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Author Topic: reading mono tapes; show me the money -- SACD; quadro beats stereo  (Read 3205 times)

Offline braver

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I have old family reels, recorded on the first Soviet consumer high-quality machine, Astra-2.  (The qualifiers are from its manual.)  It's a half-track mono machine, two tracks, you turn the reel over to listen to the other side, as usual.  Being a quadrophonic fan, I got an Akai GX630D-SS, and discovered that listening to my family tapes is a stochastic experience.  The quadro mode helps very much to get all contents, but not very reliably.  Usually, I get the original forward side from quadro track 2, or backward from track 3.  In both cases I feed the RCA outputs to Edirol UA-1EX and record on a Mac with Audacity at 96 KHz, and the backward one can be time-reversed and listened to with the same quality.

What I notice is, I pick up different amount of cross talk each time I play the tape -- as if the quarter-track heads wobble between and around the half-track recording's actual tracks.  The original voice recordings had many usual real-life pauses and shifts in the recording level, so I'm not sure whether the gaps and sudden level drops are original or caused by the 2/4 tracks mismatch.

In any case, when researching the issue, and googling for something like "reading mono tapes on a stereo reel to reel tape machine," I've stumbled upon this amazing project.  Kudos to all!  If I get a Technics 1500, will it read properly the mono tracks I have?  Remember I get the signal from track 2, so apparently it's the upper half of the tape being the forward side -- does it match the Technics layout?

Also, with all due respect, quadrophonic surround beats any type of stereo quality; being a long-term SACD fan, I can hardly imagine a stereo tape beating the immersive experience.  I noticed the nuance such as the sound of fingers plucking strings first thing listening to jazz.  In order to achieve a true quality comparison, I suggest the guys in charge issue SACDs accompanying the tapes, so that we can really compare sound, not nostalgic biases/hindsighted justifications of expense.  SACDs are not copyable still, so adding them to a license wouldn't be too hard, IMHO.  Why not produce the original masters in multitrack on quadrophonic tape?  I'd be really curious to compare the quality obtainable from a Technics to that of a quadrophonic Akai.

Cheers,
Alexy

Offline ironbut

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Re: reading mono tapes; show me the money -- SACD; quadro beats stereo
« Reply #1 on: February 09, 2009, 07:33:47 PM »
Hi Alexy, welcome to the forum. Unfortunately, I'm not personally familiar with the track layout used with the Astra-2 so I can't give a definitive answer why you would get varying amounts of crosstalk on 1/2 track mono tapes with your Akai. Since it is a 4 channel machine, have you  tried playing back with tracks 1 and 4? Those are the "outside" tracks on a 4 channel head and would yield the greatest distance between tracks being played. There are several reasons that the crosstalk might occur, but only a few that would change from one playing to another. . There could be problems with the tape, such as poor slitting (tape is made in large widths and then cut or slit to the smaller sizes). This would allow the tape to wander across the width of the head. This is much more likely than the head moving. Next time you play the tape, use a strong light and watch as the tape crosses the head. I should cross in a straight line and not move laterally at all. It may even be that the tape is not 1/4" in width (exactly). When it's threaded is there an observable space on either side of the tape to the guide edge? If there is, make sure that the tape guides and heads are scrupulously clean since and uneven friction will pull the tape to one side.
Regarding the playback of these tapes on a Technics, I think you'll have similar problems with crosstalk on it since it's playback is either 1/4 track stereo (tracks 1&3 are channels left and right or after flipping the tape, tracks 4 & 2 are channels left and right) or 2 track stereo. With 2 track stereo, you could get the same playback as you're getting using tracks 2&3 (or 1&4 as I'd suggest) but the space between the two tracks (safety track) will still be the same.
Without knowing the track layout of the Astra, all this is a guess of course. If you'd like some more background information about track layout, check out the "Beginners Guide" in a sticky at the top of the General forum.
steve koto
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Offline steveidosound

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Re: reading mono tapes; show me the money -- SACD; quadro beats stereo
« Reply #2 on: February 09, 2009, 07:55:59 PM »
Uh Ironbut Steve, do you want to answer? You're the audiophile with tact, I'm just the technogeek who happens to own an Akai quadraphonic deck :)
OK, you answered while I was typing my answer...

Seriously, Braver/Alexy, your old family tapes, if mono with only one track per side of the tape (turn the reels over for side 2 program) and not "4 track mono", should play well enough through the left channel output of a conventional stereo deck. That should be "front left" of a quad deck). No gap on a 4 track stereo head is perfectly aligned to play these tapes. A 2 track stereo deck, such as used for tape project tapes should play them perfectly aligned on it's left channel. The top half of the tape as viewed by looking at the heads with the tape running left to right is normally what is recorded by a consumer  2 track mono machine. I guess the old Soviet Union COULD have produced a deck in some other nonstandard (to the west) configuration.
I refer you to the thread in"general discussion",  "beginners guide to tape recorder basics" that I wrote on making sense of interlaced stereo tape tracks and other format issues.
Perhaps your tapes were wandering in alignment when recorded? Or they might be shedding oxide. After cleaning does your Akai play other tapes normally?


As for digital high quality multichannel vs analog high quality stereo, I will bow to others opinions. I like multi channel and I like "found ambiance" in stereo played with L-R recovery. I like higher quality digital better than normal CDs or worse mp3s at lower bitrates, but I like high quality analog even better.
Even in normal stereo.
Steve Williams

you don't want to know what equipment I listen to...

Offline braver

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Re: reading mono tapes; show me the money -- SACD; quadro beats stereo
« Reply #3 on: February 09, 2009, 08:47:57 PM »
ironbut, steveidosound -- thanks for the info!  I can read the tracks allright, it's just seems that the pauses are different sometimes.  The tape seems to go absolutely straight through the Akai -- I got it from an audiophile single owner, it's very well preserved.

I thought that 1/2-1/4 capability means separate heads for separate number of tracks.  What about the width of the tracks on the mono systems?  Intuitively they can be wider and would benefit from the 1/2 wide heads.  Looks like ideally I'd get a mono deck, but I loath to get some old crap with worn out heads while I have a later GX heads, yet narrower.  That's why I was so curious about the dual width capability of the Technics/Otari.  Does anything move vertically when you switch 1/2 vs 1/4?  Because if it's only the matter of picking the active tracjs, my quadro will get all there is out of a tape, compared to any other 4-track heads which is switched to only 2 active for mono.

Offline ironbut

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Re: reading mono tapes; show me the money -- SACD; quadro beats stereo
« Reply #4 on: February 09, 2009, 09:08:40 PM »
The 1/2 track and 1/4 track on the Technics/Otari are both stereo formats. The 1/2 track uses the full width (except for the safety track that separates the two) while the 1/4 track head uses half of the tape width (staggered-track 1 and 3). The other two spaces on the head are blank so when the tape is flipped, it's still using tracks 1 and 3.
steve koto
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Offline braver

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Re: reading mono tapes; show me the money -- SACD; quadro beats stereo
« Reply #5 on: February 09, 2009, 09:57:18 PM »
ironbut -- thanks much for explaining!  So the bottom line seems that using 1/2 mode of a Technics/Otari should be better than just using a purely quarter-track tape machine such as an Akai, correct?

Cheers,
Alexy

Offline steveidosound

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Re: reading mono tapes; show me the money -- SACD; quadro beats stereo
« Reply #6 on: February 09, 2009, 10:46:07 PM »
ironbut -- thanks much for explaining!  So the bottom line seems that using 1/2 mode of a Technics/Otari should be better than just using a purely quarter-track tape machine such as an Akai, correct?

Cheers,
Alexy

Yes, that is what I was trying to say. The left channel of a 2 track stereo machine covers the exact same half of a tape width as the 2 sided 1/2 track mono format of your old machine.
Steve Williams

you don't want to know what equipment I listen to...