Rasp-Pi, USB to I2S, DAC, Class D amp, B&W 805s

2014-03-02 18.12.30.jpgSo I decided that getting a home made R-Pi based thing going was going to be my Christmas project.
I’ve got MP3 streamers in most rooms - Slim Devices Slimp3s and some Squeezeboxes. All from the proper Sean Adams days. I’ve also got some high end stuff based on Linn streamers, Naim amps and B&W speakers (lossless).

The idea first started as my Slimp3s are slowly dying. So I planned to just get a Pi to stream from the squeezeserver through the analogue out. This worked and is ok, but the analogue out is poor as we all know. I had a gismo to get the audio stream out of the HDMI which was actually quite good.

Then I came across RaspyFi and liked the idea of seeing how it could all compare in the lossless world. I bought a USB to I2S board plus a DAC and started soldering. Not hard but a bit of a learning curve.

So that was all together last weekend. Time to get it all working. Took me a while to get to the FLACS on the QNAP, but got there in the end.

So all plugged into the NAIM preamp alongside the Linn streamer. Utterly fantastic comparing complete budget lossless audio with the top end from Linn. This is with 4xNaim 250s biamping a paid of B&W 802s. Really hard to tell the difference!

I also bought a cheap class D 2x15w amp kit off ebay for £8 plus £4 postage. Lots more soldering. Well that got finished today and it works. I’ve got it hooked up to a pair of B&W 805s (which are by far my favourite speakers of all time).

It sounds astonishing. I’m listening to Scratch my Back by Peter Gabriel.

There is an occasional slight small pop, not sure if it’s the amp or from the Pi/DAC setup yet.

All I can say is well done and thanks to everyone involved in the Volumio project.

Next stop hifiberry to get rid of the USB part and reduce the power supply needs.

Graham

Can you do some a/b comparisons of the songs with 802s and the power amp that drives them relative to Linns?

Great speakers!! :sunglasses:

Yes, I have attempted that. The main problem is volume levels. The Linn DS is much louder than the R-Pi/DAC setup. I can’t think of a way to get the two levels the same - without manually changing the volume level via the gain on the Naim pre-amp.

When I do this - swap between sources and adjust the level, the overall impression is of very similar sound quality. Which is astonishing frankly - although it’s the whole point of Volumio!

Anyone have any clever ideas on how to equalise the volumes? Rasp-pi quieter than the Linn DS?

Graham

Graham, I suggests you take a look at PeteManchster’s MediaPlayer project on GitHub. Completely compatible with your Linn setup and equally good sound quality. Pete is also developing some nice goodies around it.

I am using the same D-amp for one if my setups. I replaced the caps with higher end ones. Amazing price/quality ratio.

Guus

what chipset are the class D amps using ? :question: