Mark’s CT-F850 arrived- some questions…

MarkWComer

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#41
Exactly! Looking for a calibration tape. If the deck goes at 2ips, playback at 2ips will sound perfect- until it’s played on another deck.

Yeah, I know this is a bogus way to check speed…
Oh- this was one of those Warmalt tapes…
 

MarkWComer

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#43
2) the only proper way to check/set speed is to use a proper speed reference tape (usually with 3000 hz or 3150 hz tone recorded on) and a frequency meter....
it's easier, faster and more precise than what you just tried there.
TWO of the Warmalt tapes ran short for a 43min program, the TDK D90 had length to spare. The one WM tape was a fluke, watching the tape counter, I FF each cassette and found that they are shorter than the TDK. The one “long” WM tape read 660 on the counter, others read from 585 to 620. Yes, again, this is not a truly accurate means of measurement.
 

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#44
evidently, the walmart tapes are shorter than expected.
it's more typical, loke on the TDK, that a tape has some more to spare, sometimes up to almost 2 minutes more.
 

vince666

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#45
Opinion on this calibration tape, please! Description states it was recorded on a quartz locked deck. $7 on the bay…

https://www.ebay.com/itm/294378850553

I bought one…
i cannot have an opinion about that tape.
i just hope he compared it against some true reference.
quartz locked decks are quite precise but there might still be some minor difference... i.e. my Sony TC-K750ES reads like 3151Hz with a 3150Hz speed tape while my Technics RS-B965 reads like 3162 Hz.
it's a small difference and within accepted tolerances, though.

then, for example, if i want to make a speed tape on my RS-B965 which still follow the true reference, i should record just a 3162 Hz tone (for a 3150 hz reference) or about 3011 to 3012 Hz for a 3000 hz reference.
so, i hope that guy has a true reference tape and checked his quartz deck with it.

anyways, my advice is to check/set speed with that tape by avoiding a few minutes at the beginning and at the end of the side but to stay about at the half of the side or so.
 

vince666

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#46
anyways, my advice is to check/set speed with that tape by avoiding a few minutes at the beginning and at the end of the side but to stay about at the half of the side or so.
I feel I need to be more clear/detailed about this point.

it's quite common that decks usually can be a hair faster at the beginning of the side and a hair slower at the end of the side... easy to check this while playing a proper speed test tape (with "proper" i mean a true one where the recorded tone is at constant speed throuout the whole side of the tape) and it's the normal behaviour of so many decks out there.

But, when going to record a homemade speed tape on a deck which has some speed differences throughout the whole tape side (usually just at the beginning and at the end zones of the side) , it's just the (homemade) test tape which has some inherent speed differences and while mixing this with the speed difference throughout the tape side of the deck under test, all bets are off because you cannot know what is due to the (homemade) test tape and what is due to the deck under test.

So, to try to minimize such variables a bit, it's better to stay around the center zone of the tape.

But, if you have a proper speed test tape, you will know that any differences throughout the tape side are due just to the deck under test (and quite normal that there are some)... another nice thing related to a proper speed test tape is that it's also good to measure Wow and Flutter in a reliable way while the "homemade" ones would have too high inherent W&F just recorded on the tape so that they aren't suitable to measure W&F properly, and especially on those decks with very low W&F which is most likely lower than the inherent W&F of the (homemade) test tape.

So, it's OK for you to use that speed tape from ebay (which is of "unknown" quality and precision, after all) but it's wise to avoid relying on it just blindly, unless you also have a proper one to compare it against.
In other words... people like, i.e., our Alex/A.N.T. are perfectly able to check the actual quality of such cheap test tapes available on ebay... while the rest of us (myself included) are not able to check and know it so, our best bet is to try to keep our hands on a few proper test tapes which can be taken as a reliable reference without worrying. ;)
(of course, the proper ones are noticeably more expensive... and for a few good reasons)

I hope it helps.
 

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#48
Atomic clock locked direct drive.

HP had a rack mount cesium clock (I saw one at the clock museum here in CT). I'd like to use that output as a digital master clock...
 

MarkWComer

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#49
I feel I need to be more clear/detailed about this point.

it's quite common that decks usually can be a hair faster at the beginning of the side and a hair slower at the end of the side... easy to check this while playing a proper speed test tape (with "proper" i mean a true one where the recorded tone is at constant speed throuout the whole side of the tape) and it's the normal behaviour of so many decks out there.

But, when going to record a homemade speed tape on a deck which has some speed differences throughout the whole tape side (usually just at the beginning and at the end zones of the side) , it's just the (homemade) test tape which has some inherent speed differences and while mixing this with the speed difference throughout the tape side of the deck under test, all bets are off because you cannot know what is due to the (homemade) test tape and what is due to the deck under test.

So, to try to minimize such variables a bit, it's better to stay around the center zone of the tape.

But, if you have a proper speed test tape, you will know that any differences throughout the tape side are due just to the deck under test (and quite normal that there are some)... another nice thing related to a proper speed test tape is that it's also good to measure Wow and Flutter in a reliable way while the "homemade" ones would have too high inherent W&F just recorded on the tape so that they aren't suitable to measure W&F properly, and especially on those decks with very low W&F which is most likely lower than the inherent W&F of the (homemade) test tape.

So, it's OK for you to use that speed tape from ebay (which is of "unknown" quality and precision, after all) but it's wise to avoid relying on it just blindly, unless you also have a proper one to compare it against.
In other words... people like, i.e., our Alex/A.N.T. are perfectly able to check the actual quality of such cheap test tapes available on ebay... while the rest of us (myself included) are not able to check and know it so, our best bet is to try to keep our hands on a few proper test tapes which can be taken as a reliable reference without worrying. ;)
(of course, the proper ones are noticeably more expensive... and for a few good reasons)

I hope it helps.
Disappointed that I can’t get accuracy to the quintillionth of a part…

Yes, lots of variables to consider. Standards of weights and measurements can’t truly be exact until they quantify the exact number of atoms in a weight! How many Quartz atoms in a clock circuit (or is that a defining factor) determine a frequency? Cesium clocks depend upon decay of the atoms- so does it gain or lose accuracy?

You confirm what I knew. “Close enough is going to be good enough,” and nobody will know the difference. Professional calibration tapes, despite their supposed accuracy, are still subject to numerous variables at the time of manufacture as well as time of use, in differing temperature and humidity conditions.

I thought records were complicated…
 

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#53
Disappointed that I can’t get accuracy to the quintillionth of a part…

Yes, lots of variables to consider. Standards of weights and measurements can’t truly be exact until they quantify the exact number of atoms in a weight! How many Quartz atoms in a clock circuit (or is that a defining factor) determine a frequency? Cesium clocks depend upon decay of the atoms- so does it gain or lose accuracy?

You confirm what I knew. “Close enough is going to be good enough,” and nobody will know the difference. Professional calibration tapes, despite their supposed accuracy, are still subject to numerous variables at the time of manufacture as well as time of use, in differing temperature and humidity conditions.

I thought records were complicated…
Don't forget Gravity!
 

vince666

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#54
I'm sure glad sarcasm translates!!
Yeah that! :D

I realize I was risking to get a bit too much into "technical hair splitting" mode so, thanks to the sarcasm, our friends got me back into the right path. :cool:

that said, if any of you happen to need any hair splitting from here, you only have to ask for it... I am just specialized in splitting hairs. :p

But, for sure, I do love and enjoy the sarcasm and the humour of any kind. ;)
 

MarkWComer

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#57
Yeah that! :D

I realize I was risking to get a bit too much into "technical hair splitting" mode so, thanks to the sarcasm, our friends got me back into the right path. :cool:

that said, if any of you happen to need any hair splitting from here, you only have to ask for it... I am just specialized in splitting hairs. :p

But, for sure, I do love and enjoy the sarcasm and the humour of any kind. ;)
Ah! You’s are getting to know me well, and understand my sarcastic nature! I didn’t even need to use emojis!
 
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