needed.

That being said, here is a link to a source of high temperature tolerant (red) o-rings that fit the devices in my system.  You can evaluate their performance yourself.
https://www.amazon.com/011-Silicone-Ring-Durometer-Width/dp/B000FMWNZ8/ref=pd_bxgy_sccl_1/137-4744714-5170642?pd_rd_w=Z0ghl&content-id=amzn1.sym.a6bed837-ef89-4bc6-a842-3962a5387175&pf_rd_p=a6bed837-ef89-4bc6-a842-3962a5387175&pf_rd_r=D3NV3AMD68NP47JK6ETB&pd_rd_wg=bKRZ4&pd_rd_r=377bc34b-31a5-4c46-bd3c-ca43d8bc7460&pd_rd_i=B000FMWNZ8&psc=1

Regarding other tube damping solutions, I haven't tried the various other damping devices, but once I replaced my various tube damping rings (where the damping ring is rolled onto the tube) with the Herbies devices, it was clear that those tube rings were smearing the sound.  It sounded like the damping ring was storing the vibration and releasing some of it slightly delayed.

[GregC]

I ran Herbies Ultrasonic SS tube rings with a Dodd battery powered preamp and I was happy with the results.

[ketchup]

That being said, here is a link to a source of high temperature tolerant (red) o-rings that fit the devices in my system.  You can evaluate their performance yourself.
https://www.amazon.com/011-Silicone-Ring-Durometer-Width/dp/B000FMWNZ8/ref=pd_bxgy_sccl_1/137-4744714-5170642?pd_rd_w=Z0ghl&content-id=amzn1.sym.a6bed837-ef89-4bc6-a842-3962a5387175&pf_rd_p=a6bed837-ef89-4bc6-a842-3962a5387175&pf_rd_r=D3NV3AMD68NP47JK6ETB&pd_rd_wg=bKRZ4&pd_rd_r=377bc34b-31a5-4c46-bd3c-ca43d8bc7460&pd_rd_i=B000FMWNZ8&psc=1

My man!  Thank you!  You just saved me some work.  Those are 0.035" undersized which seems just about perfect.  Thanks again!

[kernelbob]

If the size of the rings at the link aren't correct, a variety of sizes are available from the same source.  There are also standard black versions which are not high temperature tolerant.