Increasing 386 output - Page 3 - Electronic Circuits Projects Diagrams Free

audioguru · 19th January 2006, 10:45 PM

The LEDs won't do anything with the diodes in parallel with them. Therefore the 1st transistor doesn't do anything.

joecool85 · 19th January 2006, 11:00 PM

First off, why don't they do anything?

Second off, someone that built my pedal (I posted the schematic on diystompboxes.com) had said the same thing, but then tried it and noticed a difference when using both trannys.

here is the link:
http://www.elixant.com/~stompbox/smf...?topic=40831.0

audioguru · 19th January 2006, 11:41 PM

The LEDs won't do anything with diodes in parallel with them.
The sim looks like an ordinary "soft clipper":

joecool85 · 19th January 2006, 11:50 PM

Well, first of all, you changed the schematic.

It uses MPSA13s, which are darlington trannys, unlike 2n3904s.

Also, Q1 doesn't feed into Q2 like you show, both bases are connected to input line only. They are running in parallel.

audioguru · 20th January 2006, 12:36 AM

Quote:

Originally Posted by joecool85

Well, first of all, you changed the schematic.

It uses MPSA13s, which are darlington trannys, unlike 2n3904s.

My simulation software doesn't have a small darlington, so I made one with two 2N3904 transistors. Same thing.

Quote:

Also, Q1 doesn't feed into Q2 like you show, both bases are connected to input line only. They are running in parallel.

Transistors in parallel work only with the strongest one and the weakest one does nothing. Therefore I used only a single darlington.

An LED needs 1.8V or more to function. The ordinary diodes in parallel with them limits the voltage to 600mV so the LEDs do nothing.

Your circuit has a symmetrical clipped waveform, therefore doesn't produce even harmonics. The Hendricks circuit I posted has an unsymmetrical waveform, therefore produces all harmonics.

joecool85 · 20th January 2006, 12:54 AM

nm, I would have known that if I thought about it lol. I still don't know why, but for some reason it effects the guitar's sound using one on tranny or both...

audioguru · 20th January 2006, 12:59 AM

The small capacitance of the 2nd darlington might cut the high frequencies a little. So would a small capacitor.
The LEDs didn't light, right?

joecool85 · 20th January 2006, 02:18 AM

Correct, no light from the LEDs. And you may be right. I'll have to play with it some more when I get the chance.

**edit**
What do you think would happen using one 1n914 and one LED for diodes on a single MPSA13 circuit?

audioguru · 20th January 2006, 10:20 AM

Quote:

Originally Posted by joecool85

What do you think would happen using one 1n914 and one LED for diodes on a single MPSA13 circuit?

Sorry, I didn't save my simulation so I can't try it with different diodes. It would probably make both even and odd harmonics, and the LED will light continuously if it is one of them and only when you play if it is the other one.

joecool85 · 20th January 2006, 11:10 AM

you mean according to which direction the LED is facing?

audioguru · 20th January 2006, 01:17 PM

Quote:

Originally Posted by joecool85

you mean according to which direction the LED is facing?

Both diodes must have opposing polarities so swap them to change whether the LED lights continuously or not.

Roff · 20th January 2006, 02:50 PM

The LEDs probably won't emit enough light to see, since you are only driving microamps into them.

joecool85 · 20th January 2006, 03:19 PM

With the bazzfuss circuit the LED emits enough light (when playing it goes along with how hard you are playing).

http://home-wrecker.com/bazz.html

Roff · 20th January 2006, 03:52 PM

Audioguru (and anyone else), I made a symbol for an NPN Darlington for SwitcherCAD. Copy the code below into a file called npndarlington.asy and save it in C:\Program Files\LTC\SwCADIII\lib\sym\Misc.

Code:

Version 4
SymbolType BLOCK
LINE Normal -16 0 0 0
LINE Normal 0 32 0 -32
LINE Normal 64 -48 0 -16
LINE Normal 64 48 0 16
LINE Normal 48 32 64 48
LINE Normal 42 44 48 32
LINE Normal 64 48 42 44
LINE Normal 64 48 80 48
LINE Normal 80 80 80 16
LINE Normal 144 0 80 32
LINE Normal 144 96 80 64
LINE Normal 128 80 144 96
LINE Normal 122 92 128 80
LINE Normal 144 96 122 92
LINE Normal 144 -48 64 -48
LINE Normal 144 0 144 -48
SYMATTR Prefix X
SYMATTR Description NPN Darlington
PIN 144 -48 NONE 8
PINATTR PinName C
PINATTR SpiceOrder 1
PIN -16 0 NONE 8
PINATTR PinName B
PINATTR SpiceOrder 2
PIN 144 96 NONE 8
PINATTR PinName E
PINATTR SpiceOrder 3

Copy the code below into a file called mpsa13.sub and save it in C:\Program Files\LTC\SwCADIII\lib\sub.

Code:

*Si 625mW 30V 500mA pkg:TO-92B 1,2,3 
.SUBCKT MPSA13 1 2 3 
Q1 1 2 4 QMOD .1 
Q2 1 4 3 QMOD 
.MODEL QMOD NPN (IS=360F NF=1 BF=337 VAF=98.6 IKF=.5 ISE=637F NE=2 
+ BR=4 NR=1 VAR=40 IKR=.75 RE=3.5 RB=14 RC=1.4 XTB=1.5 
+ CJE=133P VJE=.74 MJE=.45 CJC=14.1P VJC=1.1 MJC=.24 TF=1.27323N TR=17.4N) 
.ENDS MPSA13

Click on the .op icon on the toolbar and enter ".lib mpsa13.sub". Place this on the schematic.
Place the NPN darlington symbol on the schematic, right-click on it, and enter "mpsa13" in the SpiceModel line. You might want to make this visible.

audioguru · 20th January 2006, 04:12 PM

Quote:

Originally Posted by joecool85

With the bazzfuss circuit the LED emits enough light (when playing it goes along with how hard you are playing).

http://home-wrecker.com/bazz.html

Hi Joe,
I would not want to play my very low distortion stereo through one of those circuits. :cry:
The fuzz term, "octave-doubler" describes even harmonics since the 2nd harmonic is one octave above the original, then the 4th harmonic is another octave above.

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19th January 2006, 10:45 PM	(permalink)
audioguru	The LEDs won't do anything with the diodes in parallel with them. Therefore the 1st transistor doesn't do anything. __________________ Uncle $crooge

19th January 2006, 11:00 PM	(permalink)
joecool85	First off, why don't they do anything? Second off, someone that built my pedal (I posted the schematic on diystompboxes.com) had said the same thing, but then tried it and noticed a difference when using both trannys. here is the link: http://www.elixant.com/~stompbox/smf...?topic=40831.0 __________________ Life is what you make it.

19th January 2006, 11:50 PM	(permalink)
joecool85	Well, first of all, you changed the schematic. It uses MPSA13s, which are darlington trannys, unlike 2n3904s. Also, Q1 doesn't feed into Q2 like you show, both bases are connected to input line only. They are running in parallel. __________________ Life is what you make it.

20th January 2006, 12:54 AM	(permalink)
joecool85	nm, I would have known that if I thought about it lol. I still don't know why, but for some reason it effects the guitar's sound using one on tranny or both... __________________ Life is what you make it.

20th January 2006, 12:59 AM	(permalink)
audioguru	The small capacitance of the 2nd darlington might cut the high frequencies a little. So would a small capacitor. The LEDs didn't light, right? __________________ Uncle $crooge

20th January 2006, 02:18 AM	(permalink)
joecool85	Correct, no light from the LEDs. And you may be right. I'll have to play with it some more when I get the chance. edit What do you think would happen using one 1n914 and one LED for diodes on a single MPSA13 circuit? __________________ Life is what you make it.

20th January 2006, 11:10 AM	(permalink)
joecool85	you mean according to which direction the LED is facing? __________________ Life is what you make it.

20th January 2006, 02:50 PM	(permalink)
Roff	The LEDs probably won't emit enough light to see, since you are only driving microamps into them. __________________ Ron

20th January 2006, 03:19 PM	(permalink)
joecool85	With the bazzfuss circuit the LED emits enough light (when playing it goes along with how hard you are playing). http://home-wrecker.com/bazz.html __________________ Life is what you make it.