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lovetone big cheese how does it work ?

Started by Yahoo67, March 12, 2020, 02:07:32 AM

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Yahoo67

I made a couple of OSHpark feta complis board and was thinking of doing my own board with some mods.
https://oshpark.com/shared_projects/vh6bA8u6

I did try to swap q2 with a 2n1308 germanium transistor. It really mellowed the volume and distortion, it made it more bassy too. Looking at the schematic I don't understand , is it a op amp fuzz ? To me it looks more like a type of hybrid. Also what are q1 and q3 for ? My guess is q3 is for the tone control. I only got q2 socketed at this time but would love some ideas you guys might have for mods. I can read a schematic ok, but circuit design I am pretty much at novice level! I am trying to do these types of projects to hopefully learn a bit and do something cool :) I love this fuzz so much and would love any feedback or ideas on what I could do to mod it or any info how it works !

So far I wanna have a switch to change q2, thinking of putting the gate control as a knob. I would also love to had switches to change some components value that might help change the character of the fuzz. Maybe adding the octave part of the retrograde would be cool... As I am writing this I realize that I should really buy and learn how to breadboard xD well anyway hope someone can help me with this! Thanks in advance !!!

BuGG

It's a transistor fuzz similar to a Tone Bender or Fuzz Face with an opamp-based input buffer and tone recovery / output stage.

Q3 is used as a clipping diode, it's the counterpart to D1.

The tone control is similar to a 'Muff.

Yahoo67

#2
Ahhh oki cool thanks BuGG! So the op amp is just a input buffer and recovery stage. Ok then I will try socketing q1 too and not q3 since it's a clipping transistor. I also did try to have the cheese option grounded via foot switch... It did work but it cut like 15% of the volume :/ don't know what I was expecting xD it does the same when using the selector switch... But I can now use the gate setting with the no tone or regular tone selection... Not the most useful mod but I am having fun tinkering on the circuit :) maybe I could make a small boost circuit for the gate mode... Anyway thanks for the info again ! I am gonna try and do a board for a stand alone life pedal green ringner and stick it in the pedal ^^ you should maybe think about making a board for it BuGG ^^ it's a lot more useful than the classic tentacle/green ringner !

Yahoo67

#3
i have made a schematic! but i wanna run pass here just to be sure that it would work before i oshpark it.
would the switch for changing Q2 work ? or do i have to use a dpdt one ?
Also if it does work can i use a dpdt switch and use the other side of the switch to change Q1 if i wire it the same way ?
my guess is no but you never know until you ask !!

Thanks !


m-Kresol

hi there,

I am not sure about your Q2 switching, but I guess it should work.

Some other things I would improve or check:

  • I would change the D2 in the power section for a 1N5187 as it has a much lower voltage drop
  • Change the electrolytics in the power section to 1x 47 µF. The way you have the two caps in parallel, just adds there capacities, so 22u + 22u =44 µF. No need to have 2, if you can just use one cap instead.
  • I don't have the original schematic on hand, but make sure Q2 and Q1 are wired correctly. The nets crossing at the base of Q1 are not connected. This is likely correct (the base controlled by the guitar signal), but I find this hard to read and I usually draw small ars in the schematic. This is tedious in Eagle, but worth for ease of reading imho.
  • have a look at fuzz face and tonebender schematics with Si and Ge versions. I think just replacing the transistor might not be enough. It's likely you should also switch some other parts, so that both sound good. just guessing again, though
I build pedals to hide my lousy playing.

My projects are labeled Quantum Effects. My shared OSH park projects: https://oshpark.com/profiles/m-Kresol
My build docs and tutorials

Yahoo67

Hi m-kresol !!
Thanks for the pointers! i will try the improvements on the power section.
Funny you should be the one answering me :p i just finished one of your hydrogen fuzz oshpark project last night !!!
As for this schem i used the feta complis one on oshpark just because its the one i used for my big cheese clone and i like it a lot !

As for the transistor switching, a lot of other projects i have looked at usually use a dpdt for one transistor, they keep the signal part running into the base of both transistor but have the collector and emitter switch on the selected transistor. Since the signal is going into the base i just tough why not keep C and E connected and just change the signal path to the transistor i wanna use. The thing is i don't know what effect having the C and E connected all the time :/.