Red Llama build/mods

[JohnnyCrash]

In addition to my SS 2w Ruby amp build and my Rat clone pedal build, I'm starting a Red Llama clone build.

The thing looks extremely basic, so maybe this question is dumb, but: Are there any mods you'd recommend?

[ibobunot]

A very nice mod is to make a footswitchable 'extra channel' by adding the 10M resistor in the first feedback loop like in the Tube Sound Fuzz. I breadboarded mine before I started the actual soldering, so I had a chance to try some different values in various places. I must say that the original components are very well chosen. Adding an extra resistor in series with the 100K that goes to the 1M Fuzz control will drive up the distortion a lot. I added 4M7 which I thought was better-sounding than 9M4 (two 4M7s). The Fuzz pot will become nearly useless then but that's OK. You can have a regular drive channel, controlled by the pot, than a fuzz channel which is just way huge (ha). I thought about installing a switch but decided against it so it was all stock and because I thought it might not fit in the box. In retrospect, it probably wouldn't have. Luckily I ordered two CD4049s so I can build another incarnation of this device, which I intend to modify and add some switches and pots to. The variations are endless!

Since, I've found a lot of other cool projects using the CD4049, like the Runoffgroove's Double D and their Mr. EQ, Frank Clarke's Hot Harmonics and Tim Escobedo's CMOS boost. These all look exciting, especially since a lot of the gates of the IC remain unused (there are six inverters!) and circuits can be added with a few variations. So for example a clean boost into a Red Llama into an eq.

remmelt.com

[Robbie W]

There really aren't alot of mods that will do anything other than detract from the sound. The output impedance of the 4049UBE hex inverter is very high, I have seen people try to add a tone control directly after the output. Unbuffered cmos outputs can not drive a tone control properly. Even a small capacitance will drop the bandwidth very low. The supply voltage also effects the gain and bandwidth.

The Red Llama is essentially the Tube Sound Fuzz project from Craig Andertons "Electronic Projects for Musicians". A few minor parts value differences but I don't know that they even make an audible difference.

I have built quite a few clones of this circuit that use the Anderton TSF component values. I have had guys put them side by side with a Way Huge Red Llama and say they can't hear the difference.

I would use the Anderton values of 100uF/100 ohm in the power supply filter section versus 330uF/1K as used in the Red Llama. Also, just use .047uF caps for the first two coupling caps, 10uF tantalum for the output cap.

I built the first 60 or so Mule pedals for Tone Factor, and built about 25-30 pedals under the RGW Electronics "Dirty Dan" name (both were Red Llama/TSF clones).

Great circuit. I love the sound of the pedal and have one on my pedal board.

[Guitar_Ninja]

About all I did with my build was decrease the size of the output cap to 4.7uF and switch it to an aluminum electro for a touch more treble and bite. I also increased the size of the power supply cap to 1000uF and dropped the value of the resistor in series with the battery from 1K to 56 ohms. The circuit draws around 3.6 mA, so that leaves you with only a 0.2V voltage drop across the resistor, as opposed to a whopping 3.6V drop using the stock 1K value.

[JohnnyCrash]

Originally Posted by Robbie W

I have built quite a few clones of this circuit that use the Anderton TSF component values. I have had guys put them side by side with a Way Huge Red Llama and say they can't hear the difference.

I don't mean to sound rude, but if they sound the same side-by-side, why do you prefer the other values?

Originally Posted by Robbie W

I would use the Anderton values of 100uF/100 ohm in the power supply filter section versus 330uF/1K as used in the Red Llama. Also, just use .047uF caps for the first two coupling caps, 10uF tantalum for the output cap.

With your first statement above, is this why you'd recommend the 100uF? I mean to ask, that if noise filtering and tone are the same, 100uF's might be cheaper to do the same job?

As far as the 10uF tantalum, I'm sorta limited on parts. I know tantalum has less noise than using an electrolytic in coupler spots, but I've only heard a noticeable difference where there were several electros in the signal line.

For the first coupler (0.068uF) I was going to parallel a 0.047uF with a 0.022uF (for a total of 0.069uF), then for the second coupler (0.033uF) a 0.022uF with a 0.01 (for a total of 0.032uF)... like I said I'm sorta limited on parts HAHA!

Hmm... I might as well bump up the second to 0.047uF to increase mids/bass...

Thank you for the help so far!

[Robbie W]

Originally Posted by JohnnyCrash

I don't mean to sound rude, but if they sound the same side-by-side, why do you prefer the other values?

With your first statement above, is this why you'd recommend the 100uF? I mean to ask, that if noise filtering and tone are the same, 100uF's might be cheaper to do the same job?

This is exactly why. I buy parts in bulk and try to buy parts that can be used in several different pedal circuits versus just one pedal.

So I wouldn't say that I prefer them from an "audible difference" point of view, but more of a "practical parts to use" point of view. Especially when the same sonic results can be achieved. I regularly stock a lot of .047uF caps, and 100uF caps. Since the original schematic calls for these, I use them. I didn't want to order .068uF caps, .033uF caps, and 330uF caps that could only be used for that specific pedal.

As far as the 10uF tantalum, I'm sorta limited on parts. I know tantalum has less noise than using an electrolytic in coupler spots, but I've only heard a noticeable difference where there were several electros in the signal line.

For the first coupler (0.068uF) I was going to parallel a 0.047uF with a 0.022uF (for a total of 0.069uF), then for the second coupler (0.033uF) a 0.022uF with a 0.01 (for a total of 0.032uF)... like I said I'm sorta limited on parts HAHA!

Hmm... I might as well bump up the second to 0.047uF to increase mids/bass...

Thank you for the help so far!

That will be fine, I used 10uF electrolytic in almost all of the clones I built. I think tantalum is a slightly better choice when available which is why I recommended it, but again it goes back to bulk parts stock, etc.

take care,
Robbie

[JohnnyCrash]

Very cool! Thanks so much Robbie!

[Robbie W]

Originally Posted by JohnnyCrash

Very cool! Thanks so much Robbie!

No problem, this is great sounding little box. Very organic and natural, like a tweed amp cranked up all the way. I probably use this overdrive more than my other Tube Screamer based clone that is on my pedalboard.

BTW I forgot to mention that in the Red Llama it uses a 51pF in one feedback loop and a 100pF in the other. I use 51pF in both loops as per the original schematic out of the Anderton book.

take care,
Robbie

[JohnnyCrash]

Originally Posted by Robbie W

No problem, this is great sounding little box. Very organic and natural, like a tweed amp cranked up all the way. I probably use this overdrive more than my other Tube Screamer based clone that is on my pedalboard.

BTW I forgot to mention that in the Red Llama it uses a 51pF in one feedback loop and a 100pF in the other. I use 51pF in both loops as per the original schematic out of the Anderton book.

take care,
Robbie

Doh! Well I'm sorta screwed there... I don't have any caps under 120pF right now (except for a lone 80pF). I hope my electronics shop is open tomorrow, but I doubt they are on Sundays.

Do you feel the 100pF is too boomy? If so, I may go with 51pF on both - I mainly use P-90s and humbuckers. I do like mid heavy tones though, maybe 51pF and 80pF would do it...

[Robbie W]

Originally Posted by JohnnyCrash

Doh! Well I'm sorta screwed there... I don't have any caps under 120pF right now (except for a lone 80pF). I hope my electronics shop is open tomorrow, but I doubt they are on Sundays.

Do you feel the 100pF is too boomy? If so, I may go with 51pF on both - I mainly use P-90s and humbuckers. I do like mid heavy tones though, maybe 51pF and 80pF would do it...

Those caps are to control possible oscillations, so they have the effect of rolling off high end frequencies. Making the caps too big starts to take away from the bite (and gain) of the circuit. Anything above 51pF starts to do this in my opinion. So it is kind of a trade off, I would only increase them if I was getting oscillations or thought the pedal was too bright. All my guitars have single coils and the tone is great, I would think P90's or humbuckers would more than be fine.

The 4049UBE isn't even designed to be an audio chip. It was the result of Craig Anderton thinking "hhhhmmmm.....what would happen if I put an audio signal into this digital inverter chip.....". So all the optimum things you want out of an audio circuit go out the window with the 4049UBE chips (high output impedance, etc.).

I would try the 80pF and the 120pF and see what you think. You never know it may be just what your looking for.

As far as the different parts in the Red Llama versus the Tube Sound Fuzz, Jorge Tripps of Way Huge has said he just used random parts that he had on hand versus the parts shown in the schematic when he built the prototype. They weren't the result of "tweaking the sound".

take care,
Robbie

[Robbie W]

Correction:

I used 10pF caps in the feedback loops, which is what the original Tube Sound Fuzz project called for.

Sorry, I haven't built any of these in a long time

I would still try the 80pF and 100pF you have on hand first and see if you like the results.

[JohnnyCrash]

Originally Posted by Robbie W

Those caps are to control possible oscillations, so they have the effect of rolling off high end frequencies. Making the caps too big starts to take away from the bite (and gain) of the circuit. Anything above 51pF starts to do this in my opinion. So it is kind of a trade off, I would only increase them if I was getting oscillations or thought the pedal was too bright. All my guitars have single coils and the tone is great, I would think P90's or humbuckers would more than be fine.

I don't want to chop off too much treble, especially seeing as how I'm mainly a darker humbucker guy. Thanks for explaining... looks like I need other stuff anyway, so I might as well pickup 51pF caps while I'm there

Originally Posted by Robbie W

The 4049UBE isn't even designed to be an audio chip. It was the result of Craig Anderton thinking "hhhhmmmm.....what would happen if I put an audio signal into this digital inverter chip.....". So all the optimum things you want out of an audio circuit go out the window with the 4049UBE chips (high output impedance, etc.).

HAHAHA!

Somehow, especially with Rock and Roll, doing things wrong seems like the way to do things right!

A million thanks! I'm looking forward to building and hearing this simple circuit...

[11 Gauge]

Inverters are really cool, even if they've been repurposed for the use in stompers.

The Blackstone Appliances Mosfet OD has an op amp stage driving 3 inverters that are directly coupled.

But as to some TSF mods, here are some of my faves, but they are a bit radical, so just keep that in mind.

- Swap the coupling caps, so that the first one is smaller. This will reduce the pedal's ability to fart out at higher settings. I actually go pretty small on the first one, no bigger than roughly .022uF.

- I usually don't go any bigger than .047uF on the 2nd coupling cap.

- After messing with the couplers above, you can then bump up the cap in the first loop, especially if your first coupler is "treble booster small," i.e. roughly .01uF or so. I've gone as high as 150pF, but prefer 120pF in most instances. But I still keep the cap in the 2nd loop small.

- Reduce the resistor in the 2nd loop. The pedal will still have plenty of gain. Better yet, put a temporary pot or trimpot in there. You can then mix and match the two inverter stages different tonal mixtures. Gain pots with inverters should always be linear units to get a good sweep.

- I also use a very small level pot as well - typically 5K (LOG).

Just some ideas. It makes for a pretty cool twist on the stock theme. Another advantage of these mods is that you can stack the pedal with something in front of it (like a TS or other dirt box with the drive relatively low), and get some really nice higher gain tones.

[JohnnyCrash]

Final question. What do you guys think of adding some sort of "insane-o" switch that adds an unused inverter gainstage into the mix? Too much?

PS
After hearing several clips, I think my BMP covers that whooly sound well, so I think for the RL I'll be thinning out some whool and reducing some cap values to put the RL between my TS808 and BMP in sound.

[Robbie W]

Originally Posted by JohnnyCrash

Final question. What do you guys think of adding some sort of "insane-o" switch that adds an unused inverter gainstage into the mix? Too much?

PS
After hearing several clips, I think my BMP covers that whooly sound well, so I think for the RL I'll be thinning out some whool and reducing some cap values to put the RL between my TS808 and BMP in sound.

That is certainly an option and there are circuits out there that use the unused inverter stages. The Snarling Dogs "Black Dog" pedal was a 4049UBE based circuit that used three gain stages if I recall correctly.

Personally.....anything more than two gain stages and things get a little too ragged for me. The same for switching in a high value resistor in the first stage feedback loop (i.e. 10M on the original TSF for a "lead" switch). It just gets too over the top and notes become indistinct.

But these are just my personal opinions, it may be just what someone else is looking for.

[11 Gauge]

Originally Posted by Robbie W

Personally.....anything more than two gain stages and things get a little too ragged for me.

I agree, but also because the opportunity to introduce oscillations and bring up the hiss level unacceptably are also very real.

That said, you may want to investigate the 3 Legged Dog, the Bounce channel of the Double D, the UBE Screamer, and the 22/7ths.

The 3LD and DD require jFETs, however, which throws in additional complexity.

If you tweak the Tube Sound Fuzz circuit the right way, it's amazing how much distortion you can get out of just two inverters - case in point.

[Anwar]

Hey Johnny seems were running in parrallel sorta. I will be rigging this up as per schematic to see how it sounds.

[JohnnyCrash]

I just finished it... had trouble with an overly shallow enclosure shorting the 3PDT switch when I closed it up HAHA!

I did this on perfboard, and let me say - DON'T EVER BUILD ONE THIS WAY. Talk about cramped board space!

I used 0.047uF couplers (instead of the 0.068uF and 0.033uF) and 68pF's. I also used a 10k drive pot.

Way Huge is also a great description. This overdrive is juicy. I get added fatness and thickness, but not the over the top whool of a BMP. It's not as out of control as I thought in the gain department too, but it is still a mighty boost nonetheless (single coils hum a little like a beehive when everything is dimed).

I'd say as far as my current overdrive/boosts go, this one has kicked my TS808 off of the pedal board. It's very cool. I am thrilled by the sound!!!