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-   -   Multichannel I/V stage for Buffalo III? (http://www.diyaudio.com/forums/digital-line-level/228981-multichannel-i-v-stage-buffalo-iii.html)

Crumboo 30th January 2013 07:46 AM

Multichannel I/V stage for Buffalo III?
 
Hi,

I'm looking for a 8 ch I/V stage for use with my Buffalo III dac that I'm putting together. Are there any available options for this? All I/V-stages I've found so far are mono or stereo only. Of course it is possible to use several of them, but maybe there is a neater, not to expensive, solution? Only balanced outputs are required, so no BAL/SE conversion is needed.

Best regards,

Mattias

qusp 30th January 2013 08:42 AM

nope, you will have to make your own i'm afraid, but it will basically just be 4 x 2 channel IVs tied together, because thats what it is, there is no short cut if you want an active solution. you will have to take into account the 4 x lower current available per channel, for your choice of IV resistors and filter values.

knuisje 30th January 2013 09:08 AM

3 Attachment(s)
I developed an ES9016 based dac with 2 I/V converters onboard. I have an expansion board available for 6 additional I/V converters that can be stacked onto the dac board.

At the pictures you can also see the supply and controller boards.

qusp 30th January 2013 03:49 PM

well there you go...

how do you find the 9016? seems just 9018 without external DVDD. seems to just be the same die. do you have much experience with 9018 to compare? the reason I ask is I have started planning my own 9016 board for my subs, as well as a small multichannel to play with. i'm running 2 x 9012 dacs for 2 ways with discrete SS IV stages, but wanted to do something a bit less involved for the subs

knuisje 30th January 2013 05:53 PM

I haven't heard the 9018 but the 9016 sounds excellent. About 10 of these dacs are built by members of a Dutch diy forum with very positive feedback. And as you say the dies are probably identical.

georgehifi 30th January 2013 07:54 PM

Why not use 8 of these, with or without the built in buffer.
http://www.diyaudio.com/forums/digit...ml#post3316991

Cheers George

qusp 30th January 2013 08:15 PM

Quote:

Originally Posted by georgehifi (Post 3349025)
Why not use 8 of these, with or without the built in buffer.
http://www.diyaudio.com/forums/digit...ml#post3316991

Cheers George

because he needs 8 x balanced; 16 of them is a touch OTT

Crumboo 30th January 2013 09:28 PM

Quote:

Originally Posted by knuisje (Post 3348310)
I developed an ES9016 based dac with 2 I/V converters onboard. I have an expansion board available for 6 additional I/V converters that can be stacked onto the dac board.

At the pictures you can also see the supply and controller boards.


Wow, that looks like something I was looking for; thank you. I don't know about the difference between ES9016 and ES9018 either, but do you think that board would work with Buffalo III? Are the connections to the DAC lined up accordingly?

Otherwise; can you share a schematic of the board and BOM so I can do an own PCB layout based on your work?

knuisje 30th January 2013 09:44 PM

The layout of the expansion board is specifically designed for my dac board and doesn't fit the connections of the buffalo dac. Have a look at the TPA IVY-III for an I/V schematic you can use for the buffalo dac.

qusp 31st January 2013 05:55 AM

Quote:

Originally Posted by Crumboo (Post 3349159)
Wow, that looks like something I was looking for; thank you. I don't know about the difference between ES9016 and ES9018 either, but do you think that board would work with Buffalo III? Are the connections to the DAC lined up accordingly?

Otherwise; can you share a schematic of the board and BOM so I can do an own PCB layout based on your work?

I do know the difference objectively, I have the datasheets for both and have been playing with 9012/9018 for years. the output SNR, DNR and THD are lower, roughly 10-15db vs the premium parts, but as far as I can see, this is only created by less pins being brought out and thus more voltages generated internally from other voltages, maybe a slightly different process and smaller die perhaps. but otherwise the part is identical, firmware for 9018/12 should even work with minimal changes if any. operating points, supply voltages, digital filters, MUX, voltage and current on the outputs and operating points are all identical. thats why I think its just the same part, perhaps less discriminating internal element matching as well as the other stuff above brought the lower, nbut still pretty stellar performance.

the board above is a standard opamp based IV, nothing tricky there, look for the es9008 application note, there is a multichannel schematic and good layout recommendations/application note. again it should be able to be applied with decent results.


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