As good as possible, I've tried to guess the 8 individual capacities, adding up to a total of 1.1nF.
All cap values are inserted in your .asc file, and the coils are increased to 2.7H as measured by sheldon.
In the Image below on the left side the FR as seen on the 8 sections and to the right the step response, where the time delay between sections is nicely visible.
Next step will be to integrate this beast with the transformers.
Hans
View attachment Quad 63 Delay Line V2.asc
I can't remember but he did call once to tell me he updated a mixing desk with AD744's for Fleetwood Mac's HBO special.
I'm pretty sure that Crystal Clear used the 3 mike technique (with 40KHz B&K mikes) with the Arthur Fielder 'Capricco Italien' recording at Boston Symphony Hall in 1977 in a direct disc recording, essentially flat to about 30KHz. (record cutting limit) Only John Meyer knows for sure.
Another laugh from the past! He spent some time with us converting the filters in our Sony 1630's in the late '80s and trading stories of doing live sound with Richard Clark who had started Maryland Sound. I remember doing pulse and square wave testing with the units and seeing the difference/improvement. When the Apogee AD/DAs were released in the early '90s we converted all of our mastering and QC suites to them. From my perspective they were very reliable and sounded good...
Ancient memories...
Howie
According to the 1630 service manual, used the same Butterworth 9nth order as anti-aliasing filters and anti-imaging filters (in the monitor section) as well. Specified with - 3dB at 24 kHz which is IMO hard to believe for a 44.1 kHz Fs sampling rate.
Any chance that you remember (or have still some notes) about that?
Whats your point? Instruments are pyhsical systems that can be modeled.
Immink wrote in 2018 another (shorter) article about the invention of the CDDA and again expressed his thoughts about the real reasons why the disc diameter, initially agreed upon by both parties, had to be changed, but this time could add this piece 😉 :
Kess A. Schouhammer Immink; How we Made the Compact Disc; Nature Electronics 1, 260 (2018)
Kess A. Schouhammer Immink; How we Made the Compact Disc; Nature Electronics 1, 260 (2018)
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We'll obviously continue to agree about where the line in audibility should be drawn, but I think we're both comfortable with the idea that the choices the recording staff/artists make to the sound will be more audible than not (gross manipulations). I consider it an art (which obviously encapsulates a tremendous amount of skill and technique to pull off).
I take a hedonic approach -- do I like the music? Yes, great, enjoy. No? Find something else or a different recording of the same piece, what have you. We are not starving for music options. But we can continue to raise Cain about loudness wars very definitely ruining most music. 🙂
Those look to be pretty good guesses. I'll measure several ways when the panels get here. I may open the dead quad to access an inductor for more info.
Your networks show pretty linear response to 30 KHz and then an abrupt rolloff. Looking at the impedance there are fluctuations above 20 KHz as well. Once we have all the pieces we may better understand the actual impedance and phase stuff.
I saw some stuff on ditching the dust cover with no ill effects over as much as 5 years. If so that would be remarkable and promising.
That the time domain envelope changes when content above Fs/2 has been removed and Gibbs ripples have been added, has been mentioned by me at least 5 times, this was already obvious at least 40 years ago and was shown in various sims that I made.
So you are reinventing the wheel when you talk about "the mechanism has now been identified".
With an envelope in the time domain being changed because of this HF filtering, there are two possibilities:
either we are 1) sensitive to envelope information or 2) we are not.
No machine or software can help to find out.
This can only be done by well controlled extensive listening tests such as Oohashi tried, but where he failed IMO.
So why not provide these test, preferably all in 192/24 having content above 20K , plus their brick wall filtered versions stopping at 20Khz.
"H"
P.S. And when you don't like my exp sim, come with a better version instead of whining. I'm looking forward.
From what I read today many early recordings were possibly full of aliasing artifacts. FDNR (frequency dependent negative resistance) filters were of interest back then and I think Bruce inspired me to put this on one of my data sheets. It's an anti-imaging filter for 88.2k up sampled CD audio and not an abrupt brick wall but flat group delay up to 20k.
I never mentioned that I met my wife working on the AD711/12/13, she ran a fab experiment to grade the gates on our FET's to eliminate the impact ionization.
Attachments
Thanks Scott. If we double the value of the capacitors, will this be good for 44.1kHz SR?
Gosh! Love over the sand
George
Gosh! Love over the sand
George
That's interesting info, John, thanks! Did they used your mic preamps too?
There's a bit of information out there regarding this session. Apparently there was Soundstream system running in parallel to lathe as well as Ampex ATR 100. Why Ampex? Didn't Crystal Clear had your A-80 by then?
Info courtesy of Tom Fine, the son of Bob Fine
http://www.aes.org/aeshc/pdf/fine_dawn-of-digital.pdf
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Negative. That project was before I headed engineering there and I was merely an audio engineer doing alignments and mods in the audio plant, so it would have been in Richard Clark's files...come to think of it, many filing cabinets full of such notes, mods, etc. were landfilled during the shutdown...quite a shame considering the leadership role AMI had in replication and all the equipment we designed. But the vast majority would be of no use other than historical interest now. Time inexorably moves on...
Cheers,
Howie
That's interesting info, John, thanks! Did they used your mic preamps too?
There's a bit of information out there regarding this session. Apparently there was Soundstream system running in parallel to lathe as well as Ampex ATR 100. Why Ampex? Didn't Crystal Clear had your A-80 by then?
Info courtesy of Tom Fine, the son of Bob Fine
http://www.aes.org/aeshc/pdf/fine_dawn-of-digital.pdf
"The 3M system was later finalized and put to market and by 1979 several studios were making all-digital multi-track recordings. The first all-digital album made in the traditional multi-track way used for most popular/rock/jazz albums since the 1960swas Ry Cooder's "Bop 'Till You Drop," released by Warner Brothers in 1979.The album, pro- duced by Cooder and engineered by Lee Herschberg,was recorded at Warner Brothers' North Hol1.ywoodstudio in California"
This album still sounds really good to me. Music wonderful! Probably because the tech was science and not market driven. Filtering must have been adequate in the A/D line.
//