Almost all my 4049 based stompboxes sounds horrible...

[gigimarga]

Hello,

I'd finished to built a couple of 4049 projects and i am dissapointed because they have too much hiss and/or a very muffled sound:

1. Mark Hammer's Forty Niner - the only that sounds really good, but without Anderton's booster (i hope to repair it...)
2. Twenty-Two-Sevenths - nice, but i think it needs more gain and a better tonestack (i can use the tonepot only in 2 positions...)
3. Red Llama - almost OK, but needs a booster in front of it and you can obtain only 2-3 good tones
4. Hot Harmonics - the Octave pot seems useless and the sound is very muffled
5. 3 Legged Dog - hiss and squeal generator
6. EHX Hot Tubes - too much hiss and sounds gated on some settings

I didn't try yet Smooth-o-matic (where i can find some clips?) and Double D (seems a combination of the stompboxes above).

There is a problem with these circuits? I must to bias them or to customize some components?

Thx a lot!

[nelson]

I think that you have a recurring problem. I bet it is your power supply. Also, are you using unbuffered 4049's?

[gigimarga]

Thx for your answer nelson!

My power supply is a new alcaline battery because i want to avoid in the test phase all the hum/hiss problems.

And yes, i'd used in all pedals HCF4049UBE.

[nelson]

Thx for your answer nelson!

My power supply is a new alcaline battery because i want to avoid in the test phase all the hum/hiss problems.

And yes, i'd used in all pedals HCF4049UBE.

Maybe you just don't like the sound of 4049's?

There is usually a "sweet spot" when it comes to 4049's current. Why not breadboard a jfet variable current source, remove the current limiting resistor from the V+ pins and dial in a point where the CD4049UBE sound best?

[gez]

Your 'new' battery probably isn't so new anymore.  When CMOS inverters are run at 9V their current consumption is pretty high and can suck the life from a battery pretty quickly if you're running a circuit comprising a few stages.  That's why the EX hot-tubes used external power.  Use a wall wart and tweak input and coupling caps between stages to shape the tone.  This should get rid of any muffled sound. 

Two stage designs can sound a little tame, so don't expect miracles. 

Edit: IIR the Lama uses a current limiting resistor so is more battery friendly.

[stm]

I think some time ago there was a thread where someone said a particular brand of 4049 UNBUFFERED didn't work properly, even though it was UNBUFFERED.  I searched for a while with no luck, but IIRC even Steve Daniels mentioned something about this, but I could be wrong.  This thread shouldn't be older than a year, and maybe someone else remembers it.

In case of doubt, I'd suggest trying a CD4049UBE instead of the HCF, if you can get one.  Another possibility is to simply try with a CD4069 instead (watch out the pinout!)

[gigimarga]

Thx a lot for your advices!

I measure the battery every time i use it, so it's sure new (i always have 2-3 new batteries...)
I like very much the sound of 4049 (a boosted Red Llama using a MOSFET Booster is one of my favourite)...
I will try to adjust the current and caps when i will have time!

Thx a lot again!

[Steben]

remember there are MOSfets inside. Prone to voltage destruction... Always ground yourself while using MOSfets...

btw: What amp / speaker do you use?

[gigimarga]

I use an old romanian 20W full-tube amp which has only one clean channel which was modified by a friend of mine to sound Fender-like.
It has a no-name 12" speaker.

[snap]

I think some time ago there was a thread where someone said a particular brand of 4049 UNBUFFERED didn't work properly, even though it was UNBUFFERED.  I searched for a while with no luck, but IIRC even Steve Daniels mentioned something about this, but I could be wrong.  This thread shouldn't be older than a year, and maybe someone else remembers it.

In case of doubt, I'd suggest trying a CD4049UBE instead of the HCF, if you can get one.  Another possibility is to simply try with a CD4069 instead (watch out the pinout!)

That was about the PWM section and / or of the switched resistors in a MXR (envelope?) filter.

[gigimarga]

Could anyone to post voltages for any of the projects above?

[WGTP]

I'm messing with one on my breadboard, and it seems to be more "variable" than other distortion projects.  One day I get it tweaked and think it sounds pretty good, the next day, without any changes, it's squealing and farting and sounds like ****.  It seems that the cap values and calculations that usually work for bass and treble rolloff come out different than usual, as if the impedance is higher than it seems.  I'm assuming it is the voltage variations of the batteries causing some of this, or the distortion gods want me to use op amps and discrete Mosfets instead of CMOS.   

[mojotron]

I'm messing with one on my breadboard, and it seems to be more "variable" than other distortion projects.  One day I get it tweaked and think it sounds pretty good, the next day, without any changes, it's squealing and farting and sounds like ****.  It seems that the cap values and calculations that usually work for bass and treble rolloff come out different than usual, as if the impedance is higher than it seems.  I'm assuming it is the voltage variations of the batteries causing some of this, or the distortion gods want me to use op amps and discrete Mosfets instead of CMOS.   

Each wire has an associated parasitic capacitance that changes with their position. On a breadboard things can change quite a bit with the way the wires are positioned from one day to the next. On thing that can help is to use the shortest length wire as possible, and run the wires flat across the breadboard. The other thing to look out for is a hole where the wire/componenet is either too big or too small, or will not fit into the hole and make good contact. this will cause intermittent opens and shorts - possibly even limiting the current to marginalize your signal integrity.

[gigimarga]

I've built all on PCB's...but i will try to follow your advices regarding the wiring...thx a lot!

[WGTP]

That's a good point.  Having 6 little gain stages all jammed together on the breadboard in close proximity probably doesn't help things any.  Also, the distortion stays pretty smooth at rediculus gain levels, so it doesn't sound that dirty even when it's maxed.   

[zencafe]

I think your problem maybe the very very high harmonics generated by 4049UBE when distorted... I love the way it clips the signal, but it is true that the distortion can get very frizzy and harsh, specially at high gain settings...
What I do is let them generate all the harmonics they want... and then, at the end, add highpass filters to attenuate the wants I don't want.
Try cutting of harmonics over 10kHz. To my taste, thats just the sweet spot.

[gigimarga]

thx a lot zencafe!
your advice sounds right to me.
Today i will receive some CD4049UBE and after i will replace the HCF's that i used i will insert a high pass filter.

[Brian Marshall]

I have never cared for any of the 4049 based overdrives i have built or tried.

those who were mentioning the power supply may be on to something.  The tubesound fuzz i breadboarded sounded way better on an almost dead battery than a fresh one.

One of the problems i see with using inverters is that the output impedance is relatively high near centervoltage, and very low.  This means that any filtering following each stage could be adversely affected by really strong signals.  Basically it exhibits a lot of the problems with class ab amplifier circuits, but seems to be more problematic since they were never meant to be used as an audio amplifier.

[gez]

One of the problems i see with using inverters is that the output impedance is relatively high near centervoltage, and very low.  This means that any filtering following each stage could be adversely affected by really strong signals. 

Try buffering the output and then filter.  Example (of non-clipping buffer due to different voltage for the FET) here:

http://www.diystompboxes.com/smfforum/index.php?topic=64846.0

Personally, I don't bother filtering after each inverter.  I add a multi-pole filter after the buffered output.

[frankclarke]

From my site:
"It does seem that the manufacturer of the CD4049UBE chip used makes a big difference. It's worth trying a couple of manufacturers. Harris (CD4049UBE H9801) and ST Microelectronics (HCF4049UBE W990A9828 MALAYSIA) work for me."

I admire your perseverance .