craig anderton's old EPFM bass fuzz, converting to single 9v batt.

[rhinson]

hey guys, just a question about all the old anderton stuff. in this book most of the stuff runs on a bipolar supply and i was wondering how to run the bass fuzz on the standard 9v batt. supply. i tried just biasing the non-inverting inputs with 1/2 supply (4.5v) with a voltage divider of 10k resistors and then another 10k to each inverting input--just like the tubescreamer for instance (i'm using a 4558 here---so you can ignore the pinout numbers in the schematic---his projects used an old dual opamp with 14pins no longer available, so i used the converted layout from GGG and just moved things a bit with regard to parts for the biasing).

my problem is i get very little volume out of this thing at all like this. i connected lug 1 of the int. pot to the 4.5v bias instead of ground and it got just slightly better, but still nowhere near usable. anybody know the correct way to do this and get the volume and gain the circuit should have in its orginal form? should i use different values in the voltage divider? thanks very much.

[alparent]

I do this http://www.geofex.com/circuits/+9_to_-9.htm

But I don't use the MAX1044. I use the TC1044 from Mouser (cheaper and good up to 12v)

[rhinson]

I do this http://www.geofex.com/circuits/+9_to_-9.htm

But I don't use the MAX1044. I use the TC1044 from Mouser (cheaper and good up to 12v)

yeah i know about using those.   i was wanting to convert it to a single 9v batt. only (non bi-polar supply)---no extra chips, daughter boards, etc.       thanks.     rh

[alparent]

If you find out how........ post it. I would also like to know.

[jimbeaux]

Try adapting a similar 2 stage distortion pedal that is powered by a single 9 volt supply.

The Rosey-Ray may work - first stage > reverse the inputs / 2nd stage looks similar. Might work.

http://hammer.ampage.org/?cmd=lt&xid=&fid=&ex=&pg=3

(about half way down the page)

[rhinson]

Try adapting a similar 2 stage distortion pedal that is powered by a single 9 volt supply.

The Rosey-Ray may work - first stage > reverse the inputs / 2nd stage looks similar. Might work.

http://hammer.ampage.org/?cmd=lt&xid=&fid=&ex=&pg=3

(about half way down the page)

yeah i had thought about doing something like that,  and in the long run may have to.  but i really wanted to make it work without a redesign,  OR alternatively understand WHY it doesn't work with just biasing those other inputs, since that seems like all the bipolar supply does.  perhaps it's an impedance issue or something that i don't know about.  i wish some of the ee's on here would chime in---they would quickly resolve it i'm sure!       r.g.?    rh

[SonicVI]

Anderton suggests how to do it in the Q&A section in near the back of the book.

[rhinson]

Anderton suggests how to do it in the Q&A section in near the back of the book.

WOW!   i'm not at home now but i'll have to dig it out tonight.   except for when i looked at this project again last week, it's been yrs since i looked at it  (i built most of that stuff back in the 80's)----i don't remember anything like that being in the version i have--i think i bought it about 86 or 86,  but i don't remember a lot of stuff these days!    thanks for the tip      rh