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Vintage Tape (Audio), Cassette, Wire and Magnetic Disc Recorders and Players Open-reel tape recorders, cassette recorders, 8-track players etc.

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Old 16th Nov 2022, 11:56 am   #1
Martin Bush
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Default Tape transfer to digital question

Hi all

Hopefully this is in the right section - not sure if it's best here or modern tech.

If I want to transfer a cassette to my computer via a USB audio interface would I be OK going in via the "instrument" inputs?

My interface has inputs for mics (clearly not the right input), inc phantom power, and "instruments" which go in via 1/4 in jacks. I know that the interface works well with Audacity (in so far as I used it for something else recently and didn't have to faff with drivers etc).

I ask as I will have to buy a lead to do this.

I do have a couple of those ION things, but prefer to do a transfer via my proper deck.

Martin
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Old 16th Nov 2022, 12:00 pm   #2
paulsherwin
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Default Re: Tape transfer to digital question

You need a flat line level input. Presumably that's what the 'instrument' sockets are, rather than an input for an unamplified guitar pickup. The documentation should cover this.
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Old 16th Nov 2022, 12:02 pm   #3
Malcolm G6ANZ
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Default Re: Tape transfer to digital question

I do the same thing, cassette to PC. The USB goes into a port on the PC and the cassette goes to the line in on the USB interface. In your case this would be 'instrument' jack.
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Old 16th Nov 2022, 12:05 pm   #4
Nickthedentist
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Default Re: Tape transfer to digital question

Yes, that sounds sensible.

I'm transferring some at the moment. Using a late 1970s JVC deck connected (2 x phonos to 3.5mm stereo jack plug) to the audio input of my HP desktop from forum member Unrealdave, with Audacity.

Results are very good IMHO.
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Old 16th Nov 2022, 12:31 pm   #5
Martin Bush
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Default Re: Tape transfer to digital question

These are the specs for the interface: https://www.presonus.com/products/Au...-96/tech-specs

You can go direct in with a guitar although I would be tempted to go in via the line out of my amp to get a bit of tone variation.
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Old 16th Nov 2022, 1:14 pm   #6
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Default Re: Tape transfer to digital question

It's funny that they don't give you an audio spec for the instrument i/p, yet do for the mic. Were you trying to capture something from a modern digital source, I'd suggest finding an interface with a dedicated Line i/p, as the 0.5Meg Ohm instrument i/p may not have noise performance that's as low as, say, a 20KR dedicated line i/p.

However...we are talking about cassette here, so whatever noise advantage is offered by a dedicated line i/p will be swamped by cassette's inherent hiss. If the intrument i/p has L/R gain controls, then make sure they are nicely balanced, as it can be easy to make a discrepancy in L/R balance. Record and be happy

NB - the instrument i/p will likely have a lot more gain than is needed for a line source. Try to get as hot a level as possible out of the tape deck, and as little make up gain as you need from soundcard. If deck has an o/p level pot, don't distort the instrument i/p, though!

Modest soundcard = 90dB SNR
Cassette (no Dolby) = ~60dB SNR

If you record with a few dB margin under 0dBFS, don't worry!
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Old 16th Nov 2022, 9:40 pm   #7
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Default Re: Tape transfer to digital question

Quote:
Originally Posted by Martin Bush View Post
These are the specs for the interface: https://www.presonus.com/products/Au...-96/tech-specs
Those inputs will be intended to take anything from a line-level output from a keyboard to a DI guitar/bass, hence the wide range of input gain. It won't be quite as good as the likes of a Focusrite Scarlett which switches between instrument and line (main change is the input impedance - Focusrite switch between 60k and 1.5M, your Presonus takes the middle ground at 500k) but it's what you have and I doubt it'll make any difference from cassette.

I'd take it straight from your tape deck to the input. Handle anything else in software.
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Old 16th Nov 2022, 10:35 pm   #8
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Default Re: Tape transfer to digital question

an important point often overlooked to get the best possible results of digitizing is to 'peak' the tape head azimuth for the current tape being played, which on a domestic equipment is quite likely a bit off when it was recorded.

https://thegreatbear.co.uk/audio-tap...-cassettes-cd/
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Old 16th Nov 2022, 10:54 pm   #9
paulsherwin
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Default Re: Tape transfer to digital question

Also, don't digitise at the 0dB level, as this will cause clipping and there's no benefit. -6dB is a good starting point, though it varies with the source material. You can normalise the recording once you have it in digital form.
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Old 17th Nov 2022, 11:41 pm   #10
jamesperrett
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Default Re: Tape transfer to digital question

Looks like Presonus have skimped on those instrument inputs. Most manufacturers offer switchable line/instrument settings on the jack inputs. If you keep the cables to the interface as short as possible you should be OK using the instrument inputs provided that the output level from your cassette deck isn't too high.

As colourking says, for best results you need to match the playback head azimuth to each cassette - I find that this makes a big difference to the end result. And as Paul says, keep the level reasonably low when recording because you never know when an unexpected peak might come along. For reel to reel tapes I set 0dB on the deck's meters to -18dBFS on the digital side but you may get away with a little less headroom with cassettes. If this is too quiet, you can always process the files afterwards to bring the level up.
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Old 18th Nov 2022, 10:22 am   #11
Martin Bush
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Default Re: Tape transfer to digital question

Yes, I was expecting to find some line inputs, but I bought it for recording guitar and mics so it generally does the job. I wonder whether if, at the time, I thought I would get a small mixing desk (which I have not done so far).

I will go carefully with the head azimuth. What is an appropriate tool for this? I may try it on my 15 deck rather than my nice one
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Old 18th Nov 2022, 11:36 am   #12
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Default Re: Tape transfer to digital question

A suggestion - dont use compression... at first the digital recording would sound great but in years to come, every time you play them you will rue the day you pressed that compression button...

...or...

do two copies. One compressed for use in your car, and a true copy for home
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Old 18th Nov 2022, 11:45 am   #13
Martin Bush
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Default Re: Tape transfer to digital question

Good point Phil.

I think my transfers will be few and far between. I have some quite primitive stuff recorded with my band (via headphones as a mic in some cases!) and the odd bit from the radio here and there.
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Old 18th Nov 2022, 11:52 am   #14
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Default Re: Tape transfer to digital question

I'm going to have to respectfully disagree with the idea that you need to tweak azimuth on each cassette, unless you have a machine that's designed to let you do it (several Nak models). You will note that the screws are locked with varnish. They should have been calibrated correctly at the factory, using a dedicated tape (good azimuth tapes are expensive now). Off top of head, I'd say that the dangers of tweaking azimuth on a machine that's not designed for the purpose are:

loosening up the screws (are you going to lock them with varnish after every tape?) long term, making azimuth inconsistent from tape to tape. AZ could potentially move every time the solenoid triggers if they get loose.

putting wear on the head threads, creating slack (see above)

going too far in your tweaking, skewing the tape and potentially creasing it

leaving your machine in a completely un-calibrated state, whereby it no longer works as well as it should were you to play a tape that has pristine shell / manufacturing tolerance azimuth

Unless you have a reference azimuth tape and plan to put the head back to factory spec with varnish after you've finished, you could open a can of worms. Nakamichi put R+D effort into mechanisms that enabled easy and repeated AZ adjustment. If your machine was set at the factory and has the screws set with varnish, my advice is to leave them well alone unless you have a test tape and can prove AZ is out of whack.

If you have precious tapes that have been handed down over the years, in all honesty, they probably won't have the HF response to warrant much azimuth tweakery. Secondly, if they are precious, then you should save up for a Nak DR1 / CD1 (same machine, different clothes - has front pot for azimuth), 582, CR7 (pricier than the others).

NB - I know some of the group's members such as Tim have fashioned tools to easily adjust AZ and may disagree with me. But bear in mind that these are people with decades of experience with tape machines, who perform complex maintenance and also have test tapes to reset everything.
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Old 18th Nov 2022, 12:51 pm   #15
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Default Re: Tape transfer to digital question

And another thing: if you are using a 2-head deck, when adjusting PB azimuth, you will also move your recording AZ... This could render any tapes made on the machine at odds with the azimuth on other machines. The tapes could have unique azimuth that only your machine tracks correctly. You will be in the same situation if you have a 3-head machine that has a sandwich head. If you have discrete heads, you will be able to realign the PB head using the record head once you have transcribed.
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Old 18th Nov 2022, 1:18 pm   #16
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Default Re: Tape transfer to digital question

I certainly agree that you shouldn't repeatedly fiddle with the head alignment on your main machine, though ex factory alignment can be surprisingly hit and miss.

Even good decks are quite cheap though, so it's easy enough to dedicate a machine to this task. You just need to listen to the tape to be digitised with a good pair of headphones, and adjust the head for the best fidelity. This is very easy to do and usually involves less than a quarter turn of the screw.

You would have to make an awful lot of adjustments to wear out the screw thread.
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Old 18th Nov 2022, 3:15 pm   #17
Ted Kendall
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Default Re: Tape transfer to digital question

Quote:
Originally Posted by paulsherwin View Post
You would have to make an awful lot of adjustments to wear out the screw thread.
It can be done, though - I once had to change the headblock casting on a Studer, no less, because an operator went mad with the azimuth screw and stripped the mating thread, which was tapped direct into the block.

Dual capstan transports, properly adjusted, reduce the need for tweaking because they remove the influence of the shell on azimuth
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Old 18th Nov 2022, 3:36 pm   #18
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Default Re: Tape transfer to digital question

It will obviously depend on the number of cassettes played and adjusted. Prior to a big digitising project I removed the azimuth screw and applied heavy grease to the thread before refitting it. I suspect many such screws were fitted dry ex factory with the assumption most users would rarely if ever move it.
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Old 18th Nov 2022, 11:01 pm   #19
jamesperrett
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Default Re: Tape transfer to digital question

Perhaps I deal with a higher proportion of cassettes that were recorded under less than ideal circumstances but I find it essential to adjust the azimuth before transferring a cassette. My tape machines are only ever used for playback so I'm not particularly worried about knowing whether the azimuth is absolutely correct - it just needs to match the tape that I'm playing at the time. I'm also not looking for long term stability - just sufficient stability to stay correctly adjusted for the length of a tape.
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Old 20th Nov 2022, 9:01 pm   #20
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Default Re: Tape transfer to digital question

Like James I rarely if ever make recordings to cassettes these days. It's pretty much playback only. When I transfer tapes to digital I generally act as if this or that tape may not be ever digitised again and the owner may well only retain the digital copy and throw the tape away or lose it. So for me correcting playback azimuth errors at time of transfer goes without saying. I just do it. So I've made it easier for myself to adjust it with the minimum of fuss. That doesn't mean it's always easy to achieve or done perfectly. But knowing how common is azimuth error especially on slow speed tape formats, I make the effort. That doesn't mean I think that everybody else, regardless of situation, should attempt do the same.

Last edited by TIMTAPE; 20th Nov 2022 at 9:08 pm.
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