Anderton's Preamp (EPfM)

[meigwil]

I am currently breadboarding this project from the book.

Unfortunately there are a few creases that I am trying to iron out. First up is part J3. There is no mention of this in the text, but it is in the schematic, and the parts list does not give me any more details, other than it is ‘optional’. Also, on the picture in the book, there are two switches, the dirty/clean, and another (can’t remember the label).

Can anyone help with this? If J3 is optional, then how do I build the preamp without it?

Plus, just a breadboard question. I used breadboard about 9 years ago, and I am working under some assumptions.

My breadboard:

ooooo    ooooo
ooooo    ooooo


-123456789etc
aooooooooo
booooooooo
cooooooooo
dooooooooo

Now I’m sure that the columns are connected, and the rows are not. Right?

Also the groups of two rows of 5 holes at the edge of the board, how are they connected? I think I remember them being for the supply(?)

Thanks for any help/assistance.

Hwyl,

Mei

[Mark Hammer]

First, off, there is really no reason to build the EPFM one over any of the other clean boosters.  At the time EPFM came out, there were maybe two comparable commercial products with reasonable visibility in stores (MXR MicroAmp, DOD BiFet Preamp), and few published projects attempting to do the same thing.  These days, you can accomplish the same thing in a million ways, and probably better and cheaper too.

The EPFM-II preamp came with an option for sticking a pair of LEDs in the op-amp feedback loop for some modest clipping capabilities (though not a "fuzz" by any stretch), and an option for having balanced output for going over long lines to a mixer, and an option for running a meter in parallel.  If your goal is to just goose the signal to feed another pedal, then most of the options included in the design are unnecessary.  My vote would be to make yourself a MOSFet or JFET booster.  Smaller, cheaper, simpler, and probably cleaner.

I'm not dissing Anderton, but the published design is a solution to a set of problems you may not have.

[ErikMiller]

Columns are connected, rows are not. The columns break in the middle of the board.

The rows of holes at the top and bottom are connected as power busses, not to the columns.