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amp wiring help

So I bought a little 'amp" circuit on ebay based off of some comment I saw here on the nation metioning them. It was only 3 bucks, so I figured what the heck. anyway, it showed up, but no wiring diagram, and I don't want' to fry it. It has some marks on it, perhaps someone has some knowledge on it. the white circle with the slot turns....I think some sort of gain/vol. then 4 prongs on right side say grd, grd, in and vcc. then other side, i assume is speaker out, has green plastic bracket with screws that tighten down (I assume you clamp wires in there) and they are labeled grd and out. My assumption is the "in" is the feed from jack, the vcc is the hot from battery, and then the grd are the respective grounds for them, which I assume all ground are interchangeable. thanks for your thoughts!

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Replies to This Discussion

Permalink Reply by Blind Lemon Cello on June 26, 2013 at 11:02am

Yes, you are correct with your connections. I have the 200 gain circuit & it can drive a 2X8 cab pretty well. You can also add pedals & the board seems to hold up. Have fun!!

Permalink Reply by David L. on June 26, 2013 at 11:11am

Hi Harley,

They caught my eye too but mine is still in the post.

I think you have sorted it out by yourself.

My thoughts are

from other circuit boards I have played around with

The green connections on the left will be to the speaker.

For the other 4 pins IN will be the hot input wire

VCC will be the 9v postitive from the battery

The other 2 GND need one for the battery negative and one for the guitar input negative.

If wired like this and it doesn't work then add another wire across the two grounds as I think this gap is to isolate the battery from the circuit using a break in the battery negative lead so you can easily add a switch here or use a stereo jack socket as a switch.

(Jack plug as a switch - you can wire the two GNDs one to each of the two negative lugs on a stereo jack socket so it acts as an on/off switch. When you plug in a mono jack plug from a guitar lead. - the shaft of the plug connects the two GNDS so the battery becomes part of the circuit and it switches on).

Good luck and let us know what you think of the sound.

Regards,

David

Permalink Reply by David Clark on June 26, 2013 at 11:11am

vcc is +voltage in. grounds should be the same electrically. Your other assumptions sound correct. email ted crocker to verify. good luck

Permalink Reply by Bryon Dodds on June 26, 2013 at 3:16pm

do u have a link on ebay 44 this amp?

Permalink Reply by David L. on June 26, 2013 at 7:51pm

http://www.ebay.co.uk/itm/380594834236?ssPageName=STRK:MEWNX:IT&...

Permalink Reply by HarleyTodd on June 27, 2013 at 6:11am

http://www.ebay.com/itm/300842633350?ssPageName=STRK:MEWNX:IT&_...

I think this is the one I bought...David's link is good too...they have a few different "models"...not sure on difference. Thanks to everyone for comments on my wiring, I will hook it up this weekend and see how it sounds..then report back.

If it works, can't beat the price. I will add that if price isn't an issue, I have the MAH 5 from guitarfuel.com and it is a great amp...about $40, but I put it in a cigar box and it has multiple tone and distortion adjustments, mp3 imput so you can play along to songs, etc.

Permalink Reply by David Clark on June 27, 2013 at 9:46am

The MAH 5 is a really good amp. I had some old JBL surround speakers and used the 4 inch speakers out of them and put them in a craft box from hobby lobby and it really rocks. Give it a try.

Permalink Reply by Blind Lemon Cello on June 27, 2013 at 8:40am

These are only about .5 of a watt, but they do crank for "watt" they are!!

Here's another I tried, has external volume pot & a pin to go from clean to gain, not a bad unit. These are actually quite a bit larger then the one shown in this post. I had thought that a LM386 would only be one size, but apparently not.

http://www.ebay.com/itm/Low-Voltage-Audio-Mono-Amplifier-Module-NJM...

Permalink Reply by HarleyTodd on June 27, 2013 at 9:27am

Would you say the one you tried (and the link you posted) is louder/better? is it more wattage? For $7 it's still a bargain.

Also, for yours or the .5 watt one I posted above, does anyone have thoughts on 4 ohm or 8 ohm speaker? I hear a lot about that in discussions but never really understood it. thanks.

Permalink Reply by The Mad Scientist on June 27, 2013 at 8:52pm

I've got that module in an old bakelite speaker cabinet from the 1940's (the speaker cone is from the same era too) and it sounds really great. Far better than you would expect. I've bought a few more and am on the hunt for some more vintage speakers to hook them up to. I'll try and take some pics later and post them :)

Permalink Reply by Blind Lemon Cello on June 27, 2013 at 10:00am

Hey Harley, I would say the 7$ one is a little louder, but having the option of a clean or gain amp is nice, or you could add a gain pot for adjustment. I run both at full volume & find for me I like lower ohm speakers for low watt applications as it adds to the DB level. I have 2 8" 4 ohms in parallel in a 20w buskin amp I built that also has the option as being a cab & the little boards drive them pretty good. I also built this little radio amp with the 7$ board into a 4" speaker & it sounds nasty!!