Just built a Red Llama - should there be farty/fuzzy bass notes when chording?

[grolschie]

Hi there,

I have just built a Red Llama using Andrew Carrell's layout. With gain on 0, it's a mild crunch. Gain on full, and it's wall of sound. While mine is sounding good (might very bright) for lead, for power chords the bass notes are kind farty/fuzzy. Is this par for the course? Basically, the bass notes on chords when using anything other than my bridge pickup is bad sounding unless gain at almost 0. I am using a regulated Boss PSA240 9vDC adapter rather than batteries. I am using a CD4049UBE IC.

If this is not expected behaviour, I guess I need to start with the debugging and posting of voltages etc. But not if it's simply the expected behaviour of this pedal. Any feedback, greatly appreciated. Thanks in advance.

Cheers,
grol.

[joelap]

Hi, kind of funny as I was just messing around with one on breadboard today and found similar results.  I found it to be a compromise, especially using my les paul in the neck position.  In order to make notes not boomy in the neck position, things were a bit too bright in the bridge position.  Then again, I was using many different cap values as I didnt have ny .068uf or .033uf's on hand.  But I found .1's to be too much and .022's to be too little, so maybe the correct values should be ok?  Try experimenting a bit... I had the input cap at .022uf, the cap between stages at .047, and the output cap I changed from a 10uf electrolytic to a .22 or .47 film cap... I wasnt immensely satisfied though.  In the end, the more I fooled with it, the less satisfied I was.  I'll probably go back to the stock values and start again.  But yes, farty is an issue I encountered and am still figuring out how to deal... especially with my open back AC30.

Did you notice an interaction on the volume control?  As the volume is lowered, gain is decreased as well as treble content.  I put a .0022 treble bypass cap across the volume pot, but still as the volume is lowered, the gain is effected as well.  Did you notice this too?  I'm contemplating finding another way of controlling the volume in this circuit... thought about placing a buffer after the output cap and putting a volume knob after that... not sure if that will matter though... can't tell if its an issue of impedance or what.  Maybe someone more experienced can chime in.

[grolschie]

I noticed some interaction with the gain and volume knobs, but mainly volume changes. Basically, I built mine stock to Dragonfly's vero layout with a fairchild CD4049UBE. I find with everything stock, the pedal fails the "Open E chord test" on any setting other than the bridge pickup alone on my strat. Anything more than 2 strings at once starts fuzzing out into a mess. Did you notice that at 0 gain, the pedal ain't really that close to being clean? My amp isn't an AC30. It's a Laney LC50 (2xEL34 openback, feedback loop removed to make it more VOX'ish).

[DiamondDog]

Any feedback, greatly appreciated.

Not in my band it's not... 

Please define a chord. And open E as in 0 2 2 1 0 0, or x 2 2 1 x x  or...?

When I use the Llama, I use it on double stops, individual runs, and the like. the more notes at the same time, the more at has to process. I wouldn't be too worried at this stage.

[grolschie]

Please define a chord. And open E as in 0 2 2 1 0 0

That's the one. So to use it on AC/DC style open chording riffs, of even bog-standard-generic power chords is kind of sad even at lowest gain setting even. Not that I want an Marshall-In-A-Box^TM. Just a usable low-medium gain overdrive/distortion of a different flavour. I have a Rat and a Bad Monkey (modded to be TS808ish), but people have said that CMOS distortion is where it's at - so for fun I built one. Just wanting to know if this is normal expected behaviour from the pedal. Basically I can see zero use for it at present for rhythm playing on any setting. For lead it definitely has possibilities.

If this is par for the course (or if mine needs debugging), then maybe I could tweak it somewhat e.g. perhaps I could try rolling off the bass somewhat at the input.

[markm]

Sounds like there may be some other issues at hand here grolschie,
Mine doesn't do what you describe.....maybe check resistor values? 

[joelap]

I noticed some interaction with the gain and volume knobs, but mainly volume changes. Basically, I built mine stock to Dragonfly's vero layout with a fairchild CD4049UBE. I find with everything stock, the pedal fails the "Open E chord test" on any setting other than the bridge pickup alone on my strat. Anything more than 2 strings at once starts fuzzing out into a mess. Did you notice that at 0 gain, the pedal ain't really that close to being clean? My amp isn't an AC30. It's a Laney LC50 (2xEL34 openback, feedback loop removed to make it more VOX'ish).

I did notice that at zero gain, but came up with a solution for it.  In place of the 100k resistor after the 1M fuzz pot, I put an 82k resistor (you might want to try 68k here as well) in series with a trimpot set as a variable resistor.  The highest value trim I had was 250k, but you might want to try 500k or 1M.  I think the way I'm going to do it when I get to soldering it, is to put the 68k resistor in series with a 1M trimpot.  From there, turn the drive knob all the way to zero and adjust the trimpot to the point you want the drive knob to start at.  Or, conversely crank the drive knob and then adjust the trimpot to the max setting you like.  I'd start with 1M trimpot, as the 250k didnt make that huge of a difference really.

I really liked the sound of it set for a mild od into my cranked AC30, but I'm still trying to find the optimal cap values for the circuit to strike a balance.  Its perfect on the bridge position but bassy on the neck, or its bright on bridge and perfect in neck position.  I generally like interactive controls, but my volume control is adding highs and distortion as it is turned up, and I'm not too thrilled about that.  Ideally I'd like to find a way to keep the volume equal to the volume of my AC30 when cranked.  But the fuzz/treble response suffers a bit.  I'll try placing a buffer after the circuit and let you know if that solved my issues or not.

[markm]

For bridge position, I just roll down the Tone pot of my Tele a bit and everybody's happy! 

[joelap]

For bridge position, I just roll down the Tone pot of my Tele a bit and everybody's happy! 

hehe... unfortunately if its bright on my Les Paul, its going to give permanent hearing damage on my tele!

[joelap]

I was able to remedy the problem of being too bright or too muddy by removing the output cap (10uf electro on the red llama) in favor of a bandpass filter.  Try adding a band pass filter with values of .01uf and 47k for the high pass portion and 33k and .0047uf for the low pass portion.  I then added a tone control on the output of the volume pot.  I'm using a 10k for the pot and a .047uf cap to ground to control a bit of the high end "presence".  See if that works for you... its made this much much better for me.

[grolschie]

Sounds like there may be some other issues at hand here grolschie,
Mine doesn't do what you describe.....maybe check resistor values? 

Thanks Mark. I will start the debugging later. 

Actually, it's not 100%. I just remembered that I used a 1N4007 instead of a 1N4001. That won't make any difference will it?
grol

[grolschie]

Voltages on the CD4049UBE:

Pin1:    5.47
Pin2:    1.77
Pin3:    1.74
Pin4:    0.0014
Pin5:    5.47
Pin6:    0.001
Pin7:    5.47
Pin8:    0
Pin9:    5.47
Pin10:  0.0018
Pin11:  5.47
Pin12:  0.0023
Pin13:  0.0002 (could be 0 I guess)
Pin14:  1.78
Pin15:  1.79
Pin16:  0.0002 (could be 0 I guess)

Front:
http://i220.photobucket.com/albums/dd249/grolschie/Other/llama2.jpg

Back:
http://i220.photobucket.com/albums/dd249/grolschie/Other/llama1.jpg

Case:
http://i220.photobucket.com/albums/dd249/grolschie/Other/llama0.jpg

I gave the gaps between the tracks a got scrape. As you can see, I had to parallel two caps (18pf and 33pf) to equal 51pf.

[grolschie]

Double checked the resistors. They are the correct values (i.e. 2x1M, 2x100k, 1x1k). Pots are B1M and A10K.

[Pushtone]

Hi, kind of funny as I was just messing around with one on breadboard today and found similar results. 

Thanks Joe!
I was going to build this one today!
I was going to skip the breadboard and head straight to perf.

I would not have been happy with the stock sound thats for sure.
You just might have saved a perf project from the dud file.

I took your advice and have it on the BB now, still messing around with it.

I think your both right about the sound, too much bass.

I was just doing AB test with a dual effects loop.
I have the Llama in one loop and the BSIAB and Thunderchief in the other.

When going back and forth between the Llama and the other two, the llama has the most bass response of the three.
The Thundercheif has all the bass response I would ever want. It establishes a limit for ultra thick sound.
The BSIAB seems to have the least amount of bass, but has sounded "just right" in jam sessions with my 4x12 cab.

I'm going to tune the Llama to match the response of the BSIAB and see if I can skip the tone control.

Hey grolschie,
I get about the same voltages on the CD4049 as you posted.
I also subbed a 4007 for the 4001. Makes no difference.
I based my perf off a PCB layout by Gaussmarkov.
That makes three out of four builders who consider the stock values farty, or as I like to say, voiced a little to much in the lower registers.

I do not find any interaction between the GAIN and VOLUME controls.
With the GAIN maxed out, I tried cranking the VOLUME up and the amp down.
Then I turned the VOLUME down and the amp up - same distortion/gain.

Any other distortions out there that use a 4049 hex buffer? To compare.

[grolschie]

Do my voltages look ok? Should a 1k resistor drop the voltage from 9v to 5.47?

[remmelt]

I've built three, all on my own perf layout. If anyone's interested, drop me a line, it's tried and tested and smaller than the vero one, and I don't think I've seen a pcb this small for it either. Either way, it's a simple circuit so no rocket science involved.

I have a fairly bright strat and mine all sound sort of muddy on the lower E. They all sound really really good with 5 chords like so: E5 = xx245x. Double stops are amazing as well. I've only recently had the chance to hear it with a loud setup, and man, this pedal is the shit. A tight tone, yet not muddy or too fuzzy (nothing wrong with that, though!) ABed with a Rat, the Rat was more open sounding, more like a distortion should. The Llama kind of skips the distortion step and combines overdrive with fuzz.
One of the ones I've built went to a bass player, who wanted his pedal stock as for guitar. No arguing with that, he seems to like the sound (so much that they recorded an album with it) so I don't know about farting/buzzing. Either he likes it or it doesn't do that on bass? Interesting stuff. Another to a guitarist (with the loud setup) and he seems to like it with lower chords as well.

All three sound basically the same, so don't worry about the lower chords not working for you. There are tighter pedals for that.

[markm]

I suppose I'm probably not using this circuit as Cranked-Up as you fellas? 

[grolschie]

I am using the pedal with gain set real low.

[markm]

I am using the pedal with gain set real low.

Okay.
I'll sit down now.   

[grolschie]

What should the voltages be on this IC in this circuit? Do mine look ok? Or maybe I should've socketed the IC rather than heat it up with my soldering iron?