+9v and -9v from a single battery - what's the best way to do it?

[alparent]

This is my first post on this forum (I just joined 2 days ago) and I already learned a lot!

After searching this site and others I've found 3 ways of getting -9v from a single battery:

1. Using the MAX 1044 chip
2. Using the ICL7660
3. Using a 555 timer

I really need your advice on witch method is best and why.
(If there are other methods.........feel free!)

Thanks!

[petemoore]

  MAX1044 is a 'good' way..

[alex frias]

I thought ICL7660 and MAX1044 were the same device...

[R.G.]

7660 is good - but it uses a switching frequency in the audio range, so this usually makes a detectable whine in pedals using it.

MAX1044 is pin-for-pin compatible with the 7660, but when you connect pin 1 and pin 8, it raises the switching frequency above audio, so any whine cannot be heard.

LT1054 is pin-for-pin compatible with the 7660 and the MAX1044, but it allows an input power supply of up to 15V; the 1044 is 10.000000V max, which is tight in a 9v setup where a fresh alkaline battery may be 9.3-9.5V and there are techo-guys with BUMS who may just want to stick 12-18V into a pedal to see if it sounds better somehow. The LT1054 will be more durable, and switches above audio too.

[gez]

Edit: Scratch...wasn't thinking.

[Andi]

I thought the 7660 had a boost function too. 

[alparent]

Just to had another twist to my question.

Is it better to use 2 batteries (if I have the space) or does it make any difference?

[frequencycentral]

I thought the 7660 had a boost function too. 

No boost on the 7660.

Microchip TC1044SCPA or the TC1044SEPA are cheaper than MAX1044 (and LTC1054) and go up to 13 volts.

Topic: Cheaper, (possibly) better MAX1044 alternative with boost: http://www.diystompboxes.com/smfforum/index.php?topic=73759.msg598509#msg598509

Just to had another twist to my question.

Is it better to use 2 batteries (if I have the space) or does it make any difference?

I'd go with a charge pump rather than two batteries - unless the application is drawing loads of ma.

[Andi]

Ah - it's the ICL7660S I've used. My mistake - sorry.