Planing on putting together a booster that can handle loud input signals and boosts fairly clean.
From the start I set out to build the super classic Micro Amp but in lack of 10M & 22M resistors and the 1N4001 rectifier I am forced to look for alternatives. I only got a bunch of 1M ones and a SB340 that has a bit lower DC blocking (40 Vdc).

Thing is.. I can only use what I got in stock right now! YAY!  
Got a few op amps to choose from: TL061CN, TL061CP, MC1458P, MC1458CP and RC4558

edit:spelling

+ a 5218A

Had a feeling that the response to this topic wouldn't be overwhelming. hahaha

Also got a bunch of medium to high gain NPN transistors and some PNP too (don't remember which ones right now though...) Does anyone have a good PNP booster in mind? I got no 2n2222 though!  

You can build the Micro Amp with 1M resistors instead of the 10M and 22M resistors. There should barely be any difference.
The diode isn't critical either. Just about any diode should work there, including your SB340.

Take a look at the Beginner Project on this forum for a transistor booster. Your medium/high gain NPN transistors will work in that.

the gus smalley npn boost , is the beginner project , i tried several circuits and felt is was the least coloring , there also is a version 2 of the circuit , which i did not realize , when i built my stereo boost .

i tried several different transistors in it , i ended up with 5088 i think ... if you look around you can get an original hand drawn schemo with more trannie options on it , just google image search eventually you will see there are a bunch of actives that work in this circuit well . i would advise ver 2 , from what i have heard it IS better .

http://www.diystompboxes.com/smfforum/index.php?topic=97041.0



there is always the lpb-1 , amz , sho , mosfett , etc ...

AMZ mosfet booster, clean and loud. 

Wow! Thanks for the response guys!

Maybe I'll try the Mirco Amp after all... but then again a NPN booster should be fun, a bit of coloring might not be bad. We'll see! Thanks again!

Quote from: JebemMajke on April 21, 2012, 03:23:27 PM
AMZ mosfet booster, clean and loud.  

Too bad I don't have any mosfets... or do I, hm...?

BS170 is a mosfet. 2N7000 too.

+1 for the mosfet boost , i have one that i boxed up here .

for the other application ( a mini amp with automotive bi-axle speakers ) i found it a bit too bright and bass cutty , so i went with the npn for that one but YMMV !!

i THINK the lpb-1 is darker , if memory serves . i found breadboarding these is to be pretty quick, painless procedure .

I'm a total newbie on mosfets, could a "K2717" work?

http://pdf1.alldatasheet.com/datasheet-pdf/view/30671/TOSHIBA/K2717.html

Not sure, but u should definitely try. Check the pinout.

For maximum headroom for your loud inputs and minimum distortion, an opamp booster running at 15v or more is your ticket (like the Barber Launchpad at 24v). The Microamp is but one variant you can build off of. What chip you use ideally depends where this booster will go in your signal chain, and therefore what impedances it expects to see at both ends. If you want color, just start breadboarding--the choices are pretty broad. BJTs, FETS, mu-amps--everything has its place.

JebemMajke : Pin out says it is most definitely a Mosfet. What are the most important things to look for when choosing a mos?

Hi Ben! 
Having a very thick, bassy and loud fuzz signal I can't afford to make it even muddier and with even less dynamics, so a Opamp booster at the very end of the signal chain or maybe at the effects loop would probably do the trick. Thanks for helping out!

Ok, so I have tried to build two completely different op-amp boosters but with the exact same problem: No sound coming out of the "output" pin of the TL061, brand new ones and I'v tested them both.  The layout and schematic I followed was GGGs Micro Amp.

I substituted the following parts.

1. R1 & R2 10 & 22Mohm >1Mohms
2. R6 2.7K >3.3k
3. C2 47p >150p
4. C5 15Uf >22Uf
5. D1 1N4001 >PR1507
6. 500k Rev Log>500k Lin

Schematic
http://www.generalguitargadgets.com/pdf/ggg_mamp_sc.pdf?phpMyAdmin=78482479fd7e7fc3768044a841b3e85a

Layout
http://www.generalguitargadgets.com/pdf/ggg_mamp_lo.pdf?phpMyAdmin=78482479fd7e7fc3768044a841b3e85a

If you want big signal out, you have to have a big power supply, no matter what circuit you use. If you go opamp (highly recommended, BTW) figure a way to run it on +/-9V or 18V.

Quote from: Woolly Mother Mammoth on April 30, 2012, 02:02:32 PM
Ok, so I have tried to build two completely different op-amp boosters but with the exact same problem: No sound coming out of the "output" pin of the TL061, brand new ones and I'v tested them both.  The layout and schematic I followed was GGGs Micro Amp.

What are the DC pin voltages with no signal into it? (N.B. See "Debugging; what to do when it doesn't work")

Quote from: R.G. on April 30, 2012, 02:14:29 PM
If you want big signal out, you have to have a big power supply, no matter what circuit you use. If you go opamp (highly recommended, BTW) figure a way to run it on +/-9V or 18V.

Quote from: Woolly Mother Mammoth on April 30, 2012, 02:02:32 PM
Ok, so I have tried to build two completely different op-amp boosters but with the exact same problem: No sound coming out of the "output" pin of the TL061, brand new ones and I'v tested them both.  The layout and schematic I followed was GGGs Micro Amp.

What are the DC pin voltages with no signal into it? (N.B. See "Debugging; what to do when it doesn't work")

Yeah, but first I need to get the signal to run all the way through the pedal.   As stated before, the signal is dead/cut off after the opamp (and I have checked the pinout, twice).

What are your DC voltages on the opamp pins (all of them)

Quote from: Gurner on April 30, 2012, 03:57:46 PM
What are your DC voltages on the opamp pins (all of them)

I tried to remove and turn the opamp around before reading your post so no readings, sorry. Now I got signal though! It sounds like fuzz! Could it be lack of voltage running to the opamp? change diode maybe?

Ben, go read and follow "Debugging: what to do when it doesn't work". It will save you a whole lot of time and trouble.

http://www.diystompboxes.com/smfforum/index.php?topic=29816.0