Author Topic: Fender Frontman 15R mods  (Read 744 times)

Renegadrian

Re: Fender Frontman 15R mods
« Reply #20 on: April 17, 2019, 05:41:21 AM »
just two easy mods and it's more usable.
r12 10k cures the volume bump.
r22 has to be lowered I now have a 120k. still too much gain when maxed but hey i's better than before...
Still I'm not satisfied with the sound...I hoped it could give out something more 'true' not sterile sounding.
Any hints?!
« Last Edit: April 17, 2019, 04:41:29 PM by Renegadrian »
Done an' workin'=Too many to mention - Tube addict!

Mark Hammer

Re: Fender Frontman 15R mods
« Reply #21 on: April 18, 2019, 09:27:20 AM »
Quote
That's a job for Stabilant 22.
I've never tried products like that.  Any success stories with pots?
The person who initially recommended it to me did so primarily for pots.  He runs a busy (and occasionally award-winning) studio, and uses 2" tape for master recordings and has a mixing desk with 6" faders.  So he needs absolutely crackle-free pots.  The stuff used to be marketed to audiophiles under the brand name "Tweak".  The assumption was that you'd use it on your RCA jacks and such, but as the corporate appnotes pages shows, it has much wider application than that ( http://www.stabilant.com/NoteList.html#appnotes )

At the time (15 years ago) a local retailer had a bin of 1/2ml "sampler" vials for 50 cents a pop, so I snapped up a bunch, and am glad I did.  I'm down to my last two, now.  The stuff is bloody expensive, but works like divine intervention.

Imagine a paved road.  Fresh asphalt is dead quiet to drive on, because your tires make perfect contact with the surface at all times.  Flash forward a couple of years, and the road will be noisier because of all the stuff/gravel on top.  Sweep all that stuff away,and the noise will be lower but there will still be noise because cleaning the surface does nothing about the pits that have been created.  Stabilant acts as a contact enhancer, rather than cleaner, because it fills in those pits in the resistive strip, recreating continuous contact between wiper and resistive strip.  Ideally one uses it with contact cleaner in complementary fashion, after having shpritzed in contact cleaner, and allowing the pot to dry.  The cleaner may remove oxidation from the wiper, and sweep away any residue on surface of the resistive strip, but does nothing about the imperfections/pits in the strip created by rubbing the wiper against it.  Stabilant remains viscous for the life of the product, be it pot, switch, edge-connector, conductive contact (e.g., TV remotes), but because it does not dry, you can't build up coats/layers.  Within those limits, however, it's a pretty impressive product.

I've brought all sorts of stuff "back to life" with it, and successfully quieted plenty of pots.  If I have a microSD that doesn't seem to be behaving reliably, I wipe a bit on the contacts, and I'm back in business.  And because its viscosity doesn't go away, I'm surprised that no manufacturers take steps to pre-treat high-use pots with the stuff.  The vials/containers come with plastic applicators.  I find for a typical 12mm Alpha pot, you're looking at 2-3 sesame-seed-sized droplets to cover the entire surface of the resistive strip.  It can be diluted down to a 6:1 ratio with isopropyl alchohol, and can be purchased prediluted or full strength.

What is a complete mystery to me is why it doesn't conduct "sideways".  If I've smeared it over the entire surface of the resistive strip, and it behaves like a liquid solder joint between the wiper and resistive strip, how come it doesn't conduct along the resistive strip from one end to the other?  ??? :icon_confused:

In any event, back to the thread, already in progress....

The network formed by R16-18/C9-10 is largely identical to the midscoop filter found on countless fuzzes, intended to provide "doom" sounds with big bottom and sizzling top in the overdrive channel.  The "big bottom" leaves something to be desired, and the sizzling top just adds stridency, rather than character.  The value of C10 should probably be lowered a bit to raise the corner frequency of the bass side and make it a little more vocal-sounding, and there should probably be a fixed resistance in series with C9 to reduce the shrillness. I'll suggest .022 for C10 and 2k2 for the added resistor.