Stereo low level output hack.

[chuxterofdoom]

First of all, this is my first post and thanks for looking at it.  I've been interested in wiring up Alexa to my in home audio system using a low level output from Alexa into an amplifier that will feed the sound to the rest of the house.  I found some schematics for the amplifier chip on Alexa and was wondering if soldering a few leads off of these particular points on the chip would give me the low level output I need.  The labels seem to identify it as Left(Right) In Positive and Negative respectively.  Any thoughts or trials on this?

[firewiredv]

I have been looking at the same thing however it seems to me it would be safer and more reversible in case of issues to just get a 2 pin connector and splice it in where the speakers plug in to the board.

[jmayes]

I was overjoyed to see the title of this post as I too want a stereo output from the echo however after doing my own research I found that the two amps in the stereo chip are used for the two speakers which are assigned to bass and treble so therefor it would be reasonable to assume that what you will receive from those points chuxterofdoom pointed out would be the same mono signal and each equalized for their respective frequency band.  I have not hooked it up yet but plan on mixing them together and re-eq'ing them in order to achieve a reasonable full sound plus putting it through an stereo simulator of some kind to make up for mono.   I can hope that each speaker will be driven with respective L& R signals (each with special eq) but chances are pretty slim.  The only way I believe true stereo will be achievable is going to be with a software hack and another DAC added to the hardware (or find a hook that is already in the software). (or open up the bluetooth??)

I will report back after I hook up my sound system and let you all know how it went.  Also for anyone else trying this be sure to use some series blocking caps because of the 3v bias voltage on those pins. (10uf should do nicely)

Jmayes

[jmayes]

Ok, I did the hack and am now enjoying the Echo music on my house music system.  As expected it's just mono, the two outputs are Bass and Treble equalized for their respective speakers.  I put both channels into a simple POT so I could dial up a quick eq mix and it seems to be working well.  Future plans are to pipe it through a stereo simulator, I found a cheapo kit on eBay for $16 waiting on it now.

Also I found both signals on the top of the board near the DAC chip and also found that there are already blocking caps on the inputs between the amp chip and the DAC so that was a better spot to grab them as they are biased at zero volts there.  Below are some pix and a quickie schematic.

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Not sure why but the board won't let me put any images or attachments in this post, if someone is interested post back and I will get them up somewhere.

Enjoy,
J

[dj_skully]

Would love to see the pictures! Can you post to imgur or something? Thanks. 

[jmayes]

Hi, too busy to post right now but I zip'd them up here;
http://jmayes.com/Pix/Echo_Audio_Hookup.zip

J

[Ultramanv]

Awesome job ! Thanks for the info JMayes !

[dj_skully]

Thanks!

[Rantlers]

Hey, really interested in doing this, but having trouble understanding the wiring schematic.  From what I can tell:

1. Take the positive signal from both the bass and treble (pins 3 & 12)
2. Connect a 0.1uf capacitor to the positive treble line (soldered to the board?)
3. Connect a 1.0uf capacitor to the positive bass line (soldered to the board?)

Unfortunately after this I'm not sure what needs to be done.  Ultimately I want to feed the signal to an amplifier for use with external speakers.

Any support would be much appreciated.

[jmayes]

Hi, you are correct on what you posted, all that remains is to connect each cap to to any type of pot (volume control).  (5k to 50k ohm pot will work fine) Each cap goes to one end leg of the control and the middle leg goes to the amp.  Adjust the pot for the best sound (it goes between bass and treble). 

Good luck,
Jmayes

[Rantlers]

Much appreciated, jmayes, can't thank you enough.  If I could pick your brain one more time, did you have any luck with the stereo simulator?  My current amp (http://www.amazon.com/gp/product/B00026BQJ6?psc=1&redirect=true&ref_=ox_sc_sfl_title_1&smid=ATVPDKIKX0DER) only has stereo inputs, was thinking of just using one of these:

http://www.amazon.com/gp/product/B000M52X62?psc=1&redirect=true&ref_=ox_sc_act_title_2&smid=A2NNIDG2L0EQ4O


Lastly, if using an RCA connection, any advice on where to grab the ground connection from?

[MDQBoX]

Pardon my ignorance, but why would you need to include the capacitors?

[WadeK]

Does anyone still have the information Jmayes linked to? I am trying to do exactly this same thing. I found this

https://medium.com/@MathiasHansen/hacking-an-amazon-echo-and-integrating-it-with-sonos-75dbcc02f5b5

but believe there is a better way than using the speaker output as a line level output.

Thanks