need help again

[nikkram17]

what are this..

on the image

[bluesky6]

Diodes.

Probably used for clipping?

[nikkram17]

here are some pics.. really need a help..

[DrGonz78]

They both look like zener diodes for clipping of the inverted signal. Perhaps this is just soft clipping and not hard clipping of the wave form... Here are a couple pics for reference.

[nikkram17]

thanks a lot sir..

[Roly]

Can you please post the circuit/schematic, or link to it?  It would be more informative than the layout.

[nikkram17]

here it is sir

[bluesky6]

These are clipping diodes. The schematic has a note about what they are.

You can google for "diode clipping guitar" which gives you a ton of articles on what they are and options e.g. types of diodes to use.

I have bookmarked articles such as the following:
http://krooshof.home.xs4all.nl/instrumenten/fuzzing.html
http://www.diystompboxes.com/cnews/mods.html

[nikkram17]

so thus this mean,putting this diodes running on the lm781 replaces the mpf102 on the schema from the original noisy and improved its gain? am i right?

[bluesky6]

If you are trying to replace the MPF102 on the Noisy Cricket, use the whole 741 op-amp section of the schematic.

The point of the op-amp in the schematic is to create some grit/distortion/overdrive.

I don't think gain with the LM386 is a problem. If you look at the Smokey Amp design, it didn't even have a pre-amp stage.

For my first DIY guitar amp, I used an overdrive pedal (Joyo Vintage) feeding into a TDA7052A audio amp kit. I didn't bother to use a pre-amp stage since (a) the TDA7052A has enough gain to deal with guitar-level signals and (b) the overdrive pedal took care of the "sounding like a guitar amp" feature...

[nikkram17]

if i follow that,will i be able get the same result as the noisy cricket claimed to be ran at a 4x12 cabinet?


i just want want an amp that has a volume control and a tmb knobs,coz i have a zoom multi effects and can ran into a 4x12 cab,. and specially its non complex and simple as the noisy cricket to built?

[Roly]

This is a great little find!  Well done!   :dbtu:

This is great starting point to get going and easily improve/expand in stages. <3)

Strongly advise you build pre and main amps on different assemblies, PCB, stripboard, bare matrix, tagstrip, birdsnest, whatever; input to the pot, alone, to the main amp (power with main).

Use good quality IC sockets - you will be changing stuff.


The clipping diodes limit the output by turning the op-amp into a a Voltage Follower, its gain reduced from the small signal value - it's an amplitude limiter.

{IN} goes to the non-nverting input of the op-amp and is effectively a very hi-Z input, similar to a FET, and with the TL07x-series it actually is a FET.

Google some basic op-amp theory.


I think it would be at its best into a big cab like that, more cone area the better, but that "Output Volume" pot is very optional.  You can stick it in later if you feel the need, but there still seams to be heaps of control.

I love this circuit as an exploration tool! <3)

{pre/clipper/gain1}-{volume}-{power/gain2}-{spkr}

{pre/clipper/gain1}-{TMB-EQ}-{volume}-{power/gain2}-{spkr}

Should work. :dbtu:

[nikkram17]

@roly
thanks!.. it seems that i found his enclosure was so cool, and explored it accidentally finding out this type of circuit,, :lmao: i noticed i didnt see a FET on it,perhaps i see another chip..


now i'm starting to understand the concept a bit.. is it like this?? input sound--pre-amp(optional) or used pedals as pre-amps---op amps (with optional preamps)-- speaker/ output??


{pre/clipper/gain1}-{volume}-{power/gain2}-{spkr}
{pre/clipper/gain1}-{TMB-EQ}-{volume}-{power/gain2}-{spkr} <--- just this thing in here i didn't understand (the pre/clipper/gain1) and (power/gain2)

whats pre? and gain1? and gain2?  :loco
sorry..  still learning..heheh


@bluesky6
thanks  :tu:

[nikkram17]

@roly

im just wondering if i can do this? would this work??


(see attachment)

[Roly]

http://youtu.be/V5P1Vkzel4k


Some other ways (could mod for op-amps);

Conventional Fender tonestack;


My quasi-parametric;


etc...