Demeter - Fat Control - Guts, Schematic  [traced]

General documentation, gut shot, schematic links, ongoing circuit tracing, deep thoughts ... all about boutique stompboxes.
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IvIark
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Post by IvIark »

checco1280 wrote:what is the sense that pin4 of IC has reference to Vee through R1 and also to ground?
Thanks for this. The 100K from Vee to ground completes the bias divider
"If anyone is a 'genius' for putting jacks in such a pedal in the only spot where they could physically fit, then I assume I too am a genius for correctly inserting my legs into my pants this morning." - candletears7 - TGP

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Greg
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Post by Greg »

checco1280 wrote:This is the scheme with the values....

what is the sense that pin4 of IC has reference to Vee through R1 and also to ground?
I think pin 4 connects to the other side of the (100K) resistor as a voltage divider ?
Connected as shown, pin 4 is grounded.
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checco1280
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Post by checco1280 »

.... :slap:

can you fix it?
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Tonebender
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Post by Tonebender »

Always been curious about this one! Thanks!

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gilmour_pugliese
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Post by gilmour_pugliese »

Hi! it's possible to substitute the LF442 with a OPA2132 or OPA2107 but having the same sound?

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Sari
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Post by Sari »

gilmour_pugliese wrote:Hi! it's possible to substitute the LF442 with a OPA2132 or OPA2107 but having the same sound?
Will probably get a "better" sound in terms of "audio quality" - whether you'd like it or not, is up to your ears to decide :)

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Post by gilmour_pugliese »

thanks sari... it's the same story on every IC-based-stompbox :lol:

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Post by gilmour_pugliese »

hi guys...
someone has built this pedal? :mrgreen:

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vot
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Post by vot »

Hello!
Two variants of perfoboards (notverified).
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ryanuk
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Post by ryanuk »

Thanks for the effort to RE this one guys. I may give it a whirl!

I was always a fan of the Fender EC boost, and I can see vague similarities in the schems i.e. both have a buffer/midboost circuits and you can mix between the two.

From reading the thread and reviews, I think the Fender buffer is more of a treble boost, whereas the demeter buffers is supposed to be more nuetral.

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phazerz
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Post by phazerz »

Thanks for this project guy, but I must admit that I don't have any clue on how to wire the switch with the wire that come from lug 2 and lug 1 ? Analoguru says lug 1 (green wire) is for bypassing so should I assume that lug 2 is the mid boost on ?
2. The peak frequency is around 200Hz, which seems a bit low for a mid boost... any thoughts?
Any ideas to raise it around 700Hz or more ?

Thanks for your help !
Best'
--phazerz

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Post by alexradium »

the switch selects the buffer wire (green/violet) or the boost wire (grey) and goes to the output,a simple deviator,no TB here.
this pedal is never bypassed because there's a 3 db signal bump because of the buffer,so you leave this always on and then switch a preset midboost .

mid frequency: i wouldn't go over 400 Hz,thats the best one when you want a solo sound that stands out,anyway if you look at the frequency diagram,on full you have a boost from 200 to 1Khz (14 Db) then it decreases

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Post by alexradium »

I personally have the original onboard version of this midboost,which is exactly the same as this pedal version!
notice that if you buy it from Demeter the pedal costs 219 $,now 189, and the onboard 79, i mean 110 $ in a box,switch and jacks?

anyway,what about the resistor on the output jack,is that essential for the pedal? i'm thinking about putting my onboard gut in a box....

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Post by phazerz »

Thank you very much alexradium !
Where did you find the frequency diagram ? Never mind I trust you and I will first try it like it is !
Hard to find a LF442 in my country though.... any substitute possible ?

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Post by alexradium »

If you're in Europe buy at Banzai effects they have everything
diagram was included with the boost
I also believe the frequency should be higher because at maximum value is too muddy
There is another version with Tyler guitar specs,same circuit with some different
capacitors,but someone said its even lower eqd

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Post by mxrmxr »

Does anyone have the Tyler guitar specs of this circuit ? That would be very useful.

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Post by alexradium »

Tyler is more bassy sounding than this,and its alot...even at minimum value has a mid bump.
i wouldn't change it since i know the Demeter's sound very well.

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Post by lhy0312 »

not in the schemetic, there is a 220K resistor on 'output' jack tip ~ gnd.(for both MB out / buffer out) My bass playing fella said this resistor exists on bass preamp too. Probably.. for output impedence match..? :?

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Post by lhy0312 »

what is the diode? I think it is not looks like 1N4148 or 914, or 1n400x. is that zenner or something..?

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Post by lhy0312 »

I planned to install this circuit on my guitar, but the 'footswitch' was some pain in my ass. I need extra truebypass switch for effect chain problem - such as

FUZZ situation. When the buffer comes in front of fuzz, the sound might be awful since the impedence matching problem. This can be solved by adding a

true bypass switch. The pedal version don't need TB swith though. ('cause it's movable)

So.. I need 2 switch on my scratch plate? no-no It'll look like........ ugly.


But I figured out what the switch is for.

When it comes to onboard, the 'switch' can be omitted. (I'v not seen the onboard version in real, but I assume there's no switch)

This switch just works like 'pot kill'.


In this pedal, boost pot works like a kind of 'mixer' between neutrally buffered signal and full- midboosted signal.

To be specific, the line to the lug 1 of boost pot is buffered signal / and the line to lug 3 is full-boosted signal. (So lug 2 is mixed signal)

Therefore, switching lug 1 with lug 2 is exactly same situation when the pot is turned down to zero.

So, the footswitch is just for.. turning the knob down to zero instantly.... WITH FOOT.

If this citcuit installed on guitar, simply rolling the knob off works like 'footswitched-off' pedal.

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