freestompboxes.org

What did you do on Boxing Day - I built a pedal from scratch - okay , I had worked out the board layout and PCB earler, with help from More Cowbell and Super Velcro Boy etc., but never got around to building it - curiosity got the better of me and I realised I could fit it in a 15090B case quite easily - 4.5 hours later and here is the result

I did not use the fancy dpdt relay switching - I used the 3pdt blue new sensor switch and wired it for true bypass.
notice the last picture of the baseplate - there is a sheet of clear mylar film attached to the inside to prevent the circuit board from shorting out, and notice the flange filed off on the bottom corner - saves mutilating the 9v battery case.
As usual no sound samples - my guitar playing is shocking , but how does it sound - WELL - i was amazed - the bottom end is round and full and it does not turn to mud when the fuzz is turned up - say what you like about noisy LM386 power op amps but they are the closest I have heard to a good tube amp overdrive - definately not a Tube Squealer clone and worthy of further study by yours truly
A truly Great design from Fran - I have never heard a 9v pedal with this lush a bottom end - seriously folks Well worth the effort building this baby - I used MKT 100v film caps - Fran uses high voltage tube amp caps in her pedals - I do not know if there is any sonic difference, but I am more than happy with my non mojo build.
cheers
bajaman

Nice work Baja !

Another nice job! Liking the Graphics! The peach fuzz is an interesting design - I've never seen two 386's used in that fashion. Nice to see a fresh design

bajaman wrote:- say what you like about noisy LM386 power op amps but they are the closest I have heard to a good tube amp overdrive -

The D*A*M Sonic Titan uses the 386 chip and it also does a pretty good tube amp imitation.

Another sweet build Bajaman. looks graet.

The D*A*M Sonic Titan uses the 386 chip and it also does a pretty good tube amp imitation

any gutshots or schematics???
bajaman

bajaman wrote:

The D*A*M Sonic Titan uses the 386 chip and it also does a pretty good tube amp imitation

any gutshots or schematics???
bajaman

Here ya go (JFET is a 2N3819):-

Trace side Greg?



(Thank you!)

LM386 chip datasheet

Havin a cap across pin 1 and 8 gives increase to gain .....(looking at the gut pic above)
On the Peach Fuzz the TL022 does most of the 'fuzz' and the input resistor takes care of that....similar to the muff fuzz which has a 100k for 1458 chip. So the twin LM in the Peach i assume, just gives it the muscle ..

Important Update
The type of Lm386N is important . The Peach Fuzz uses the LM386N-1, which is designed for 0.25 watt output from a 6 volt supply rail (when used as a power amplifier into an 8 ohm speaker load).
there is alsoo a LM386-3 (9 volt at 0.5 watt output), and a LM386-4 (16 volt device).
After studying the gutshots more closely, i believe the TL022 is NOT the correct op amp to use in the input stage - one of the photos clearly shows TLC (the rest is obscured by wiring unfortunately). I believe this to be a TLC2262 cmos rail to rail op amp - also used by Tech 21 NYC in their Sans Amp designs.
After changing this input op amp in my build, I noticed a much smoother tone with a more pronounced midrange and less fizzy top end - the bottom end deep bass remained unchanged, and I suspect that this is where the "muscle from the LM386N-1" as Senior Loco said makes the difference .
cheers
bajaman

The Flickr link to the schematic doesn't work. Is there an update?

weird - I do not remember placing that flickr link
I will see if i can find the schem
bajaman

Thank you!

HI, baja please post the label. if you don't mind. I really dig the E H vibe.

no chance anyone would have a vero layout for this? if not how would you go about removing the relay system?

I'm interested in the relay switching here; dont have much experience using relays so I'm a little clueless.

Here's my understanding...

The switches located by the in/out in the schemo represent the DPDT contacts of the relay; the other SPDT in the schemo is a footswitch, yes?

When the footswitch is in the NC position, the relay/LED are fed to ground and therefore "ON". The relays contacts switch the effect in accordingly.

When the footswitch is in the NC position, the relay and LED are lifted from ground, therefore the circuit gets true-bypassed and LED is off. A bias voltage switches the NPN on, grounding the circuit output.

Am I making any sense?

RyUK

whipped up a vero layout
3 ICs = millions of trace cuts but i think this makes sense

Wow, that´s a nice and small layout. Is it verified?
btw: Bajaman mentioned, that he replaced the tl022 with a tlc2262...

yeah i tried to get it small enough to be 1590B-worthy, it's not verified sorry way too many exams, diylc seems to be the perfect procrastination tool however

headless wrote:the perfect procrastination tool however

A cool name for a delay pedal...