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Author Topic: The Seventy Nine Dollar Converter  (Read 21888 times)

Jim Williams

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The Seventy Nine Dollar Converter
« on: September 19, 2008, 11:24:55 am »

Here's a nice low budget DAC;

MCM Electronics P/N # 50-7774

www.mcmelectronics.com

It's a 24 bit 96k dac with 2 coax and 2 toslink inputs, a fixed and variable output and a headphone amp. It uses a nice BurrBrown PCM1716 dac chip with a crystal CS8414 input reciever chip. The caps are all 105 degree rated. The weak spot is the 4558 opamp, I replaced it with a National LME49722MA, a very nice improvement.

It's on sale until Oct. 18 for $79.95. Use the source code 808A28 for the discount.
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Jim Williams
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hargerst

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Re: The Seventy Nine Dollar Converter
« Reply #1 on: September 19, 2008, 11:35:13 am »

Looks nice, Jim.  Do they have a cheap (but good) A to D converter?
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Harvey "Is that the right note?" Gerst
Indian Trail Recording Studio

Jim Williams

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Re: The Seventy Nine Dollar Converter
« Reply #2 on: September 20, 2008, 12:02:11 pm »

No budget A/D from them but another source is available for that.
BurrBrown makes a very nice A/D evaluation pcb for the PCM4222 A/D converter, their top-o-line chip. It's the PCM4222EVM.
Get one direct from TI at:
www.TI.com
Search the PCM4222EVM and it comes up. It costs $149 and requires a power supply with + - 15 volts and a single 5 volt rail. Power One/Condor makes a nice small 3 output power supply that runs around $70. You can get that from digi-key.
This converter has bested some very expensive products in the $5k price zone, so it's a serious contender. It has DSD outputs, dual s/pdif and AES outputs, digital filters, etc. all selectable via dip switches.
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Jim Williams
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elie

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Re: The Seventy Nine Dollar Converter
« Reply #3 on: September 21, 2008, 11:59:42 am »

Hi Jim!  In which context do you use the DAC?  In your point of view, how does it perform compared to more expensive units?  

About the TI ACD: I've been considering getting one of these for a while...  Would you care to explain exactly what kind of work should I expect to have it boxed and running?  How much soldering, wiring, etc?  

Thanks for the good info!

E
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Jim Williams

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Re: The Seventy Nine Dollar Converter
« Reply #4 on: September 21, 2008, 12:48:26 pm »

I have the Seventy Nine Dollar Converter wired up with multiple sources like the soundcard out, the DAT, the CD player. That feeds the 2 track return of the console for monitoring. I have better stuff here for tracking/mixing like BB PCM1704, 1792, etc, but this is convienient as I just pop the switch and listen though the console or headphones. I like this DAC better than the top-o-line Crystal CS4398, their top-o-line part. The imaging is good on this BB part.

The PCM4222EVM needs a power supply, that's it. Everything else is mounted, balanced XLR/TRS inputs, dual s/pdif and AES outputs. Add + and - 15 volts and + 5 volts and it's ready to go. A better value will not be found.
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Jim Williams
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elie

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Re: The Seventy Nine Dollar Converter
« Reply #5 on: September 21, 2008, 01:26:21 pm »

Thanks for the info!

What do you say is your favourite dac for mixing?  Is there a good dac eval kit which you'd recommend?  

It seems like a great value indeed!
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Jim Williams

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Re: The Seventy Nine Dollar Converter
« Reply #6 on: September 22, 2008, 10:59:24 am »

My favorite dac at the moment is the BurrBrown PCM1792. I have a BB lab pcb of that and the PCM1704. They are fitted with direct coupled class A TI THS high speed opamps and some nice resistors, caps. BB doesn't offer these boards anymore, besides they used to cost $900.

Cheapy A/D's are a bit harder to find. The BB PCM4222 EVM is the best value at $149 sans power supply.
www.TI.com
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Jim Williams
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marcel

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Re: The Seventy Nine Dollar Converter
« Reply #7 on: September 22, 2008, 12:45:11 pm »

Jim:

Is the National op-amp a direct replacement?

Thanks.
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Rod Affleck

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Re: The Seventy Nine Dollar Converter
« Reply #8 on: September 22, 2008, 02:19:53 pm »

Jim Williams wrote on Sun, 21 September 2008 13:48


The PCM4222EVM needs a power supply, that's it. Everything else is mounted, balanced XLR/TRS inputs, dual s/pdif and AES outputs. Add + and - 15 volts and + 5 volts and it's ready to go. A better value will not be found.


Okay this sounds exactly like what I need right now, except for one concern--if I output the s/pdif from this into the s/pdif input on my Motu 828, am I going to see any gain in a/d conversion quality through this unit, or is everything going to be limited by the Motu? I obviously have no idea how s/pdif works.

Moderators, since this is getting off topic if you want to split this into a separate thread that's fine.
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brett

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Re: The Seventy Nine Dollar Converter
« Reply #9 on: September 22, 2008, 07:13:19 pm »

evil robot wrote on Mon, 22 September 2008 19:19

Jim Williams wrote on Sun, 21 September 2008 13:48


The PCM4222EVM needs a power supply, that's it. Everything else is mounted, balanced XLR/TRS inputs, dual s/pdif and AES outputs. Add + and - 15 volts and + 5 volts and it's ready to go. A better value will not be found.


Okay this sounds exactly like what I need right now, except for one concern--if I output the s/pdif from this into the s/pdif input on my Motu 828, am I going to see any gain in a/d conversion quality through this unit, or is everything going to be limited by the Motu? I obviously have no idea how s/pdif works.

Moderators, since this is getting off topic if you want to split this into a separate thread that's fine.



it's $79. do you really beleive this will improve your sound by any measurable amount regardless of what you read on a forum?  
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Tomas Danko

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Re: The Seventy Nine Dollar Converter
« Reply #10 on: September 23, 2008, 03:42:44 am »

brett wrote on Tue, 23 September 2008 00:13

evil robot wrote on Mon, 22 September 2008 19:19

Jim Williams wrote on Sun, 21 September 2008 13:48


The PCM4222EVM needs a power supply, that's it. Everything else is mounted, balanced XLR/TRS inputs, dual s/pdif and AES outputs. Add + and - 15 volts and + 5 volts and it's ready to go. A better value will not be found.


Okay this sounds exactly like what I need right now, except for one concern--if I output the s/pdif from this into the s/pdif input on my Motu 828, am I going to see any gain in a/d conversion quality through this unit, or is everything going to be limited by the Motu? I obviously have no idea how s/pdif works.

Moderators, since this is getting off topic if you want to split this into a separate thread that's fine.



it's $79. do you really beleive this will improve your sound by any measurable amount regardless of what you read on a forum?  



I wonder what the pricetag would be if a known company boxed it up, put their brand name on it and did some marketing... Let alone making an 8-in 8-out interface like that.

That's really the price range one should compare it to. I wouldn't be surprised if it sounded better than the Motu 828. Imagine the cost of that Motu if they had put a bunch of these boards in there (since it's a multi I/O converter). Most definitely the analog back end of the Motu DAC is not as solid as the National opamp Jim uses instead of the 4558. Otherwise companies such as Black Lion Audio wouldn't bother modding Motu's.
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Rod Affleck

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Re: The Seventy Nine Dollar Converter
« Reply #11 on: September 23, 2008, 07:12:01 am »

That's my thinking precisely. (Also for the record I was inquiring about the Texas Instruments evaluation module a/d converter which is $149.) While I'd love to have a good-to-great 8 or 16 in converter like an Apogee or Lynx or whatever even fancier name you want to insert here, realistically if I can add two good channels to my existing mediocre eight channels for $300 or so (once power supply and case are factored in) then I'd be extremely happy.
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Tomas Danko

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Re: The Seventy Nine Dollar Converter
« Reply #12 on: September 23, 2008, 07:23:15 am »

Ah yes, it was the A/D converter you meant. Well, the MOTU interface can be transparent when hooking the TI A/D into S/P DIF no worries.
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Jim Williams

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Re: The Seventy Nine Dollar Converter
« Reply #13 on: September 23, 2008, 10:48:17 am »

marcel wrote on Mon, 22 September 2008 09:45

Jim:

Is the National op-amp a direct replacement?

Thanks.


Yes it is. Just snip off the leads of the 4558 with fine tipped cutters and use a solder iron to melt away the remaining pins off the pads. Remove excess solder remaining. Solder on the new part. Other parts also may work well but since it's surface mount I don't have a socket to play with so I selected the best part that wouldn't cause problems.
The LME49722MA is available direct from National, it's too new to be found at Digi Key.
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Jim Williams
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hargerst

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Re: The Seventy Nine Dollar Converter
« Reply #14 on: September 23, 2008, 01:27:32 pm »

evil robot wrote on Mon, 22 September 2008 13:19

Moderators, since this is getting off topic, if you want to split this into a separate thread, that's fine.

Since the original topic was basically about a low cost D/A converter, I don't see that this new discussion about a low cost A\D converter is way "off topic".

Kinda like two sides of the same coin.


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Harvey "Is that the right note?" Gerst
Indian Trail Recording Studio

Jim Williams

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Re: The Seventy Nine Dollar Converter
« Reply #15 on: November 06, 2008, 11:02:08 am »

This converter was on sale until Oct.16, it's now on sale again until Jan. 3 for $79.95.
Use source code 810A36 for the discount when ordering.
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Jim Williams
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chorga1

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Re: The Seventy Nine Dollar Converter
« Reply #16 on: November 28, 2008, 03:28:02 pm »

So I got the opamp replaced with the analog devices opamp mentioned over on gearslutz. Huge imporvement in sound! Bass is noticably tighter.



However I am having trouble finding this part you mentioned: MIT .1 uf caps (in place of the .1 ceramics)

Pardon my lack of knowledge - this is only my second mod - but when I search for MIT caps all I get is info about massachusetts institue of technology...



Also - Stanley Beresford - the guy who designed the unit - told me to replace R11 and R14 with a solder bridge. Any idea how this will affect the sound?


Thanks for any info y'all may have.
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maarvold

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Re: The Seventy Nine Dollar Converter
« Reply #17 on: November 28, 2008, 09:38:55 pm »

chorga1 wrote on Fri, 28 November 2008 12:28

...I am having trouble finding this part you mentioned: MIT .1 uf caps (in place of the .1 ceramics)....



Do a search for Michael Percy Audio in Nevada City, CA.  And they're called Reliable Capacitor now.  Designed by Richard Marsh, same as MIT MultiCaps.  And brace yourself for the price.  
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Jim Williams

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Re: The Seventy Nine Dollar Converter
« Reply #18 on: December 02, 2008, 10:56:58 am »

There are also a pair of 10uf tantalum coupling caps off the converter output to the filter/opamp. They are on the other side of the opamp from the output caps. I used 47 uf Panasonic FM with Wima .1 or MIT .1 uf's across them.
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Jim Williams
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danickstr

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Re: The Seventy Nine Dollar Converter
« Reply #19 on: December 03, 2008, 09:43:24 pm »

Now if someone would add a BNC word clock "kit" to it...
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Jim Williams

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Re: The Seventy Nine Dollar Converter
« Reply #20 on: December 04, 2008, 10:51:55 am »

No need for that, all DAC's clock off the incoming data stream.
ADC's are a different situation...
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Jim Williams
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danickstr

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Re: The Seventy Nine Dollar Converter
« Reply #21 on: December 05, 2008, 07:45:11 pm »

funny I don't care about DAC - blasphemy I know, but I look at it like a crummy walkman.  I wonder about the ADC app, but I use my Verb now, Rumour.
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johnR

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Re: The Seventy Nine Dollar Converter
« Reply #22 on: December 06, 2008, 02:39:57 pm »

Jim Williams wrote on Thu, 04 December 2008 15:51

No need for that, all DAC's clock off the incoming data stream.

But you'll need something between the CS8414 and the DAC chip's clock input to remove the jitter that the 8414 can't remove (which is a lot). That would take a VCXO or a much better quality PLL than the 8414 contains. That's where most of the cost of a high end DAC comes from.
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Enola

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Re: The Seventy Nine Dollar Converter
« Reply #23 on: February 07, 2009, 01:55:59 am »

Wordclock has no benefit at all for DAC?
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Jim Williams

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Re: The Seventy Nine Dollar Converter
« Reply #24 on: March 12, 2009, 10:26:12 am »

The MCM converter is back on sale for $79.
1-800-543-4330
Use source code 902D02 for the discount.
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Jim Williams
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organica

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Re: The Seventy Nine Dollar Converter
« Reply #25 on: March 22, 2009, 05:21:52 pm »

Jim Williams wrote on Sat, 20 September 2008 12:02

No budget A/D from them but another source is available for that.
BurrBrown makes a very nice A/D evaluation pcb for the PCM4222 A/D converter, their top-o-line chip. It's the PCM4222EVM.
Get one direct from TI at:
www.TI.com
Search the PCM4222EVM and it comes up. It costs $149 and requires a power supply with + - 15 volts and a single 5 volt rail. Power One/Condor makes a nice small 3 output power supply that runs around $70. You can get that from digi-key.
This converter has bested some very expensive products in the $5k price zone, so it's a serious contender. It has DSD outputs, dual s/pdif and AES outputs, digital filters, etc. all selectable via dip switches.


?;
is there any way to run this ADC via firewire or lightpipe ?  
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Galil

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Re: The Seventy Nine Dollar Converter
« Reply #26 on: August 31, 2009, 11:37:23 am »

I had followed this thread with some interest, since I have an Alesis Masterlink which works well but the A/D and D/A technology was getting a bit old and I thought that new converters might be the best way to upgrade the sound.  This past spring, I ordered the TI PCM4222EVM. It turns out that the PCM4222EVM has been back-ordered for at least four months.

The information I have gotten from TI is that they expect it to be available in the fall.  This might not be a bad time to order these if anyone else has an interest.

Galil



-
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Halfway Competent

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Re: The Seventy Nine Dollar Converter
« Reply #27 on: September 28, 2009, 02:14:23 pm »

Jim,

What about an 8-channel ADC that outputs over optical?  Is this something really specialized that you're not going to find off-the-shelf?

I may just rack up this $79 DAC.  I'd been intending to procure a Wolfson DAC EVM and put it in a rackmount case...  But it's almost $300, rather than $80.
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TB-AV

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Re: The Seventy Nine Dollar Converter
« Reply #28 on: February 27, 2010, 11:13:58 am »

Can someone tell me if these Eval units are still valid or is there possibly something else out there now that I might want to look at.

Also, I have searched DigiKey and Mouser and am having a lot a problem finding a decent and affordable power supply. I have searched linear power supplies and that usually ends up with something in the $150 range and perhaps on ly one of those. Anyone have a specific part number I might look for?

Thanks for any help.

Tom B.




Reference from Page 1 ----

Quote:

No budget A/D from them but another source is available for that.
BurrBrown makes a very nice A/D evaluation pcb for the PCM4222 A/D converter, their top-o-line chip. It's the PCM4222EVM.
Get one direct from TI at:
www.TI.com
Search the PCM4222EVM and it comes up. It costs $149 and requires a power supply with + - 15 volts and a single 5 volt rail. Power One/Condor makes a nice small 3 output power supply that runs around $70. You can get that from digi-key.
This converter has bested some very expensive products in the $5k price zone, so it's a serious contender. It has DSD outputs, dual s/pdif and AES outputs, digital filters, etc. all selectable via dip switches.
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