ELECTRA: Modular Powered Circuits - MPC11 Frognose Amp

Onto the Frognose - weird name right?  It's based on the LM386 IC, which is an audio amplifier capable of driving a small 8-ohm speaker.

In the configuration below, it's capable of 20x gain, so it's a pretty decent booster.

If you aren't familiar with the LM386, two of them are used in the Earthquaker Devices Acapulco Gold, and one is used in the D*A*M Sonic Titan with a JFET boost in front.  So if you put the Electra Power Overdrive in front of this, and added an extra cap to the LM386 you would have something resembling the Sonic Titan, or my version of this, the Kool Thing Distortion.  Not bad....  

FROGNOSE MPC11 - SCHEMATIC

Schematic was drawn by Steve - thanks Steve, hope you don't mind me posting it here.   

As you can see, the Frognose is an almost part-for-part copy of the implementation provided by the manufacturer of the LM386.

VIDEO DEMO

This is a nice easy one - think it might have been my first IC-based guitar pedal builds.  

The Earthquaker Devices Acapulco Gold is quite the beast.  So loud...  the 22k resistor going to volume 3 helps pull the level down a bit.  It could even be a bit bigger or not there at all if you want something monstrous.

It just does one thing, and it does it pretty well.  If you like 386-based distortions, well, this is one 386 firing straight into another 386.   It’s a Doom box, which is perhaps why it has been compared to a Sunn amp.  The circuits are not even vaguely similar, but I can see where the comparison comes from.

There’s a reasonable amount of room on the board, but given it’s such a small circuit, it hardly matters.  It still easily fits in a 1590B enclosure.   I’d even be tempted to add another row to get the two 10u caps a tad further apart (I have built this using this layout, and they fit just fine).   I replaced the 1u electros with box poly caps just because I felt like it on my last build.

EARTHQUAKER DEVICES - ACAPULCO GOLD

EQD ACAPULCO GOLD MODS

It's so loud that some people like to add a 1M pot to control input levels.   Input to pin 3, pin 2 to the regular input on the board, and pin 1 to ground.

EQD ACAPULCO VIDEO DEMO

BALMORAL ELECTRIC: Kool Thing Distortion

This is an LM386L based distortion that I've been playing with - I called it Kool Thing as I was testing it on one of my guitars that has an open tuning (DADDAD for the record), and I was getting a distinct Sonic Youth vibe - which is not all that surprising with that tuning. 

It's basically a variation of a Spaceman booster up front, and the LM386L section is based on the data sheet, with some inspiration from the D*A*M Sonic Titan.  I did add a gain control to the 386 and have set this circuit up so it can run from clean to quite a lot of distortion, which is pretty cool.

I also tried the Q3 section of a MKIII style circuit after the amp to give it a bit more flavour - it was interesting but not worth the trouble.

It’s debatable that it actually needs two drive/gain related knobs, but I like the flavours you can get by combining the two.  If I had the drop one, I’d remove the gain control and just set the LM386L to full (cap jumpering pin 1 and 8).

I kept the value of the cap used in the tone control quite low to, as I don’t like tone controls that cut really heavily.  Even with a 2n2 this has plenty of roll-off.

It will sound different / not as good if you use an LM386N, for me, the LM386L is definitely better.

BALMORAL ELECTRIC: KOOL THING LM386L DISTORTION - VERO LAYOUT

 V2:  correction, had the LND upside down on V1

KOOL THING SCHEMATIC

ON THE SCOPE / FFT

CAUTION:  Start with device volume very low; these are 440hz sine waves that vary in level

 

Boost stage

 

Drive sweep, 0 to 100.  Gain 100

 

Gain sweep, 0 to 100.  Drive 100  

 

Drive sweep, 0 to 100.  Gain 50

Tone sweep, Drive & Gain 100

 

Clean Boost

FRANTONE: Lo-Tone Classic Fuzz

I just found an old, nearly finished layout for the Frantone Lo-Tone Classic Fuzz in my files, so I thought now is as good a time as any to finish it.  After the D*A*M Sonic Titan, I thought I would see what else has an LM386, and this popped up.

Kind of unusual with the incredibly low input impedance for a guitar pedal - it’s about 10k.  Fran has designed some pretty exciting stuff, whereas I with approximately zero interesting things...  so I will not be too critical about this.   

FRANTONE LO-TONE CLASSIC FUZZ - VERO LAYOUT

D*A*M: Sonic Titan ST-07

This is as close as I could get to the original layout for the D*A*M Sonic Titan.   It's pretty much a JFET smashing the LM386 with level, but in the nicest possible way.  I've read a 10k level pot can brighten things up a little. Apparently, this was on some of the earlier versions.  

There's also a bit of discussion around how the tone control functions and interacts with the level control, resulting in the third layout below, using the Sonic Samurai mods.  Other issues include DC causing crackle down the line (no cap on the input to the FET) and 386 note decay issues. 

D*A*M SONIC TITAN - VERO LAYOUT

The original used a 2N3819 JFET - I've listed a J201 as it's the same pinout as some other common FETs, and I have a few and like the sound.

Notice any similarities between the layout above and the circuit from the datasheet below? David Main from, or who is D*A*M, mentioned that the Sonic Titan is a couple of circuits jammed together.  One is straight frodatasheet sheet, and the other is a standard JFET boost.

TITAN VIDEO DEMO