Layout for Hammer's LM380 Miniamp

[bancika]

Anyone has layout (either perfboard, PCB or veroboard) for LM380 based 2W amp from Hammer?
Tnx

[Mark Hammer]

1) I only built it.  Not evenly remotely my design or idea.  It's from an old Japanese projects book.

2) There is a layout for it, which I thought I had posted, but apparently I didn't.  I'll see if I can put it up on photobucket this weekend.  Keep tabs on this thread for a signal.

[bancika]

Do you have some clips of it?
I need something like that for two reasons:
1) as standalone mini amp when my firefly isn't around
2) since my firefly tube amp doesn't have fx loop (and I'm using it's distortion) I made line out box and plan is to use firefly -> delay pedal -> other poweramp. I think that 2W is just enoug for this. So I'm thinking about DPDT switch that will bypass whole preamp part right before master volume pot. So when used with firefly only poweramp will be on. By the way, is poweramp clean?
Do you think whole this idea might work?
Thanks!

[Mark Hammer]

I don't have clips, and I don't think they would help, because the speaker (a Marsland 6" with a big ceramic magnet) and cabinet play a much larger role in how it sounds than anything electronic.  It is, however, plenty loud if powered by 8 C-cells, and is more than powerful enough to  get a big sound from big speakers.  I built it for a cross-country trip, and it served me well then, and serves me well now as my gear-test amp for the bench (hate waiting for tubes to warm up only to find the pedal under test is missing something critical; I like a fast turn-on time in a test amp).  The Preamp part is not really any better or different than what is found in the PocketRockit: http://ampage.org/hammer/files/PocketRockit.PDF

[bancika]

Speaker is not a problem, I'll use it with 1x12 cab loaded with Celestion Greenback 12".
In case you don't come across layout, can you just help me with stuff from schematic. What are those CP1-CP5? What's (T)? Why do I need bot +Vcc and B+, which one is used at power amp because it says only .+?
One more thing, I'm planning to use it with my power supply, is that ok? It has 1.2A transformer and 12V 1A, 9V 1A regulators
HUUUUGE Thanks!

[Mark Hammer]

Ignore those CP points.  I gather they were test points for which there were expected signal levels or voltages listed in the original article.    Not being able to read Japanese, I couldn't tell you!

If I remember correctly, B+ (the full +12v) is used for the amp, while Vcc (11v after the 150R current-limiting resistor) is used to power the op-amps.  The bias voltage is simply half of Vcc.  I think I just used 12v for everything on mine, and I know I did not include the headphone jack.