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Grace 901 replacement: Grace m902 - Page 9

post #121 of 209
One thing that helps me when making a purchase like this (particularly in cases where I can't get my hands on a unit first-hand before ordering) is to see if the product manual is available online. It gives you a good sense of the product - assuming that the manual is truthful of course, and doesn't contain major errors or oversights.

And Grace definitely has their product manuals available online without needing some cryptic login or anything special to read them. Looking forward to seeing the 902 manual online when the product is released. Kudos to Grace for their all-around excellent customer service & support, lots of other manufacturers could stand to take a lesson here.
post #122 of 209
Quote:
Originally Posted by vpolineni
I would be looking at these other units as well... but the grace has one feature that puts it at the head of the class for me-the optional remote control. Michael, do you know how much this option will cost? The usb input is what got me interested...but the reason i'm buying it is because of the headphone amp. there's a slight possibility i'll be forced into a headphone setup rather than my current 2-channel setup so this would be the perfect option. (i'm relatively new to the world of headphones-i own senn hd590's. what headphones could run off the grace? i'm assuming the akg 1000's couldn't.. are the senn 650's and grado rs-1's the best possible headphones for this amp?) For now, this would serve as my dac/preamp in my 2-channel setup so for me, this is truly the ideal product. Michael, do you know what size coupling capacitors are used in the unit? i would look into replacing them with a teflon capacitor. thanks for such a great product-i hope to get my hands on one soon.
The remote is going to be about $150.
The m902 is capable of driving almost any dynamic phones. The core output amplifier section was designed originally for my Grado HP-1000s. These are my favorite for recording monitoring where neutrality and accuracy are paramount. I also love listening to HD-600s, Stax Lambda Pro (with the SRD7 Pro interface) and Sony MDR-7506s for listening with isolation. The m902 will also drive the AKG K1000 with no trouble. Maybe a little better than the 901
since the m902 has a larger power transformer.
The coupling capacitors are 4.7uF.
post #123 of 209
Quote:
Originally Posted by DukeTogo
vpolineni - what would you hope to gain by swapping in these teflon caps? Just curious.

Maybe Michael has comments there about the appropriateness of such an upgrade. Maybe there are tradeoffs in designing a product that leave room for someone to tweak it a bit, if they feel like investing that extra time and energy. I'd hope though that the Grace Design team would have built a unit that was more than the some of its component parts, that in choosing the parts in it, they made the appropriate selection for the best overall sound. I guess though that if their decisions had to necessarily include cost constraints to be marketable and on the other hand you have the extra $$$ to tweak it, then it makes sense assuming you have the requisite skills.


But personally the LAST thing I'd ever do is crack open a $2000+ (Cdn) product and have at it with a soldering iron. Probably because my skills with a soldering iron extend to knowing what one looks like, and having a basic understanding of the process, heh. But even still, it costs too much for me to fool with. Don't expect to make any claims under warranty! :-)

While I would say that the component quality in the m902 is uncompromised I would also say that it is not a "cost not object" design. This product lies in a sort of "no man's land" between esoteric hi-fi and high-performance-but-practical professional gear. Teflon caps might sound better than the metalized polyethylene terephthalate but then again they might not. While the dielectric properties or teflon are nearly ideal the physical size of teflon caps can be problematic. Especially in balanced interfaces where physically large caps can degrade common mode rejection.
I can't condone this type of modification but I would be interested in hearing your results
post #124 of 209
Quote:
Originally Posted by 00940
Still a little curious. Did you make any test about the jitter of the pcm2902 ?
I suppose it's no ?
post #125 of 209
Quote:
Originally Posted by OracleGuy
It's a little rich for me right now (man, I feel like a piker considering the toys you've got on display!) and I've got a Gilmore Lite in the mail right now.

That Xitel is looking like a real weak link now though. I've already contacted Perreaux about their USB DAC. I couldn't get any pricing out of them unfortunately. I've contacted the Canadian distributor, but they won't have pricing until January.

I'm keeping my DAC options open for AOS too--he says he'll have something to announce "hopefully soon" in the way of a USB DAC.

Anyway, Mark Levinson is definitely on my post-Lottery-win shopping list!
Hey with all due respect don't ever consider your self a "piker" (don't know what that means, tho!) not for one second. I am no better than the next headfier just because I have this system. When I joined headfi. All I had was a hd600 and a crappy av reciever. We all start somewhere! Why don't you try talking to me and then you'll see. I am just like you. I love ice hockey, I smoke (although not in the same room as the ML,tho), I have been warned about my swearing more times than I can remember, I love beautiful women, I love music.

But when you win the lottery can you give a few pennies. I would love to upgrade the 30.5 dac to a 30.6 dac
post #126 of 209
Quote:
Originally Posted by 00940
Still a little curious. Did you make any test about the jitter of the pcm2902 ?
I'm setting up the m902 on the test bench to check two things:
Check the jitter on the spdif line coming out of the PCM2902. I need to tie into this line before the s-Lock PLL to see the actual jitter from the usb interface. Luckily the s-Lock PLL virtually eliminates any jitter on the usb line.
Next, we will check that the data coming from the usb line is bit for bit accurate when using the usb interface with Max OSX. I did a cursory test today and found no problems with the m902 and Power Book G4 at 44.1kHz or 48kHz sample rates. What I did discover, however, is that you need to open the Midi/Audio control panel to manually set the output (playback) sample rate to match the file you are playing. It plays music either way without any pitch shifting so I am assuming the the Mac (Core Audio perhaps?) is sample rate converting if the file sample rate and the output rate setting are mismatched.
A bit test and jitter test with the Terrasonde Digital Audio Toolbox will verify what is going on.
Cheers,
Michael
post #127 of 209
What language is this???OMG it's technospeak, arrrggggghhhh
post #128 of 209
Michael : Thank you a lot. It should be the first known jitter measurements of the spact system recovering the data from USB. Something we've been curious about for a few months now.

GoRedwings : come on, go have a trip to this thread . That's I would call technospeak
post #129 of 209
Wow, that looks like quite the fun test & analysis tool Michael!

Check it out guys - wow.
http://www.terrasonde.com/products/dat.php
post #130 of 209
Ok I spend WAY too much time thinking about this stuff, I can't wait to buy something and get on with my life. :-)

I didn't see anyone comment on my previous statements, so I just wanted to clarify: It is my understanding that a SACD player using digital outs, would output a DSD encoded data-stream (forgive me if this is the wrong term) instead of PCM like DVD-A. Therefore can one say conclusively that the m902 would not be able to decode that data from the SACD, and therefore unable to playback digital SACD output?

I was reading about new Cirrus DACs that seem to support both:
http://www.enjoythemusic.com/news/

excerpt:

"Cirrus Logic's two new 24-bit/192 kHz, multi-channel digital-to-analog converter (DAC) chips, the CS4365 and CS4385, support six and eight audio channels and decode Super Audio CD (SACD) and DVD-Audio."


I know there is tremendous reluctance in the audiophile community to jump one way or another while the whole "Next Digital Format(tm)" is decided (aka fought out in the stores & trenches)... so I just wondered what people thought of that. How "future proof" would one say the Grace m902 (or any similar device) is? I realize the future is a vague ever-shifting beast at best... :-(
post #131 of 209
Quote:
Originally Posted by DukeTogo
Ok I spend WAY too much time thinking about this stuff, I can't wait to buy something and get on with my life. :-)

Some more questions...

#1
does the USB connection require the use of any drivers?
or is the m902 seen as a standard USB 1.1 audio device?

#2
I assume the USB connection is USB 1.1 spec? Or is it 2.0?
What limitations are there on sampling rates across USB?
(Similar units like the Apogee are limited to 48K via USB)

I guess the only advantage it 2.0 *might* be that it would support higher sampling rates (I don't know this for a fact, just guessing) and that if it was USB 2.0, it shouldn't drag down the speed for any other USB device connected to the same controller.

#3
I didn't see anyone comment on my previous statements, so I just wanted to clarify: It is my understanding that a SACD player using digital outs, would output a DSD encoded data-stream (forgive me if this is the wrong term) instead of PCM like DVD-A. Therefore can one say conclusively that the m902 would not be able to decode that data from the SACD, and therefore unable to playback digital SACD output?

I was reading about new Cirrus DACs that seem to support both:
http://www.enjoythemusic.com/news/

excerpt:

"Cirrus Logic's two new 24-bit/192 kHz, multi-channel digital-to-analog converter (DAC) chips, the CS4365 and CS4385, support six and eight audio channels and decode Super Audio CD (SACD) and DVD-Audio."


I know there is tremendous reluctance in the audiophile community to jump one way or another while the whole "Next Digital Format(tm)" is decided (aka fought out in the stores & trenches)... so I just wondered what people thought of that. How "future proof" would one say the Grace m902 (or any similar device) is? I realize the future is a vague ever-shifting beast at best... :-(
I'll take a stab at your questions:
1) I believe that Michael has said the unit is seen as a generic usb audio device, using the burr brown chipset.
2)I'm assuming the unit is usb 1.1.. although it doesn't matter even if it is usb 2.0. It is limited to 16/44.1 because that is what usb allows so far. Hopefully down the road usb 2.0 will support 24/192-allowing users of this unit to take full advantage of the dac.
3) I believe you're right in that the unit will not decode sacd-but what use would it be even if it did? the unit has one set of analog output for 2-channel use, not multi-channel. I guess the only trade-off is that it can't decode 2-channel sacd but haven't you heard? sacd is dead
I think what makes this unit so appealing is that it offers (imo) a proper implementation of usb-not a conversion seen in the m-audio transit or even the perreaux usb dac. also, the s-lock should eliminate any jitter from the usb or any of the other digital inputs... all around it looks like a great unit. can you tell i want one?
post #132 of 209
vpolineni,

Darn I tried to delete my old questions but you beat me to it :-)
(read this thread front to back and found some of the answers...)

1. - Confirmed: Michael said it was a generic audio device.

2. - Correction: Michael said the USB was limited to "16bit/48kHz" not 44.1

3. - I'm probably less concerned with SACD per-se than I am with "whatever format wins out" ... and while Grace Design obviously cannot see into the future, it'd be nice to have a unit that supports that format, if say it was DSD based. The odds of that may be slim though, and you just have to pick something and go with it sooner or later.

Anyway, I look at my CD collection and acknowledge that it will probably be a cold day in hell before I replace any of them just to get the new flavour of the week.

I agree, this unit looks phenomenal, and I'm already counting out the beans.
"Pay the man"

Now to pick out some 'phones to go with it...
Thinking ATH-W1000, maybe PRO700's for work/transport
or the Beyerdynamic DT860/880, maybe AKG K271

Those new Sony Qualia's are calling me though, perhaps the MDR-SA line is more budget-ready. Looking for a closed can though just due to environment considerations. Some day I'll get an open design. Some day. (sigh)
post #133 of 209
those sony qualia's look nice... pardon my ignorance, but they're a closed design, right?
post #134 of 209
For anyone burning away the hours until the m902 is released and interested in the operation of USB audio, this article (and subsequent Part II) might be of interest:

http://www.planetanalog.com/showArti...cleID=12801995

Found it off a link to DIY Audio that someone posted earlier I think.
Reading that sure beats pulling your hair out at the malls right now, what a zoo.
Christmas shoppers... I'm 92% done! :-)
post #135 of 209
vpolineni,

I believe that the Qualia's are open.

I believe that the MDR-SA (5000,3000,1000) line are a mix of open/semi-open and closed. Or something like that. I'm having trouble Googling up that info again.

Hell for $2100 (US!) less, I can get the MDR-SA5000 and pay someone to make me fancy red leather earpieces and just posture like I'm made of money.
heh

You can find the MDR-SA here:
http://www.ecat.sony.co.jp/avacc/hea...&KM=MDR-SA5000
http://www.ecat.sony.co.jp/avacc/hea...&KM=MDR-SA3000
http://www.ecat.sony.co.jp/avacc/hea...&KM=MDR-SA1000

Unfortunately I don't read Japanese. Seems to be a requirement when you're into high-end headphones, what's up with that? Why aren't these things released domestically (ie. North America)? Anyway...
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