Red Llama woes

[audioguy]

OK I built 3 red llamas from http://www.freewebs.com/loudnoise/Red_Llama.pdf hoping each would solve my problem but it never went away. Whats happening is that when I turn the gain pot to about 95% it cuts out.
I've tried 3 different builds of the board, and MANY different pots, and I get the same thing everytime. The unit sounds great up to that point, but I'm trying to find the solution because its driving me nuts.
Thanks!

[stm]

Man, the PCB layout doesn't follow the schematic!

In simple words I would say the PCB layout is WRONG in several aspects:

1) The main problem seems to be that the order of the 1K resistor that feeds the CD4049 and the 330uF filter capacitor is inverted in the schematic.  As such, the capacitor won't filter the supply of the CD4049, and when you demand more juice from it, eventually it will shut down momentarily.

2) I am not convinced by using one of the "unused" CD4049 outputs to supply the LED, unless this is actually done in the original Red LLama.  The reason is that the LED current consumption will produce an extra voltage drop in the 1K feeding resistor which may impair circuit operation.

3) There are two 1N914 diodes facing in the same direction (in parallel), so one of them is redundant, or misconnected.  These diodes and associated circuitry are not shown in the schematic also.

In summary, strip out anything that is not drawn in the schematic and make sure what remains is connected in the exact order as in the schematic. That should work out your blues and leave you with a great pedal!

Regards,

STM

P.S.  The moral is: don't trust a PCB unless it is actually tested and reported good by several independent people AND yourself!

[audioguy]

Hmm all of that sounds good
Does anyone have a tested and working Red Llama layout?

[audioguy]

I just found this layout- http://users.bigpond.net.au/styrowfoam/redllama.pcb
but there are no values... any ideas?

Thanks for the help!

[The Tone God]

The best way to deal with an unconfirmed layout is to trace through it while comparing it to the schematic. It will take time and you have to be honest about errors even though you might be excited that all the work may be done for you. Its the only way to be sure.

Andrew

[MartyB]

Wondering if anyone has had a listen to the red llama and compared to other CD4049UBE circuits.  I've always wanted to build the Hot Harmonics at Frank Clarke's site.  My layouts (yes, I tried one before getting breadboarding to work - %^&*y and dumb) haven't worked for the HH.  If  somebody gets the WH RL to work I'd like to hear from them.  I have a mess of CD4049UBE's brand new.

MartyB

[toneman]

quickly looking at layout U referenced.
remove 4001, put in jumper.
diode is actually blocking gnd.
unused gates should go directly 2 gnd.
pcb & pinout looks correct.
the 330uf cap on pin 5....
move + side of cap from pin5 2 pin1.
U want 2 filter pwr in, not gnd.
BTW,  Plus(Vdd) is pin1.
Gnd(Vss) is pin8.
try it again...
tone

[Michael Allen]

The LED is a Millenium C circuit. Shouldn't have enough voltage usage to really affect the circuit, I don't think. The two 1N914s are inplace as high leakage diodes. Try one first and if you need a second, then you can put it in.

I'll try to fix the pcb (Yeah i didn't give enough attention to the importance of the 1k first) this week sometime.

[audioguy]

Michael-
The sound is great! I just want to be able to have the full range of motion from my distortion pot.

Thanks!

[mrsage]

The LED is a Millenium C circuit. Shouldn't have enough voltage usage to really affect the circuit, I don't think. The two 1N914s are inplace as high leakage diodes. Try one first and if you need a second, then you can put it in.

I'll try to fix the pcb (Yeah i didn't give enough attention to the importance of the 1k first) this week sometime.

Any progress on this?

I'm getting ready to build a Llama, and I want to make sure I've got all the info I need ahead of time!

[audioguy]

I would LOVE to see this 100% functional.
What I was able to build sounded fantastic... keep us posted.

Audioguy

[william]

Where are people getting their IC's for this project?

[audioguy]

www.TI.com

[mrsage]

I just got the IC from Mouser. I don't think it's an exact match, but it's a substitute.

[puretube]

IP timed out...

[mrsage]

"substitutes" may cause problems, here...

Hmmm...

I used the HCF 4049 UBEY:
http://www.mouser.com/index.cfm?handler=displayproduct&lstdispproductid=207806&e_categoryid=289&e_pcodeid=51102

What kinds of problems could that cause?

[puretube]

>UBE< sounds good - dunno bout the >Y< (?)
try!

[mrsage]

1) The main problem seems to be that the order of the 1K resistor that feeds the CD4049 and the 330uF filter capacitor is inverted in the schematic.  As such, the capacitor won't filter the supply of the CD4049, and when you demand more juice from it, eventually it will shut down momentarily.

How would one go about doing this? I'm not that great at reading schematics, and I can't make sense of how this one relates to the layout...

For instance, I can't figure out why pins 4, 6, 9, and 11 are connected to each other on the layout, but not on the schematic.

Anyway, what should I do to the components on the PCB I have to make them match the schematic?

quickly looking at layout U referenced.
remove 4001, put in jumper.
diode is actually blocking gnd.
unused gates should go directly 2 gnd.
pcb & pinout looks correct.
the 330uf cap on pin 5....
move + side of cap from pin5 2 pin1.
U want 2 filter pwr in, not gnd.
BTW,  Plus(Vdd) is pin1.
Gnd(Vss) is pin8.
try it again...
tone

I understood some of this, but need clarification...should the 1N4001 not be in the layout at all? It's on the schematic...Did you mean one of the 1N914s?

Next, should the (+) of the 330uf cap be going to pin 5 or to pin 1? It doesn't look like it's going to pin 5 right now...unless I removed one of the diodes and put in a jumper. Also - and this could just be my newbie schematic reading - it looks like it's supposed to go to BOTH pins 1 AND 5...Is that the case? :?:

And what would I do to move it to pin 1? It looks like it's already going there...it just has that 1k resistor "in the way." Should I move that resistor somewhere else?



Any help from the pros?

[puretube]

never trust a schematic on the web!

[mrsage]

never trust a schematic on the web!

Hmm...

Okay, I guess people are a little tired of the Red Llama woes. I've populated the PCB as shown in the layout...

I'm just hoping for some last suggestions before I move the 1k resistor around and try the circuit out.

Should I just move the 1k resistor and see if that works, or would it be better to scrap the PCB I have and do a perfboard layout, per the schematic?