THUNDERCHIEF build question

Barcode80 · November 16, 2006, 07:27:05 PM

still wondering, any ideas about q4's bias?

Meanderthal · November 16, 2006, 08:39:13 PM

Maybe you could try a 200k trimpot. That's what I used for my Thunderchief build, but only because it's what I had laying around. The 201s squirmed and tried hard to avoid biasing, but eventually they got with the program. be aware that using a higher value trimpot will be very sensitive unless you use a multi-turn. I didn't, and they were VERY jumpy and squirrely- I had to turn them VERY gently to find the microscopic sweet spot!

KerryF · November 16, 2006, 08:49:15 PM

Im pretty sure its not a layout problem because I checked the whole thing and we found all the mistakes.

Maybe like Meanderthal said, try a larger value pot. I would tell you if I have the same problem, but I need a few caps to finish it.

Barcode80 · November 16, 2006, 09:53:45 PM

dang, 100k is the most i've got. this is FRUSTRATING.

KerryF · November 16, 2006, 10:11:04 PM

Barcode, and others... http://www.diystompboxes.com/smfforum/index.php?topic=51570.msg387327#new .

I need some values to finish this up. I can buy them from you and you can send via envelope in the mail. Thanks.

Meanderthal · November 16, 2006, 11:01:40 PM

You could easily get more resistance by ... using a resistor in series with the trimpot. Or use 2 trimpots in series.

Barcode80 · November 16, 2006, 11:18:56 PM

well, i just went ahead and plugged in the thunderchief, unbiased q4 and all, and i STILL LOVE THE SOUND. i could use a little more low end, but otherwise, it still sounds great. so i'm going to call the build a success and box it up. i will probably try again at some point with a different layout.

1800, i'm out of most of those parts because i ordered them just for the thunderchief. order them from small bear, he'll get em to you faster than i would.

Meanderthal · November 16, 2006, 11:47:29 PM

Yeah, it's lacking in bottom end by design- it's emulating the early Eddie VH sound. Listen carefully to early VH and you'll see what I mean. That can easily be fixed, but then you don't come as close to truly capturing that tone. But if you don't care about nailing someone else's sound, then by all means, mod away!

Barcode80 · November 17, 2006, 12:42:04 AM

yeah, i don't really like evh's guitar tone (*duck to avoid chair thrown by a shredder*). it sounds great with some production, but i am looking for gig pedals, and i just don't like the bottom end to suffer. so i guess a larger output cap? or input cap? what do you think?

Meanderthal · November 17, 2006, 06:56:09 AM

Yep, see that 15n cap at the end of the circuit? That's the one... raise the value. .1 uf ought to do it.

powerplayj · November 17, 2006, 08:09:32 AM

Personally, I think it has been eq'd perfectly, at least for my rig. The bright switch mod is also kind of cool and seems to give it more of a JCM quality. It cleans up real nice with the guitar volume knob as well. Here is a simple clip in which I have the gain at 12:00 and simply increased the guitar volume from 3 to 10 and then used an OD for the last chord passage.

http://www.soundclick.com/bands/pagemusic.cfm?bandID=619453

Barcode80 · November 17, 2006, 09:39:30 AM

yeah, i'me just not a huge treble person. i do think you need more treble for clarity's sake, but i need a little meat in my tone. i'll try that .1uF when i get home today.

awilson40 · November 17, 2006, 11:28:30 AM

I'm thinking about doing the same thing to mine, post back as to how you like it.
Thanks

Barcode80 · November 17, 2006, 10:36:56 PM

the .1uF COMPLETELY changes this pedal. i love it! it kind of changes it (sound-wise) into an OD/dist hybrid. it sounds great, i highly recommend the mod. I've got it boxed in a recycled box, so when i get a new one with a nice paint job and such, i'll post pics.

KerryF · November 17, 2006, 10:38:26 PM

is it worth a switch to change between the two? and, where did you put the .1uF?

Meanderthal · November 18, 2006, 06:13:53 AM

Quotewhere did you put the .1uF?

Quotesee that 15n cap at the end of the circuit? That's the one...

KerryF · November 18, 2006, 07:45:52 AM

k, cool I will try it.

awilson40 · November 18, 2006, 09:37:43 AM

last night I looked at mine which another guy built. It had a 10nf cap.
No wonder it was so bright.
I tried a .047uf first as I thought the .1 would be too big a diff.
The .047 sounds great, like you said, it really changes the charactor.

Barcode80 · November 18, 2006, 10:39:21 AM

i don't know about witching, though that would be kinda cool, but i would at least socket it.

Barcode80 · November 18, 2006, 11:54:22 PM

okay i've tested the pedal on a variety of amps, and i've realized that although the sound is good, without that 4th tranny working properly there just isn't enough distortion. so i'm just going to rebuild with a diff layout.

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THUNDERCHIEF build question