Group:
I have a DEM-PCM63 demo (evaluation) board that was sold by Burr Brown in the mid 90's. It is in fact, a complete stereo DAC that just needs +/5 V supplied to it. The chip lineup is: Yamaha YM3626B receiver, B-B DF1700P 8x filter, pair of PCM63 DACs. The I/V uses OPA 2132s. I plan to scrap the I/V section and replace with either a tube I/V or a resistir I/V followed by a tube gain stage.
Specific Questions:
1. Does anybody have the original ap notes for this demo board, and also for the DF1700 filter chip? They are NOT available on the B-B (now TI) website!
2. Are there any pin-compatible chips that I can use to replace either the YM3626B or DF1700P? Great advancements have been made in these two areas since this demo board was designed.
3. Any other mods suggested? What about the clock? B-B uses a a 16.9344 MHz crystal for the filter chip. I undersatnd that there are small, highly-stabilized oscillator modules available that could reduce jitter. Any recommendations?
I realize this is an OLD ladder DAC and that many of you will scoff at it's implementation. However, I have heard some wonderful DACs using the PCM 63, even by today's standards, so please spare any abrasive comments. The demo board was free, and newer does not automatically translate to better sound. Vacuum tubes are a case in point.
Looking forward to any discussion this thread might promote...
I have a DEM-PCM63 demo (evaluation) board that was sold by Burr Brown in the mid 90's. It is in fact, a complete stereo DAC that just needs +/5 V supplied to it. The chip lineup is: Yamaha YM3626B receiver, B-B DF1700P 8x filter, pair of PCM63 DACs. The I/V uses OPA 2132s. I plan to scrap the I/V section and replace with either a tube I/V or a resistir I/V followed by a tube gain stage.
Specific Questions:
1. Does anybody have the original ap notes for this demo board, and also for the DF1700 filter chip? They are NOT available on the B-B (now TI) website!
2. Are there any pin-compatible chips that I can use to replace either the YM3626B or DF1700P? Great advancements have been made in these two areas since this demo board was designed.
3. Any other mods suggested? What about the clock? B-B uses a a 16.9344 MHz crystal for the filter chip. I undersatnd that there are small, highly-stabilized oscillator modules available that could reduce jitter. Any recommendations?
I realize this is an OLD ladder DAC and that many of you will scoff at it's implementation. However, I have heard some wonderful DACs using the PCM 63, even by today's standards, so please spare any abrasive comments. The demo board was free, and newer does not automatically translate to better sound. Vacuum tubes are a case in point.
Looking forward to any discussion this thread might promote...
Diogenio said:
http://www.abcelectronique.com/simu...chaine_hifi/data_sheet_composants/DF1700P.pdf
No.
http://www.tentlabs.com/ProductEntities/XO/XO.html
or for a more comprehensive clock upgrade
http://httpd.chello.nl/~m.heijligers/DAChtml/dactop.htm
and for those with idiosyncratic hearing
http://www.geocities.com/nonospcm1704/
Compared to the TDA1543, thats all the rage at the moment, the PCM63 is right out there on the leading edge.
Re: Re: Re: Re: B-B PCM63 Demo Board as DAC...any Mods?
Many thanks to all whom have responded so far! The low-jitter clock links are exactly what I have been looking for!
Arne, I've heard good things about the HDCD filters (as used in non-HDCD mode), but it is very hard to get data on the Pacific Microsonics products. Can you please give me a link to the data sheets for this chip, or possibly email me a scan of the main pages?
What is the best way for me to get one of these chips? Does anybody have a stock, or must I buy an old DAC on EBAY and gut the chip out? Which popular (and cheap enough to butcher) DACs used this chip?
Thanks again,
Dennis
Cobra2 said:
Many thanks to all whom have responded so far! The low-jitter clock links are exactly what I have been looking for!
Arne, I've heard good things about the HDCD filters (as used in non-HDCD mode), but it is very hard to get data on the Pacific Microsonics products. Can you please give me a link to the data sheets for this chip, or possibly email me a scan of the main pages?
What is the best way for me to get one of these chips? Does anybody have a stock, or must I buy an old DAC on EBAY and gut the chip out? Which popular (and cheap enough to butcher) DACs used this chip?
Thanks again,
Dennis
Re: Re: B-B PCM63 Demo Board as DAC...any Mods?
For the I-V stage you could try something like the one Jocko wrote about here:
Jocko´s simple I-V stage
I use it myself together with a pair of PCM63´s...
As for the PCM1700 I think it is pin compatible with NPC SM5813.
And last about the reciever:I use the YM3623(haven´t checked the data sheet for 3626 so I don´t know how similar it is),but the clockmod Arne K is writing about is probably this one:http://www.diyaudio.com/forums/showthread.php?postid=281012#post281012
Haven´t tried that in my DAC...yet....
BTW:Arne,didn´t you use Jocko´s original I-V stage in your DAC?
Diogenio said:
Cobra2 said:
For the I-V stage you could try something like the one Jocko wrote about here:
Jocko´s simple I-V stage
I use it myself together with a pair of PCM63´s...
As for the PCM1700 I think it is pin compatible with NPC SM5813.
And last about the reciever:I use the YM3623(haven´t checked the data sheet for 3626 so I don´t know how similar it is),but the clockmod Arne K is writing about is probably this one:http://www.diyaudio.com/forums/showthread.php?postid=281012#post281012
Haven´t tried that in my DAC...yet....
BTW:Arne,didn´t you use Jocko´s original I-V stage in your DAC?
Clock upgrade
As for a clock upgrade this one looks really promising.
Guido Tent´s low jitter clock for DAC´s
As for a clock upgrade this one looks really promising.
Guido Tent´s low jitter clock for DAC´s
Re: Re: Re: Re: B-B PCM63 Demo Board as DAC...any Mods?
Yes, so long as you disregard the odd control pin or two. Put the DF1700P pinout alongside the PMD100 pinout and then tell me they are pin compatible. Standalone or Program mode, it would need major surgery to fit the PMD100 in place of the DF1700P.
Cobra2 said:
Yes, so long as you disregard the odd control pin or two. Put the DF1700P pinout alongside the PMD100 pinout and then tell me they are pin compatible. Standalone or Program mode, it would need major surgery to fit the PMD100 in place of the DF1700P.
That counts for both of us then.
BTW my main system is OS and I listen to that one most of the time, so I am reasonably unbiased ( although it may seem otherwise on this forum ). I can enjoy both anyway. Reason for being stubborn in casu non os is the biased way some look at non os systems. Most of them argue without having heard them or draw conclusions based on measurements/hearsay. Same towards people that always find the need to make a negative remark towards the "other camp".
BTW my main system is OS and I listen to that one most of the time, so I am reasonably unbiased ( although it may seem otherwise on this forum ). I can enjoy both anyway. Reason for being stubborn in casu non os is the biased way some look at non os systems. Most of them argue without having heard them or draw conclusions based on measurements/hearsay. Same towards people that always find the need to make a negative remark towards the "other camp".
jean-paul said:
Are you sure that is a wise admission to make? It is a bit like the Chief Rabbi admitting to a preference for pork chops.
I very much doubt that the nossers need any defenders, biased or otherwise. The hallmark of most of the true believers in the way of the nos, is an absolute certainty that they are right and all others are wrong. Throw in a '1543 or two and they make the Taliban seem quite moderate.
jean-paul said:
There are non nossers that suffer from the same phenomenonIn fact it is quite common in places where people are.
But I can understand your way of thinking Rfbrw and I respect it.
Please back to the subject, we are thread jacking Rfbrw.
Thanks again for all the commentary, whether pertaining directly to the subject at hand or not. Personally, I regard overzealousness as just that...emotions run out of control, driving one's perceptions, rather than the preferred alternative: perceptions driving one's emotions. I am certain that both OS and NOS systems can be made to perform very well, just as tubes and solid state can be either good or bad...depending on the implementation. I just happen to be working with an OS board as my basis, so be it!
Going back to the subject, I have see some designs use a pulse transformer-coupled input (Sheldon Stokes tube DAC), and some with a transformer-coupled OUTPUT (Andrea Ciufoli). Transformer output seems rather elegant, but I wonder about output impedance...I imagine it would be rather high. And...hum pickup might enter the equation. Transformer input...but why? To isolate the DAC from external HF noise, or to protect the driving source from noise generated by the DAC itself?
Have any of you experimented with transformer coupling, either on the input or output? Comments?
Any links to suitable transformers for these uses?
Thanks again,
Dennis
San Diego, CA
That asks for the Search function ! There are numerous threads why to choose for input buffering of the digital receiver ( IMO preferably with pulse transformers for simplicity and performance ). CS8412 performs better with it.
Ground separation, better adaption to CS8412 inputs etc. Brands that produce such transformers are Pulse Engineering, Schott and Scientific Conversions. Despite all the negative comments of many here I still like Lundahl LL1566. It is still being sold as I recently understood. Just to name a few.
I can not comment on output transformers as I have a prejudice against them and always find ways to use other devices
Ground separation, better adaption to CS8412 inputs etc. Brands that produce such transformers are Pulse Engineering, Schott and Scientific Conversions. Despite all the negative comments of many here I still like Lundahl LL1566. It is still being sold as I recently understood. Just to name a few.
I can not comment on output transformers as I have a prejudice against them and always find ways to use other devices
Diogenio said:
I only know of one design using the YM3623B with an input transformer, though I don't doubt there are others. Other designs I've seen, from organisations that one would think are competent in this arena, precede the input of the YM3623B with a fast comparator. I've tried my Audionote DAC3 with and without txfrs and can't say I noticed any difference.
Don't like txfrs on the output, even removed the txfr i/v in the audionote, so can't comment on that either.
See here for some that do like transformers.
http://www.raleighaudio.com/passive_output.htm
If CS8412 and NPC5813 is compatible...
I'll give you (for free) a pair of these chips. I have one tube of each.
If your board is indeed pin compatible with these, let me know.
I'd prefer to give them to people who have an immediate application
as to people who might just want to "accumulate" neat parts.
Re: I/V stage. The thing to use is the Sowter 8347 step-up transformer.
It's designed explicitly for this purpose. You need a high quality 25 ohm
resistor to do the I/V. For that, I'd use a low-noise bulk-foil like such
as a Caddock or an Audio Note Tantalum Nitride.
Let me know
-- Jim
I'll give you (for free) a pair of these chips. I have one tube of each.
If your board is indeed pin compatible with these, let me know.
I'd prefer to give them to people who have an immediate application
as to people who might just want to "accumulate" neat parts.
Re: I/V stage. The thing to use is the Sowter 8347 step-up transformer.
It's designed explicitly for this purpose. You need a high quality 25 ohm
resistor to do the I/V. For that, I'd use a low-noise bulk-foil like such
as a Caddock or an Audio Note Tantalum Nitride.
Let me know
-- Jim
Re: If CS8412 and NPC5813 is compatible...
Hi Jim:
Thanks for your offer of the chips! I do not know if the parts you listed are pin-compatible with the ones on my Burr-Brown demonstration board. Perhaps someone more familiar with these devices can comment for us?
My board uses the Yamaha YM3623B receiver and Burr-Brown DF1700P 8x over sampling filter chip. Even if pin compatible, are the parts you mentioned significantly better than the ones B-B originally used? Guess it's worth a try, at any rate!
Regards,
Dennis
jrdmedford said:I'll give you (for free) a pair of these chips. I have one tube of each.
If your board is indeed pin compatible with these, let me know.
I'd prefer to give them to people who have an immediate application
as to people who might just want to "accumulate" neat parts.
Let me know
-- Jim
Hi Jim:
Thanks for your offer of the chips! I do not know if the parts you listed are pin-compatible with the ones on my Burr-Brown demonstration board. Perhaps someone more familiar with these devices can comment for us?
My board uses the Yamaha YM3623B receiver and Burr-Brown DF1700P 8x over sampling filter chip. Even if pin compatible, are the parts you mentioned significantly better than the ones B-B originally used? Guess it's worth a try, at any rate!
Regards,
Dennis
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