Damp Tube Microphonics

Do it Yourself

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
use.

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.

R.G.

Index:

A B box	ABY box	Aging Grill Cloth	Available Pot Evaluation
B plus Precautions	B plus Safety Tips	Best Guitar Cable	Bias Jig
Biasing by Scope	Build an AB box	Cabinet maker	Cable Shield Conducts
Caig ProGold GxL	Cap Orientation Test	Cap Temp Ratings	Cathode Current Biasing Error
Champ line out	Cheap Headphone Amp	Cheapo amp	Cigar Box Amp
Damp Tube Microphonics	Darkness	Decontaminate Ckt Board	DIY Bias Probe
DIY Coil Winder	DIY Tube Dampers	Dr Z Kit	Eyelet Board
Fitting Grounded Cords	Fix Stripped Baffle Screws	Fixing Faded Knobs	Forming Caps No Variac
Good Pot Cleaners	Groove Tubes	Grounded Cord Codes	Heat Shrink On Cables
Hot Transformers	How To Lacquer Tweed	How to Measure Wattage	Installing Grillecloth
Light Bulb Cap Formers	Light Bulb Current Limiter	Low Drain Buffer TL061	LV Switchcraft vs Neutrik
Making Decals	Maxi Matcher Review	Measure Amp Power	Mounting A Variac
No Tuner Cleaner	Ohms Law Calc Online	Potting Transformers	Powering up old amps
Re Tolexing	Reconditioning Checklist	Reduce AC Voltages	Reducing Hum
Remove Ground Switch	Resistor Differences	Retensioning Sockets	Scooter Takes The Juice
Solder Types	Speaker Cable Guage	SwAMP ChAMP	Tolex Cleaner
Tolex Repairs	Tone Stack Calculator	Transformer Adapter Plate	Tube Font
Tweed Deluxe Clones	Why Orange Drops