Earthquaker Devices - Acapulco Gold  [schematic]

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Earthquaker Devices - Acapulco Gold

Postby Hexjibber » 09 Oct 2015, 09:55

Apologies in advance if I have posted this in the wrong section, I didn't think of it as a request as I have some pictures to share, albeit not great ones!

Really like this sound of this pedal and am hoping to build my own one, other forums have suggested a similarity to the DAM Sonic Titan or ROG Grace/Big Daddy due to the LM386 usage but it doesn't look quite the same as there are two of 'em? I'm no expert on these things so thought I would pass along to other more savvy people! There is obviously not a huge amount going on circuit wise in terms of complexity but the results sound great to me.

Managed to glean some pics on the internet, the trace side one is a bit small and possibly not much use but you can make out some detail;

Component Side:

Image

Trace Side:

Image

Cheers!

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Re: Earthquaker Devices - Acapulco Gold

Postby Nocentelli » 09 Oct 2015, 16:12

Three resistors, five caps. I'm crap at reading blue five band resistor codes, or I'd knock up a schematic now. Not much it could be other than:

Input to pull down R and input cap, input cap to pin 3 of first 386, pin 2 and 4 grounded and pin 6 to +9v (power and grounds same on both chips). Output from pin 5 on first 386 through a (probably) a resistor and cap to pin 3 of second 386, output of that from pin 5 to electro output cap to 100k volume pot. Third resistor will be LED CLR. Two big electro may be either for supply filtering on pin 6s, or possibly from tied pin 1+8 to ground.

Seems like a very stripped down version of Beavis's "Tufnel distortion" (the only other 2 x 386 dirt circuit I remember). Beavis has completely disappeared from the web, but there is a vero layout for it at tagboardfx. It's pretty complicated compared to this with a gain and tone control iirc.
mmolteratx wrote:absolutely zero commercial use allowed. If I find anyone selling these, I'll fly to your house and kick you in the nads. And you may or may not find yourself in trouble.

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Re: Earthquaker Devices - Acapulco Gold

Postby Hexjibber » 09 Oct 2015, 17:28

Nocentelli wrote:Three resistors, five caps. I'm crap at reading blue five band resistor codes, or I'd knock up a schematic now. Not much it could be other than:

Input to pull down R and input cap, input cap to pin 3 of first 386, pin 2 and 4 grounded and pin 6 to +9v (power and grounds same on both chips). Output from pin 5 on first 386 through a (probably) a resistor and cap to pin 3 of second 386, output of that from pin 5 to electro output cap to 100k volume pot. Third resistor will be LED CLR. Two big electro may be either for supply filtering on pin 6s, or possibly from tied pin 1+8 to ground.

Seems like a very stripped down version of Beavis's "Tufnel distortion" (the only other 2 x 386 dirt circuit I remember). Beavis has completely disappeared from the web, but there is a vero layout for it at tagboardfx. It's pretty complicated compared to this with a gain and tone control iirc.


Cheers for the detailed reply! I've had a stab at it in Eagle which is no doubt wrong but hopefully on the right track at least?

I can see a diode under the pot and from looking at the trace side there looks to be an electro hiding under the pot too, some kind of power filtering perhaps?

Image

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Re: Earthquaker Devices - Acapulco Gold

Postby Nocentelli » 09 Oct 2015, 17:33

Diode and electro next to power is almost certainly for filtering. On further reflection, I think that you can connect the guitar directly into the input of the chip, so it's possible your schemes not on the money (though it is exactly what I had in mind).
mmolteratx wrote:absolutely zero commercial use allowed. If I find anyone selling these, I'll fly to your house and kick you in the nads. And you may or may not find yourself in trouble.
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Re: Earthquaker Devices - Acapulco Gold

Postby Nocentelli » 09 Oct 2015, 18:27

Pin 1 and may well be tied on each chip.
mmolteratx wrote:absolutely zero commercial use allowed. If I find anyone selling these, I'll fly to your house and kick you in the nads. And you may or may not find yourself in trouble.
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Re: Earthquaker Devices - Acapulco Gold

Postby Nocentelli » 09 Oct 2015, 18:29

... 8......
mmolteratx wrote:absolutely zero commercial use allowed. If I find anyone selling these, I'll fly to your house and kick you in the nads. And you may or may not find yourself in trouble.
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Re: Earthquaker Devices - Acapulco Gold

Postby Nocentelli » 10 Oct 2015, 08:50

Maybe -

acapulco_maybe.png
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mmolteratx wrote:absolutely zero commercial use allowed. If I find anyone selling these, I'll fly to your house and kick you in the nads. And you may or may not find yourself in trouble.

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Re: Earthquaker Devices - Acapulco Gold

Postby Hexjibber » 13 Oct 2015, 10:47

Thanks for the replies! I think you're right, pins 1 and 8 do look tied via that electro, I've tried to update my schem to show that along with some values I've worked out. This schem includes all the components I can see in what appears to be how they are laid out on the board, what do you reckon?

Image

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Re: Earthquaker Devices - Acapulco Gold

Postby allesz » 13 Oct 2015, 13:34

R1 shoul be a 1M.
But reading 5 bands resistors value (in particular since they are 1/8 watt) is difficult.

I watched a video of the pedal... not bad, I expectet more distortion. The nice thing is that it should serve as overdrive and also power a small speacker.

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Re: Earthquaker Devices - Acapulco Gold

Postby Hexjibber » 13 Oct 2015, 14:40

allesz wrote:R1 shoul be a 1M.
But reading 5 bands resistors value (in particular since they are 1/8 watt) is difficult.

I watched a video of the pedal... not bad, I expectet more distortion. The nice thing is that it should serve as overdrive and also power a small speacker.


Cool thanks, I've updated my schem, can see where I went wrong! :)

I think it's the tone of it and the simplicity that is appealing to me, can see it being a really beefy rhythm sound which is why I'm looking to build one. Need to get myself a breadboard really and test this schematic out, still missing a fair few values but without access to the original it's pretty hard!
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Re: Earthquaker Devices - Acapulco Gold

Postby Hexjibber » 13 Oct 2015, 15:56

Found a bigger pic of the trace side;

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Re: Earthquaker Devices - Acapulco Gold

Postby Hexjibber » 15 Oct 2015, 12:20

Here's the schem as I have it currently, anyone up for verifying at all? Obviously there are values missing for some of the caps! ;)

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Re: Earthquaker Devices - Acapulco Gold

Postby captain_tango » 18 Oct 2015, 12:02

I don't ever post here (actually I think this is first post), but I'm intrigued by the concept of having a low parts count single "Power Amp Stage" to put as a tail end on stuff, so I ordered up some 386s and will be breadboarding and doing some research when the package from Tayda shows up in a week or two! Will let you know about the results. I think this little number sounds immense on the videos hitherto posted, and am looking forward to trying to tweak and play with it! I'll certainly share my findings. Thanks for the schematic so far!

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Re: Earthquaker Devices - Acapulco Gold

Postby Hexjibber » 19 Oct 2015, 10:44

captain_tango wrote:I don't ever post here (actually I think this is first post), but I'm intrigued by the concept of having a low parts count single "Power Amp Stage" to put as a tail end on stuff, so I ordered up some 386s and will be breadboarding and doing some research when the package from Tayda shows up in a week or two! Will let you know about the results. I think this little number sounds immense on the videos hitherto posted, and am looking forward to trying to tweak and play with it! I'll certainly share my findings. Thanks for the schematic so far!


Cool thanks for the reply, will be interested to hear how you get on! :)
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Re: Earthquaker Devices - Acapulco Gold

Postby thesmokingman » 19 Oct 2015, 22:19

tracing out the pot
looks like your power filter cap, 1n4001 protection diode, and pin 1 of the pot go to ground at the same spot.
pin 2 goes directly to output
pin 3 to a 1uf 50v cap
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Re: Earthquaker Devices - Acapulco Gold

Postby thesmokingman » 19 Oct 2015, 22:42

NM ... known info ... will work on the unknowns ... really wish there was an edit function.
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Re: Earthquaker Devices - Acapulco Gold

Postby bigbonedstacks » 20 Oct 2015, 01:04

Someone confirm this!!!! I need it in my life! Also if anyone wanted to put this on vero I wouldn't be mad lol.
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Re: Earthquaker Devices - Acapulco Gold

Postby toxsyn » 24 Oct 2015, 01:07

I'll be putting together a stripboard layout in the next couple days. Did anyone confirm the capacitor values for this yet?
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Re: Earthquaker Devices - Acapulco Gold

Postby albru80 » 24 Oct 2015, 17:20

This matches the latest schematics.
Still with unknown values.
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Re: Earthquaker Devices - Acapulco Gold

Postby toxsyn » 25 Oct 2015, 09:29

A friend of mine bought the pedal and wants to trade it to me for a couple of my builds. I don't really have any interest in keeping the original so I was wondering if anyone wanted to buy it from me after I trade for it? If I do take it from him I'll only be using it to find the missing values. Does anyone want to take the original off my hands when I'm done? What's your price? PM me.
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