freestompboxes.org

jalmonsalmon wrote:

DrNomis wrote:

sickman82 wrote:Interesting, it's been a while since I looked at those schematics. It seems that it's the 56k that was dropped and the 47k moved. I had noticed that 470k change, I had that in there for a while, but changed to 180k and for me it seemed to work better.

I also noticed a few pages back that Dave had a 3n or 4n cap to ground on the input too.. low pass filter? I don't quite get it.. too big a cap to be a noise filter surely?

I swear this pedal could take over your life if you allow it.

He probably put that 3 or 4nF cap there to tame high-frequency screeching.....

Question about that cap to ground on the input... how is it that it kills the screeching?
I feel kind of dumb here LOL
Would think I could just use the stock schematic without that issue, or maybe I just have crap transisters LOL

The cap to ground probably forms part of a low-pass filter on the input I guess......

I think I am getting close with this one finally... Using this layout https://www.freestompboxes.org/viewtopic.php?f=7&t=12720
I socketed a 1nf cap on the input to ground and I am still tweaking with different transistors. The bias should be 8k2 - 10k on Q2c , but so far I notice about a 4k resistor there is sounding good to me. I have been yanking out that 1nf cap on the input and it has a slight screech to it but not too bad, so I will not give up and keep tweeking... I love that layout and this pedal is almost where it should be... soon as I get it where it needs to be I will post my data and a sound demo...

THANKS

this must be the only forum where very long threads make for a very good read!
I keep coming back for more/reading this from the top again!

Just been doing some experimenting with some AC125 Ge PNP transistors I recently bought off eBay, pretty much all of them turned out to have leakages ranging from about 620uA to just over 1 mA, anyway, I wanted to see how they would perform in the Mk I circuit so I selected three of them, turns out they sounded better/more gainier than the three AC128 transistors I was going to use, I think I have well and truly nailed it in my build this time, I'm going to make a couple of mods to the first transistor stage in my build, firstly I noticed that the biasing point of the first stage kept dropping with a 1M base biasing resistor so I tried changing it to 2M2 to see if that would help stabilize things, it actually made the bias point slowly increase, then I decided to try adding a 1M from the base of Q1 to the -V supply and I noticed that the bias point stabilized at about -5V, I also noticed that the gain-sweep from minimum to maximum was alot smoother too, the second mod I'm doing is to add a 10nF cap from the input to ground to stop the screeching, incidentally, while I was using my Oscilloscope to track down the cause of the screeching I noticed that reversing the orientation of the 22uF coupling cap between Q1 and Q2 seemed to get rid of the screeching, but, it made the fuzz control work backwards, so I put the 22uF cap back in the correct way, going to be working on putting the tagboard in it's box this week, will see if I can post a pic and a link to a soundclip so you can hear what my build sounds like.......stay tuned.....

DrNomis wrote:Just been doing some experimenting with some AC125 Ge PNP transistors I recently bought off eBay, pretty much all of them turned out to have leakages ranging from about 620uA to just over 1 mA, anyway, I wanted to see how they would perform in the Mk I circuit so I selected three of them, turns out they sounded better/more gainier than the three AC128 transistors I was going to use, I think I have well and truly nailed it in my build this time, I'm going to make a couple of mods to the first transistor stage in my build, firstly I noticed that the biasing point of the first stage kept dropping with a 1M base biasing resistor so I tried changing it to 2M2 to see if that would help stabilize things, it actually made the bias point slowly increase, then I decided to try adding a 1M from the base of Q1 to the -V supply and I noticed that the bias point stabilized at about -5V, I also noticed that the gain-sweep from minimum to maximum was alot smoother too, the second mod I'm doing is to add a 10nF cap from the input to ground to stop the screeching, incidentally, while I was using my Oscilloscope to track down the cause of the screeching I noticed that reversing the orientation of the 22uF coupling cap between Q1 and Q2 seemed to get rid of the screeching, but, it made the fuzz control work backwards, so I put the 22uF cap back in the correct way, going to be working on putting the tagboard in it's box this week, will see if I can post a pic and a link to a soundclip so you can hear what my build sounds like.......stay tuned.....

You got my attention!
I have a variation of this circuit that seems to work well but always open for any updates. Mk1 is by far my favorite out of control sounding fuzz bar none! hehee

I just finished putting my Mk I build in it's enclosure and it's working good, will post a pic of the insides and a link to a soundclip soon.....

Ok, here's a pic of the insides of my Mk I build.....

looks good!

Just thought I'd post a schematic for my Mk I build showing the mods I made to the original Mk I circuit plus some specs for the three transistors I used....

Okay, at long last here's a link to a quick and dirty audio demo of my Tonebender Mk I build I uploaded on soundcloud, I have not applied any plugin effects to the recording, so that what you hear is what it sounds like, let me know what you think......

DrNomis wrote:Okay, at long last here's a link to a quick and dirty audio demo of my Tonebender Mk I build I uploaded on soundcloud, I have not applied any plugin effects to the recording, so that what you hear is what it sounds like, let me know what you think......

Nice! Thanks for the demo, sounds great, I will have to check out that schematic and do some breadboarding since I have a ton of AC125s to check out

jalmonsalmon wrote:

DrNomis wrote:Okay, at long last here's a link to a quick and dirty audio demo of my Tonebender Mk I build I uploaded on soundcloud, I have not applied any plugin effects to the recording, so that what you hear is what it sounds like, let me know what you think......

Nice! Thanks for the demo, sounds great, I will have to check out that schematic and do some breadboarding since I have a ton of AC125s to check out

Cheers for that, I compared the sound of my Mk I with some demo clips on youtube and to my ears my Mk I sounds very close, maybe a bit smoother perhaps, I also uploaded a soundclip of my Mk II with low Hfe OC81D transistors, you can find the link in the workbench section.....

Here's a little tip: use a 50k log pot for the Attack control if you want a more-gradual change in gain as you turn up the Attack control, if you use a 50k linear pot you'll find that there's a sudden change in gain at about the 9 oçlock position......

Sup kids? Here we go go go again.
Bought 2 sets from Smallbear, one w/ oc75's and the other generic germs.
Built two stripboards for the generic set, worked at first then started making a bit of whizzing and noise, static or whatever as if the pedal wasnt properly grounded (it was).
I decided to go with 5% tolerance spanking new stuff and new xicon carbon comps-and i rebuilt it point to point.
SAME STORY- static noise when the guitar is not playing and a bit of pops and cracks even when its played!
But then i checked a video on youtoobe called 'tonebender mki 1965' and at the very end of the video the cat leaves the pedal on by itself:check it out...static, hissin, etc. So i guess my builds were proper!

https://masutopedals.wordpress.com/2014 ... ki-builds/
Notes n pics of my builds

And heres the video

DrNomis wrote:Ok, here's a pic of the insides of my Mk I build.....

Nice. Is that my layout, Simon?

sinner wrote:

DrNomis wrote:Ok, here's a pic of the insides of my Mk I build.....

Nice. Is that my layout, Simon?

Yep, that's your layout and I can confirm that it works perfectly, so it's verified.....

ljn wrote:Just tried. It doesn't show a "create account" button. It just loads up and freezes. Oh and it says in big letters, " We can't find this user". Thanks for trying, though.

Try this link, you should get the "Create Account" button this time:


https://soundcloud.com/

so i ended up buying a repro clone of this after so many times getting mine to sound brilliant up until the farting out note decay.

the clone sounds great but it's not board friendly at all so i figured that i would see why the clone works so well and then clone the clone.

they use essentially sinner's layout with remakes of the original transistors, a 10n from circuit in to ground, a 56k instead of a 47k at the end....and the secret sauce is a 680k from q3's base to the power.

i put a 2M pot on my battered mkI test board and the little sucker works! and as far as i can tell there isn't a difference in the tone. be careful turning that pot, though, because turning it all the way down caused some sparks and smoke.

and the hfe's are around 120 and the leakage is around .3 on all the ac125 transistors.

Hi guys.
Recently i was really into Doyle Bramhall II, and in his Reverb interview he talked about the Zonk Machine as a secret weapon.
So i decided to build a Tone Bender MK1 just to see what it is.
I didn't have fancy 60s transistors, so i used some russian ones. They say you need leakage for MK1, but these are very low.