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Author Topic: Mono prerecorded tapes  (Read 12388 times)

Offline steveidosound

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Mono prerecorded tapes
« on: January 10, 2009, 10:55:57 PM »
I was surprised to learn that there were tapes released in the 2 track / 2 sided mono format at 7 1/2 ips.
Until I ran across some in a lot of tapes I bought on Ebay I would have not thought they existed.
Stereo tape was the first application of consumer stereo sound, predating stereo records by at least 3 years and stereo FM by 9 or so.
So, since stereo was sort of the point of prerecorded tapes, I was surprised to see mono ones.
The ones I have are on the HiFi label with George Wright at the Organ.
They have a "7 1/2 HT" (half track) designation on the box and inside it states that they are available on records and in monaural and stereophonic for "stacked heads" (2 track) tape. I also happen to have some of the same titles in vinyl, some mono and some stereo as well as one later 4 track stereo tape. The only sad thing is that someone switched reels, so I don't have the original reels for any of the 3.
The sound is OK but not as good as some of my other 2 track tapes.
Have other people here run across any mono prerecorded tapes?
« Last Edit: January 11, 2009, 01:57:19 AM by steveidosound »
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Offline ironbut

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Re: Mono prerecorded tapes
« Reply #1 on: January 11, 2009, 12:45:36 AM »
 I don't have any 1/2 track mono at 7 1/2 ips but I do have a staggered head 1/2 track stereo tape. I wish it was dated because it must be pretty old. I usually don't buy large lots of tapes but I've often wondered about some of the tape sellers on eBay like "reel lady" who buys nothing but huge lots and just seems to sort them as she gets them ready to sell. I bet there's quite a few unusual formats sitting in some corner of her shed. I hope she doesn't just toss the ones that don't seem like anyone would want.
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Offline classicrecordings

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Re: Mono prerecorded tapes
« Reply #2 on: January 13, 2009, 09:10:19 AM »
There are quite a few of these tapes around.  I had many mono 7.5 ips 2 track tapes on the UK EMI/Columbia releases of their early opera recordings.  The only tape I kept was the Beethoven Piano Concerto #4.  There is no conductor listed, but I am pretty sure it is Furtwangler.

The sound of these tapes was OK, but nothing outstanding.  The thing to remember when playing these tapes is to to reverse phase so that you get a proper mono presentation.  If you don't want to reverse phase, then listen with only one channel.

There was also a period of time when EMI released some 2 track 3.75 ips tapes on 5" reels; you can find some Beatles releases like this.  I have also seen some Karajan Beethoven on DGG in the same format.  Personally, I would not bother with them unless you collect performances or performers.  Those that I have heard; like some EMI operas, were not very good, at least to my ears. 

David
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Offline steveidosound

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Re: Mono prerecorded tapes
« Reply #3 on: January 13, 2009, 10:53:47 AM »
The sound of these tapes was OK, but nothing outstanding.  The thing to remember when playing these tapes is to to reverse phase so that you get a proper mono presentation.  If you don't want to reverse phase, then listen with only one channel.
David

Can you elaborate on this part?
I understand relative channel phase in a stereo system but I have a feeling you are talking about absolute phase from the original studio performance - which I don't know if there is a way of determining on a reel to reel tape, mono or stereo.

In my other post on listening to mono in the Tape Tech category, I was suggesting for the new TP releases of mono material on 2 identical tracks that the best thing might be to listen to one track of the tape - the "left" would be the equivalent of these old 2 track 2 direction mono tapes - through only one speaker. I suggested it would not be a good idea to electrically combine the 2 identical tape tracks before the speakers because it would show up any minor misalignment of your machine to the TP tapes. 
If you do decide to listen through both speakers to a single mono track, I would think normal phasing as used for stereo playback would be the most appropriate - thus giving a solid phantom center image which your system should be capable of. Throwing the speakers out of phase with each other and playing a mono track will result in decreased bass and no center image.
« Last Edit: January 13, 2009, 11:04:49 AM by steveidosound »
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Offline classicrecordings

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Re: Mono prerecorded tapes
« Reply #4 on: January 13, 2009, 02:05:39 PM »
Can you elaborate on this part?
I understand relative channel phase in a stereo system but I have a feeling you are talking about absolute phase from the original studio performance - which I don't know if there is a way of determining on a reel to reel tape, mono or stereo.

I guess I should explain that the tapes I am referring to are 2 track mono tapes that have only one channel per track, and must be flipped over to play the remaining material.

I am not sure what phase you would call it, I can only explain what is experienced when it is heard. 

When I wrote about the reason for reversing phase to hear the mono correctly, I was referring to what is similarly experienced when playing a mono LP with a mono or stereo cartridge, but played back through a stereo system.  I may not know the terminology to explain it, but without reversing phase either by a switch on the pre-amp, or reversing phase on a speaker cable, you end up with a wide image spread between the speakers, but when phase is reversed, the image solidifies into a single point between both speakers, and this will give you the illusion of a single speaker playing back the material.  Just like you would get if you Like you are listening in mono.  If you have stereo a test record with a phase test, you will experience the same thing in stereo.   

I have no idea what will be heard with the TP's mono tape.  I do not know if this effect can be changed by having a double mono signal.

David
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HK Citation 1 Pre-amp, Thorens TD-124, Ortofon 309S arm, SPU cartridges, mono block tube amps, Ars Acoustica LaDiva speakers, and I'm still trying to decide what machine to go with.
http://www.classicrecordings.ca

Offline Ben

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Re: Mono prerecorded tapes
« Reply #5 on: January 13, 2009, 02:37:55 PM »
I think I know what you mean here. With left and right channels the same phase
you have the wide sound. If you change phase on one channel -- say the left
you have a point source sound in the middle. Easy to do ... just switch the black and
red speaker connections when I play a tape like Saxophone Colossus.
« Last Edit: January 13, 2009, 02:40:29 PM by Ben »
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Offline steveidosound

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Re: Mono prerecorded tapes
« Reply #6 on: January 13, 2009, 02:40:19 PM »
Perhaps we should move this to tape tech under my topic of listening to mono tapes...

AFAIK the correct phase relationship for both mono and stereo listening is the same.
Maintain an in phase condition between the 2 speakers by connecting positive amp output to positive speaker input and negative to negative, the same for both channels.  This will give you a phantom center point source for mono and proper stereo image.
« Last Edit: January 13, 2009, 03:22:56 PM by steveidosound »
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Offline Ben

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Re: Mono prerecorded tapes
« Reply #7 on: January 14, 2009, 01:25:58 AM »
And this what we call the muppet show .
Well I tried it with both speakers in phase and with the left speaker
180 degrees out phase. To my ears you lose a few DB with the speakers
out of phase, but the mono source (the muppet show) seems to sound
more in focus and centered.

Also  after watching the Muppets again,
Horn Players tend to not have eyes, but rather dark glasses of some
kind, and a BIG nose and blue in color.
« Last Edit: January 14, 2009, 01:46:04 PM by Ben »
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Offline steveidosound

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Re: Mono prerecorded tapes
« Reply #8 on: January 14, 2009, 02:33:25 PM »
I would respectfully submit then that there is something else playing with the phase relationship of the 2 channels.
However you have to connect the speakers, if you get a more focused center image with a mono source then, that is the "in phase"  condition for both channels for the system as a whole. And that should present proper imaging in stereo as well.
But if that is the case only when you reverse positive and negative at one end only, on one channel only, between your amp and speakers, so it is "wrong", something else more complicated is going on.
Culprits could include phase reversal or extreme phase shift in your amps that is not the same for both units, something about the phase of the drivers or crossovers in your speakers, or even very hard room reflections.
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Offline Ben

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Re: Mono prerecorded tapes
« Reply #9 on: January 14, 2009, 05:05:46 PM »
I suspect that I get the direct sound from the speakers and any  reflections later
more phase canceled. It seems just give a little more detail for the high notes.
Mind you The muppets is not exactly the best music source, but it is the only
mono music I could  think of at the time.
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Offline EMB

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Re: Mono prerecorded tapes
« Reply #10 on: July 16, 2009, 10:00:50 PM »
Beatle EMI tapes from the UK were available in mono.

Offline barretter

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Re: Mono prerecorded tapes
« Reply #11 on: July 18, 2009, 06:08:55 AM »
Mono half-track pre-recorded tapes at 3 3/4" per second are extremely common in the UK, on eBay and stalls in street markets, particularly those produced by the World Record Company. The recordings were mostly licensed from EMI, but also from Westminster, Erato and other European sources, and some original recordings, including some British jazz.  The sound is usually quite acceptable.