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Digitising Cassettes

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Re: Digitising Cassettes

Postby TheBev » Mon Sep 28, 2020 10:03 pm

Thanks for that James, that looks reassuringly cheap. :mrgreen:
I'll head over to that thread maybe and ask if Dave (ef37a) ever took one apart and what the verdict was.
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Re: Digitising Cassettes

Postby ef37a » Mon Sep 28, 2020 10:26 pm

TheBev wrote:Thanks for that James, that looks reassuringly cheap. :mrgreen:
I'll head over to that thread maybe and ask if Dave (ef37a) ever took one apart and what the verdict was.

I can preempt your question and tell you, no. However, a potentiometer in a box and two RCA (look to be both female) cables? "What could possibly go wrong?"

Really, not a lot. They would have to be incredibly incompetent to bugger that up!

If you have a lot of copying to do it might be an idea to make a 'calibration' tape? You can generate a tone in any DAW (def' Audacity) I suggest the standard 333Hz for cassette at Dolby level (just because it is there!) Then set that to some chosen level in the recording process, say -12dBfs. You are very unlikely to have cassettes with level that far above Dolby.

That might seem a low level in the DAW but is not really and you can boost it digitally at the finish, even at 16 bits, noise will be way,way below even Dolby B tapes.

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Re: Digitising Cassettes

Postby TheBev » Mon Sep 28, 2020 10:42 pm

Thanks Dave, that's me sold then. :thumbup:

Most of my tapes were already copied some years ago but I'd like to redo a few as I'm one of those eejuts who strayed into (well into) the red on occasion.
Out of interest though is the box a better approach than say the Canford solution?
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Re: Digitising Cassettes

Postby James Perrett » Tue Sep 29, 2020 12:38 am

TheBev wrote:Out of interest though is the box a better approach than say the Canford solution?

Electrically they'll do pretty much the same thing. The Canford attenuators look very robustly built and they look like they are closely matched so that you know the attenuation with two of them in use will be within 0.2dB at worst. The variable attenuator box is more versatile but channel matching may not be as good and it will probably break if you tread on it.
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Re: Digitising Cassettes

Postby Tim Gillett » Tue Sep 29, 2020 12:51 am

TheBev wrote:
James Perrett wrote:
12" singles also often overload the inputs when fed from a Rotel receiver. I ended up making some attenuating cables for mine - I used 22k ohm resistors in series with the input (which already has a 22k resistor from signal to ground inside the unit) but if I was doing it again I'd go for a slightly higher value.


Hi James, sorry an old thread resurrection / question if I may.
I was wondering what value of resistor you would go for now, if you did this again. I ask because getting some cables made up for just this scenario could be very useful for me and I was thinking of approaching Orchard Electronics.

And thanks btw, I never even knew this could be a 'thing'.

I would only attenuate if on the loudest cassette using your cassette deck, the converter clips. Otherwise there's no point.
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Re: Digitising Cassettes

Postby TheBev » Tue Sep 29, 2020 7:22 am

James Perrett wrote:
The variable attenuator box is more versatile but channel matching may not be as good and it will probably break if you tread on it.

So long as it doesn't break when I look at it I suppose, thanks James, more food for thought and all good info


Tim Gillett wrote:I would only attenuate if on the loudest cassette using your cassette deck, the converter clips. Otherwise there's no point.

Yes Tim, that was kind of the whole point.
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Re: Digitising Cassettes

Postby ef37a » Tue Sep 29, 2020 7:46 am

Tim Gillett wrote:
TheBev wrote:
James Perrett wrote:
12" singles also often overload the inputs when fed from a Rotel receiver. I ended up making some attenuating cables for mine - I used 22k ohm resistors in series with the input (which already has a 22k resistor from signal to ground inside the unit) but if I was doing it again I'd go for a slightly higher value.


Hi James, sorry an old thread resurrection / question if I may.
I was wondering what value of resistor you would go for now, if you did this again. I ask because getting some cables made up for just this scenario could be very useful for me and I was thinking of approaching Orchard Electronics.

And thanks btw, I never even knew this could be a 'thing'.

I would only attenuate if on the loudest cassette using your cassette deck, the converter clips. Otherwise there's no point.

Unless I have missed it and things have moved on? The UCA202 is the interface and these can have their inputs overloaded but this is unlikely IMEx from a cassette deck. I would never hit one harder than -6dBfs.

CLUCK it! I shall HAVE to do a headroom test now to sort the matter out in MY brain!

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Re: Digitising Cassettes

Postby Tim Gillett » Tue Sep 29, 2020 8:06 am

TheBev wrote:
Tim Gillett wrote:I would only attenuate if on the loudest cassette using your cassette deck, the converter clips. Otherwise there's no point.

Yes Tim, that was kind of the whole point.

Ah so when you spoke of occasionally going into the red you meant digitally, not when recording the cassettes?
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Re: Digitising Cassettes

Postby Mike Stranks » Tue Sep 29, 2020 8:48 am

There are plenty of this type of attenuator around which appear a bit more robust...

I have used: https://fostexinternational.com/docs/products/PC-1eBW.shtml

and

https://www.monacor.com/products/pa-technology/volume-controls-and-accessories/volume-controls/ila-100rca/

There's also the Behringer 'Monitor 1'...

... but all varying degrees of more expensive than the one already discussed here! :)
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Re: Digitising Cassettes

Postby TheBev » Tue Sep 29, 2020 8:59 am

ef37a wrote:
CLUCK it! I shall HAVE to do a headroom test now to sort the matter out in MY brain!

Dave.

Dave - we're talking about tapes that were absolutely saturated going into the red but maybe they weren't clipping and I've misremembered, t'was as I say some years ago now.
But going forward it was more for vinyl transfer tbh than the half a dozen or so 'songs' that I abused, they were simply an afterthought really, just to see if there could be any improvement.

I find with my set up even some LP's clip, or are v close to it, let alone 12" singles which James mentioned and is what initially piqued my interest.

And Tim, see above, but in short it was both.
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Re: Digitising Cassettes

Postby ef37a » Tue Sep 29, 2020 9:18 am

TheBev wrote:
ef37a wrote:
CLUCK it! I shall HAVE to do a headroom test now to sort the matter out in MY brain!

Dave.

Dave - we're talking about tapes that were absolutely saturated going into the red but maybe they weren't clipping and I've misremembered, t'was as I say some years ago now.
But going forward it was more for vinyl transfer tbh than the half a dozen or so 'songs' that I abused, they were simply an afterthought really, just to see if there could be any improvement.

I find with my set up even some LP's clip, or are v close to it, let alone 12" singles which James mentioned and is what initially piqued my interest.

And Tim, see above, but in short it was both.

No, still going to do the test to keep me happy!

Now, copying vinyl is different I think level wise.
Whereas tape can really not go more than few dBs about Dolby level, you can get massive spikes off discs. I therefore record at 24 bits and way down at -30dBfs so that spikes do not clip the converter.

I did this for a stack of my daughter's 45s then de-noised and de-clicked them using the free demo time of Sony (then) Sound Forge. Then boosted to around -6dBfs top whack.

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Re: Digitising Cassettes

Postby jimjazzdad » Tue Sep 29, 2020 10:59 am

Does no one use a good, transparent, analogue clipper/limiter on the way into their AD interface? For years I have had an Aphex 720 strapped on the end of my analogue chain - its carefully calibrated and completely inaudible unless you deliberately 'slam' it. I do a lot of radio segments for upload and it is indispensable there but it also comes in very handy preventing occasional digital 'overs' when dubbing all sorts of analogue media...
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Re: Digitising Cassettes

Postby TheBev » Tue Sep 29, 2020 11:16 am

ef37a wrote:
Now, copying vinyl is different I think level wise.
Whereas tape can really not go more than few dBs about Dolby level, you can get massive spikes off discs. I therefore record at 24 bits and way down at -30dBfs so that spikes do not clip the converter.

Dave.

I would be interested in the results Dave if you have the time

I *was* leaning toward the Canford jobbies, they seem pleasingly discrete for my already cluttered desktop but am now thinking they may not offer enough attenuation, I was aiming for-18 to -20dbfs for the vinyl and don't think the Canfords are man enough for the job.
And now Mike has thrown some more options into the pot to confuddle me further. Thanks Mike btw. :D
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Re: Digitising Cassettes

Postby Mike Stranks » Tue Sep 29, 2020 11:23 am

TheBev wrote:And now Mike has thrown some more options into the pot to confuddle me further. Thanks Mike btw. :D

My pleasure! :lol:

... and there's also Fentronix... I have a couple of their useful little gizmos - including a well-made attenuator. Happy hunting!
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Re: Digitising Cassettes

Postby James Perrett » Tue Sep 29, 2020 11:33 am

Mike Stranks wrote:... but all varying degrees of more expensive than the one already discussed here! :)

Don't forget that we're talking about £20 audio interfaces here. You could buy a proper audio interface with input level controls for the price of that Monacor level controller.

In fact this part of the thread seems to be a little out of proportion generally. If you are going to spend £30 or more on attenuators then you might as well just buy something like the Behringer UMC202HD which gives you level controls, 24 bit convertors and high sample rates (which can be useful for de-clicking vinyl).

If you have a spare phono cable lying around and a few resistors then making your own attenuator cable makes sense but buying attenuators at full price for a £20 audio interface doesn't make sense to me.
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