Rotosound Mark III

[theemadcap1]

No argument from me, the Park is a great MKIV! I had one, I passed on a few years ago, liked the Yellow Solasound ToneBender (Dave now owns...) better. All those MKIV/MKV pedals from 72-ish sound pretty close. I would like to try a Park 2 knob, but Dave tells me this Roto sounds really close to Graham's 2 knob Park, but has more Fuzz and more Volume on tap. In fact, Dave said this Roto was the heaviest gated, fuzz-i-est MKIII he has ever heard!

Maybe not mass produced, but there were adverts in Beat Instrumental.

Interesting that it says "Fuzz Box" because that was what the MKII version was named. I wonder how many made it out? I think there were very few produced. What month/year is that 'Beat Inst.'? Maybe it would maybe point to which pedal it is? I would guess 67-68? Maybe no one ordered any and that was why they never went into production?

are you sure that resistor wasn't stock?

Going on what Dave said here. It had a 470K resistor as a 'brake' where the limiting resistor goes on later ToneBender MKIII/IV/V pedals, to cut down some Fuzz, but was an afterthought (same as teh 'Shunt' cap on the back too) as there is no place for it on this circuit. You can see where they cut the tracing and that was where they put the "brake" resistor and you can see there were no holes for a resistor there. It had that odd 250K Volume pot (oh how I wish the original pots were good!!) Dave replaced it with a 100K Volume pot, so he thought it would sound near the same without the resistor (as it was originally) and the 100K pot as with the 250K pot and the 470K resistor...?
I am happy as a clam with it as is!

Interestingly, this Rotosound (Nor my original ToneBender MK1.5...?) wont really work that well at all with any guitar except my LesPaul with PAFs and BumbleBee caps...? Totally craps out with my '54 LesPaul Jr (doesn't have the proper old caps, but which is finding a new home...) and my other Les Paul Custom Shop(which is going to get a pair of Bumblebee caps to see if that is the difference?!!), it just doesn't sound quite as sweet. Though with my main LesPaul it simply sings with violin tones and near infinite sustain!! I would say it is perfectly biased for this guitar...!!! So crazy! Makes one wonder if say Mick Ronson might not have had such a sweet tone with a different set up? Where timing meets preparation? The combination of this 68 LesPaul and the setup it has with a Brown Fender Deluxe running a 1x12" Tone ring cab is too sweet!! I have a friend that is going to help me record...! I wonder how much the impedance of the pickups and the type of tone caps used in a guitar affects the tone of the Fuzz pedal??? We shall see...

[Electric Warrior]

are you sure that resistor wasn't stock?

Going on what Dave said here. It had a 470K resistor as a 'brake' where the limiting resistor goes on later ToneBender MKIII/IV/V pedals, to cut down some Fuzz, but was an afterthought (same as teh 'Shunt' cap on the back too) as there is no place for it on this circuit. You can see where they cut the tracing and that was where they put the "brake" resistor and you can see there were no holes for a resistor there. It had that odd 250K Volume pot (oh how I wish the original pots were good!!) Dave replaced it with a 100K Volume pot, so he thought it would sound near the same without the resistor (as it was originally) and the 100K pot as with the 250K pot and the 470K resistor...?
I am happy as a clam with it as is!

It sure was an afterthought, but possibly a factory afterthought. The one you posted on the MKIII pedal porn thread had the 470k added as well:



and API's MKIII has an additional 1M resistor:

[1bottlerocket]

I am digging those Brimar transistors in there.

[melodichaotic]

are you sure that resistor wasn't stock?

Going on what Dave said here. It had a 470K resistor as a 'brake' where the limiting resistor goes on later ToneBender MKIII/IV/V pedals, to cut down some Fuzz, but was an afterthought (same as teh 'Shunt' cap on the back too) as there is no place for it on this circuit. You can see where they cut the tracing and that was where they put the "brake" resistor and you can see there were no holes for a resistor there. It had that odd 250K Volume pot (oh how I wish the original pots were good!!) Dave replaced it with a 100K Volume pot, so he thought it would sound near the same without the resistor (as it was originally) and the 100K pot as with the 250K pot and the 470K resistor...?
I am happy as a clam with it as is!

It sure was an afterthought, but possibly a factory afterthought. The one you posted on the MKIII pedal porn thread had the 470k added as well:



and API's MKIII has an additional 1M resistor:

Hey, that MK III with the AC113's be mine...and I think it has the sexiest guts of all courtesy of those yellow jacket AC113's

All original it appears, no changed pots, parts, except for the battery clip/wires. Sound? This is what a true MK III is supposed to sound like. TONS of gain, older and "more brown" sounding than the Sola MK IV, Yellow TB, or later MK IV/V circuit variants including the 3 knob Park. Very distinct like the difference between an MK I and an MK II.

Never seen another true (60's) MK III with that tranny set-up...was lucky enough to score a small cache of those EXACT same transistors NOS, so I'm happy. I'm sure this is a very early one while they were still trying shit out.

I mean we all know far and away to "Hail to the Thief", aka Greedy Graham for his most obnoxiously awesome collection, but it's nice to have a couple of rare killer sounding freaks in the nest.

[Electric Warrior]

Hey, that MK III with the AC113's be mine...and I think it has the sexiest guts of all courtesy of those yellow jacket AC113's

yup, very sexy
I can see it has holes for the shunt capacitor drilled. Does it hide underneath the board or has it been left away?

[Philip]

Interesting that it says "Fuzz Box" because that was what the MKII version was named. I wonder how many made it out? I think there were very few produced. What month/year is that 'Beat Inst.'? Maybe it would maybe point to which pedal it is? I would guess 67-68? Maybe no one ordered any and that was why they never went into production?

The advert is from the July 1967 issue.

[melodichaotic]

Hey, that MK III with the AC113's be mine...and I think it has the sexiest guts of all courtesy of those yellow jacket AC113's

yup, very sexy
I can see it has holes for the shunt capacitor drilled. Does it hide underneath the board or has it been left away?

Yeah, it's there, jess like the others. I'll post more complete pix this weekend.

I actually have another original 60's MK III enclosure, no circuit board, but complete with original bottom plate, foot switch, jacks, knobs, and all three original sealed metal shaft Erie pots
gonna dooze me up a righteous clone with those spare AC113's.
When I get properly set-up for higher quality video demos, gonna tear up some ripping fuzz mayhem for y'all!

[theemadcap1]

It sure was an afterthought, but possibly a factory afterthought. The one you posted on the MKIII pedal porn thread had the 470k added as well:

I agree 100% and Dave can chime in, but to paraphrase what he said was that it looked like the Brake was added after this circuit appears to have been made...like whoever made it was like, "Wow, that's too fuzzy. That is too much Fuzz volume!..." or maybe whoever had the say production-wise. I looked for the pic Dave has of mine when it was built to stock, before the new pots got added. to throw up next to these...? I wonder if the other early MKIIIs have a 250K Volume pot too? I wonder if there is any hope in the world, with all the rebuild/re-use, that those pots could be rebuilt?

I agree the early circuit is super thick and has a different sound then the later ones. This Roto is 'gate-city'! Too much so with single coils but then only sometimes..? I have found that most my early germaniume devices (Rangemaster, MK1.5, MKII SupaFuzz, Roto et al...) seem to have so much character, they seem to sound slightly different each time you jam on them. I seem to have stumbled onto some magical combinations of guitar/pedal/amp.

What is interesting to me, is to sit back and let the components tell a story. If you look, they were experimenting with a bunch of different company's components. Like trying out different transistor combinations. I wonder if they could have built these pedals with samples? I mean the later MKIII/MKIV, the majority have no markings on the transistors. Seems that once they got to the STC tophat (which my guess is an ACY69...? or TK23C model? though, I have seen some marked as 'OC71') they wanted to obscure what they used. It's cool to see Dennis' and see that those one were NKT233s. Seems that they used Iskra and Hunts caps, as well as the 'tropical fish'(Mullard?) caps. It's cool to see the differences in the three pedals and how they went through, what appears like 'phases'. The "Using Hunts cap" phase, the "using tropical fish caps","using a 4th transistor as a diode" phase. Weird how on mine the 4th 'odd man out' transistor is part of the darlington pair, as opposed being the diode(?) This all is just conjecture and from my experience....
Someone needs to dig up pictures of Graham's 2 knob Park circuit and line all 4 of these early MKIIIs up! Any more early reverse circuit MKIIIs out there? Seems like someone else has a 2 knob Park too??

I wonder who the builder (or builders) were? was it one person or DAM-type project?

[Electric Warrior]

This forum certainly is the place to find out about the 250k volume pot

Here's Graham's two knobber: http://dam.10.forumer.com/viewtopic.php ... fuzz+sound I believe he has two of them now.
Stu also has an reverse board MKIII, but with an MKIV circuit: viewtopic.php?f=6&t=1101&hilit=park+knob

I guess we don't have enough data to be able to tell about the transistors. Maybe they just changed suppliers early in production? Seems like Brimar and STC were affiliated, look at this: http://www.transparentsound.com/transis ... brimar.htm
http://homepages.nildram.co.uk/~wylie/STC/STC.htm

I wonder about the value of the electrolytic next to the volume control. Many MKIVs had 5 or 6.4µF in that position, but I suspect they startet out with 10µF (and went back to 10µF after a while). Can anybody confirm this?

Yeah, it's there, jess like the others. I'll post more complete pix this weekend.

I actually have another original 60's MK III enclosure, no circuit board, but complete with original bottom plate, foot switch, jacks, knobs, and all three original sealed metal shaft Erie pots
gonna dooze me up a righteous clone with those spare AC113's.
When I get properly set-up for higher quality video demos, gonna tear up some ripping fuzz mayhem for y'all!

Thanks for confirming. I'm looking forward to seeing your pics!

[The Captain]

I wonder about the value of the electrolytic next to the volume control. Many MKIVs had 5 or 6.4µF in that position, but I suspect they startet out with 10µF (and went back to 10µF after a while). Can anybody confirm this?

T'other Roto has 25uf ...



Personally, I think the variation of parts from one pedal to the next was just because they were making these things in low numbers. If the first Roto's were being knocked out in late 1967 the MKII would still have been the main staple of their production. Maybe the early MKIII's were to test the water, so to speak .