Red Llama woes

[audioguy]

Which layout did you use? The layout I used sounded great, I just couldnt resolve the problem I was having with it quitting out when the pot got to 95%.

[mrsage]

Same one you posted...from Loudnoise.

Did you try any of the suggestions from this thread?

Seems like moving the 1k resistor is pretty easy to do...I guess I'll try that first.

Did you use Millenium Bypass? Why is there an LED in the circuit and also a pad for an LED on the PCB? (second one from the left)

[puretube]

sorry: "never trust a PCB on the web"...   :x

[R.G.]

"never trust a schematic on the web!"
"never trust a PCB on the web"...

I believe that you meant "never *blindly* trust ..."

[puretube]

*blindly* hits it to the point!
(I don`t even trust my own layouts, till I repeated/stuffed it 3 times, soldered it 2 times, hooked it up at least once, and listened to it 100 times...)

BTW: there has been some talk about that PCB before, on the forum, IIRC

[audioguy]

Same one you posted...from Loudnoise.

Did you try any of the suggestions from this thread?

Seems like moving the 1k resistor is pretty easy to do...I guess I'll try that first.

Did you use Millenium Bypass? Why is there an LED in the circuit and also a pad for an LED on the PCB? (second one from the left)

I did not use an MBP- I used what was built on the board and t worked just fine. everything about the layout worked, it just shuts down when you open the pot up (regardless of pot value) to about 95%.
I have yet to attempt any of the fixes listed here... I moved on to some other stuff. I might pick it back up in a few days.
My first priority for tomorrow is to DeTick a Pulsar from Tonepad.

[Michael Allen]

sorry i've yet to redo it guys, college is rough. maybe on spring break

[mrsage]

Okay. The extra pad that's marked "LED" must be for the millenium control on the switch. Cool.


And the reason I'm posting is because I don't trust the layout. Or the PCB.

I trust the schematic a bit more than the PCB, but not enough to dive in yet...

So I'm asking for some help from people who have built this before...or maybe the Anderton TSF, which has a very similar schematic to the Llama schematic from the original post in this thread.

[audioguy]

Thats exctly correct on the LED thing. I would say build it- its pretty simple and sounds freakin killer.

[Michael Allen]

Ok guys seriously, if you don't trust the pcb all you have to do is go through it with the schematic. With a pcb this simple it should take about 1 mintue. That's all you have to do to verify a layout.

Here's as per schematic. I didn't lable the parts but they are in almost the same spots as the layout on my site so you should be able to figure it out.

http://img.photobucket.com/albums/v368/soma_hero/Red_Llama_lay.bmp
http://img.photobucket.com/albums/v368/soma_hero/Red_Llama_pcb.bmp

Hope it helps

[mrsage]

Thanks Michael...I appreciate the work you've put into this.

I'm new to reading schematics, so it took actually took me a good 15 minutes or so to figure out what was what between the layout and the schematic. Some of it makes sense now (like the added diodes and resistor for millenium bypass), but some of it still doesn't (like why the schematic shows pins 9 and 11 connected to pins 5 and 7, but the layout has pins 9 and 11 connected to 4 and 6).

As a result, I decided to do a couple of builds just for fun. I had some perfboard and extra parts laying around, so I decided to do two versions...one using the original PCB that was posted and one based on the schematic.

The only change I'm making to that "original" PCB is to put a jumper in place of the 1k resistor. Then, instead of attaching the power directly where it says "9V," I'm attaching one leg of the 1k resistor there and attaching the power supply to the other leg.

Seems like that should do the trick. I'll wire the rest up for millenium bypass, as shown. Seemed to me like there were a few other issues with the layout (as I mentioned above), but that's probably because I don't understand how the opamp works. I've been working on reading schematics...Next step is learning how opamps work.

My perfboard layout is going strictly by the schematic, and will be wired up with "traditional" true bypass. So far the perfboard one is looking a lot like the layout you just posted.

We'll see if they sound exactly the same!

Thanks again for the help. I know this is a simple build, but there have been a few concepts I haven't had to tackle previously...and that's usually when I learn the most.

[mrsage]

Okay, here's my official report.

I built two Red Llamas: one using the original PCB that was posted (moving the 1k resistor to its proper location), and one on perfboard from the schematic.

They sounded exactly the same.

And they both cut out when the drive knob was maxed.

So I figured I'd try what someone else here suggested: use a 500k pot. I figured I could later put a 470k resistor on a switch and have a "more/less drive" toggle...keeping it under the full 1000k that seemed to cause it to cut out, but still allowing for close to the maximum drive that the original had.

However, it still cut out even when the 500k pot was maxed out!

Weird, huh?

Any ideas what would cause a generic pot to cut out when maxed? It's not just the resistance, since it happened both with a 500k and a 1 Meg pot...

[audioguy]

Thats exactly what I was saying my problem was. ANY pot value cut out at just before max. from 5k to 1m

[toneman]

old thread...i haven't read in a while.....
if same thing happens, something is basicly(consistantly) wrong.
whip out the ohmmeter....(sound effects, please!)

U removed 1K to +9V?
installed a jumper?
shouldn't make that much diff cause the 4049 pulls small current.
make sure of 4001 polarity(?)
neg side(cathode) goes to +9V.
(this is the "polarity protector")
Oh Kay.......
Ohm out +9V to--
pin1  (Vdd)
pin5  unused input
pin7    "
pin9      "
pin11      "
shouldB Zero/ohm.
(all unused inputs pulled hi)

Ohm out gnd to-
pin 8(Vss)
bottom of volume pot.
shouldB Zero/ohm.

measure gain stages--
pin 3 to pin 2
shouldB 1M
pin 14 to pin 15
shouldB from 100K min, to 1point1M
this is the "drive pot"

look 4 solder bridges.
don't truse your (younger) eyse.
use a magnifying lens!!
about all i can help from this far away.
make sure your ohmmeter "zeros" when U touch the leads 2gether.
make *sure* your batt is good.
that is, *make sure* it reads *above* 9V.
staytroubleshooting
(but not 4 long)
Tone

[mrsage]

Thats exactly what I was saying my problem was. ANY pot value cut out at just before max. from 5k to 1m

Yeah...

I was hoping that moving the 1k resistor and/or building it directly from the schematic would fix some small problem with the original layout.

No such luck!

I'm giving this a rest for a while...I've got a few other builds to do anyway. Maybe someone will pop in with an epiphany at some point between now and when I pick it back up...Otherwise I'm eventually gonna double check for errors that would have been consistent between the two builds...

[WGTP]

Frank Clarks minimum version Hot Tubes rocks and is a great place to start for more mods.  

[Alpha579]

i cant find frank clarkes site, anyone got a link?

[toneman]

it's dead Jim.

[puretube]

link vanished...

[Alpha579]

thanx puretube!
EDIT: Does anyone have a schem of the 'basic hot harmonics', because its not on the site...