Ohhhhh Kay!!

[Bret608]

Hi everyone,

Here is my attempt at a re-draw of Kaycee's layout in DIYLC. We arrived at a couple of tweaks and layout efficiencies, but have still pretty much kept it set up for a 1590bb in a landscape layout. Kaycee has looked at it for me, but I have not built this up and verified it just yet, so feel free to let me know if you spot any mistakes. Not bad for a first time using this program!    Just take care of the track cuts under the resistors that are rendered transparent. I will do my best to build one of these up myself between now and the holidays. And of course, thanks again to Mark for making this possible.

[duck_arse]

except for Q2 when it is a bc109, I think yr transistors are shown backwards.

[Bret608]

Ah, I see. The EBC labeling is correct, but I should have flipped the transistor body images to match the 2n3904, etc. pinouts. Thanks for the spot!

[Bret608]

Sorry to dig up an old one here, but I finally got the chance to build up one of these. I can confirm my slight redraw of Kaycee's layout works. Thanks again to Mark for some great mods. This is a fantastic sounding fuzz!

[Mark Hammer]

Don't thank me.  Thank Daniel Lanois for making the stock Kay sound so inspiring.  It got me interested in playing with the circuit and pushing it a little farther.  And stuff just sorta happened. 

[Bret608]

Well, they just sorta happened in the right way!    Yeah, he does completely rock that old Kay though, doesn't he?

[aron]

The sad part is I don't even remember redrawing that circuit! Sounds great Mark!

[francis1978]

hello there, I'm looking for some expertise.
I built a clone of the Kay Fuzz using the original schematics and the fuzztone layout at ustomp.com.
However my pedal suffer the volume drop "syndrome" and I've read that adding a trim pot into the circuit can boost the output volume.

Question #1 : Does the trim pot replace one of the resistors or it's really an addition? Some readings suggest to replace the last resistor (100K) by a 100K trim pot.

Question #2 : If the trim pot does replace the aforementioned resistor, will it be wired like in the attach picture.

Thanks for your help!

[iainpunk]

hello there, I'm looking for some expertise.
I built a clone of the Kay Fuzz using the original schematics and the fuzztone layout at ustomp.com.
However my pedal suffer the volume drop "syndrome" and I've read that adding a trim pot into the circuit can boost the output volume.

Question #1 : Does the trim pot replace one of the resistors or it's really an addition? Some readings suggest to replace the last resistor (100K) by a 100K trim pot.

Question #2 : If the trim pot does replace the aforementioned resistor, will it be wired like in the attach picture.

Thanks for your help!

this:

cheers, Iain

[francis1978]

Hello Ian,

thank for the advice!
Jest a few things (sorry for being a bugger):

Wouldn't be better to have the middle lug of the trimmer wired directly to the output, rather than going thru the 100K resistor?

From what I read, that resistor is there to change the linear curve of the 250K pot to a LOG curve

Lastly, what would be a suitable value for the trimmer (I put 100K but that was a supposition)

Thank again!  cheers!

Francis

[iainpunk]

Hello Ian,

its Iain

thank for the advice!
Jest a few things (sorry for being a bugger):

no problems, its not like i am hard at work, haha, dont tell my boss

Wouldn't be better to have the middle lug of the trimmer wired directly to the output, rather than going thru the 100K resistor?

no because the trimmer reduces mid scoop, not volume.

From what I read, that resistor is there to change the linear curve of the 250K pot to a LOG curve

yes its filtering out a bunch of mid and high frequency on a log scale to make is feel more natural (log feels more natural when it comes to frequency or volume)

Lastly, what would be a suitable value for the trimmer (I put 100K but that was a supposition)

i guess 100k should work fine, maybe go up to 500K but 100K seems enough.

Thank again!  cheers!

Francis

i think that the mid scoop is part of the sound but if you really want to mend its problems, you could be better off putting in another filter section all together:
those controls are 100k and 30K i suggest the names 'body' and 'treble'


cheers, Iain

Ps. the kay fuzz has no volume control, im personally not a fan of puting one in, but if you decide to, why not add an output buffer while you are at it.

[francis1978]

Oops sorry for misspelling your name. Got it know!

Thanks for the explanations. It shows me that I'm still on the learning curve! LOL

Actually, my intention is to have an output buffer to increase the overall volume; and although I did mention it on my original post ("boost output volume"), perhaps it wasn't worded properly.  My bad.

So yeah, I want to have an output buffer. The question now is where do I put that and how it is wired..

Cheers Iain!

[iainpunk]

boosting output volume can be different things, especially when there is a heavy toneshaper as the last part of the circuit, those toneshapers can take off quite a bit of volume, that's why i suggested using a pot to ''move it away from ground'' so you loose less sound, thus, boosting. but you want to keep the sound the same but just more volume,
a buffer doesn't make the output volume higher, it makes the impedance lower, so it can drive a load (like long cables and some vintage effects) more easily, i guess you need an output recovery stage to actually boost the volume, just like in a big muff pi. i suggest you just copy the big muff's output stage and slap it on after the existing circuit.
https://www.electrosmash.com/images/tech/bmp/big-muff-pi-v3-output-buffer.png

cheers, Iain

edit: other general purpose transistors will do as long as its NPN and not PNP

[francis1978]

boosting output volume can be different things, especially when there is a heavy toneshaper as the last part of the circuit, those toneshapers can take off quite a bit of volume, that's why i suggested using a pot to ''move it away from ground'' so you loose less sound, thus, boosting. but you want to keep the sound the same but just more volume,
a buffer doesn't make the output volume higher, it makes the impedance lower, so it can drive a load (like long cables and some vintage effects) more easily, i guess you need an output recovery stage to actually boost the volume, just like in a big muff pi. i suggest you just copy the big muff's output stage and slap it on after the existing circuit.
https://www.electrosmash.com/images/tech/bmp/big-muff-pi-v3-output-buffer.png

cheers, Iain

edit: other general purpose transistors will do as long as its NPN and not PNP

You're awesome!
After checking a review video of the Big Muff Pi on YouTube where a guy messes with the volume that's exactly what I was looking for
How come I never though about this before? LOL
Well, it did help to get some expertise from here
Though I would use a trimmer so I won't drill a new hole to the case but I guess an audio pot seems to be more suitable

Thanks mate!

[iainpunk]

you are welcome! i'm glad i could help

to be honest, i'm not a fan of adding any sort of volume control to the kay fuzz, or other low volume japanese fuzzes for that matter, i like misbehaving 'problematic' and 'quirky' pedals and low volume is part of that, but i guess its quite useful for most people to have a bit of boost and control for volume matching.

cheers, Iain

[kaycee]

Some 6 years on from the original post and the schematic and layout have disappeared. So I went through my pile of drawings and re-drew them both from my originals. I added a boost after the modified Kay Fuzz, if you don't want that then take your output from Tone 2 and add a 100k to ground.

I had a good play around with octave fuzzers at this point, and thought this a very versatile incarnation, although in the end I settled on a Superfuzz variant modded by Rob A that has an octave cancelling feature that gave a very meaty distortion that has stayed on my board since those days.





I made and sold two of these back then, I wonder if they are still mangling signals somewhere?

[pinkjimiphoton]

Daniel Lanois is in town tomorrow, and that got me interested in the Kay fuzz.  The Kay is essentially a Superfuzz, with a simpler front end, no variable drive, no output level control, and no gain recovery stage after the mid scoop.

Looking at it, I thought it might benefit from a few things.  First, the emitter bypass cap on the input stage is kind of small at 100nf.  I installed a 3-way toggle that patched in a 680nf or 10uf in parallel with the 100nf.

Next, I stole a trick from ZVex and inserted a 10k Lin pot between the diodes and ground.

Next, I stuck a 10k pot between the 100nf cap in the mid scoop and ground.

The  50k foot treadle pot was replaced with 100k and the 200k ground resistor replaced with 150k.

The 3way toggle is KILLER.  Feel free to experiment with other values but there is no reason to go beyond 10uf.  And at  10uf, the octave blooms beautifully, like a feedback simulator.

The diode pot helps soften the clip and vary the degree of growl vs sizzle.  Useful.  Just note that reducing the clipping action raises the volume.

The variable scoop works as expected, but interacts with both the foot treadle control and the other installed options...in a good way.  Because these options alter the volume level, I'll swap out the 100k output resistor for a 100k volume pot.

The Kay fuzz is a very nice unit.  But this....this is better.  Much better.  Jimi, I hear your soldering iron calling.

i cannot believe i never saw this thread til now, 6 years later

[francis1978]

Hi all,

After inserting the output buffer stage of the Big Muf Pi 3, third pic is the schematic I ended up with. Pretty similar to yours @Kaycee with the exception of one/two caps/resistors less. I don't know if that'll make a big difference.

The first (and second pic) is the first version I made a few years ago using a snapapble breadboard. As it can be seen, it looks a bit messy specially the jumpers. The circuit is retrofitted into a Dixon CB-200 wah enclosure.

Last pic is version 2.0 on a real stripboard. The board is bit smaller than the previous one but more tidy.  Most of the components in v1.0 will be salvaged to make v2.0

I also thought of building an Univox SuperFuzz. But who knows, maybe in the future I'll make a Univox and Kay within the same enclosure à la Deucetone Rat... (and maybe add Big Muff Pi circuit while at it!)

Thank you all for your input and knowledge!

[iainpunk]

the kay fuzztone and the univox superfuzz sound 95% the same. only the superfuzz has a cool 'tone 1//2' switch and a less-shitty enclosure.
i think the shin-ei companion fuzz is a better suitor to pair up with the kay/super fuzz, its also scooped an buzzy, but in a different way. the hardest thing is finding suitable transistors, i am going to build one (a companion fuzz rite hybrid) with BD139 transistors when im done with my current projects.

cheers, Iain

[francis1978]

Hi all,

I never thought I would get to ask this since I was able to debug by myself the board I previously built.

I built version 2.0 with the added buffer and well it ain't working. No bloody sound at all.  Bypass is going thru but nothing else. The board is getting power up to a certain point (I believe) according to the reading I made. I've check and fixed all cold joints, routing as it appears the image on the previous post had a few mistakes.

After trying many times (days) I can't seem to go further. So perhaps you will see something I don't.  My patience is running over and now I wonder that I should have kept the old board and just retrofit the buffer stage

The readings were taken using a DC adapter, 8.97V.  When using a battery the differential voltage was 9.54V
As instructed in the debugging post:

V cir (+) = 8.97V
V cir (-) = 0.0V

Q1  C=3.27  B=0.78  E=0.27
Q2  C=6.06  B=3.27  E=2.82
Q3  C=7.53  B=0.80  E=0.24
Q4  C=7.53  B=0.80  E=0.24
Q5  C=4.10  B=1.49  E=1.00

D1  A=0.00  K=0.04
D2  A=0.00  K=0.04

c1+  pos=0.78  neg=0.00
c2+  pos=2.78  neg=0.79
c3+  pos=6.10  neg=0.80
c4+  pos=0.30  neg=0.00
c5+  pos=7.40  neg=0.04
c6+  pos=0.04  neg=0.00

Pics:
1st = original kay fuzz board
2nd = Kay_F v2 schematic
3rd = Kay_F v2 board
4th = bypass switch on the v1 board

Notes:
V1 board was built as per original board (no 200K resistor at the end of pot)
DPDT was wired as per this site: http://www.generalguitargadgets.com/pdf/ggg_sw_dpdt_tb_gi.pdf
Because of their 0.00V reading, I suspect C1+, C4+ and C6+ may have been blown when soldered

Hope you can find what I'm doing wrong.  Thanks!!