New Blues Blaster Overdrive Distortion

[Ben Lyman]

I had to make another Xmas present and after some experimentation I came up with this, it's nothing really new but it is simple and sounds great.
I started out trying to breadboard a Dan Armstrong Blue Clipper but none of the schematics seemed to work at all. Luckily, I came across the
Runoffgroove "New Clipper" and after some adjustments I ended up with what I think is better than my tubescreamer. I wanted to share in case anyone
wants to make a simple, low parts count distortion box because I think it is really good. Also, if anyone makes this but with improvements, please let
me know what changes were made. I plan on making another one for myself after I finish my never ending fuzz pedal creation.
Input cap and diodes are socketed and I ended up really liking the "big sound" of the .1uF input cap and my mysterious HP diodes.

Schemo:


Layout:


Reverse Trace

[Ben Lyman]

I used a row of sockets on the board and soldered another row of sockets to the hookup wires to make my own plug. The LED + goes right into a socket. My daughter did the graphics with Sharpie paint pens and then I sprayed clear engine enamel over it, I think her Grampa will love it. 

[Gus]

10k input resistance and sounds good?

[Ben Lyman]

10k input resistance and sounds good?

That's the output, I'm not sure why it is there but maybe it works with the .0033uF as a tone thing at the output?
I used a 100k pot at the input for a drive control but a 500k could be used if you wanted more "cleaner" cleans. I just wanted OD at one end of the spectrum and distortion at the other.
Anyway, yes this thing sounds great, after it is unwrapped on Festivus I will try to make a demo vid.

[PRR]

>> 10k input resistance and sounds good?
> That's the output

Gus is looking at the two "20K" resistors at the INput. 20K||20K= 10K.

10K loading sucks all the highs and a third of the low/mids off a naked guitar. Adding series resistance (an input pot) does change this.

If you are happy we are all happy. But it is an odd setup.

[Ben Lyman]

oh, ok I see. All I can say is try it out, it sounds better than an MXR Dist+ (too much highs imhop)
The original Dan A. BluClip had some kind of resistors right there but it didn't make any sound but a short, gated splutter when I tried it. The New Clipper has two 22k's right there but I just used what I had (2 20k's)

PRR: If I remove both 20k's will this circuit still work in theory? I can try that on my BB when I make another one.
Again, this thing sounds better than any of my TS pedals, and I've owned a lot, both stock and modded by the "Big Guys"

[pinkjimiphoton]

my "pink's clipper"
is the same, almost... the 10k onput impedance seems fine, i use it live endlessly, probably the most used pedal on my board.

i run it after my volume/wah as a lead boost, it kicks total ass and is loud as @#$%



not exactly the same circuit, but similar. i didn't even realize it was similar to the dan armstrong when i cobbled it together.

if ben's pedal sounds anything like mine (and i bet it does) i know it sounds great.

and if ya think about it, doesn't a low input z equate to better interaction with effects before it?

look forward to hearing it ben

[Mark Hammer]

Consider putting a 330-470pf cap in parallel with the 150k feedback resistor to make it warmer and less fizzy.  You already have the 3300pf treble cut cap, but why settle for one pole of lowpass filtering when you can easily have two?

I salute your paint-pen work.

[PRR]

> If I remove both 20k's will this circuit still work in theory?

No.

How would the opamp "know" what DC level to idle at?

You can use larger values. Even 1Meg each.

There IS a better way to set bias. Rejects supply garbage, allows easy change of input impedance. Often worth 2 extra parts.

[Ben Lyman]

That sounds great Jimi, mine is very similar but maybe a little more distortion at the extreme and less clean at the other end. I will try to make a quick demo vid after Xmas day. BTW, it does sound very good with my Boss SD-1 or my Thomas Cry Baby in front of it.

PRR- I will try my next one with some of The ideas I saw in Kipper's latest links.

Consider putting a 330-470pf cap in parallel with the 150k feedback resistor to make it warmer and less fizzy.  You already have the 3300pf treble cut cap, but why settle for one pole of lowpass filtering when you can easily have two?

I salute your paint-pen work.

Thanks Mark, will definitely try that, sounds easy. Artwork is by my daughter... just making sure credit is given where due

[duck_arse]

nice diode bridge, ben. be nice to the other half of your opamp, tho.

[Ben Lyman]

nice diode bridge, ben. be nice to the other half of your opamp, tho.

Thanks Duck. Umm... someone said I should run the ground line right up across all three unused legs of the IC... is that what you mean by "be nice"?

[pinkjimiphoton]

>> 10k input resistance and sounds good?
> That's the output

Gus is looking at the two "20K" resistors at the INput. 20K||20K= 10K.

10K loading sucks all the highs and a third of the low/mids off a naked guitar. Adding series resistance (an input pot) does change this.

If you are happy we are all happy. But it is an odd setup.

not to be a jerk, but imho most distortion designs i've built that use a high input impedance often have way too much high end to them.. particularly in combination with any other dirt pedals. how much treble does one really need?

all comes down to  if it sounds good, it IS good. reminds me of a few years back a tc electronic multieffect. turned out some shop had been modifying them with a lower input impedance, and they had a rep to sound great. tc investigated, and found the modded circuit, altho "the rules" say it shouldn't sound as good, in fact sounded better and began shipping modified units at a higher cost if people preferred it.

how many times has someone picked up say, a stock ds1 by boss, been amazed at the crappy tone "that's right" and modded it to better suit their needs ears and tonal requirements?

just playing devil's advocate

[pinkjimiphoton]

That sounds great Jimi, mine is very similar but maybe a little more distortion at the extreme and less clean at the other end. I will try to make a quick demo vid after Xmas day. BTW, it does sound very good with my Boss SD-1 or my Thomas Cry Baby in front of it.

PRR- I will try my next one with some of The ideas I saw in Kipper's latest links.

Consider putting a 330-470pf cap in parallel with the 150k feedback resistor to make it warmer and less fizzy.  You already have the 3300pf treble cut cap, but why settle for one pole of lowpass filtering when you can easily have two?

I salute your paint-pen work.

Thanks Mark, will definitely try that, sounds easy. Artwork is by my daughter... just making sure credit is given where due

i look forward to hearing it in action ben!
yeah, mine is less distortion sorta... i use it as a big "cleanish" boost. lotta compression and enough nuts to overdrive anything else. live, i barely crack the gain on.... mayyyyyyyyyyyyyyyyyybe 9:00, and the output pot similar. when i step on that sucker i could part a deaf guy's hair at the back of the room. very loud, very creamy. it sounds more like this in actual context, which is my ever present fuzzface into my clipper with a les paul

[R.G.]

You see that 8.2K right after the 4.7uF at the output, just before the clipping diodes? Temporarily replace that with a 1K and a 10K pot, then twiddle the pot while taste-testing.

[aron]

Hmmm.... I think I am going to experiment with lower input impedance.

[anotherjim]

I've seen a lot of squaring/fuzz that have low input impedance. It must help reduce the "harmonics of harmonics" fizz in the fuzz and let the squarers track the fundamental better. But it ceases to help if you have any buffer between it and the guitar.

[pinkjimiphoton]

sometimes, you DON'T want a buffer between your guitar and effects... put a buffer in front of a true fuzz?
heresy.

buffers often tend to make stuff sound very hard and very bright. they are by all means useful, but too many can destroy your tone.

it depends on where in the chain it is.... first in line is useful to have a lower z as the guitar will interact more with the circuit (fuzz face as example)

and in between a bunch of other effects it can be handy too, as a lower z not only allows less high end response and brittleness than a high z one,  but also makes it less susceptible to picking up noise, which high z inputs EXCELL at.

really depends on application and what you consider to be good tone, as well as where "in the chain" the effect is located.

another example is boss volume pedals. those designed for guitars have a much higher impedance than those designed as exp pedals... the lower z "plays nicer" in the middle than at the front. less noise, smoother sweep. of course this is all subjective to the rest of your rig and your own personal style,
but to me still, the best sounding box ever built is the fuzzface... i get a LOT of mileage out of mine, and play everything from folk rock to classic metal with it a couple shows a week. when i'm playing, it's almost always on...

and the worst pedal to my ear is the tube screamer..  which represents everything i personally don't like in solid state guitar technology. too bright, too nasal, way too obviously buffered for my taste...

one can always add a buffer if they need to. but as we all know, buffers sometimes are awesome, and sometimes, with their too high treble response and high input z they totally destroy your tone.
but i'm a weirdo, and i have a different approach than some folks do, being a bowed instrument guy originally. i like a longer attack, personally... but that's all apples and orangutans.

also depends on whether the box in question is an opamp or transistor, whether fet based or uni, darlington, ge or si... the list goes on.

i'm mos def not saying i'm right... but i AM saying, if it sounds good, it IS GOOD.

peace and merry christmas to those of you who celebrate that, to the rest, have a kewl yule

[amptramp]

Since you have a series diode going from the battery to the effect, the shunt diode to ground, if used at all, should come after the series diode so it prevents voltage from going too high due to leakage in the series diode.  That way, you don't discharge the battery if you put it in the wrong way.

A capacitor across the 220K feedback resistor may be necessary to avoid oscillation.  47 pF will give you a cutoff of 15400 Hz and maintain stability.  You can reduce this value slightly to compensate for the diode capacitance.

The 10K biasing resistors to ground and +9VDC should go up by at least an order of magnitude and possibly as high as 1 megohm.  The 5534 takes a fair amount of bias current, so you may have to adjust values to get the bias point at 1/2 Vcc.  The 10K in series with the input is too high if you increase the bias resistors.  I would put it at 100 ohms to 1 K so you can add a small capacitor of up to 100 pF to ground after it if it picks up radio frequency interference.

The series connection of 10K and 0.047 µF at the input does not give you the high frequency rolloff you may want because the connection to the 4.7 µF feedback cap may give dramatically different results depending on the series ESR of the electrolytic cap.

[pinkjimiphoton]

Since you have a series diode going from the battery to the effect, the shunt diode to ground, if used at all, should come after the series diode so it prevents voltage from going too high due to leakage in the series diode.  That way, you don't discharge the battery if you put it in the wrong way.

hi ron, i'm assuming your referring to my circuit from reading this, not ben's. thanks for the tip on the diodes.

A capacitor across the 220K feedback resistor may be necessary to avoid oscillation.  47 pF will give you a cutoff of 15400 Hz and maintain stability.  You can reduce this value slightly to compensate for the diode capacitance.

zero problems i've encountered with this. 15.4k is pretty high.... guitars don't have much above maybe 6k, so i don't see what the point would be of needing the filter cut off so high?

The 10K biasing resistors to ground and +9VDC should go up by at least an order of magnitude and possibly as high as 1 megohm.  The 5534 takes a fair amount of bias current, so you may have to adjust values to get the bias point at 1/2 Vcc.  The 10K in series with the input is too high if you increase the bias resistors.  I would put it at 100 ohms to 1 K so you can add a small capacitor of up to 100 pF to ground after it if it picks up radio frequency interference.

that may indeed be valid by an EE standpoint, but 10k sounded great. i started with 100k, tried 1 meg, 10k gave the best response and interaction with the guitar knobs. to me, any dirt box that doesn't clean up well from the guitar is absolutely pointless. the 10k in series may be too high if you increase the bias resistors, but it made a tremendous difference in tone and response on the breadboard, so i kept it.  if changing the circuit makes it so it may need a cap to bleed rfi to ground, how is that necessarily an improvement?

The series connection of 10K and 0.047 µF at the input does not give you the high frequency rolloff you may want because the connection to the 4.7 µF feedback cap may give dramatically different results depending on the series ESR of the electrolytic cap.

you need to understand, i am no EE. i don't really care about "rules" too much. i sit there with my breadboard and dick around til it sounds good to ME. if it sounds good to me, i'm good with it. as i recall, the high end roll off is fairly natural sounding. i've built 10 or 12 of these things now for customers and friends, and for what it was designed for (if you can call 10,000 monkeys x 10,000 years designed) it works great. this was intended to be used AFTER all dirt boxes etc to give a big boost for leads and whack the bejesus out of anything after it... works pretty well for that. it's the last thing in line before my flanger and delay, and when i kick it on, it screams. generally my guitar will only be on 2-3 when i use it anyways...  but all the "metal" guys who sit in ALWAYS turn it on and leave it on. it's a simple circuit, try it on a breadboard before trying to over engineer it. it's meant to be simple, cheap, and toneful. if it sounds good, it is good...
i'm betting ben's idea kicks total ass and am looking forward to hearing it.
like i said, just cuz something is "right" doesn't mean it sounds any better. peace!