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Post by Johnkenn on Jun 20, 2014 15:09:55 GMT -6
Just thought I would post this as some might be wondering...Man, the Apollo DA is MUCH brighter than the Ross Martin. Really feel like the Apollo has a strident top end.
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Post by indiehouse on Jun 21, 2014 6:13:11 GMT -6
You think this is a worthwhile investment?
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Apollo DA
Jun 21, 2014 9:04:19 GMT -6
via mobile
Post by ragan on Jun 21, 2014 9:04:19 GMT -6
Interesting. I think the Apollo's weakest spot is in fact the DA but I never felt it was super exaggerated one way or the other. Isn't the circuit topology really similar to the Lynx Aurora? I can't vouch for that, I've just read it.
The D Box DA definitely beats it handily so I monitor through that, but I wouldn't describe the D Box DA as less bright. Deeper, wider, clearer for sure.
Interesting though. I've never heard the Ross Martin. I wonder if it's a little on the veiled side?
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Post by jeromemason on Jun 21, 2014 23:57:28 GMT -6
Hey John, remind me again what you're clocking all this with?
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Post by jimwilliams on Jun 22, 2014 11:10:06 GMT -6
The converter chip design and the analog outputs/filters will tell the story. Most all lower cost DAC's are sigma-delta oversampled, one bit designs. Some use up to 5 or 7 bits for stepping. They tend to have a somewhat glassy, maybe exagerated top end. Some of those chips include switched filter opamps onboard, of lower quality than you can select yourself.
Compare to sign magnatude DAC's like the excellent BurrBrown PCM1794. THD is no where as close either residing at around 16 bit levels when the BB part can do -117 dbu.
One other difference is the output designs. Sigma/delta DAC's are all voltage outputs, feed from an opamp of questionable quality. The BB sign magnatude DAC's are all current output, requiring an opamp to convert current to voltage. Select an excellent opamp and better audio resolution is obtained.
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Post by kcatthedog on Jun 22, 2014 12:51:07 GMT -6
"Select an excellent opamp and better audio resolution is obtained."
^^this^^
enter bla mod to the apollo , other upgraded parts and decoupling the converters to lower the noise floor
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Post by tonycamphd on Jun 22, 2014 13:32:24 GMT -6
does anyone know what brand conversion chips are used in the apollo on both sides?, also the chip per channel ratio? I'm pretty sure the RM uses 1 to 2 channels per chip and individual power supply's per channel(which is killer), rigs like the Orion 32 use 4 or 8 channels per chip?(cant remember for sure?) and i'm not sure about the power supply's, though i am sure it's not 1:1 or even 1:2. All things being equal, multi channeling a chip/ps has a negative impact on the DR and noise floor of the conversion. i would like to hear jimwilliams take on this... |
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Post by kcatthedog on Jun 22, 2014 13:41:03 GMT -6
does anyone know what brand conversion chips are used in the apollo on both sides?, also the chip per channel ratio? I'm pretty sure the RM uses 1 to 2 channels per chip and individual power supply's per channel(which is killer), rigs like the Orion 32 use 4 or 8 channels per chip?(cant remember for sure?) and i'm not sure about the power supply's, though i am sure it's not 1:1 or even 1:2. All things being equal, multi channeling a chip/ps has a negative impact on the DR and noise floor of the conversion. i would like to hear jimwilliams take on this... this shoudl give you gear wood ! specially the HD close ups oh baby !! gearautopsy.com/bla-finally-lets-the-lion-out-of-uas-apollo/#more-474 |
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Post by tonycamphd on Jun 22, 2014 14:24:07 GMT -6
for anyone interested, here's a direct comparison between AD/DA chips in these units from the data sheets, of course the implementation of these chips greatly affects the numbers  apollo DA  rm DA  apollo AD  rm AD |
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Post by Johnkenn on Jun 22, 2014 15:34:34 GMT -6
Thanks, Tony...
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