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Speaker Treatments & Cleaning Pots

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As the Vintage Portable Amplifier project here still slowly edges towards completion (I’ve two speaker grille assemblies to create / construct for two re-cabbed Mouse amplifiers and an 8-position rotary switch to install in a Roland Cube Street)… here are a few tips, tricks and hints that I’d like to share.

(1). Considering the 40+ years that most of the original paper-coned speakers have endured and the fact that direct replacements are difficult (if not impossible) to find… here are two approaches for “treatment” of some of these old original speakers have been used here.

    [a]. Visaton (Germany) LTS 50 speaker treatment. A brush-on coating that “stiffens” seals and preserves the integrity of the paper speaker cones from the “paper-turns-to-dust” scenario of these older speakers. Sure, it affects the overall tone of the speaker after a coat or two. (It tightens and increases treble end while somewhat reducing bass.) But just try to find an 8” 2Ω speaker for a Mouse or Maxi-Mouse amp. Or… spend nearly $40.00 for a Pignose replacement speaker - direct from Pignose.

    [b.] If I use BOLD on this "b" everything after this would have been in BOLD type. So...

    [c]. And here’s a weird one… used primarily for the speaker surrounds - where the speaker cone is attached to the outer frame of the speaker. *Also used on rips and tears in the cones themselves (before the above mentioned LTS 50 treatment). Some might be more accustomed to the old fingernail-polish approach for rips & tears?

Using “Brush-On” Electrical Tape, sufficiently diluted with acetone in a separate dish to enable better “brush-ability” - I have painted some of the old decaying speaker surrounds with this mixture. As the added acetone evaporates from the applied mixture, it then leaves the flexibility of the rubberized, Brush-On Electrical tape. Time will tell if it eventually gets brittle?

(2). Potentiometer cleaning. Never completely satisfied with the performance of De-Oxit or other versions of aerosol electronic cleaners for cleaning pots - they always seem to leave some greasy, oily residue which I believe adds more dust & dirt build up gunk (over time) inside the pots after cleaning… also considering that their use doesn’t seem to always throughly clean the pots anyway? I tried something different.

Recent acquisition of a Peavey / Special 212 amplifier here (with 18 mini-pots and 6 push buttons) led me to try something that would allow better access into the pots. 91% alcohol injected into the pots via a hypodermic needle. Irrigating and flushing each pot while turning each one individually, back and forth repeatedly… led to absolute zero “scratchy” pot noise. In fact - ZERO noise. (Compressed air afterwards, assured total evacuation of any possibly remaining alcohol.) So yesterday… I went back and cleaned (only) eight other portable amps in this manner. (And now I’ve a few guitars and other portable amps to use this same method on.) *Also used alcohol on a pipe cleaner (twice-doubled) to interior clean all 1/4” input /output jacks.

Again - all perhaps unorthodox methods… and I welcome possible detractors.
Have better approaches? Do please share.

AND (as per usual) follow the above methods at your own risk. ;)

When I clean pro stuff like EV ZLX 15P https://www.thomann.de/es/ev_zlx_15p.htm I use first air compressor softly to remove most dust. Then I clean woofers with a lightly watered cloth.

In some cases like 15 years walking NEXO PS-15 or Touring systems I have applied latex to the paper, but it changes lightly the sound, because membraine "weight" more than original, but make them lightly waterproof and moisture rejector, and under normal use it only make them gain low end.

20 years ago we only had "3in1" (3 en 1) electrical contact cleaner

For Potenciometers (Pots) we use 3 kind of "CRC".

One than cleans and "eat" (disolve) most grime

One that barely cleans, but keep the carbon track of the pot "wet" ensuring contact.

Other one that was between the others

You have to understand what is fisically a pot.

What the cursor do when to move it.

It is a carbon track that makes wider and widest at the end.

When you clean and clean and clean, you end "eating" that carbon track.

If the carbon track has been ruined, best to put some new japanese metalic pots.

You want the carbon track to have some "dust" (or be wet) to fill the gaps between contacts an ensure best conductivity.

In the end, have rightly lubricated an pot is a pro task.


On lightning, moving head wants littium (white) lubricant on its step by step motors.


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