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Minisharc, 8ch Dac, 6ch Amp, 3way speaker 7 years 6 months ago #13064

  • hsmeets
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Hi,

Some stuff I'm working on and would like to share with you.

Deliverables of this project:
1) A pair of 3-way speakers, Kharma Inspired styling, Using ScanSpeak Revelator and Illuminator drivers.
2) A pair of 3ch power amps to drive the speakers. Amps will be based on Hypex UcD modules. Mostly an assembly job but it will also include a small microcontroller to be designed and built
3) A digital Pre-amp: DSP and DAC, volume controle (future source/input selection).

This project is already some months underway, It started early 2013 with the design and construction of a 3-way speaker. You can read about that here . Note: that page needs an update. Speaker build paused before the winter and will start again spring 2014. During the winter I focused on the Pre-Amp build.

To no one's surprise the PreAmps contains a MiniSharc :) The Sharc is used to do all filtering for the speakers and via I2S feed an ESS 9016 based DAC which again will drive the two 3ch poweramps.

The DAC was designed by a member of a Dutch Audio DIY forum. It is basically a kit for a digital stereo pre-amp. He also supplied, via a piggybacked PCB, an 8-ch version. The stereo version is a full digital pre-amp/dac: volume controle, input selection (2x spdif, 2x toslink, 1xI2S) and setting of some of the 9016 registers. I only use the SHARC as input to the DAC and have no use for the input selection. That is also only working on the first 2 inputs (in the standard stereo version the 8 DAC's are paralleled into 2 x 4 DAC's). I have access to the firmware and will alter some parts of the software, like fixing the input to the I2S channel. For the moment I use a Toslink receiver that is connected to the SPDIF input on the Sharc Extension Header.

Status March 2013: All parts have been connected and worked. Now working on installing it into a case.

Some pictures

Start of connecting the PCB's, so disregards the message on the display :)



All PCB's connected, Filter software talks to the Sharc, the VU meters respond to the music fed into the sharc, DAC locks onto the SHARC and outputs signal on the analog output.



The to be frontpanel (some small changed done after the rendering). The knob/dial with blue ring is from OKW, the ring is multicolor via RGB leds.



I'm currently awaiting the receipt of a PCB I designed for the XLR connectors that go onto the back of the cabinet as that is how the power amps will be connected which again is because the UcD by default are layed out for symmetrical input.

As I have access to the firmware I'll re-write some of the code, because I used the DAC as 8Ch I cannot use the standard input selection that is available on the DAC main PCB, to the DAC there is also only one input: the Sharc. I'll remove input selection from the firmware and set it fixed to I2S.

At the moment only one (optical) input suffices for me (a squeezebox). However in the future I maybe plan an input selection in front of the Sharc or maybe integrate an RaspberryPi with PiCorePlayer software and connect the Pi I2S output to the Sharc i2S input (especially now the new firmware allows for slave/master settings and use of the ARSC on the I2S input).
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Re:Re: Minisharc, 8ch Dac, 6ch Amp, 3way speaker 7 years 6 months ago #13069

  • orangeart
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That is the coolest project I've yet seen on here.

Stefan

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Re:Re: Minisharc, 8ch Dac, 6ch Amp, 3way speaker 7 years 6 months ago #13070

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Thanks for the kind words. But IMHO there is some other pretty cool stuff presented on this forum too!

Except for the loudspeakers most of the work is assembly.

For this digital pre-amp I only designed myself 2 PSU's and the XLR 'backplane'. One PSU is used to keep the micro controller powered in standby so the rest can power down. The other PSU is a replacement for the wallwart PSU that is supplied with the MiniSharc. The 8CH DAC was partial build by the designer for me because of the SMD parts and some parts of the DAC (all the through hole stuff) where soldered myself. The rest of the work is preparing the CNC work for the front and back of the case and wiring all up nicely.

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Re:Re: Minisharc, 8ch Dac, 6ch Amp, 3way speaker 7 years 6 months ago #13112

  • devteam
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Wow, That's indeed an impressive setup! Thanks so much for sharing... We'd love to be able to post these pics online. all good with you?
Please do keep us updated. A real neat setup!

DevTeam
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Re:Re: Minisharc, 8ch Dac, 6ch Amp, 3way speaker 7 years 6 months ago #13129

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We'd love to be able to post these pics online. all good with you?


Yes that is fine. It's DIY without any intention to go commercial.


Please do keep us updated. A real neat setup!

DevTeam


Sure, will post updates.

90% of wiring done (had to removed it to better fix the PCB into the cabinet) :



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Re:Re: Minisharc, 8ch Dac, 6ch Amp, 3way speaker 7 years 5 months ago #13970

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Hi,

There has been little progress as it is very busy at work and also some private stuff to take care of too.

The XLR 'backplane' for DSP/DAC is ready:



And recently I pretty much finished the CNC specifications for the backpanel of the DSP/DAC and Amplifier cabinets



and

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Re:Re: Minisharc, 8ch Dac, 6ch Amp, 3way speaker 7 years 4 months ago #14293

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Hello hsmeets,

Can you give us a little bit more information on your DAc module and the VFD module ?
Is it personal dev or standard modules ?

Thanks !

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Re:Re: Minisharc, 8ch Dac, 6ch Amp, 3way speaker 7 years 4 months ago #14295

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Hello hsmeets,

Can you give us a little bit more information on your DAc module and the VFD module ?
Is it personal dev or standard modules ?

Thanks !


Hi,

The DAC is designed by a fellow country man. It follows and borrows from the ESS reference design and the TPA version. He added a microcontroller and display (LCD or OLED, user to choose) to operate the DAC : input selection, volume, IR remote and setting some of the 9016 registers. Normally it is a two channel version. But with the stacked pcb it gains 6 additional I/V converters. It's a design from 2012. In 2013 he reworked it to allow for DSD too but at the expense of multi-channel.

That anwers your question?

Regards.

Huib

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Minisharc, 8ch Dac, 6ch Amp, 3way speaker 7 years 4 months ago #14370

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Hello,

If I understand well, you manage the volume on the DAC board and not on the miniSHARC module. Is that correct ?

I see several inputs :
- 2 SPDIF COAX
- 2 SPDIF TOS
- 8 Balanced XLR

How do you manage switching between all these inputs and send it to the miniDSP ? Do you use a specific board ? With your microcontroler, are you able to pilot the source's switching in the miniSHARC ?

Thanks !

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Minisharc, 8ch Dac, 6ch Amp, 3way speaker 7 years 4 months ago #14372

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Hi,

Yes, the volume control of the ESS 9016 is used. That is already implemented in the firmware of the controllere/DAC kit used. I set the MiniSharc to fullscale once and leave it at that.

For the moment I only use 1 TOSLInk input, the optical receiver is directly conneced to the SPDIF input on the MiniSharc Extension Header. The used TOSLINK receiver transforms the optical signal into an TTL (3.3V) SPDIF signal so no further 'glue' hardware is needed. The receiver is powered by the MiniSharc's 3.3V that is available on the Extension Header.

Some time in the future I will developed a small PCB board that will allow switching between the 2 optical, 2 SPDIF and USB inputs (using one of the USB-I2S boards), provide transformer isolation on SPDIF, adjust SPDIF levels to to TTL levels and connect to the SPDIF (or convert and connect to I2S) input on the Extension header of the MiniSharc. To control the input switching I'll connect it to the already present I2C bus between the processor PCB and DAC pcb. I'll rewrite some of the firmware. That PCB will sit on top of MiniSharc and plug directly into the Extension header.

The 8 XLR's are the analog output of the DAC and input to the 8 channel amplifier.

MiniDSP does not support and provide documentation how to communicate with these devices on I2C, SPI or similar protocolls. So I choose to do it like described above.

Regards,

H. Smeets
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Minisharc, 8ch Dac, 6ch Amp, 3way speaker 7 years 2 weeks ago #15674

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Hi,

Has been quiet for some time. The day job consumed a lot of time and energy until summer. During my summer holiday I took the opportunity to work on the speaker cabinets as I changed my mind a bit and went from vented/basreflex to a closed box with 2 woofers per cabinet.



In the same period I had some CNC work done on the aluminum cases for the electronics. Earlier this week I received it back.

These are the backpanels of the cases, on top the 8 channel amp and below the DAC and DSP.



Also the front panel was done.
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Minisharc, 8ch Dac, 6ch Amp, 3way speaker 7 years 1 week ago #15753

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Beautiful setup! Thanks so much for sharing once again and hope you're now able to enjoy your complete setup.. :-)
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Minisharc, 8ch Dac, 6ch Amp, 3way speaker 6 years 10 months ago #16215

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Sneak preview:
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Minisharc, 8ch Dac, 6ch Amp, 3way speaker 6 years 10 months ago #16235

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heheh.. It keeps improving! That front panel is really well done... Laser engraving?
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Minisharc, 8ch Dac, 6ch Amp, 3way speaker 6 years 10 months ago #16236

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Yes, it is laser engraving.

Still a lot to do. For the moment I have 1 input, a TOSlink receiver attached to the SP/DIF input and 3.3v on the extension. header. 2nd half of next year I hope I find time to build a small input switch board for some more inputs, maybe the TPA mux of something by my own design.

@Devteam: for the minisharc you rewrote the firmware and dedicated pins on the extension header to allow for master and slave use for clock signals by the user. Could you consider 1 more similar firmware change?: if pins are available: could you dedicate 2 pins to select one of the 4 filter presets so we can set filter presets (by switch or microcotroller) without the need for connecting a PC or use your DIGI input board interface and send some IR signals to the board (as one other user did/showed here in the forum).

2 pins on the ext. header to select the filter preset would really be welcome and I guess not alone for me but for more users.

Regards,

Huib.

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