[Coco] Importing CCRs

coco at yourdvd.net coco at yourdvd.net
Sat Mar 31 23:06:09 EDT 2007


I bought a Pioneer CT-W606DR. It was (I don't know if still available) a
ridiculously priced digital processing analog tape deck with amazing
fidelity. I only bought it to transfer My Stephen Moore readings of the
first four Hitch-Hiker's Guide To The Galaxy Audio Books into CD's. Now
I use it for transferring Vintage Computing cassettes. It's a nice
machine. I thought about making a cable to connect it to my coco using
a ground loop isolating transformer just to see how it would perform
:-)  -r

> -------- Original Message --------
> Subject: Re: [Coco] Importing CCRs
> From: Kevin Diggs <kevdig at hypersurf.com>
> Date: Sat, March 31, 2007 1:09 pm
> To: CoCoList for Color Computer Enthusiasts <coco at maltedmedia.com>
> 
> Gene Heskett wrote:
> 
> > Yes I am Art.  The first 'tape' recorders used a rouge coating (to
> get the 
> > iron in a fine grain condition for the higher frequencies) on one
> side of 
> > a 1/4" wide kraft paper tape.  Between the surface roughness of the
> kraft 
> > paper (your basic brown paper bag paper) and the lack of an exciting
> bias 
> > field, the recordings were poorer technically than even todays $10 
> > machine can do.  Head life was often less than 500 hours due to the 
> > highly abrasive nature of the rouge too.  When the advent of an AC 
> > magnetic bias was discovered, which linearized the magnetic
> properties, 
> > the distortion dropped from 80% to 5% in one swell foop, with an 
> > accompanying improvement in the noise ratio by about 20 db.  Then it
> was 
> > found that any harmomic distortion in this high frequency bias
> (running 
> > at 80 to 120 khz) also had a pronounced effect on the background
> hiss and 
> > by the time they were done finetuning that and the tape coatings, we
> have 
> > bidirectional stereo recordings at 3.75 ips with 15khz top ends and
> 60 db 
> > snr's.  And distortions were gradually lowered, while peak recording 
> > volumes which in the 50's were hard clipped at maybe 6 db above the 2% 
> > distortion level, to almost 16db above the 2% distortion levels.  2%
> was 
> > generally where the VU meters were calibrated to show 100%.
> > 
> You are a bottom less fountain of fascinating facts. Make sure you eat 
> plenty of broccoli, carrots, peas and corn. Get a Black & Decker Handy 
> Steamer if you have to.
> 
> What is rouge? Is it like rust water?
> 
> What do you think of cassette decks? I have a Realistic SCT-30 3 head 
> deck. It is circa 1980 and sounds pretty good. It has a record level 
> calibrate (they call it a Dolby calibrate) and a bias fine adjustment 
> knob (on the back?). I think it was made by Hitachi. I once found a 
> review of it in some magazine. And they said it was an awesome deck. 
> Dolby SNR was like 65 and the top end was around 16k. That review raved 
> about how hard you had to drive it to saturate it. I have often thought 
> of turning off the bias and seeing what the recordings sounded like.
> 
> Most cassette decks have little dolby symbols at +3 db. Do you know what 
> they mean?
> 
> And to get really silly and pointless. What kind of music quality do you 
> think you could get if you took Modem modulation techniques and know how 
> and tried to do MP3 digital music with a standard analog cassette deck? 
> A modern modem connection is about 50 Kbit, right? A cassette deck is 
> stereo (ignoring cross talk issues). I suspect that a cassette deck also 
> has greater fidelity than a phone line (ignoring wow and flutter). Think 
> it could do 128 kbit?
> 
> This is kinda what Philips tried to do with DCC (Digital Compact 
> Cassette). Only in my opinion they went in the wrong direction. They 
> came out with a new digital gadget that could play analog tapes. They 
> should have started with a really good analog deck and did the best they 
> could squeezing a digital recording ON A STANDARD TAPE. I have had VERY 
> limited success in trying to trick an Optimus DC-2000 into thinking an 
> SAQ-X tape is a DCC digital tape. It did work better than trying to get 
> a DVHS deck to think a modified normal tape is an SVHS tape. Never seen 
> more than a few still pictures with that.
> 
> What do you know about back tension?
> 
> I bought a Sony DTC-790 DAT deck off eBay. I have not quite gotten it to 
> work right. Could the head be bad? If you look at the signal off the 
> heads with a scope it is clean for the first 40% of the 90 degree arc. 
> But the last part is unstable. Either missing or comes and goes. Think 
> it is the head? Or a back tension or alignment issue? I've already 
> replaced the pinch roller.
> 
> Do you know anything about DVHS? I got one of these off of eBay. It is 
> pretty cool. Kinda like a cross between a VCR and a computer tape deck. 
> I looked at the drum once. Don't want to know what it might cost to 
> replace that thing. It has ALOT of heads! Though if you think about it I 
> don't think the information density is very high on DVHS. Couldn't you 
> get 2 hours of HD content on a DDS4 tape? Isn't the native capacity 20G 
> for DDS4? Don't know if the data rate is high enough?
> 
> kevin
> 
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