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Permalink Reply by Swamp Dawg Primal Music on September 14, 2012 at 11:45pm

Keep an eye out for the power adapter, it takes a center positive power adapter, as opposed to most pedals! I was also told by Ty not to modify the wiring at the board to a center negative.

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Permalink Reply by Tom Lauten on September 15, 2012 at 2:11am

Too right!

I've been checking every adaptor and plug that I have to make sure all is as it should be.

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Permalink Reply by Mark on September 14, 2012 at 11:07am

glad to hear you got an answer.

mah is still irrelevant to this though - the point of quoting mah figures is mostly to allow you to estimate how long a battery will take to discharge in a given application

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Permalink Reply by Tom Lauten on September 14, 2012 at 12:02pm

That was my understanding as well...like I mentioned, I think amperage is only "supplied" as the device demands it...ish.

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Permalink Reply by Tom Lauten on September 14, 2012 at 2:42pm

I wasn't asking about the role of amperage vs voltage, I was asking for help having thought I fried the amp. I have since found out that the battery connection is strictly for 9 volt only and that the external power supply connection should be used for a12 volt supply (regardless of amperage). Whats more I have been given help in terms of what to investigate (ie capacitors).

I was unsure of what happened, why, what I had done wrong, what I had assumed incorrectly and correctly and what routes for resolving my problem were available to me. I asked for help with these matters and received it here and from the supplier.

It sounds like you have taken offense somehow. Hmmmm.....

Thank you to those of you who offered advice and support. Its a great help to discuss these matters and work through the possibilities, I really appreciate it. I'm sorry if I rubbed anyone up the wrong way...wow.

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Permalink Reply by RTZGUITARS on September 15, 2012 at 4:16am

 I should of said a 9volt battery has a capacity of about 500mAh and an max output current of about 1/3 an amp. Sorry to hear your mistake I have burned my share of chips. Make sure if you use a power supply you use the recommended mA you don't want to use to low of mA. And just because it says it will handle 15v isn't always the best thing this generates heat you don't want heat.                                             .

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Permalink Reply by Bluesheart on September 16, 2012 at 1:44am

Interesting, sorry to hear about the fried amps. I was think about running 12V into my Ruby amp with a 386 chip but wonder now if I should not, or if I need to connect it to a different point on the board?

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Permalink Reply by Mark on September 16, 2012 at 1:11pm

Bluesheart, it is possible to run LM386 amps at up to 18v
You need to make sure all the components are rated for at least the supply voltage you plan to use.
LM386 chips come in several versions with different maximum supply voltage ratings. The N1 and N3 versions are rated for up to 12v, while the N4 version is rated for up to 18v.
They also have different maximum power output ratings.
For other components, such as capacitors and resistors, I generally find I end up with stuff rated at higher voltages - 25v or more - so there's rarely a problem on that front. But it's always worth double checking.

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Permalink Reply by Jim Woods on September 18, 2012 at 7:20am

I have been using the LM386 N1 chips (nominally 4v - 12v ) in my amps - I have used them w/ a "12v" car cord on the boat while the shore powered charger was on - usually about 13v with no problem.  I do use the socket for the chip, so if I fry one (haven't yet thru the 1st 6 amps) it is a 75 cent no solder swap out.  

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Permalink Reply by Maddog on September 16, 2012 at 3:12am

Good topic Tom, sorry to hear about the amps. Thanks for sharing as it helps the guys like me that are still on the learning curve so to speak, it's threads like these that a guy like me can learn a thing or 2. Hopefully the amps can be salvaged, good luck and hope it all turns out right for ya. I'll keep an eye on the thread to see the remody.

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Permalink Reply by Tom Lauten on September 19, 2012 at 3:00am

Well, one amp still lives via the external power supply jack. I wired in my 12v battery into the wiring for the jack socket and all is well. The 9 volt battery input is dead. I'm thinking a capacitor may well have blown but to be honest I'm not gonna mess with it anymore, it works and I'm happy. That 12 volt battery should run the amp for hours and it's rechargable so I will pop that into the amp box and and have a connector for it's charger...done.

The other amp is still dead no matter what power input I use and schematics aren't available so it goes into the file marked "spares from lessons learned".

 

All of this aside the amp itself sounds great with an 153X 100MM 4W 8 OHM general purpose elliptical speaker. I'm getting a 4 watt, 8 OHM round, 125mm GP speaker soon and will try that to see what the difference is.

 

Thanks all.

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