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TOPIC: Re: 6 channel Hypex AMP with built in nanoDigi

6 channel Hypex AMP with built in nanoDigi 5 years 2 weeks ago #7132

Hi guys,

Thought I would share my project here.

I built this to drive a pair of Linkwitz Orions. I have no electronics or speaker-building background, so I did it in two stages: first see if I could drive my subwoofers and old speakers with active crossovers using the amp, and next build the Orions if I could run the necessary dipole equalizers and get enough power (and no clipping). The amplifier works nicely, so now I have an all-in-one box that does what I need. :)





The amp consists of:
4xUCD180HG from Hypex
2xUCD400ST from Hypex
SMPS-supplies from Hypex to run the amps

1 nanoDigi
1 Arduino
2 solid state relays to turn on/off amplifier power in two stages (no soft-start installed)
1x Twisted Pear 4xSPDIF mux
3x Twisted Pear SPDIF->I2S tranceivers
3x Twisted Pear Opus DACs using the WM8741 DAC chip
Some logic converters (5v-3.3v) for the DAC, and some "perma-breadboards" for various functions
LCD display
Rotary encoder
IR receiver
Button
Wall-wart for low-voltage power. Might change this to better supply for the analog section of the DACs.
Case is from diygene.com
Most electronics from elfa and adafruit.

It works like this:
Four coax spdif inputs are routed to the SPDIF mux. From there the signal goes to the nanoDigi, and is split into three stereo channels (woofers, mid, tweeters). The SPDIF signals go to the tranceivers that converts them to I2S, and onwards to the Opus DACs. The Opus DACs are directly connected via balanced leads to the Hypex amps (400w for woofers, 180w per midrange and tweeter).

The Arduino controls the following:
* Power-on/off sequence, ensuring pop-free startup and shutdown of the Hypex parts
* Volume and DAC filter, by using SPI to control the WM8741 DACs (thanks to Hifiduino for inspiration). I rewrote Hifiduino's code due to a few bugs on addresses, and also because I'm using SPI (can't remember why I'm not using I2C now :))
* Music source, by interfacing with the Mux
* Standby, volume and source can be set with the button and the rotary encoder
* Standby, volume, dac filter and source can be set with a remote control

I have two neutrik USB connections on the side of the amp for easy access so that I can adjust the filters in the nanoDigi and upload new software to the Arduino.

The system works beautifully. Although I cannot say anything about S/N ratio, dynamic range yet (I have not measured it), it certainly sounds pretty much perfect to my ears. I need to reduce input gain by 14db to ensure I don't get digital clipping in the bass (the Linkwitz Orions need 20db gain at 20hz). 14db is set to ensure the Tron Legacy soundtrack doesn't clip on my system, as those tracks have more low frequency content than most music i'll ever listen to.

The nanoDigi is a great platform. Next version should have I2S outputs for each channel (and a combined one if that exists), so that one might skip the conversion from SPDIF to I2S. I like the Opus DAC, as it has balanced outputs out of the box (no need for an extra stage).

To set up the nanoDigi for the Orion, it's necessary to use the biquads extensively. I used the Active Crossover Designer tool designed by Charles Laub to match response and phase curves to the Orion ASP. The tool is superb!

If I were to do it again, I would probably use a bigger box and go straight for 8 channel, so that two subwoofers can be added. For Orions, subwoofers aren't needed unless you want extreme SPLs or watch movies with lots of LFE content at high volume.

A (poor) photo showing one of the Orion's with the amp:

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Last Edit: 5 years 2 weeks ago by martin.nore.
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Re: 6 channel Hypex AMP with built in nanoDigi 5 years 2 weeks ago #7134

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Nice!
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Re: 6 channel Hypex AMP with built in nanoDigi 5 years 1 week ago #7194

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Wow Martin, that's pretty high up there on the advanced setup we've seen here... What a beautiful setup and well thought out too!

That's a lot of components (and even a bit of firmware dev) and it sounds like you've spent a lot of hours on the whole story. Any idea of the overall man hours you've spent here?

A truly well thought out unit and Thanks again for sharing!

DevTeam
MiniDSP, building a DIY DSP community one board at a time.
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Re: 6 channel Hypex AMP with built in nanoDigi 5 years 1 week ago #7210

Thanks for the feedback! :)

I spent a lot of time... trying and failing. Many evenings. But I think somebody with any experience would be able get it done much quicker. The only thing I knew before doing it was C programming, so the firmware part was easy (Arduino is amazingly intuitive). The rest was all new. So I suppose i picked up something useful along the way. At least enough to trigger an interest in new projects. I suppose the next project would be something with your miniSharc platform - looks exciting!
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Re: 6 channel Hypex AMP with built in nanoDigi 5 years 4 days ago #7250

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Well, you can be proud of your achievement Martin!
Maybe you can have a second life doing custom audio products.. ;-)

DevTeam
MiniDSP, building a DIY DSP community one board at a time.
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Re: 6 channel Hypex AMP with built in nanoDigi 4 years 9 months ago #7983

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Wow

This is great work. I am thinking of something very similar.

Why did you not use a single Buffallo III DAC? It includes volume control, and handles up to 4 stereo pairs.
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Re: 6 channel Hypex AMP with built in nanoDigi 4 years 9 months ago #7986

Dublin78,

Thanks for your feedback.

I think I came to the conclusion that 3 Opus DACs were easier, as they are voltage output and not current output. Although I don´t recall the numbers, I believe the Opus DAC and the Hypex AMPS are a good match from an impedance perspective.

If I understand this right, the Buffalo DAC needs output stages. On the other hand, the Buffalo can accept AES3 inputs (which I believe at TTL-level S/PDIF signals). The nanoDigi outputs S/PDIF, so it might be cheaper to increase the voltage on those outputs to connect directly to the Buffolo DAC than to use S/PDIF->I2S receivers as I have done.

If you use a miniSparc, you won´t need to deal with SPDIF or AES3 at all, as the miniSparc outputs I2S directly.

As for volume control - I believe the Twisted Pear volume controls work by manipulating registers in the DAC chip, same as I have done using an Arduino. If you plan to have source selection, run the power sequence etc using an Arduino (or other platform), you might just as well do the volume control in the same way. This way you can show your volume level on the LCD for example.

If you go ahead and do something using the Buffalo, I would be very interested in hearing about your progress. Perhaps create a page here or at diyaudio.com and post your progress periodically? You might get some good input along the way from other users.
Last Edit: 4 years 9 months ago by martin.nore.
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Re: 6 channel Hypex AMP with built in nanoDigi 4 years 9 months ago #7993

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Hi Martin

Thank you for the quick response.

I had been aware of the Opus DACs but I had not looked into them much. As you say there is no need for 3x IVY output stages, and they are exceptionally good value. There is a big saving in simplicity, money, and chassis real estate. Can you run 3x Opus DACs off one Twisted Pear LCDPS? That would be great. Do you run balanced directly to the Hypex UCD units?

Since your reply, I think that my conclusion is MUX 4:1 via 12S to miniSHARC with optional volume control to 3x Opus DACS again via 12S. I have 2x Hypex UCD180HG hxr units for my main build (not completed). I am not sure that I have the budget for 6x UCD180HG hxr, or I can't justify it for a second system. I do wonder what improvements they have over the standard UCD180ST. Anyone know?

My drivers are all scanspeak revelators, so it will be a revealing (sorry) system.
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Re: 6 channel Hypex AMP with built in nanoDigi 4 years 9 months ago #7994

I run balanced directly to the hypex UCDs.

I am not sure about the LCDPS as I didn´t use it. I am running all low-voltage electronics from a cheap switching wall-wart. I suppose replacing that one would make the system even better, but I haven´t gotten around to it so far

One thing to keep in mind is that the Opus DAC is designed with separate regulators for the digital and analog sections of the DAC chip. It also has separate connections. So you could consider running an expensive power supply for the analog sections only, powering the rest of your low-voltage system (DSP, digital section of DACs etc) with a simpler/higher capacity power supply. I´m not able to tell you if it would give any audible effect though.

I used HG versions for the mids/tweeters, and ST for the woofers (but 400 though, each running 2 L26R04Y from SEAS connected in parallel). If you look at the data sheets from Hypex they should tell you what the difference between ST/HG/HXR is. I have only heard my system with Hypex amps, so I can´t really say whether there is an audible difference.

If you are going to use lots of dipole EQ, linkwitz transform on the woofers or similar, it would be good to take into account gain structure while you are designing your system. I believe I should ideally have reduced the gain on my mid/tweeter channels compared to the woofers to maximize resolution in the DSP/DACS in those two channels, since the crossover for the Orion uses lots of boost in the low end.
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Re: 6 channel Hypex AMP with built in nanoDigi 4 years 9 months ago #7995

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Hi dublin78

Very interesting project you're working on! I would also like to use miniSHARC and Opus DAC for a four way system, but I'm struggling with the I2S clock I/Os on the miniSHARC - obviously, the miniSHARC can only work in Master mode (no slave mode possible); It does not seem to have any I2S LRCK and BCLK and MCLK out pins, but they are needed for the Opus DAC...? any idea?
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Re: 6 channel Hypex AMP with built in nanoDigi 4 years 9 months ago #8003

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Have you asked miniDSP for help? They have hailed this board to be very simple to integrate into OEM systems.
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Re: 6 channel Hypex AMP with built in nanoDigi 4 years 9 months ago #8123

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svt-810

The User Manual has now been put up on the website.

MCLK: Pin 9
LRCK: Pin 14
BCLK: Pin 15

DATA IN: Pins 10 -13
DATA OUT: Pins 16-19

DIGITAL GND: 5,6,7,8,23,25,26

Please let us know whether this works.

I was planning on using a TP MUX4:1 as an input device/switch via 12S. I hope that this would connect in the same way as OPUS.
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Re: 6 channel Hypex AMP with built in nanoDigi 4 years 9 months ago #8135

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user manual is helpful. I do not yet own any miniSHARCS - since I would be using a pair of miniSHARCs (one for the left speaker, one for the right, fed with I2S comming from the all digital preamp), my real issue is that the current firmware only allows the miniSHARC to be clock master and not clock slave.

I guess I might start using a pair of miniSHARCS with SPDIF instead of I2S (assuming the SPDIF is routed to the ASRC of miniSHARC).
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