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Post by tonycamphd on Nov 21, 2014 21:19:35 GMT -6
this is cool man!
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Post by Martin John Butler on Nov 21, 2014 22:05:21 GMT -6
This is all way over my head, but I'm enjoying the process and picking up some interesting info too. If it matters, I've never liked Burr Brown converters, they always seemed warm and fuzzy to me.
Every time I've chosen a new component in my stereo system, without knowing what was inside, I've chosen products using Cirrus Logic. My Arcam surround sound integrated and my Peachtree Audio integrated amp both have Cirrus Logic chips.
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Post by Deleted on Nov 22, 2014 1:27:29 GMT -6
Well, might be true for older converter chips.
I can only speak for the TI 1794a chip that i now heard with different output opamps. It simply sounds marvellous.
We heard from ADC users of the RM unit, that they like the PCM4222 used here just as well. It uses a different chip internal converter architecture that may allow it to perform exceptionally good in comparison to the usual suspects used in most other ADCs. So i guess TI has a real pair of winners in the field now...
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Post by formatcyes on Nov 22, 2014 2:16:08 GMT -6
Around $300 I am in for one
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Post by Johnkenn on Nov 22, 2014 13:41:30 GMT -6
So - what is different about the Superbeast in comparison to the 1794?
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Post by tonycamphd on Nov 22, 2014 14:13:31 GMT -6
So - what is different about the Superbeast in comparison to the 1794? the superbeast DAC uses 2- 1794a(stereo capable dac chips) in single channel configurations with isolated power supply's for each channel(unless i'm mistaken?), that gives a whopping 132db signal to noise ratio and a dynamic range of the same 132db, those are over the moon specs, and the word on the street is it's unmatched in it's sound quality, most people think the 1794a in a stereo implementation is killer..so? If you've got a year or so, go ahead and pull the trigger lol, I hope svart doesn't deviate too far from this layout on the DAC side, it would be sick! 8) |
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Post by Deleted on Nov 22, 2014 17:48:07 GMT -6
Not to forget, the Superbeast uses different audio opamps, the ADA4898, that in my opinion are excellent opamps that make a huge part of the difference compared to the RM standard DAC. jimwilliams wanted them in his custom RM DAC and RM now uses them in the superbeast.
Therefore, we recommended them to svart for use in the ADC part as well, so the "RGO speedwagon" ;-) ADC would probably be able to even beat the RM ADC in accurate low end, which doesn't use them.
That said, even the cheapest standard RM DAC sounds exceptionally good, this high end option of opamp just puts even more cream on top of the cake. Or better - some chocolate chunks inside, making it perfect....
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Post by LesC on Nov 23, 2014 2:09:49 GMT -6
I have some questions, I apologize if I missed any answers already given in this thread:
1. My only option for connecting additional converters would be via ADAT connectivity. Not really a question, just another vote to go along with mdmitch2's request for ADAT connectivity. Very few high-end converters offer ADAT, so this option might be a way to increase your potential market.
2. Tonycamphd stated "the superbeast DAC uses 2- 1794a(stereo capable dac chips) in single channel configurations with isolated power supply's for each channel(unless i'm mistaken?)", will you be doing this as well, or at least offering it as an option?
3. Smallbutfine stated "Not to forget, the Superbeast uses different audio opamps, the ADA4898, that in my opinion are excellent opamps that make a huge part of the difference compared to the RM standard DAC. jimwilliams wanted them in his custom RM DAC and RM now uses them in the superbeast." Will you be doing this as well, or at least offering it as an option?
4. What I would really like is a one or two 19" rack unit that has one or (preferably) two ADC's, and two DAC's, with ADAT connectivity. Or what might make sense is just to buy two of your ADC/DAC units, provided that you can perform some interconnection magic so that they could both be connected using a single ADAT connection. Is either of these even a possibility? Assuming the quality is as expected, this would allow me to get rid of my Burl ADC and Dangerous DAC, plus have a high-quality DA-AD loop for 2-bus processing.
I've been thinking about a Lynx Hilo for quite a while, which is in the $2500 range, but has a lot of expensive features that I don't need. If I could get a basic, high-quality "2-ADC, 2-DAC, ADAT" unit in the $1500-or-less range, I would consider that a real bargain!
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Post by Deleted on Nov 23, 2014 8:20:40 GMT -6
ADAT to SP/DIF and reverse is not particularly easy to do.
Wavefront/Alesis discontinued on ADAT format support and chip manufacturing, as far as i know, a californian manufacturer continues to provide licensed chips in small quantities for the industry.
ADAT is somewhat limited due to beeing natively single speed lightpipe format, needs a switch to the S/MUX format to provide half of the channels double speed (88.1/96). (Sonorus implemented this early, Alesis released a paper to extend the format for S/MUX, and there are even different implementations for it that are not compatible from different manufacturers....)
This may be the reason, we see not much of ADAT connectivity in converter units providing less than 8 channels of conversion.
As for the ADA4898, if i understood it right, svart already designed his prototype PCB of the ADC to take care of the additional heat dissipation needed for this one as the input opamp. :-)
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Post by LesC on Nov 23, 2014 12:38:07 GMT -6
ADAT to SP/DIF and reverse is not particularly easy to do. Wavefront/Alesis discontinued on ADAT format support and chip manufacturing, as far as i know, a californian manufacturer continues to provide licensed chips in small quantities for the industry. ADAT is somewhat limited due to beeing natively single speed lightpipe format, needs a switch to the S/MUX format to provide half of the channels double speed (88.1/96). (Sonorus implemented this early, Alesis released a paper to extend the format for S/MUX, and there are even different implementations for it that are not compatible from different manufacturers....) This may be the reason, we see not much of ADAT connectivity in converter units providing less than 8 channels of conversion. As for the ADA4898, if i understood it right, svart already designed his prototype PCB of the ADC to take care of the additional heat dissipation needed for this one as the input opamp. :-) Thanks for the info! In that case I will have to go with something like the Lynx Hilo which has the ADAT interface. At this point I'm waiting for the next multi-channel interfaces from Lynx and Metric Halo to see if they are Hilo quality, and then I can replace my RME UFX as well as the Burl ADC and the Dangerous DAC. |
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Post by svart on Nov 23, 2014 21:29:56 GMT -6
Yes, the ADAT protocol is proprietary. I would have to buy the ADAT-to-PCM ICs from Coolaudio now, as there is no way to get a license for the technology without significant money.
I have a handful of the old wavefront ICs. Each ADAT IC does 8 channels, but SPDIF only does 2. I could certainly see about doing an adat to SPDIF converter box in the future. That way you could use multiple DACs on a single ADAT output, or multiple ADCs to one ADAT. It would be separate from the AD/DA devices though.
And yes, the ADC board has the extra ground paddles for use with the ADA4898 and other dual opamps that need the ground paddle. There is also a ground plane layer for dissipation as well. If the testing of the prototypes shows I need more dissipation, I'll move the bottom layer components and have what we call a "gap pad" underneath. That's essentially a pad of heat transferring material that I use for small spaces in designs where I can't put a heatsink but I can use the chassis as the heatsink. Besides, heatsinks don't work in boxes without airflow.
I'll be happy to use the ADA4898 but it'll probably make the cost go up about 20$ per unit. They are pretty expensive, around 8$-ish a piece in small quantity. I'll likely do a single version of the ADC and DAC. I don't want to mess around with custom stuff too much. Custom orders and too many options are a place where companies start getting hung up and delaying orders..
As it is, I'll probably need to have someone come help me assemble and ship the units once I start taking orders for them.
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Post by svart on Nov 23, 2014 21:43:11 GMT -6
I have some questions, I apologize if I missed any answers already given in this thread: 1. My only option for connecting additional converters would be via ADAT connectivity. Not really a question, just another vote to go along with mdmitch2's request for ADAT connectivity. Very few high-end converters offer ADAT, so this option might be a way to increase your potential market. 2. Tonycamphd stated "the superbeast DAC uses 2- 1794a(stereo capable dac chips) in single channel configurations with isolated power supply's for each channel(unless i'm mistaken?)", will you be doing this as well, or at least offering it as an option? 3. Smallbutfine stated "Not to forget, the Superbeast uses different audio opamps, the ADA4898, that in my opinion are excellent opamps that make a huge part of the difference compared to the RM standard DAC. jimwilliams wanted them in his custom RM DAC and RM now uses them in the superbeast." Will you be doing this as well, or at least offering it as an option? 4. What I would really like is a one or two 19" rack unit that has one or (preferably) two ADC's, and two DAC's, with ADAT connectivity. Or what might make sense is just to buy two of your ADC/DAC units, provided that you can perform some interconnection magic so that they could both be connected using a single ADAT connection. Is either of these even a possibility? Assuming the quality is as expected, this would allow me to get rid of my Burl ADC and Dangerous DAC, plus have a high-quality DA-AD loop for 2-bus processing. I've been thinking about a Lynx Hilo for quite a while, which is in the $2500 range, but has a lot of expensive features that I don't need. If I could get a basic, high-quality "2-ADC, 2-DAC, ADAT" unit in the $1500-or-less range, I would consider that a real bargain! 1. ADAT is proprietary, and you either have to buy the adat ICs or buy the license for the technology. Buying the chips would be the only option as licensing would be very expensive. I'll look into doing a spdif to adat converter in a separate enclosure in the near future. 2. I've already decided to use the 1794 IC. I'll be looking into using multiples. I'm not sure it's called for, but I'll investigate it. Also, this is meant to be a cost-sensitive product. I'll be finding the balance between cost and performance. 3. I'll be using the ADA4898 as requested by a number of people. I've not used these parts before, but so many folks are requesting them, I'll be using them probably as the only choice. 4. The main unit will be 1U. It will house both the ADC and DAC upgrade cards in one 1U chassis. Since this was meant to be an analog-to-spdif device, it will be stereo only as SPDIF only supports mono and stereo. However, as i mentioned, I'll see what I can do to make a separate ADAT-SPDIF converter. It seems there aren't many standalone converters for this. Hope this answers your questions. |
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Post by tonycamphd on Nov 23, 2014 23:46:02 GMT -6
I have some questions, I apologize if I missed any answers already given in this thread: 1. My only option for connecting additional converters would be via ADAT connectivity. Not really a question, just another vote to go along with mdmitch2's request for ADAT connectivity. Very few high-end converters offer ADAT, so this option might be a way to increase your potential market. 2. Tonycamphd stated "the superbeast DAC uses 2- 1794a(stereo capable dac chips) in single channel configurations with isolated power supply's for each channel(unless i'm mistaken?)", will you be doing this as well, or at least offering it as an option?
3. Smallbutfine stated "Not to forget, the Superbeast uses different audio opamps, the ADA4898, that in my opinion are excellent opamps that make a huge part of the difference compared to the RM standard DAC. jimwilliams wanted them in his custom RM DAC and RM now uses them in the superbeast." Will you be doing this as well, or at least offering it as an option? 4. What I would really like is a one or two 19" rack unit that has one or (preferably) two ADC's, and two DAC's, with ADAT connectivity. Or what might make sense is just to buy two of your ADC/DAC units, provided that you can perform some interconnection magic so that they could both be connected using a single ADAT connection. Is either of these even a possibility? Assuming the quality is as expected, this would allow me to get rid of my Burl ADC and Dangerous DAC, plus have a high-quality DA-AD loop for 2-bus processing. I've been thinking about a Lynx Hilo for quite a while, which is in the $2500 range, but has a lot of expensive features that I don't need. If I could get a basic, high-quality "2-ADC, 2-DAC, ADAT" unit in the $1500-or-less range, I would consider that a real bargain! 1. ADAT is proprietary, and you either have to buy the adat ICs or buy the license for the technology. Buying the chips would be the only option as licensing would be very expensive. I'll look into doing a spdif to adat converter in a separate enclosure in the near future. 2. I've already decided to use the 1794 IC. I'll be looking into using multiples. I'm not sure it's called for, but I'll investigate it. Also, this is meant to be a cost-sensitive product. I'll be finding the balance between cost and performance.3. I'll be using the ADA4898 as requested by a number of people. I've not used these parts before, but so many folks are requesting them, I'll be using them probably as the only choice. 4. The main unit will be 1U. It will house both the ADC and DAC upgrade cards in one 1U chassis. Since this was meant to be an analog-to-spdif device, it will be stereo only as SPDIF only supports mono and stereo. However, as i mentioned, I'll see what I can do to make a separate ADAT-SPDIF converter. It seems there aren't many standalone converters for this. Hope this answers your questions. aww man... do it! It's supposed to increase DR, SN ratio and cross talk specs, my console has a 92db cross talk spec, i'd love to have these live up to that and beyond 8) I'll happily pay what ever the difference and more if you can match or exceed the spec of the SB! The price you stated is way more than fair C, these units are going to be my mix console 2 buss feeding the AD and the DA back to my monitors for all my mix decisions, so my future is in your hands! lol, i expect no compromises bromee 8) |
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Post by formatcyes on Nov 24, 2014 0:01:26 GMT -6
I am with Tony I would be happy to pay more for higher spec's your current price is very low. I like your idea good conversion AD/DA spdif... K.I.S.S
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Post by LesC on Nov 24, 2014 0:13:07 GMT -6
I have some questions, I apologize if I missed any answers already given in this thread: 1. My only option for connecting additional converters would be via ADAT connectivity. Not really a question, just another vote to go along with mdmitch2's request for ADAT connectivity. Very few high-end converters offer ADAT, so this option might be a way to increase your potential market. 2. Tonycamphd stated "the superbeast DAC uses 2- 1794a(stereo capable dac chips) in single channel configurations with isolated power supply's for each channel(unless i'm mistaken?)", will you be doing this as well, or at least offering it as an option? 3. Smallbutfine stated "Not to forget, the Superbeast uses different audio opamps, the ADA4898, that in my opinion are excellent opamps that make a huge part of the difference compared to the RM standard DAC. jimwilliams wanted them in his custom RM DAC and RM now uses them in the superbeast." Will you be doing this as well, or at least offering it as an option? 4. What I would really like is a one or two 19" rack unit that has one or (preferably) two ADC's, and two DAC's, with ADAT connectivity. Or what might make sense is just to buy two of your ADC/DAC units, provided that you can perform some interconnection magic so that they could both be connected using a single ADAT connection. Is either of these even a possibility? Assuming the quality is as expected, this would allow me to get rid of my Burl ADC and Dangerous DAC, plus have a high-quality DA-AD loop for 2-bus processing. I've been thinking about a Lynx Hilo for quite a while, which is in the $2500 range, but has a lot of expensive features that I don't need. If I could get a basic, high-quality "2-ADC, 2-DAC, ADAT" unit in the $1500-or-less range, I would consider that a real bargain! 1. ADAT is proprietary, and you either have to buy the adat ICs or buy the license for the technology. Buying the chips would be the only option as licensing would be very expensive. I'll look into doing a spdif to adat converter in a separate enclosure in the near future. 2. I've already decided to use the 1794 IC. I'll be looking into using multiples. I'm not sure it's called for, but I'll investigate it. Also, this is meant to be a cost-sensitive product. I'll be finding the balance between cost and performance.3. I'll be using the ADA4898 as requested by a number of people. I've not used these parts before, but so many folks are requesting them, I'll be using them probably as the only choice. 4. The main unit will be 1U. It will house both the ADC and DAC upgrade cards in one 1U chassis. Since this was meant to be an analog-to-spdif device, it will be stereo only as SPDIF only supports mono and stereo. However, as i mentioned, I'll see what I can do to make a separate ADAT-SPDIF converter. It seems there aren't many standalone converters for this. Hope this answers your questions. Yes, you've answered my questions, thank you! I think most the guys on RGO are interested in top quality, within reason, as illustrated by what Tony said above. If you can make the ADAT-SPDIF converter, I'll be in for sure! |
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Post by svart on Nov 24, 2014 7:59:35 GMT -6
So let me ask you guys a question.. What's the difference between 129db and 132db?
It's a rhetorical question..
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Post by jcoutu1 on Nov 24, 2014 8:17:41 GMT -6
$20.
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Post by svart on Nov 24, 2014 8:25:26 GMT -6
Right now it's more like 75-100$. Just not sure that's worth an extra 3db of ENOB.. |
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Post by tonycamphd on Nov 24, 2014 8:26:24 GMT -6
So let me ask you guys a question.. What's the difference between 129db and 132db? It's a rhetorical question.. 96db when you add 32 tracks together! I swear as I've done listening demos over this past year, this is where I've seen converters fall down, they all seem to be fine when u listen to them singularly, when u stack tracks they flatten and gray out, losing depth in the image, whether it's a clocking issue or chip issue or? I don't know? But it certainly comes off as a DR issue to my ears( front to back image/ quiet vs louder, it gets even worse with the use of very necessary compression) |
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Post by svart on Nov 24, 2014 9:06:34 GMT -6
I'm not sure what you mean Tony. Summing noise, or any signal should be 10*log10(P^2n1+P^2n2, etc/P^2n0) So adding 32 channels of random -129db noisefloor should be -113-ish if the noise is completely random(white).
If there is ground hum across all channels and the signal is somewhat coherent, then it would be a 20*log10 version of above.
Anyway, 32 channels of -132 should be in the -116db range, only 3 db away.
EDIT:
I remembered about a couple of other formulas.
Adding a N number of identical noise/signal sources:
n=10(delta*L in dB/10)
Or
delta*L in dB=10*log10(n)
delta*L in dB=15.05dB level difference for 32 channels.
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Post by tonycamphd on Nov 24, 2014 9:54:28 GMT -6
I don't speak Portuguese so? 8) Jim would probably be the guy to chime in on this, as i complained my findings to him, he's explained to me a few things(also in Portuguese) that made sense as he worded them for just seconds before they flew off into the 5th dimension of the Centaurus A Nerdulous galaxy 8)
I might add that of the few peeps i know that create and mod gear on a higher level, they all say that sometimes the best spec'd parts DON'T sound good in certain layouts(i believe you're included in this), so ears have to decide what ends up. That said, my experience with Jim has been that my idea of "quality" in sound, has very much lined up with his, i think thats pretty obvious to anyone who's spent some time around here, and have endured my perpetual verbosity lol.
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Post by svart on Nov 24, 2014 10:33:21 GMT -6
It's all good. In my work, I deal with "total power" in a lot of cases, since the RF amps I use are class A, current driven devices. that means that I only have a certain amount of headroom before compression. Knowing the total power of a large number of RF channels is the only way to determine the headroom before compression, and other aspects like IP2/IP3/intermodulation points. That's essentially when you take multiple signals into an amp and the amp acts like a non-linear mixer.
anyway, it seems we have a few options for the DAC output filter/driver.
Per the datasheet, they use 2x NE5534 into a LT1028 opamp for a single channel out of the DAC. I'm guessing that we'll use the ADA4898 series opamps in place of all 3.
The question becomes, do people want differential out, balanced out or simply single-ended out?
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Post by svart on Nov 24, 2014 13:25:13 GMT -6
Besides the question of dual mono or single stereo dac configuration, we also have the question of multiple power supplies.
There is some provisioning on the DAC for multiple VCC inputs. However, there is no detailed explanation of how these are separated. We don't even truly know if they are 100% separated inside the IC.
I've never actually seen separate analog supplies for separate DAC output channels before and I've been using RF DACs that go to 3GHz for a few years now. Nobody in the commercial world would do something like this. The datasheet design meets their specs with a single 5V VCC supply from a not-particularly-low-noise LDO regulator.
So if TI can meet the specs with a single supply from a generic LDO, why do we 'need' to do special things to meet these same requirements?
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Post by tonycamphd on Nov 24, 2014 13:27:21 GMT -6
 Understood, i'm totally down with an extra $100 if that's what it takes mon! Also i'm always down with balanced/differential anywhere you can put it 8) |
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Post by jcoutu1 on Nov 24, 2014 13:36:21 GMT -6
I bet these meters would make it sound even better...
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