IQaudIO.com Pi-AMP

Audio Gear Amplifiers
1

Hi, thought you may like to see a picture of the pre-production Pi-AMP (iqaudio.com/?page_id=34).

This Raspberry Pi sized Class D stereo amplifier delivers stunning audio quality - suitable for any audio project and particularly useful when combined with i2s based DACs such as the IQaudIO.com Pi-DAC with built in hardware volume control.

The IQaudIO.com Pi-AMP is based on the Texas Instruments TPA3118D2. We’ve focused exclusively on audio quality components throughout to deliver an exceptional sonic performance. It sounds fantastic - even with a simple 12v 1.5amp wall plug!

We expect to conclude the design and sign off for mass production in the coming weeks, ready for summer - at what we believe is a great price.

There’s no special Linux driver or similar needed but for those who wish to enable / disable the amp from under software control this is possible via one of the Pi’s GPIO.

Feedback welcome.

Best regards,

Gordon@IQaudIO.com

2

This is also for headphones?? :confused:

3

No not for headphones - this is designed for output to speakers only.

4

:cry: will be great if your create a amp for headphones :mrgreen:

5

We’ve done something different for headphones - we’ve released the Pi-DAC+ (for the Raspberry Pi B+ model). It has the same great TI PCM5122 DAC but also a brilliant little headphone amp so you can use the Pi in your office, for personal listening or similar.

The Pi-AMP is in development and has morphed slightly to become the Pi-AMP+ and will now sit atop the Pi-DAC+.

More details in the coming weeks.

Gordon@iqaudio.com

6

Any recommendations re which 20 watt speakers to try?

7

That’s very interesting and would make a nice AIO solution for some compact network attached player. Add very efficient drivers with low Vas and you have a winner :smiley:, something around the Fostex 80/100mm full range drivers.

8

The Pi-AMP+ is being manufactured now. It fits on top on the Pi-DAC+ to deliver 2x20w and supports 24/192 playback.

The Pi-DAC+ also has a headphone amp and if headphones are inserted the Pi-AMP+ will auto mute.

As for speakers - that’ll be a personal choice. For drive units only I’d suggest maybe look at BMRs which are full range so no cross over needed.

BR,

Gordon

9

Great news Gordon, thanks for keeping us informed. The auto mute feature is very welcomed. About the headphone amp, how much power can it deliver ?

10

Headphone amp is the Texas Instruments TPA6133A2
ti.com/product/tpa6133a2

Best regards,

Gordon

11

IQaudIO.com Pi-AMP+ back from fabricators and under test - will be available on Tindie in the next few days.

We’ll also stock the superb 60w 15v / 4amp XPpower AC/DC adapter.

Pi-AMP+.png

12

Yes !!! :smiley: :smiley: :wink:

13

Great news. Can’t wait to see more.

14

Really great news!! :mrgreen:

15

Now available through Tindie.com

Thanks everyone.

Gordon

16

Hi everybody !
I recieved yesterday (Wenesday) my PI dac+ and PI-amp+ (ordered Saturday !!!) Thank you Gordon !
The Psu is 15V is a brick bought with the rest.
First impression : it is very small !!!
After some minutes spent to assemble with the RPI b+, it was test time !
First fear, no sound, even if lights were on.
I check in Volumio config : all was ok…
So I ask Gordon and he gave a very quick answer to unmute the amp.
About the sound ?
Fire ! Whaou!!!
I only did quick tests, but it sound very well. I was happy with my previous system (ess9023 dac and TPA3116 blueboard amp) but it is really another level. I can’t say if it comes from the dac or the amp or both. The basses are very punchy. The medium and voices are less agresifs than before. It’s very clear with a good stereo image very detailed.
So I’m going to carry on to test with various music in flac stored on my nas!

17

Hello,
The pi-amp is mute by default to protect loudspeakers when power on. It needs to be unmute and there is two ways :
hardware : just by fitting a jumper to the two exposed pins P9
software : by using GPIO ( I use wiringpi and it works)
The link for that : iqaudio.com/?page_id=485
My question is : how to set the unmute mode using GPIO in Volumio at boot time -> in rc.local ? or elsewhere
And for the shutdown of the system ?
Any advice / experience ?
Thanks !

18

Hi!
I’m stuck with this problem of unmute the pi-amp at boot time.
If I type the command given in this page iqaudio.com/?page_id=485 in a terminal, it works.
So I try to put it in the /var/www/_OS_SETTINGS/etc/rc.local

[code]#!/bin/sh -e

rc.local

This script is executed at the end of each multiuser runlevel.

Make sure that the script will “exit 0” on success or any other

value on error.

In order to enable or disable this script just change the execution

bits.

By default this script does nothing.

/var/www/command/player_wdog.sh startup & > /dev/null 2>&1
/usr/local/bin/gpio mode 3 out
/usr/local/bin/gpio write 3 1
exit 0
[/code]
But it doesn’t work.
So I wrote a script I called “unmutepiamp” containing the command

#!/bin/bash /usr/local/bin/gpio mode 3 out /usr/local/bin/gpio write 3 1 echo "pi-amp unmuted" exit
When I launch the script, pi-amp is unmute !
So I invoke this script in the /var/www/_OS_SETTINGS/etc/rc.local
But it still not works :frowning:
I did the same in /etc/rc.local and no more success.
I really don’t know how to do…

19

Sorry, I missed this post - if you don’t have it up and running yet then please download the pre-configured Volume SD card image from www.iqaudio.com/downloads

Let me know by direct email - gordon@iqaudio.com

20

You’re doing it wrong.
One good way could be:
add this to /var/www/command/player_wkr.php

$cmd = "pathtoyourscript.sh" ; sysCmd($cmd);

before (or after if you don’t wanna hear the startup sound)

//Startup Sound if (isset($_SESSION['startupsound']) && $_SESSION['startupsound'] == 1) { $cmd = 'mpg123 -a hw:'.$device.' /var/www/inc/Sounds/startup.mp3 > /dev/null 2>&1 &'; sysCmd($cmd); }

This should do the trick.
There are better ways to achieve that. Like an init script…
Let me know

@Gordon, I don’t remember you to ask me to put a modified Volumio version on your website, could you explain that?