Powering a LM386

[SirPoonga]

Could use use 2 9V batteries to make 18v then run through a 7812 voltage regulator to get 12V?  How would I create the circuit?

[Mark Hammer]

Well, you *could*, but personally I think you'd just be smarter to buy yourself an octet of AA's and a battery holder for 8 AA cells.  When you have a hum-free high-current 12v supply, these babies can really sing with authority.  In many instances too, 8 penlights will cost less than two 9v's and outlast them by a long shot.  Yes, it's a little bigger, but definitely worth it.

[Paul Marossy]

I think I am going to take Mark's suggestion and make me a little power pack for my Little Gem. That way I can take it anywhere. Right now I am using a wall wart, so if I don't have an AC power source, I'm kinda stuck...  

[Mark Hammer]

Made me an LM380-based 2W amp using an octet of D-cells.  Lotsa mileage and volume there from a simple 6" speaker and small closed cab.  Also recently put together another LM380 amp with a Thunderchief (w/tonestack) front end.  Using a pair of 6v lead-acid batteries for power until I can get to the place in town where I buy my battery holders.  Plugged it into a 4 x 8" cab and p l e n t y of oomph.  Eventually will marry it to a single 8" speaker but have to decide which of the dozen or more of those things I have lying around sounds best (resolution for New Year:  Don't buy any more 8" speakers when you see them, Mark, no matter how cheap).

[SirPoonga]

yeah, I might have to do that.  I was trying to keep size and weight down.  Might as well get some good rechargable AAs then.

[RDV]

Also recently put together another LM380 amp with a Thunderchief (w/tonestack) front end.

How well did that work out? Did you put the tonestack the same place they put on their "untested" schem?

RDV

[Mark Hammer]

Yes I did in fact.  I think I may play with the tonestack caps to get the sort of tonal changes that suit my own taste and the speaker, but other than that it sounds pretty decent.  I'm pondering whether to lift the lowpass caps in the 2-pole filter just ahead of the volume control.  One of the speakers in contention for the amp is an "Excelsior" alnico 8" that is bloody bright.  Some of the others are ceramic Radio Shack 5W "whizzer cone" types that have a better bass response but nowhere near the upper mids and bite of the alnico.  Then there is a Ross 4ohm speaker whose cone seems a little tight for full-range duty in a 2W package, and some other no-name that seem to have better bass.....

I'm using a 12v supply so the FET drains are biased to around 5.8-6v.  The taper of the pots is still a bit of an issue for me, but that is no reason why it would be an issue for others.

Like the actual Super Lead itself, you tend to need to back off on the guitar volume a bit, show restraint in use of the gain control and output level to nail a clean tone, but it CAN sound clean and do a respectable job.

There is a possibility it MAY be too hot an output for the power amp chip, though I have yet to tinker with FET biasing that is a little off-centre as a means squishing levels.

I forget where I read it but the pair of 4k7 resistors to ground also needed altering (reduction) a bit to make it work.  Finally, I'm using J201's.

[SirPoonga]

WOOHOO, breadboarded a ruby amp with bassman mods (and one other cap mod to let a little more bass through).  Sound pretty cool.  I'm going to just power it with a 9v.  I'm using it as a headphone amp.  9V does fine for that.  I have the radioshack 8 AAA holder incase I want to drive  something else.

I am busy until this weekend, doesn't look like I will perf until then.  I need to find a box now.....

Actually, while I have the simple octave up setup on the other side of the breadboard I might combine the two and see what happens