Damp Tube Microphonics

From kee–(at)–ustin.ibm.com Sun Nov 13 15:47:46 CST 1994
Newsgroups: rec.music.makers.guitar
From: kee–(at)–ustin.ibm.com ()
Subject: Re: tube covers, etc.
Originator: kee–(at)–een.austin.ibm.com
Sender: new–(at)–ustin.ibm.com (News id)
Date: Wed, 9 Nov 1994 14:20:39 GMT

In article <39mrck$a--(at)--ewsbf01.news.aol.com>, twang–(at)–ol.com (Twangr) writes:
> I’ve got a Marshall JCM 900 with a tube cover that refuses to come off one
> of the preamp tubes. Any magic tricks out there? Also, any thoughts on
> isolating microphonic preamp tubes?

For the tube cover, I’d dunk tube and all in a kerosene or light oil bath,
let it soak in, then work the cover off. After all is well, dunk them
– separately now 🙂 – in an acetone or other lighter solvent bath to get
the oil off. Obviously , be careful about the flammability of the stuff you

For the microphonic tube, get a Speidel Twist-O-Flex watch band or something
similar and make a loop of it just big enough to go snugly around the tube.
This works by lowering the resonant frequency by adding mass.

There exists a synthetic rubber-tarlike stuff that will withstand high
temps that can be gooped in a loop around the tube, both adding mass and
mechanical damping, but I forget the name of it. Try over in rec.audio.high-end,
maybe someone knows the name.



Buy the Book!

I cleaned up my tab for Sonny Boy's Help Me and made it into a short book. There's a Kindle version for 99 cents, and if you buy the paperback you get the Kindle free.

Playing "Help-Me" In the Style of Sonny Boy Williamson II: A step by step, note for note analysis of some of Sonny Boy's Signature Riffs

I also write Science Fiction, so you can sample some of my best stories. Also available in Kindle format.

Error Message Eyes: A Programmer's Guide to the Digital Soul

6V6 ? TUBE AMPLIFIER Vintage 1950s - 60s Mono Hi-Fi Guitar Project 6V6 Amp As Is

$59.00 (1 Bid)
End Date: Sunday May-26-2019 18:00:03 PDT
Bid now |
Vintage Hammond AO-35 Original Reverb Amp -- Guitar Amplifier Project

$47.00 (0 Bids)
End Date: Sunday May-26-2019 18:48:46 PDT
Bid now |
Carvin PA620 Powered Amplifier PROJECT UFIX Clean Cover no reserve

$29.99 (0 Bids)
End Date: Sunday May-26-2019 19:19:15 PDT
Bid now |
Custom Amp Cabinet Side Carrying Handles Guitar Amplifier Project Parts Hardwwre

End Date: Sunday May-26-2019 22:12:47 PDT
Buy It Now for only: $18.69
Buy It Now |
Ampeg vintage emblem logo badge for amp project or restoration METAL not plastic

End Date: Monday May-27-2019 3:25:57 PDT
Buy It Now for only: $39.99
Buy It Now |


The JT30 Page Popular links

I began collecting data about the microphones used by blue harp players before there was an internet. I began organizing it into JT30.com in the late 1990s. I accumulated more stuff than I remember. This is some of it.

Street Theory

A Harp Player’s Guide to Music Theory

Learning Harp

Picking Up Blues Harp

A guide to learning to play Blues Harp

Microphone Information

Usenet Articles

Harp Amps

I've been collecting Harp Amps for a while. This is the old Harpamps.com website. There is lots of information here. Here a coupld of links.

Harp Tab

A collection of songs and riffs that I’ve worked out over the years, plus some libraries of stuff I’ve converted to tablature. I’ve included most of the notes and instructions that helped me when I was learning to play blues harmonica.

Basic Riffs Simple harp tabs for songs Blues riffs and phrases.

Harp-L Archives 1992 to 2002


Harp Frequently Asked Questions