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WHy are the 74 min and the 80 Min formats so different

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Larry NYC

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I bought a Sony MDS-JE520 Deck and it only plays the 74 Minute Format Discs and not the 80 Minute Discs.

What dont I understand about these 2 formats and why are they so different?

I own several portable players both 74 and 80 minute Players?recorders- They are not compatible with each other.

Please explain why the Deck cant play both?

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My JE520 (1998) is perfectly happy with 80 minute discs.

The 80 minute discs use a slightly finer pitch of the tracks (see this FAQ). I'm not aware they are incompatible with any MD machine but I guess I wouldn't be surprised if the very earliest machines (early 1990's) couldn't use them. At the beginning of MD there were 60 minute and 74 minute discs.

I'm not sure I understand your title though - what do you mean by format? The blank discs don't have a format as such, however you can record in SP, LP2 or LP4 on either. As BearBoy suggests, discs with an MDLP recording (LP2, LP4) will play as silent on your JE520 which doesn't support MDLP.

Kevin

Ooops maybe I dived in and got a bit technical, I can see BearBoy has been giving you a better intro on the other thread...

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Thank you guys for replying. I just got the JE520 today and tried to play the 80min disc as well as the 74 min. my previously recorded discs in the 74 min played and the 80min discs wouldnt.

I have not tried to record on either Disc yet. Im also curious if there is a Service manual that can show me how to adjust the internal settings for better alignment.

I have an Electron ic background and a Bench full of the latest Electronics. Scopes, Meters. generators, etc.

 

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It's quite unlikely that the difference between 74 and 80 is your problem.

More probable is that they have different reflectivities. There's supposed to be circuitry which (mainly at record time) fixes that problem. I know that some disks (of one type) recorded on a portable absolutely refused to play on a deck, when I started out. After that I was more careful with recording. It depends how they were made, recording takes 10x as much power as reading, and it could be you were trying to run on rechargeable batteries. It should work but on older machines there is adjustment of the power circuits (on portables) to be done.

What model numbers are we talking that recorded?

I am guessing that if you can record on the deck you will be able to play back on everything (portables and deck).

BTW the other possibility is that all your 80 minute disks were recorded at MDLP - this thread doesn't say how the failure occurs. Do you get playback but no sound, or is there a C13 or C14 error?

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There is a service manual available but there is no manual adjustment to be done. There is a complex electronics-based servo mechanism built into the drive that aligns the laser to the tracks automatically. This is similar to a CD player which largely uses the same tracking mechanism.

See minidisc.org for the SM and the Minidisc technology tutorial:

MDS-JE520 page with Service Manual

Minidisc technology tutorial

Stephen talks about different reflectivities. But as far as I know this is only a difference between the high-reflectivity prerecorded (stamped) discs which are pretty much like CDs physically (pits and lands) and the recordable (magneto-optical) discs which are low-reflectivity. With the MO discs, the Kerr effect (light polarisation affected by magnetic polarisation) is used to determine data content. You don’t need to know or care about any of this, the deck works it out automatically. 

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5 hours ago, kgallen said:

There is a service manual available but there is no manual adjustment to be done. There is a complex electronics-based servo mechanism built into the drive that aligns the laser to the tracks automatically. This is similar to a CD player which largely uses the same tracking mechanism.

See minidisc.org for the SM and the Minidisc technology tutorial:

MDS-JE520 page with Service Manual

Minidisc technology tutorial

Stephen talks about different reflectivities. But as far as I know this is only a difference between the high-reflectivity prerecorded (stamped) discs which are pretty much like CDs physically (pits and lands) and the recordable (magneto-optical) discs which are low-reflectivity. With the MO discs, the Kerr effect (light polarisation affected by magnetic polarisation) is used to determine data content. You don’t need to know or care about any of this, the deck works it out automatically. 

Maybe I'm muddling my terms - maybe it's the stray light adjustment. All I recall is that some disks, when borderline, seemed to have a problem with playback. By "some disks" I mean that different makes and models OF DISKS behaved differently. The ones that have given me problems are some types (but not all) with transparent cases - whereas the ones with opaque cases passed the test in the situation where the transparent ones failed. I believe the adjustment I'm talking about is only a thing on portables.

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Thank you for that education everyone. I recorded a 74 min disc in the JE530 deck and it plays in my 2 portables. One newer one I've always used 80 min discs and an older portable came with a box of 74 min discs. Each unique disc wouldn't play in the other size player.

Do it's not a format that's not the issue but the disc or the recorder.

Larry

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They should be 100% interchangeable. You never indicated about what happened when they "wouldn't play". Error codes are helpful. Certainly putting an LP disk (being accurate, a disk with LP tracks on it!) in the JE530, would get you no sound, but also no error.

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I own a MZ-R37 Recorder/Player and it came with 74 Minute Discs. I also own a MZ-N707 which always played 80 Min discs. When I try to put either disc into the "other" Player, I dont get any errors, I get no sound, but the counters just keep ticking up like its corretly playing it. Burning a 74Min and 80 Min Disc on the newly purchased JE520 deck and both Discs play in eithe r Unit. Some of the older 80 minute discs will not play (give off sound) in the JE520 Deck and some do play.

 

Thank you all for the replies

Ive learned so much here.

 

Next I need software that runs on a Windows 10 PC, or is that even possible. I want to upload and down load music from/to my Mini discs.

 

Larry

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1. You cannot upload from your units to the PC (using USB that is)
2. Yes, you can send music to the MZ-N707, by all means try the new gizmo that all are talking about, or you could set up SonicStage. You'll need the 64-bit driver and you'll need to turn off driver signing enforcement on Windows 10 for long enough to install the NetMD driver for your N707.
3. If they play and give no sound, that's the symptom of an MDLP disk in a SP-only player. By design.

I'm certain you can record on the two MD portables and play on each other - but you MUST pick standard mode (SP) for the recording. I'm not even certain what happens when you play a MONO disk in the NetMD portables. It's not a recording option, so maybe it doesn't play back either. Guessing the ones from the R37 might be mono.

So many variables!

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To add to what Stephen is saying regards SP and MDLP:

- Your MDS-JE520, MDS-JE530, MZ-R37 machines only support SP (standard play) - they pre-date (only just for the 530) around 2000 when MDLP (minidisc long play) was introduced [*].

- Your MZ-N707 will support SP plus the two MDLP modes LP2 and LP4. So if you record a disc on the N707, you need to use SP mode (it will be in the menu somewhere) if you want to play that recording on any of your other machines.

As Stephen says, if you record in LP2 or LP4 on your N707, those tracks will play back silent (by design) on the other machines - you may see "LP:" on their display. A disc can have any arbitrary mixture of SP, LP2 and LP4 tracks on it. The whole disc doesn't need to be the same mode (although in practical terms they usually are!) - but those LP2/LP4 tracks will play back silent on a non-MDLP machine and the track timer will increment as usual as the track progresses. All tracks should play back fine on your N707 and the machine will automatically recognise the mode (SP/LP2/LP4) of the track and configure itself accordingly.

I hope this is making some sense!

Kevin

[*] They may pre-date MDLP (just), but in my opinion the 520 and 530 are still fine machines. My 520 probably gets the most use of all of my MD machines (and I have a lot!) - my "baby" from new in 1998/99.

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