philips A/D converters on CD recorders

Ray J

New member
Every time I check the specs on these units '1 bit analog to digital converter' keeps showing up. I was considering the 775 dual tray cd recorder but all the non consumer decks usually include 20-24 bit A/D.

I thought I sort of understood the A/D thing but 1 bit? Is this as bad as it sounds? or does philips use another scale or something. Is this somehow equivalent to 16 bit? I will be going analog in because I use a Yamaha Md8 and would like to mix down to CD RW. How much of a difference will this make (1 bit vs 24 bit)?

Certainly the resolution on the Tascams etc. won''t be 24 times better would they?
 
Whew, tough crowd. Does anyone know what I'm talking about? Or more importantly, do I know what I'm talking about. Anything? Anyone?

Ray J
 
Hello Ray J! Don't fret! I have the answer at home(I'm at work) As soon as I get home I'll respond to your question!
 
Per Wayne Handers,authorized Phillips repair technician
@ Sound Labs and Repairs located in NYC (plus a good friend of mine who's been trying to hook up with my sister for the past 10 years) "Phillip c/d recorders model#'s 765 thru 780 contain 20 bit AD/DA converters
with a sampling rate 44.1".
Though this is less than other models that have 24 bits,
20 bits do provide excellent audio reproduction and conversion .I own the 775 which i bought from a friend
and it does a excellent job! Not the best but I'm satisfied!
Also you can by-pass the SCMS serial management system by recording using the analog inputs rather than
the digital!
Hope this helps.
Peace
Mr.Q
 
wow

Thanks,

That was very informative, and good news. I wonder why they state 1 bit on the specs? Anyway, thanks, I was hoping to hear something like this before I went out looking for one.
 
The number of bits specified rarely have anything to do with how many bits actually are used. 24 bits might just as well mean a 16 bit conversion with some heavy oversamplig, to give the equivalent of 24 bit signal-to-noise ratio.

That may be why they say 1 bit in one place, because thats what they are using. But I thought the 1 bit technique was out of vogue, and that nobody used it today. So maybe it's just a misprint.
 
http://www.ee.washington.edu/conselec/CE/kuhn/onebit/primer.htm

A little primer on one bit DAC's... Which really looks very similar to the explanation in my electronics course last year. I knew the guy wasn't really that smart. I really did. :)

This technique is/was popular because the high cost of high accurate high resolution DAC's. The one bit DAC uses very simple hardware, and takes the problem to a software level... And you need, as stated in the primer, very high speeds. So it's just another way to solve the problem with it's own pro's and cons. Silicon techniques improve every day, so by now it may again be cheaper to just use an ordinary 24bit DA.

Just don't worry about it. The engeneers will do that for you...
 
I think that covers it. "I thought I sort of understood the A/D thing"...........ok, maybe I didn't.

But between the 3 of you, I think it's well covered now. Thanks.

Roel, do you think you could send something with a little more detail next time? ......Just kidding, thanks, that was a great link.

Ray J
 
Just admit it! You didn't read half of it!!

Well... I didn't. :D But I really remember it from last year. I always tend to forget that not everyone has an electronics background. Sorry.

To bleep or not to bleep, that's the question...
 
I had a question - maybe misterQcue can answer conserning the SMCS- can I make a compilation of different stuff on a CD and then make copies of that CD using just the two trays? Or is the only way around it to use an exteranal CD recorder. I heard somewhere also - if you know how and where - you can actually cut the SMCS wire so it won't ever write any of that stuff into it. Is that true?
 
Just an FYI.

Going 24bit doesn't automatically save you from this pulse width modulation technique. In fact, the new 24bit ADC's and DAC's are almost never of the current summing variety. Virtually all of them are "multibit" Delta-Sigma modulators, where multibit usually translates to around 5 bits.

Still, they are much better than what was before.

barefoot
 
Darkhorse, there will be no need to cut any wire,chip or doodad if you simply use the analog inputs rather than
the optical or digital. I have done the same thing recording various groups and jazz musicians and then make a compilation of their best hits on 1 C/D using the tray-to-tray option.
 
Thanx Q - Hey does anybody know why I get so much hiss when I try to mix from my 488 Tascam analog 8 track to the CDR 775 - When I mix on my stereo to tape I don't get as much hiss. I would think it would be the other way around. If I get to loud the sound in-level bar on the CDR goes to the end and turns red or whatever, then I have to turn it down - till its almost too quiet. Does this have anything to do with ther berng no noise reduction on the CDR?

I've never experienced this much hiss on anything I've mixed to before. The audio cables are good. There is nothing wrong with the 8-track that I'm aware of. Is there something I need to buy that goes somewhere inbetween the 8-track and the CDR? At this point I would rather mix to a tape, then just put the tape on CD - though I would rather just mix to the CD of course.

ANy ideas would be helpful
 
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