RobRob Ruby eyelet amp build

Discussion in 'Shock Brother's DIY Amps' started by dfrosto, Dec 10, 2019.

  1. dfrosto

    dfrosto TDPRI Member

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    I bought some parts on eBay, figured I' d do a practice run on an "easy" Ruby SS amp, get a little practice in before working with the high priced components.
    Not going great so far... melted one of the contacts right off the IC socket board. oops, temp was a little hot for that tiny contact. Anyway, finally got 8 wires soldered to the 8 pin socket. Is there a recommended procedure for this, mine was a wing job!
    What's the easy way? Clearly not the way I did it!
    A little discouraged... brand new soldering station, not high end, but I don't know what task merits which dial setting yet. And so the voyage begins...
     
  2. GARAGE HERMIT

    GARAGE HERMIT Tele-Meister

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    sounds like you just need a bit more practice soldering component's, just keep at it,
    here's a "smokey" type lm386 amp i made using an old draw and a fane 15 ohm 12" speaker,
    fan 1.JPG fan2.JPG fan3.JPG fan4.JPG fan5.JPG

    very simple circuit, i think it sound's fine for what it is, i added a 10k pot to control the gain, 9 volt battery powered,
    sa1.jpg

    here's a little sound video,
     
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  3. dan40

    dan40 Tele-Afflicted

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    For those small connections, I like to use a very fine point tip in my Hakko station. The tip is much smaller than the tip I would normally use for tube amp joints. I keep the heat about the same (650-750) so that I can get on and off the pins quickly. Be sure that your tip is clean and well tinned before heating the joint. A dry tip will not transfer heat quickly and you risk damaging components.
     
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  4. cometazzi

    cometazzi TDPRI Member Silver Supporter

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    I agree with Garage Hermit- you just need some practice. I've been using a $22 iron I got at Radio Shack about 15 years ago, and I do ok. I munged a few things at first though- melted stuff, killed transistors. Keep at it and you'll get it.

    Also, those LM386 guitar amps are a big load of fun. It's one of the first things I built and I've lost count of how many variations of it I've made. In fact I just dug some stuff out of the Circuit Mausoleum because I have some ideas for another LM386 variation.

    Here was my very first one, in a Sterilite tub:

    [​IMG]
    [​IMG]
     
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  5. dfrosto

    dfrosto TDPRI Member

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    Since my first post, I've had some growing pains, and some growth! I ordered a bunch of mini -amp parts, By themselves they comprise something between a Smokey and a Ruby. So , I built 3 of these, burned/ ruined up 2 IC sockets. 2 of the amps work fine, the first one has yet to "find its voice". Doesn't work. 1217191803.jpg 1217191803.jpg Don't know what's wrong with it, probably never will! Good practice, though!
    Started the Ruby eyelet build. Sorta waiting on a 386 socket, to replace the one that lost a tab at the 11th hour. Waiting a couple more days for replacements!I was briefly discouraged, but it's only rock and roll!
     
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  6. dfrosto

    dfrosto TDPRI Member

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    Somehow I posted the same pic twice last night. Here is a pic of the no-name 1217191900.jpg mini LM386 amp I'd intended to post. Sounds much better and louder than I expected.
    Started laying out the eyelet board. My main issue is that everything is so damn small- wire runs of 5/8 of an inch, etc. That's beyond the fact my hands aren't as steady as in days of yore, and I can't do anything without my reading glasses!
    Just to keep me on my toes, the red cartridge on my printer ran out, so the color coding on my diagram is screwed up. Where's that orange Sharpie?
     

    Attached Files:

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  7. GARAGE HERMIT

    GARAGE HERMIT Tele-Meister

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    two out of three isn't too bad, like anything practice make's perfect,
    i'm the same with those small part's, i need my reading glasses plus a magnifying glass, getting old suck's,
     
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  8. cometazzi

    cometazzi TDPRI Member Silver Supporter

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    I'm far-sighted with astigmatism. My trick is putting a set of large-lens drugstore readers right over my prescription glasses.

    Now, if I could just find a set of over-the-glasses safety glasses with something like a +4.00 magnification, I'd probably be set for another 5 years.


    I was quite surprised by how loud 1/2W could be, even through a $6 wal-mart 6x9 speaker. I was also surprised at how quickly these little amps eat 9v batteries.

    That said, check the manufacturer's datasheet for the specific device you have. LM386N-1, LM386N-2 and LM386N-3 can usually take 12V-15V. If it's an LM386N-4 it can take upwards of 18V-22V (and put out 1.25W). Texas Instruments is the one that claims the higher voltages, but most of my chips are natsemi, so I go off of their sheet. In any event, if all the other relevant parts on your board can take it, you can increase* the voltage from 9V for more clean headroom, and decrease it for more distortion. The output level will also go up or down a bit with the voltage changes. Watch the temps of the chip with higher voltages, and if it gets hot either back the voltage down, put a heatsink on it, or both.




    *No warranty express nor implied when you attempt Cometazzi's Mad Scientist Hot-Rod Tricks(tm). Cometazzi and Phaeton Research Institute LLC not liable for damages, injuries, spousal complaints nor any other forms of incidental wreckage and ruin
     
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