Recording Quad-CD4 Vinyl LPs to Magnetic Tape and Playback via Tape

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cometphoton

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Hey, What do you think about recording CD4 vinyl Lps to tape and playing them back?
Just like excersizing my tape decks for fun. This is what I was thinking.

Equipment I am using:
Source to record from: Marantz CD 400 Demodulator, 4 Channel CD4 cartridge & Turntable / 4 channel Receiver / playing CD4-LPs
Recoding and playback device: 4 Channel Reels, 2 & 4 Cassette decks and 4 channel 8 Tracks. I will start the process with the 4 channel casssette.

Options:
1. Record outputs directly from CD4 Demodulator direct to 4 Channel deck.
2. Record 2 channels from Turntable direct, no demodulator, then playback using CD4-Demodulator circuits.
( I wonder if I have to calibrate the deck like a turntable )

What do you think? This is going to be fun. (y)
 

kfbkfb

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CD-4 requires a bandwidth of 45kHz, no compact cassette deck has a wide enough frequency response and I doubt if open reel tape decks have enough to copy a CD-4 disc directly.

Another option is to play the (CD-4 capable phono cartridge) output into a computer (line level audio in, using a suitable amplifier) and save the audio data in a file on the computer.

The computer audio output (reduced in level to that of a phono cartridge) can then be input to a CD-4 demodulator and decoded into the 4 discrete channels.


More about CD-4:


Kirk Bayne
 

The Bushmaster

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No problem cometphoton. I do it all the time. As long as you go from turn table to CD 4 demodulator to tape deck you will be fine as long as you record the record to a Quadraphonic tape deck I use a Dual CS 721 to JVC 4DD-5 to An Akai GX 270 DD.
 

par4ken

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No problem in doing that. That's what many of us used to do, as long as you can get satisfactory CD4 playback to begin with. Today I would be making a digital copy instead. A digital recording will be virtually lossless and you can apply click removal if needed. Then again I too like to play around with vintage formats (tape) once in awhile, just for fun!
 

cometphoton

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Hows this sound, I connect the decoder into: Presonus Firestudio Project Line preamp. Then use PC software with Bandwith at 4800 to record.
Do the same thing,

Options:
1. Record outputs directly from CD4 Demodulator direct to PC daw ( CD4 turntable connected to CD4 demodulator )
2. Record 2 channels from Turntable direct, no demodulator, to PC daw then playback using CD4-Demodulator circuits.
 

cometphoton

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No problem in doing that. That's what many of us used to do, as long as you can get satisfactory CD4 playback to begin with. Today I would be making a digital copy instead. A digital recording will be virtually lossless and you can apply click removal if needed. Then again I too like to play around with vintage formats (tape) once in awhile, just for fun!
check this out Stereo Lab - JVC CD-4 Decoding in software
 

cometphoton

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Too bad that software is only for a MAC... I wonder if you can work it inside Virtual Box. Did anyone try ?
 

kfbkfb

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Too bad that software is only for a MAC... I wonder if you can work it inside Virtual Box. Did anyone try ?
Yes, it works using an Apple emulator/virtual machine:

(some QQ members assisted with the development of the CD-4 software decoder)


Kirk Bayne
 

cometphoton

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How about turntable -> CD-4 demod -> Matrix encoder -> CD re
Yes, it works using an Apple emulator/virtual machine:

(some QQ members assisted with the development of the CD-4 software decoder)


Kirk Bayne
Working on VM ware now. I already have Virtual Box but no experiences with VM ware yet. I will keep you posted.
corder
 

cometphoton

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Yes, it works using an Apple emulator/virtual machine:

(some QQ members assisted with the development of the CD-4 software decoder)


Kirk Bayne
Ok, I have virtual Box running MacOs on a PC, and I have Stereo Lab running inside this as well. Now how dose this work?

I want to decode CD-4 and SQ vinyl records from my collection.
Looks Like Stereo Lab converts files? So How do I get my CD-4 and SQ tracks from the vinyl to a file that Stereo Lab can work with. Can I connect Stereo Lab to my Turntable ? This is a real adventure and I am enjoying it. Most of all thanks for all your help. I just don't understand the hardware and software configurations.

Thanks again.
 

kfbkfb

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A flat frequency response amplifier is needed:

Also, a partner company to Pspatial Audio/Stereo Lab sells suitable amplifiers:


Signal flow:
CD-4 phono cartridge output from turntable -> amplifier (see above links) -> computer stereo audio input -> Stereo Lab software -> 4 channel output data files


Separate computer software can be used to convert the 4 channel output data files to DTS, which can be recorded on CD-Rs or DVD-Rs for playback on regular CD/DVD/Blu-ray players.


Kirk Bayne
 
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cometphoton

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I got it! Truly amazed at the work completed for this subject: Stereo Lab software. What a project!!!

I can't image the hours spend developing the math for the modeling software. The software and explanations on the site are incredible. I am buying the software for sure. The documentation done deserves reconition as its just " Above and Beyond"! Past Audio engineers like Edison and all the Bell Labs engineers are in the after life smiling that what they worked so hard for is not forgotton. I can't say enough about this project. It has history and its all about preservation. Hats off to the team that developed the software.

Next I will build a phono circuit that removes RIAA and start my adventure with Stereo Lab.

All I can say is WOW. I sold my Tate II and now moving toward needle drops with Stereo Lab.
Need a laugh a few days ago I was asking my self what is a Needle drop?

Everyone who inspired me to go down this rabbit hole....Thanks for taking the time to help me I can't wait to hear my new recordings.
 

cometphoton

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How about turntable -> CD-4 demod -> Matrix encoder -> CD recorder.
Well, Thats the way I do it now. It works pretty well too. Just looking for another way to skin the cat with software and I found it. Yea you can't beat playback hardware your right. That Tate II was the best darn product to reproduce older Quad records too. But Not anymore...Im moving on.

I have learned what it takes to get the new adventure done. Not as easy as I wanted but Kirk pointed me to this rabbit holes documentation and Im in it full bore. I sold my Tate II to fund my new adventure but I will keep my older Marantz 400 demodulator and SQA encoders until I have my collection of software files built. Heading to the old record store today to purchase a few more old Quad vinyl records and I never thought for one second that I would be running Mac os...my kids will be lauging at me the old PC / Win guy now in the Mac world.

Thanks for reminding me that you have to keep Turntables with a good shibata cartridge, cd-4 demod's, Matrix encoders and just a
way to record in analog or digital...Well I still have R-T-R, 4 channel cassette recorders too. Its a real pleasure making and recording music. My life is just better with music and the people who help us find paths to how we listen and record are just touching. It all about help! Everyone tells you about the adventures they spent and we all enjoy hearing about it. Most of all Thanks for the reminder
 

cometphoton

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Too bad that software is only for a MAC... I wonder if you can work it inside Virtual Box. Did anyone try ?
It works! Wonderful Stuff....VM ware has costs associated with it but it runs for free for a while.
Virtual Box is free I have both up in test mode. I will test first then buy my first Mac... then I will eat my word "I will never own a Mac"
 

kfbkfb

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A lot of QQ members have wanted an all software CD-4 decoder for some time (the newest hardware CD-4 demods are about 45 years old by now), we were thrilled (myself included) to finally get one.


(I may go the software route too [I don't have many CD-4 albums though], my Technics SH-400 works ok, but it is just consumer grade tech and could fail any time)


edit: The AES paper describing the operation of the Pspatial Audio/Stereo Lab software CD-4 decoder is included in the Needledrop Handbook:


Kirk Bayne
 
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cometphoton

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cometphoton

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What do you think of this circuit for a needle drop without RIAA?
 

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kfbkfb

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I would build the one sketched by Richard Brice of Pspatial Audio/Stereo Lab (linked in post #12) or buy one of the basic/entry level needledrop amps from Phaedrus Audio:


(looks like the Groove Sleuth MICRO would be a good choice)


Kirk Bayne
 
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