IQAudIO Pi-DAC+ "plus"

[gswg]

Hi all, let me answer both recent questions in this post (if I can).
1) Does the PI-AMP only offer volume control through the software (e.g. Rune UI)?

GG: The Pi-AMP takes the variable output of the Pi-DAC+, the Pi-DAC+ has a built in hardware volume control which is adjusted through standard Linux ALSA commands.

2) Is there any benefit, in principle, of having the amp hardwired onto the DAC, without the need to run signal out via phono to an external amp?

GG: The Pi-AMP+ will back power the Pi / Pi-DAC so there is a benefit there. In terms of audio, the two could be connected via cables but we have tried to reduce the need for these.

3) It seems as though the PI-AMP may require some user soldering to attach extra pins, is this correct?

GG: Yes, it's a balance - Do we solder the pins on to the DAC+ for everyone (and increase the build cost which effects the cost to users OR do we leave it up to the AMP+ users to do the soldering but keep the Pi-DAC+ costs lower? We may at some point just solder the headers on but at the moment we're not.


4) Is this TPA3118 amp board likely to sound any better than one like the SMSL mentioned above, which seems to be generally favorably reviewed? I'm wondering whether it might possibly offer better electrical components than the SMSL?

GG: We're not going for low cost electrical components - period. Where a component has an effect on the audio path then we don't cost reduce. Where it doesn't effect the audio we'll use the best we can for the lowest price.


5) Perhaps integrating a power switch circuit would be possible, so that the Pi can be switched on/off via a switch rather than pulling the power connection manually?

GG: We thought about this but decided that people have different needs so we've just made it so that if you want to add a power switch then the Pi-AMP can be powered via a JST connector rather than the barrel connector. So you can use your own power source / soft switch etc.

We may change the spec a little but it'll be pretty close to what we've suggested above.

Gordon@iqaudio.com

[LC1]

Thanks Gordon, exactly the information I needed to make a decision on this - I'm sure the PI-AMP will be fantastic and as much as I'd love to have an all-in-one integrated unit, I would ideally like a physical volume control (well, my wife will probably insist on it!) and I have zero soldering skills

[Fishstix]

Hey Gordon,
I am not sure I am seeing the layout correctly; maybe this wouldn't be a solution. Could you offer a combined Dac+/Amp+, pre-soldered? Folks like me that like their DIY amps would use the Dac+, and the folks that are looking for a complete system and small form factor could still have their plug-and-play system. I assume the amp+ wouldn't work joined directly to the B+ anyways, so it wouldn't clutter up your online store with too many extra options. All of this is assuming that doing the extra soldering at your shop wouldn't blow the price out of the water, maybe it would. Considering the nice componentry this is a relatively low price point, which I greatly appreciate. Makes it accessible to those of us priced out of the standalone DACs. Thank you!
-Fishstix

[gswg]

A combined unit - yep we could look at that. There are other alternatives too (which we have played about with) but they need more software changes.

Gordon

[franz159]

[gswg]

So let me get this right, a single purchasable item which will just fit on top of a Raspberry Pi B+
- no soldering on the user's part. Just all slot together with all mountings etc.

What about external power brick. You'd want one included too?


Gordon

[Fishstix]

[Stwert]

Hi Gordon,
I've just received my PiDac+ and am eager to get it all working together. I'm trying Volumio right now to see whether previous problems I've had are related to hardware or Rune, while I wait for 0.3 beta. Anyway, the point is, I've got a couple hardware questions about the DAC. What is the little button on the board for? I see in the image from the first post that it says "Wrt Prot" beside it. Any way to change what the input does? I can think of a few handy functions it could have.

Also, I'm wondering if there's some documentation or tutorials around for using the hardware rotary encoder. I'm not very experienced with electronics, but I'm sure there's some info out there on how to approach that.

Thanks!

[gswg]

Hi, the button is for programming the HAT spec EEPROM. By default the EEPROM is write protected, but as the HAT spec is still a little fluid and not everything is set in stone wrt auto loading of linux drivers we've (like others) had to ship boards before the final details are concluded. So once we have final information from the Pi-Foundation we can tell customers how to program their Pi-DAC HAT EEPROM with the correct data. It was easier putting a push button on the board than asking users to link two jumpers etc.

It's got nothing to do with audio.

Rotary encoder - there are loads of examples on the web and I've placed code (source and pre-compiled) on github.com/iqaudio/tools

just connect the three legs of the encoder to gpio23, ground (normally the middle pin of the rotary encoder) and gpio24, and run the pre-compiled code (IQ_rot) with root privileges from the Pi's terminal and you should be good to go.

PM me if you need an encoder and are in the UK - I may have one lying around somewhere.

Gordon

[Stwert]

Thanks Gordon, appreciate the info. I'm in Canada, but once I get the rest of the setup working I may look into the rotary encoder setup further.