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PhiDAC hex kits with pre-built filters

Update 13th April 2021

Here is where you can find a guide to soldering up your Phi DecaDAC kit : PhiDAC hex kits with pre-built filters

Update 8th Feb 2021

Prices for PhiDeca DAC :

Kit with ready-made 7th order filter : 480RMB (~$72)
Kit with ready-made 3rd order filter : 260RMB (~$39)

For existing customers of PhiDAC hex only, Deca baseboard kit : 160RMB (~$24)

Fee for assembling kit and testing DAC : 200RMB (~$30)

Update 6th Jan 2021

PhiDAC hex is in the process of being superceded by Phi DecaDAC - the latter using 10 DAC chips in parallel rather than 6 as in the 'hex'. PhiDeca DAC kits are going to be simpler to build and hopefully will be available from mid-Feb. The vast majority of the SMD passive parts (Rs and Cs) plus SOT-23s will be pre-soldered at the factory. This leaves the builder to solder ICs, a handful of discrete semiconductors and the through-hole parts (caps and connectors).

PhiDeca DAC needs a 15V regulated power supply, max current draw is 160mA. A 500mA rated linear wall-wart is suggested.

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Orders now are open on PhiDAC hex kits with pre-built filters - feel free to PM me. In your message please let me know your location and your choice of payment method and shipping, then I'll have enough info to give you a firm quote.

Preferred payment method is via Transfer Money Online | Send Money Abroad with TransferWise which typically adds a 2% fee. Our receiving currency is USD or Euro. PayPal may also be used, in USD but will attract higher fees, about 16%.

Kit for PhiDAC hex mainboard with 7th order filter pre-built and tested : 470RMB (~$70)
Kit for PhiDAC hex mainboard with 3rd order filter pre-built and tested : 280RMB (~$42)

Kit for PhiDAC hex with both filters 560RMB (~$84)

Shipping rates are in addition and depend on your location and speed of service. Courier (FedEx, TNT, DHL) typically takes 8 - 10 days and e-packet two to four weeks. Not all locations can be serviced by e-packet though.

I have prepared (mostly the work was done by my wife) a graphic of how to proceed with soldering your PhiDAC hexkit. Its here : lingDAC - cost effective RBCD multibit DAC design
 
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Yes - if you buy the two filter option, both filters will be populated and tested. You can change them but the connectors used are not designed for many reinsertions. There are two 20way 2mm pitch pin headers on the filter boards which fit into receptacles on the mainboard. A bit of wiggling side to side is recommended to prize the two apart - you don't want to flex the filter board.

You also had questions (by PM) which are good to raise here as I would guess others may well have similar ones.

What else is needed to make this fully operational?

The DAC needs a single power supply of 12V minimum, 15V maximum. The current requirement is under 150mA. I'd recommend not using an unregulated supply as it might not stay within those limits.

The digital input is I2S, three signal wires plus 0V. Some digital sources provide I2S (for example Raspberry Pi) but others may use S/PDIF or USB. To handle those interfaces you will need a separate PCB to convert to I2S. I can supply one of those if you ask me at the time of ordering your kit - the interface won't be of my own design, rather one I source on Taobao.

The outputs from the DAC are standard 2VRMS as would come out of a CD player. No connectors are supplied with the kit - if you want RCAs you can have them for a small additional fee.

As for support, yes I fully intend to support all builders of this kit who have questions. I also plan to make build recommendations available - for example sequencing the build so you get to test the power supplies first to minimize risk to other components should you introduce an error. Test points are provided on the PCB so you'll want to have at the very least a digital multimeter that can read mA and mV so you can verify the correct operation of your build. If you don't have one already, this is the one I use and highly recommend : ZT219?4??19999????????????ZOYI???????-???

What's supplied in the kit?

The bare PCB for the mainboard (100mm * 62mm) plus all components that mount on this board (ICs, resistors, capacitors, ferrite beads etc.). There are some through-hole capacitors (10mm diameter electrolytics) but by far the majority of components are surface mount, 0805 size, none are smaller than that. The ICs are all recycled ones (some, including the DAC chips are no longer in production) and for those where I've found potential reliability issues I include a spare. The pin pitch of the ICs used is 1.27mm. If you order the filters they are fully built and tested for frequency response before being shipped.
 
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Wonderfull project. Seems to be one of the only real DIY DAC products out here, that are not absurdely expensive.

  • how does this DAC compare to commercially available products? I read up on hacaday.io, but cannot seem to find any reviews or listening impressions, besides your own.
  • does it support digital volume control, EQ? If not, can it be easily implemented?
  • The input is I2S, so together with an I2S input selector, bluetooth to I2S, usb to I2S, Toslink to I2S and a RPI this can be built into a "full" integrated product. Correct?

Thanks!
 
Wonderfull project. Seems to be one of the only real DIY DAC products out here, that are not absurdely expensive.

Thanks for your kind words, appreciated!

how does this DAC compare to commercially available products? I read up on hacaday.io, but cannot seem to find any reviews or listening impressions, besides your own.

Its a new design so very few people have heard it beyond the walls of my apartment. The lingDAC thread which this thread is spawned from has a few impressions of the earlier generation (PhiDAC) and to my ears (and my wife's too) this is a step up over that. The technical improvements are threefold - firstly paralleling several DAC chips lowers the DAC-generated noise, subjectively providing more low-level details, especially ambience. Secondly the improved ultrasonic rejection of the 7th order filter subjectively gives a lower noise floor and better dynamic contrasts. Lastly the bypassing of the opamp classAB output stages with SE classA stages subjectively cleans up the higher frequencies.

As to how this DAC compares to commercially available products - if there was an affordable one that I found satisfying to listen to I would very likely not have spent so much time developing this one. But that's just my particular slant, I don't think I have mainstream tastes in music, my diet is predominantly classical: solo piano, choral, orchestral and opera. In my view these kinds of music are more demanding of DACs than the more popular genres.

does it support digital volume control, EQ? If not, can it be easily implemented?

There's no digital processing on-board no. But digital volume and EQ can be implemented up-stream of the DAC with the caveat that it only accepts 16bit inputs.

The input is I2S, so together with an I2S input selector, bluetooth to I2S, usb to I2S, Toslink to I2S and a RPI this can be built into a "full" integrated product. Correct?

That is the aim, yes. I'm not 100% confident about building it into the same enclosure as a RPi though as that's known to be something of an EMI aggressor.
 

terranigma

Member
2007-02-11 12:06 am
There are a couple using CM6631A that look suitable to me. I prefer the CM6631A to an XMOS solution - for PhiDAC hex we don't need any sample rates beyond 192k nor DSD.

???CM6631A USB?I2S????/USB????/????/XMOS DAC-???

????CM6631A????I2S SPDIF??24Bit 192K 384K ASIO-???

If you have your own preference then sure, we'll order the one you want to accompany your PhiDAC hex order.

I ordered 7th order kit and two usb interfaces of my choice. Thank you for cooperation. DSD format or absurdly high sample rates are not my main interests. I rather look at PCB and component quality, especially oscillators.
 
Happy to hear you find it so interesting - the original thread is here, scroll down to the most recent posts for PhiDAC hex pictures and schematic : lingDAC - cost effective RBCD multibit DAC design

A couple of pictures of the DAC with the two filter options to whet your appetite are attached.
 

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George is planning to wind the P14s (ferrite cores) himself as he has an inductance meter. The coil is about 10m of 0.33mm wire, sufficient for 6 inductors.

The yellow PCB is the SE buffer board from lingDAC - you can find schematic and gerbers on that thread. Could be George wants to use that to drive headphones as PhiDAC hex doesn't provide a direct headphone out.
 

terranigma

Member
2007-02-11 12:06 am
I have a LCR (CHY 21) with 1μH sensivity and ±5%+20 accuracy at 4mH step. Do you think that this device is within the limits?

I'm using a passive preamp (10k pot) to drive my amplifer. Could this cause stress on Phidac's output without buffer? I don't like active parts on signal path if they are not crucial.