Mastering from tape to digital rig question

[hannahjazzz]

I’m trying to hook up a revox A77 1/4 inch and get it into my pro tools via an Avalon 96k interface.

I’m wondering what leads I need with minimal interference? Stupid question I know. The Avalon only takes XLR input I think. Ordered it but it hasn’t come yet so
Need to confirm.

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[James Perrett]

I'm a little confused - I can't see any audio interfaces in Avalon's product range. Or is there a different Avalon company that Google doesn't know about?

It would help if you could give us the make and model number of all the devices that you are using in your signal path.

[Hugh Robjohns]

I'm not aware of any DAW audio interface made by Avalon, so can't offer any advice on its connectivity. Can you share a link to the specific product, please?

And what are the available output connectors on your specific model of Revox A77. I've seen some with RCA-phono (cinch) and/or DIN connectors, and others with XLRs.

[ef37a]

Having refreshed the old brain, the A77 has both RCA phono and DIN ('radio') outputs but the DIN is via a 4k7 resistor and attenuated by at least 6dB. The RCA output looks to be low source resistance at ~400 Ohms.

I would therefore suggest a simple RCA to 1/4" TS (guitar) jack cable as it would be a strange interface that did not have jacks?

But yes, give us the full SP!

Dave.

[Hugh Robjohns]

Having refreshed the old brain, the A77 has both RCA phono and DIN ('radio') outputs but the DIN is via a 4k7 resistor and attenuated by at least 6dB.

The 'radio' connection conformed to the old DIN hi-fi standard which evolved with valve equipment and passed the signal as a current, rather than a voltage.

The equivalent input voltage when connected to modern voltage-fed equipment is entirely dependent on the device's input impedance, at a nominal 1mV/ 1k Ohms.

So 100k Ohms input impedance gives 100mV signal level.

[ef37a]

Having refreshed the old brain, the A77 has both RCA phono and DIN ('radio') outputs but the DIN is via a 4k7 resistor and attenuated by at least 6dB.

The 'radio' connection conformed to the old DIN hi-fi standard which evolved with valve equipment and passed the signal as a current, rather than a voltage.

The equivalent input voltage when connected to modern voltage-fed equipment is entirely dependent on the device's input impedance, at a nominal 1mV/ 1k Ohms.

So 100k Ohms input impedance gives 100mV signal level.

Yes Hugh, a lot of people slagged off the DIN connection standard but they did not understand it and it was entirely appropriate for valve based equipment in 'domestic' circumstances. 'Pros' of course could afford cathode follower stages and transformers!

I was in fact expecting a much higher resistance than 4k7? I guess because of the transistors they, like so many others went 'half way'.

Dave.

[Tim Gillett]

The A77 was Revox's first transistor model (all silicon) and an excellent machine. I've never seen one with XLRs though. Output level is adjustable at the front panel.

[James Perrett]

Revox themselves didn't make any with XLR's (as far as I know) but various third parties modified them to add balanced inputs and outputs on XLR's.

[Hugh Robjohns]

I've never seen one with XLRs though.

The A77 tape machine was intended as a domestic/consumer hi-fi product and came with RCA-phono and DIN connections as standard. But the machine became a popular low-cost alternative to professional studio recorders and many were 'studio-ised' which included retrofitting XLRs -- at least in the UK and Europe.

[Tim Gillett]

I've never seen one with XLRs though.

The A77 tape machine was intended as a domestic/consumer hi-fi product and came with RCA-phono and DIN connections as standard. But the machine became a popular low-cost alternative to professional studio recorders and many were 'studio-ised' which included retrofitting XLRs -- at least in the UK and Europe.

Yes, not surprised as they were more compact and much lighter than the Studer equivalents. I believe their much greater portability and general audio quality made them popular for location live to stereo concert recordings on 10.5" reels. Onboard Dolby B was an option, making for potentially even better quality live recordings.

[Nazard]

Yes, not surprised as they were more compact and much lighter than the Studer equivalents. I believe their much greater portability and general audio quality made them popular for location live to stereo concert recordings on 10.5" reels.

Alfred Brendel used an A77 to listen back to his practice.

[hannahjazzz]

Yes, not surprised as they were more compact and much lighter than the Studer equivalents. I believe their much greater portability and general audio quality made them popular for location live to stereo concert recordings on 10.5" reels.

Alfred Brendel used an A77 to listen back to his practice.

Thanks for your response. Would I be wasting my time using a revox with my 1/4 inch tapes to transfer them to digital? I

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[Hugh Robjohns]

No. It's a perfectly good machine if in decent mechanical condition and when aligned correctly.

[hannahjazzz]

No. It's a perfectly good machine if in decent mechanical condition and when aligned correctly.

Thank you

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[Tim Gillett]

No. It's a perfectly good machine if in decent mechanical condition and when aligned correctly.

Thankyou.

I'd add that for top performance it needs to be in good condition in all departments related to playback of your particular tapes. The tapes themselves may need treatment even before winding or playing them. It really depends on how close to ideal you want your transfers to be. Most people seem to err by not optimising the tape playback side of things.

[hannahjazzz]

So the revox is in perfect working order. And I have tested all the tapes.

I recorded the mixes onto the 1/4 through a studer b67 from a studer a80. Everything was calibrated and I did check all of the tapes/ cleaned them in between mixes etc.

I was going to go from the revox as a sound source to the digi 003 directly into pro tools. Or I was going to go from the revox through an Avalon mic pre amp to the digi into pro tools. But I just am unsure if it’ll be high quality enough.

[Hugh Robjohns]

...I just am unsure if it’ll be high quality enough.

That's something only you can decide, because only you can hear it.

However...

I recorded the mixes onto the 1/4 through a studer b67 from a studer a80.

I'm not really sure what's going on here. It sounds like you're saying you played back a tape on a Studer A80 and re-recorded it (mixed with something else?) on a B67. And now you're going to play that new recorded mix tape back on a Revox A77.

So you've already gone down one analogue tape generation (and that's assuming the source tape was first generation and not a dub-tape itself), and there's quite a lot of scope there for head azimuths and other alignments to be non-perfect... I doubt the digital recording chain is likely to make matters any worse from a sound quality point of view.

I was going to go from the revox as a sound source to the digi 003 directly into pro tools. Or I was going to go from the revox through an Avalon mic pre amp to the digi into pro tools.

Ah... that clears up the confusion about the Avalon interface you mentioned previously. It's a Digi003 interface, to which you've connected the Avalon mic pre.

Personally, I'd connect the Revox straight into the line (or DI inputs) inputs of the Digi003, but if you want some extra 'character' then you could run it through the mic pre. In both cases I'd suggest using a pair of RCA-phono to mono (TS) unbalanced jack cables. (Connect the RCA-phono end to the A77s outputs, with the jacks going into the interface or preamp DI/instrument inputs).

[James Perrett]

The signal chain would make sense if the A80 was a multitrack machine. Then mixed down to a B67.

If the A77 is a standard high speed version then it should work fine with a pair of unbalanced phono to TS jack cables. This will give you the most accurate version of the sound on tape. Adding the Avalon may change the sound, and you may prefer that sound so it would be worth a try, but it won't be as accurate as a direct link.

[Hugh Robjohns]

The signal chain would make sense if the A80 was a multitrack machine. Then mixed down to a B67.

Ah yes, of course. Should have realised that! Thanks James.

H

[hannahjazzz]

The signal chain would make sense if the A80 was a multitrack machine. Then mixed down to a B67.

If the A77 is a standard high speed version then it should work fine with a pair of unbalanced phono to TS jack cables. This will give you the most accurate version of the sound on tape. Adding the Avalon may change the sound, and you may prefer that sound so it would be worth a try, but it won't be as accurate as a direct link.

Yea you’re correct. A80 24 track mixed through never to b67. I’m taking the reels on a revox and putting them through digi or Avalon then digi to pt to prepare for mastering. Should I give myself -7db on the Rev input or Rev output? Never done it before as I’m a musician and not well versed in mastering. Only mastered on to finalizer before. Don’t Judge me haha

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[James Perrett]

In a proper studio it is normal to add test tones to the start of each master tape so that you know what level your recorder was set to. If you have test tones on your tape then I would suggest using the tones that set your reference level (usually recorded at 0dBVU at 1kHz) to read -18dBFS in Protools LE. You should then use the tones at any other frequencies (usually 100Hz and 10kHz) to match the equalisation. The A77 allows you to switch between NAB and IEC equalisation so choose the one that matches the B67 that the tapes were recorded on.

If you don't have test tones then aim for an average level of -18dBFS on the meters and hopefully the peaks won't go too high.

I'm assuming you didn't use Dolby or any other noise reduction on these tapes but if you did then this adds an extra layer of complexity.