Parts Connexion has the Pearl Coolers or you can get them directly from Pearl. For the hot power tubes, make sure you get the 3" tall Coolers with the red silicone O-rings. The black rubber rings dry out and break after awhile.
nO LUCK YET but I'm closing in... I now know who does not have 6c33c-b tubes for sale: Parts Express, Antique Electronics. Alan welch, & Vintage Tubes. Searching here provides zip as well.
The Pearl Coolers do help with microphonics. The ones designed for small signal tubes include a carbon fiber mesh that slips between the tube & the vaned metal cooler.
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