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Re: Catalinbread Manx Loaghtan [guts]

PostPosted: 04 May 2011, 21:25
by mmolteratx
batteryacidtea wrote:Thank you! I'll post the files ASAP then!


No problem. Thanks for redoing them in Eagle. I really should download it...

Re: Catalinbread Manx Loaghtan [guts]

PostPosted: 04 May 2011, 21:30
by batteryacidtea
There you go http://www.4shared.com/file/kButZwdK/Manx_Loaghtan.html

I didn't put any values at the schematics yet, since there's some unknown values, but feel free to modify it!
:horsey:

Re: Catalinbread Manx Loaghtan [guts]

PostPosted: 04 May 2011, 21:34
by Nocentelli
OK, I'm doing a vero layout atm, and I'm puzzled by a couple of things: Firstly, there appears to be no pull-down resistor on the input - How come it doesn't pop? Is this because the 47K resistor is before, not after the input cap? Secondly, the sustain pot has no resistor to ground off lug 1 as per normal muff. I assume the 10n cap across lugs 2+3 is there to preserve treble at minimum sustain, but does it also serve to ensure the signal is not cut off entirely when the wiper is shorted to ground?

Re: Catalinbread Manx Loaghtan [guts]

PostPosted: 04 May 2011, 21:36
by batteryacidtea
I don't use any pulldown resistor in my big muff builds, and never had any kind of pop in there!

Re: Catalinbread Manx Loaghtan [guts]

PostPosted: 04 May 2011, 21:41
by Nocentelli
OK, cool. I've always just stuck one in as a matter of course in all my builds.

Re: Catalinbread Manx Loaghtan [guts]

PostPosted: 04 May 2011, 21:53
by batteryacidtea
I'm a little lazy about this, and try all my pedals without it. If it pops, what da hell, i just pup it there, cursing for the extra job. I think I just had pop issues with fuzz faces, rebotes and CE-2.

Re: Catalinbread Manx Loaghtan [guts]

PostPosted: 04 May 2011, 22:20
by mmolteratx
Nocentelli wrote:OK, I'm doing a vero layout atm, and I'm puzzled by a couple of things: Firstly, there appears to be no pull-down resistor on the input - How come it doesn't pop? Is this because the 47K resistor is before, not after the input cap? Secondly, the sustain pot has no resistor to ground off lug 1 as per normal muff. I assume the 10n cap across lugs 2+3 is there to preserve treble at minimum sustain, but does it also serve to ensure the signal is not cut off entirely when the wiper is shorted to ground?


I haven't needed one with any Muffs I've built. The input is grounded when bypassed anyways. And yes, the cap keeps the signal from being cut off completely when the wiper is shorted. I did find it odd that there wasn't a resistor to ground but lug 1 of the sustain pot goes directly to ground.

Re: Catalinbread Manx Loaghtan [guts]

PostPosted: 05 May 2011, 01:24
by Greg
Nocentelli wrote: Secondly, the sustain pot has no resistor to ground off lug 1 as per normal muff. I assume the 10n cap across lugs 2+3 is there to preserve treble at minimum sustain, but does it also serve to ensure the signal is not cut off entirely when the wiper is shorted to ground?


Yes, the cap is there for Treble bypass as the pot is turned down and I can't see how it can maintain a signal.
When the pot is turned all the way down it's grounded (as is the input to the rest of the circuit), and the fact it goes through a cap first is irrelevant.

Re: Catalinbread Manx Loaghtan [guts]

PostPosted: 06 May 2011, 00:09
by Nocentelli
Greg_G wrote:When the pot is turned all the way down it's grounded (as is the input to the rest of the circuit), and the fact it goes through a cap first is irrelevant.


mmolteratx wrote:And yes, the cap keeps the signal from being cut off completely when the wiper is shorted. I did find it odd that there wasn't a resistor to ground but lug 1 of the sustain pot goes directly to ground.


:hmmm:

Here's a quick vero (as-per-schematic as far as I can tell):
CBread_ML_v1.gif

Re: Catalinbread Manx Loaghtan [guts]

PostPosted: 06 May 2011, 01:47
by mmolteratx
:lol:

That was my understanding. Though I've only had a year of electronics and a couple of years of physics. I start EE courses heavily next year. I'd defer to Greg.

Re: Catalinbread Manx Loaghtan [guts]

PostPosted: 06 May 2011, 02:11
by Greg
mmolteratx wrote::lol:

That was my understanding. Though I've only had a year of electronics and a couple of years of physics. I start EE courses heavily next year. I'd defer to Greg.

I'm always happy to be corrected.. but as I see it, with P1 turned down the junction of C5 and C20 is grounded.
If you take the pot out of the picture, you have 2 capacitors in series with a ground connection in the middle.

Re: Catalinbread Manx Loaghtan [guts]

PostPosted: 06 May 2011, 02:18
by mmolteratx
Greg_G wrote:
mmolteratx wrote::lol:

That was my understanding. Though I've only had a year of electronics and a couple of years of physics. I start EE courses heavily next year. I'd defer to Greg.

I'm always happy to be corrected.. but as I see it, with P1 turned down the junction of C5 and C20 is grounded.
If you take the pot out of the picture, you have 2 capacitors in series with a ground connection in the middle.


Yea, you're right. I missed a 100R resistor to ground from lug 1 of the sustain pot and assumed that was how it was still working. I'll edit the schem and re upload.

Re: Catalinbread Manx Loaghtan [guts]

PostPosted: 06 May 2011, 02:21
by mmolteratx
Fixed. Sorry guys.

Re: Catalinbread Manx Loaghtan [guts]

PostPosted: 06 May 2011, 02:22
by Greg
mmolteratx wrote:Yea, you're right. I missed a 100R resistor to ground from lug 1 of the sustain pot and assumed that was how it was still working. I'll edit the schem and re upload.

Thanks mmolteratx
:thumbsup

Re: Catalinbread Manx Loaghtan [guts]

PostPosted: 06 May 2011, 04:21
by mmolteratx
No problem. FSB has given me a lot since I've joined and I figured it's time to start giving back now that I've got some cool stuff. You can call me Matt BTW.

Re: Catalinbread Manx Loaghtan [guts]

PostPosted: 06 May 2011, 06:09
by Nocentelli
mmolteratx wrote:FSB has given me a lot since I've joined...


+100

Layout fixed:
CBread_ML_v1.gif

Re: Catalinbread Manx Loaghtan [guts]

PostPosted: 06 May 2011, 06:21
by HEAD
mmolteratx wrote:Fixed. Sorry guys.


One minor fix: In your schematic you used a MOSFET symbol for the 2N5457 JFET - if it is a JFET in the real pedal. Didn't read the whole thread so I don't know.

Re: Catalinbread Manx Loaghtan [guts]

PostPosted: 06 May 2011, 06:50
by mmolteratx
Oops. Noted and fixed in my schem. Dunno how that one happened. :lol:

Re: Catalinbread Manx Loaghtan [guts]

PostPosted: 06 May 2011, 07:13
by batteryacidtea
I'll fix the eagle schematics and try to do a nice layout.

Re: Catalinbread Manx Loaghtan [guts]

PostPosted: 07 May 2011, 10:20
by burstcracksplit
Hi,

I have build it and it sounds (surprise surprise) like a muff with a huge amount of treble. But I think that the value of R21 (100R) is wrong. There's almost no sound if you turn down the sustain pot. On the guts picture R21 looks like 2K (red-black-red-gold). I changed this resistor and now it sounds pretty similar to "low gain" video on youtube.