Broken "Fab Tone" find !

[MartyMart]

I got a Dano Fabtone from ebay for £5 !!
9 volt connecion had sheared off, also disconnecting battery snap.
Fixed it in 5 mins !!
I'm not so pleased with the tone, so will try a few tweaks to the bass/treble caps and drive section.
I'll post back with some findings in a few days.

Marty.

[aron]

Don't you love the fact that you can repair things like this?

Congratulations!

[Paul Marossy]

Well, you don't have to sweat it too much if it doesn't work out they way you want it to, it's a pretty cheap test bed...  

[Fret Wire]

The Fabtone has a lot of potential. It will respond nicely to the basic clipping, gain, and EQ mods. The gain is fixed, but that's no big deal to adjust. Treble control is a little spastic, and the sustain (sat) control doesn't do a hellava lot. I got one cheap to mod, and it went into the save for a rainy day box. The problem is the jacks and switch are junk, and go intermittant pretty quick. The jacks usually fail due to the spring contacts losing tension. The jacks are also pcb mounted, god forbid someone stepped on the cords. The pots don't last very long either, they are just cheap long- shafted trimmers really. So I decided to let it sit until I could find decent replacements or a solution. There may be a way to adapt Switchcraft jacks to the plastic mount panel, but the switch looks proprietary. That's probably why no one sells them modded, kinda hard to ask $100 for a $60 pedal that will go intermittant in less than two months.

[petemoore]

Fab Tone is over the top, not an all 'rounder', cool and fun A real nasty Fuzz Box. I used 3 for years, kept getting replacements...lol. That's what a warranty is for and 'dude' just swapped 'em right over when I'd bring him the broken item, wasn't the jacks I don't think, er at least they didn't 'wiggle' badly. Just kinda half died, probably the switching. Kinda fun changing the gain with the EQ knobs 'n stuff, anything from high gain to mongoman Gain.
 I'ts got alotta parts in it, I'd probably stash or sell it and build something more 'reasonable' and durable, smaller, guts wise anyway.

[Fret Wire]

Yeah Pete they don't hold up very long. The jacks don't usually come loose or break their solder connection. The internal spring contacts just weaken and go, switches too. The case itself is pretty heavy duty. Serious output, no problem getting unity gain.

[MartyMart]

The Fabtone has a lot of potential. It will respond nicely to the basic clipping, gain, and EQ mods. The gain is fixed, but that's no big deal to adjust. Treble control is a little spastic, and the sustain (sat) control doesn't do a hellava lot. I got one cheap to mod, and it went into the save for a rainy day box. The problem is the jacks and switch are junk, and go intermittant pretty quick. The jacks usually fail due to the spring contacts losing tension. The jacks are also pcb mounted, god forbid someone stepped on the cords. The pots don't last very long either, they are just cheap long- shafted trimmers really. So I decided to let it sit until I could find decent replacements or a solution. There may be a way to adapt Switchcraft jacks to the plastic mount panel, but the switch looks proprietary. That's probably why no one sells them modded, kinda hard to ask $100 for a $60 pedal that will go intermittant in less than two months.

The sockets have "cut out" problems .... !
But for £5 the case was a bargain, I'll put something else in there - perhaps Jacks "overdrive pro" would be a good choice !!
I have to figure a way of using the original "metal" switch to push down a
3PDT , perhaps mounted on a little "jig" inside ?
The back plate will take a pair of switchcraft sockets and a 9v barrel OK

Marty.

[jmusser]

I bought one of Ebay for about $20.00 back about 5 years ago. It's just all around nasty! The sound of it, don't sound like a big jump to going to the French Toast. It's not as high pitched of course, but has some of the same grind and growl to it. I've never made a DIY pedal that has that type of distortion. I've always kind of wondered when it came out, because it is in the big housing, and not the mini housing like so much of their recent stuff. Mine still works well, so I doubt it got a lot of use before I got it.

[MartyMart]

I bought one of Ebay for about $20.00 back about 5 years ago. It's just all around nasty! The sound of it, don't sound like a big jump to going to the French Toast. It's not as high pitched of course, but has some of the same grind and growl to it. I've never made a DIY pedal that has that type of distortion. I've always kind of wondered when it came out, because it is in the big housing, and not the mini housing like so much of their recent stuff. Mine still works well, so I doubt it got a lot of use before I got it.

I think these bigger "metal" cased Dano's are from the early '90's and are still produced.
The small plastics came after.
Here's some things that I've played with for improved sound/tone :

Treble control has a 2k resistor R26 and 8n2 cap C18 going to ground from the wiper.
Playing with that combo can give more control and increase/decrease the
boost/cut freq
Bass control has a 330n cap from wiper, increase this for deeper bass
boost or make it a 33n -100n for more "mid" type boost

There's a 10k resistor from lug 1 of the gain pot, so not letting it clean up
too well, reducing that down quite a bit, perhaps 470 ohms is good also
a 370ohm 10u cap off inverting input of ic 3 causes some serious gain
that can be reduced with a 2k2 or so

The diode to ground are 1N4148's, I swopped one to a 1N4001 which is
nice and not symetrical, a pair of 1N4148's in one direction would also
do it .
Input cap C102 is a 0.047 and pre distortion there's C8/C9 0.047 and 0.033 caps - could play with those for more bass/roll off some bass

Marty.

[Fret Wire]

It's a copy of another ckt, maybe one of Marshall's (Shredmaster or Jackhammer?). It actually might be disappointing with the gain lowered too much. I'm thinking the first eq mod it needs is a log taper on the treble control. The bass and treble controls are pretty interactive, but you can get a fairly decent mid sound as is. It's not one of those "instant good tone" type of ckts. It takes a bit of treble/bass adjustment to find different sounds. Straightening out the treble taper will definately make the treble control more useable, as well as making treble/bass mods easier to evaluate. The level control needs to be a log taper also.

This was meant as a high gain distortion unit. I think most of the rewards will be in the gain/clipping section. Reducing some of the artificial dist. sound it has, and increasing touch response would make it a killer hi-gain pedal. If you want to change it's basic character and make it more versatile gain and tone wise, I'd look over the Gov'nor's gain and eq values and freq rolloff.

I'm gonna have to dig mine out, and check the jack panel and pot pin layout for replacements.

[MartyMart]

It's a copy of another ckt, maybe one of Marshall's (Shredmaster or Jackhammer?). It actually might be disappointing with the gain lowered too much. I'm thinking the first eq mod it needs is a log taper on the treble control. The bass and treble controls are pretty interactive, but you can get a fairly decent mid sound as is. It's not one of those "instant good tone" type of ckts. It takes a bit of treble/bass adjustment to find different sounds. Straightening out the treble taper will definately make the treble control more useable, as well as making treble/bass mods easier to evaluate. The level control needs to be a log taper also.

This was meant as a high gain distortion unit. I think most of the rewards will be in the gain/clipping section. Reducing some of the artificial dist. sound it has, and increasing touch response would make it a killer hi-gain pedal. If you want to change it's basic character and make it more versatile gain and tone wise, I'd look over the Gov'nor's gain and eq values and freq rolloff.

I'm gonna have to dig mine out, and check the jack panel and pot pin layout for replacements.

Fret, I have not done all the changes, its just observations from the
schematic ( marcos's site )
There's quite a bit of room on the board, so I've stuck in a few trimmed
sockets and I'm still playing !
Diode changed to a 1N4001 is very nice, with a bit of bass/treble cut
there's a nice sound with gain at 9 o'clock, I reduced the resistor off
lug one to an 820ohm - just cleans up a little at min gain, still a touch
of crunch.
I have a 150n cap on the bass pot too
I'm quite liking it now

Marty.

[cd]

It's a copy of another ckt, maybe one of Marshall's (Shredmaster or Jackhammer?).

It's actually a DOD FX69 Grunge with a part changed here and there, slightly different buffering, etc.

[Fret Wire]

It's actually a DOD FX69 Grunge with a part changed here and there, slightly different buffering, etc.

Thanks cd, that explains it's basic voicing. Of course, DOD's Grunge name doesn't accurately describe the pedals charater, much the same way Dano's choice of name and styling imply a vintage od sound.  

Marty, I've seen that schematic (Marcos'), but haven't had time to verify it. I've grown more and more distrustful of schematics that I haven't personally verified. I based my observations directly from the ckt itself, and the playing time I got in on it before it started going intermittant. I'll have to check mine against the schematic, and see if they are in agreement. I think I'll figure out some standard repair mods: jacks, pots, switch, and common tranny & FET substitutions for the switching and buffer sections, then I'll see if my gain and clipping hunches were right for a more amp like dist. and touch response. But, I'll stay within the pedal's original character, there's plenty of like-sounding od's and distortions around, but not many truly decent hi-gain types.

I approach an unfamiliar pedal like this by just playing it, not even wanting to know what's inside. Seeing what it does and does not do well for it's intended purpose. Then I ask my fellow axemen who have also  played it to compare notes. The ones I talked to had the same reliability problems, and the same "good, but missing something" comments about the sound. It's also a big "kiddie pedal".... you know with the solid state practice amp and $125 HB equipped axe..."Kewl Metal Sounds Dude". :roll: To be honest, the mods should probably be worked out on a Soldano, Mesa, or Peavy XXX, none of which I own, or desire to own. But, that's what friends are for.

[MartyMart]

I have not checked "every" section from the schem, but the tone/gain
sections seem to be correct ! and those "changes" are working.
I've been running through a Matamp C7 valve amp ( which can get quite
"hi gain" cranked ) and my classic 30.
I'm not trying to turn it into a "mild OD" circuit, just wanted a "tad less"
gain down the bottom of the pot.
I agree that the pot tapers are all "way off" but they are tiny elongated
"trimmers" really, so without a re-box and re-wire I'm screwed !!

BTW, It's sounding pretty good now and some "kiddie" pedals are a
surprizingly good source of "fun/ grown up sounds"   :wink:

M.