toneblaster mk 2.5

[pinkjimiphoton]

that last one looks perfect.
nice work, guys, thank you!!!!!!!!!!

[pinkjimiphoton]

karl, please keep me posted as to your build!

i used this thing again last nite live with my band at rehearsal, thru a solid state pignose 30/60 from the 70's, cuz i'm too lazy to keep schlepping heavy amps around, and i don't mind that one getting blowed up..

and discovered that this thing does even more than i thought... best description i can give is a compressor that thinks it's a treble booster (with the volume low) that's also an overdrive but thinks it's a fuzz, even when it's totally distorted.

i really diggit. hope you brave souls do, too!

[kodiakklub]

will do! i got a NTE103 off ebay (we'll see what shows up) and got an AC187 from mammoth. ill socket Q1 and try them both out. again, very excited to start building this after xmas and will def report with the results. COMPRESSION FUZZZZZ!!!

[pinkjimiphoton]

kewl!

used it again last nite with yet another amp...so far i've tried it live with my hot rod princeton, my little ruby, my pignose 30/60, my fender cyber deluxe, and last nite the cybertwin. works great with all of 'em, so hopefully, it's gonna be good for ya!

[Quackzed]

i simmed the first transistor stage to try and understand what was going on with that diode to ground setup, and maybee offer up some insight with my findings... no dice... in the sim - set up as shown the signal out was mere microvolts small. signal didnt get reasonable till the threshold of the diode was around 700-800mv... so i suspect that either the transistor or the diode or both must be leaky - at least to a certain degree- for this to work right.
i may be wrong about that and it may just be falsdad sim isn't good at simming germanium transistors and diodes ( a very real possibility in my experience with it) so i figured i'd see if anyone had any insight on that point ?!?..

[kodiakklub]

yeah im gonna guess even if 50 people made this pedal with the exact same parts, maybe 3 or 4 would be tested to be "identical" in outputted freq's. probably not even that many with all the GE there is in this pedal. cant simulate human error/manufacturing variances in NOS parts......yet! but based on your findings, like VR3, the difference is probably very very negligible.

[pinkjimiphoton]

i simmed the first transistor stage to try and understand what was going on with that diode to ground setup, and maybee offer up some insight with my findings... no dice... in the sim - set up as shown the signal out was mere microvolts small. signal didnt get reasonable till the threshold of the diode was around 700-800mv... so i suspect that either the transistor or the diode or both must be leaky - at least to a certain degree- for this to work right.
i may be wrong about that and it may just be falsdad sim isn't good at simming germanium transistors and diodes ( a very real possibility in my experience with it) so i figured i'd see if anyone had any insight on that point ?!?..

well, d1 is only there TO  leak. that's supposed to help compensate for the leakage of the transistor. makes it more stable to temperature changes. not for "tone".
just stability.

i'd like to see a sim of q2 a lot more!! does the diode clipper make a diff, or not? i thought it did..

[Quackzed]

see, i missed that you indeed mentioned that as a temp stabilizer for the ge q1. interesting that. let me try q2 and see what i can get. as both diodes are silicon i'm guessing leakage is a non-issue so i should be able to see what they're doin...
btw, i'm not trying to nitpick or anything, its just a real nice sounding circuit so i wanna see whats happening here and there thats contributing to the final tone. also i'm not a seller of pedals, just a curious soul. so this is just for some mutual understanding as well as inspiriation... not that you're worried, but if you'd rather i left the black box closed, i can understand and will respect that. this is after all, your circuit. but so long as you dont mind me diggin' around i'll try and see what i can find...

[pinkjimiphoton]

no worries, gil!!
thanks for taking the time to understand it, it helps ME learn, too!!

i'm real curious to see what the diode clipper there does to the signal, if anything.

gus doesn't think one of those diodes is even doing anything, and he knows ALOT more than i ever will..so if ya run some sims, wouild love to see the result!!

and...if you guys wanna build a couple, for yourselves, to sell a COUPLE, hey, i don't mind that at all...just as long as it's not used as a commercial product by someone without permission, i'm good with it. like i said...i'm just standing on the shoulders of giants, anyways.

[Quackzed]

... so, as gus said -in the sim anyway -d4 doesnt appear to be doing anything. and d5 seems to be biasing the signal along with vr1. though thats just q1 and q2, and q2 is in a fuzz arangement that has its own strange properties so it may not be fair to just look at it all alone.
one thing i did see however is where the compression is coming from. q1! as q1 begins to distort the signal it does so very asymetrically and smoothly,
only one half of the wave gets softly clipped and more and more untill finally it starts to hard clip, all this before the other half of the wave clips at all. then finally the other half of the wave hard clips... so its very soft and very asymetrical... and d5 does seem to be needed, at least i couldnt get the same bias with it replaced with a resistor and by adjusting vr1...
here import it into falstads and see for yourself... the first scope is after q1 and the second is the output after q2. the resistance slider is to adjust the volume in to sim big/small signals...
http://www.falstad.com/circuit/
 ok. stand back, here it comes... BAM!!!

$ 1 5.0E-6 0.5999443210467817 68 5.0 43
t 512 336 624 336 0 1 -6.994522920752658 0.11398097302589527 200.0
w 624 288 624 320 0
r 624 288 624 224 0 51900.0
r 416 336 416 416 0 51000.0
g 560 416 560 448 0
g 784 400 784 432 0
O 784 336 832 336 0
R 128 336 64 336 0 1 900.0 0.2 0.0 0.0 0.5
R 624 224 624 176 0 0 40.0 9.0 0.0 0.0 0.5
c 656 288 688 288 0 2.7E-8 3.868603820949441
w 784 288 752 288 0
w 784 336 784 288 0
g 416 432 416 448 0
w 656 288 624 288 0
w 688 288 704 288 0
w 720 288 752 288 0
t 224 336 288 336 0 1 -3.229837762524731 0.5618726238038014 100.0
w 288 320 288 288 0
r 288 288 288 208 0 10000.0
R 288 208 288 160 0 0 40.0 9.0 0.0 0.0 0.5
r 288 288 208 288 0 470000.0
w 224 336 208 336 0
w 208 336 208 288 0
r 288 352 288 432 0 1.0
g 288 432 288 448 0
c 288 288 352 288 0 1.0E-7 6.6889841737422815
w 416 336 416 288 0
r 208 336 208 432 0 100000.0
g 208 432 208 448 0
c 208 336 160 336 0 1.0000000000000001E-7 0.5494383296918965
d 560 384 560 416 1 0.65
w 416 288 384 288 0
r 784 400 784 336 0 100000.0
174 128 336 128 432 0 1000.0 0.5396000000000001 Resistance
g 128 432 128 448 0
w 144 384 144 336 0
w 144 336 160 336 0
w 384 288 352 288 0
w 720 288 704 288 0
w 416 432 416 416 0
d 416 336 512 336 1 0.65
w 512 336 512 288 0
w 576 416 560 416 0
w 624 352 624 384 0
w 624 416 576 416 0
w 560 384 576 384 0
w 624 384 576 384 0
o 26 2 0 34 8.183476519740355 7.991676288808941E-5 0 -1
o 6 2 0 290 10.0 9.765625E-5 1 -1

[pinkjimiphoton]

wow, that's cool!!!!! thanks bro!!

i never messed with this thing before...gotta read up on it, try and put the whole circuit in there.

i see the compression...amazing how it's working. looks like the biasing is weird from the diode maybe? i don't understand this enough.

[Quackzed]

its a cool simulator for small stuff, but sadly it gets glitchy with anything big, so for the full circuit you might have better luck with something like spice or other downloadable type circuit sim software, but falstad is great for what it is, and its really easy to use after a little trial and error.
 

[pinkjimiphoton]

i really gotta get some time to do some building...it's been like, way over a month now. every time i turn around, there's some new crap to deal with.

maybe i'm just lazy.


i've got a couple circuit sim programs, but can never seem to get 'em to work right. kinda gave up on 'em!

but i played with the sim you worked up this morning, and saw the assymetrical clipping AND the compression of the waveform... but i don't understand why it's doing that, as it's a pretty basic circuit for the most part, and really just a tonebender with some tweaks!!

[Quackzed]

this is just my 2 cents so take it with a grain of salt, but...
in the first stage, the base is biased alot closer to ground than to +9v due to the difference between the 470k resistance to +9v and the 100k resistance to ground. so its biased alot closer to ground than to +9v- its about 5 times further away from +9v than from ground. if there wasn't alot of gain it wouldn't really matter all that much and the wave would stay unclipped because it was still well within both rails... but because theres alot of gain due to the emitter goind straight to ground, the ground side of the wave will hit the rails way sooner and it will clip way sooner than the other half of the wave, theres the asymmetry... as for why it clips softly and doesnt hard clip right away, thats the nature of bjt's in cutoff, as they start to cutoff, or clip at the ground rail, less and less current flows and the result is that they slowly begin to clip, untill there is no current at which point they are basically off, and will hard clip.
if you were to swap those resistors around - the 470k for the 100k and vice versa, you'd see that the other side of the wave would clip first, but it wouldn't be nice rounded soft clipping, it would be pretty abrupt, because then the trnsistor is in saturation not in cutoff... and the result would be asymmetric hard clipping...  not too deep but the basic idea... i may be wrong tho.. , but thats at least what i think is happening...

[pinkjimiphoton]

i think i kinda understand that, seems like a logical explanation.
i was really expecting the compression to come more from the diodes in e of q2~

i guess i hallucinated the change there...i tried it directly grounded, with a pot, a resistor and single and multiple diodes, this seemed to work best.

now i know why the original was more of a compressor, cuz it totally really IS one, sorta.  that explains a lot, i think.

thanks gil!

[Gus]

I simmed a all Si transistor circuit close to what was posted.  Used a 2N4401 as the first stage you could try a med power Si transistor.  Added a simple guitar, cable and a cable, 1meg output load.  Left out the EF
EDIT R4 is 1 ohm not R1 as written in the screenshot


Green is the input blue the output, note the green curve.

[pinkjimiphoton]

what's an ef?
looks cool, but it's a different circuit. be neat to hear what it sounds like.

the falstadt sim was cool, cuz you can kinda "see" what it "sounds" like.

this is way over my head, gus!

[kodiakklub]

etched the board yesterday, in addition to a modded fuzz factory, and started populating just now and noticed i dont have any 510K's. whats going to happen if i put a 470K in R11? thanks....hope everyone's christmas was good to ya.

[pinkjimiphoton]

worst case, do a 470k and 47k in series. 470 will probably be close enough tho

[kodiakklub]

she's alive!!!

so i got her up and running with a genuine new NTE103 in Q1.

my setup: jaguar HH with SD humbuckers ----> toneblaster 2.5 ----> silvertone 1484 head w/ marshall half stack cab

thoughts/remarks:
1. volume knob should be pegged on 10 all the time. the pedal itself really kills overall output of original guitar signal
2. attack knob totally co-dependent on VR1 and there is a very tight sweet spot. does take some time to find it.
3. remember that i replaced VR3 with a 1k resistor
4. remember that i have a 470K resistor in place of the 510K in R11
5. instead of saying its a very compressed sound, i would say the pedal has a major gate effect like a wolly mammoth. overall the pedal is very similar to a WM, just not as aggressive.
6. it certainly has a lot of range from gated fuzz to severe LOFI

any suggestions jimi?