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Adding a 3rd Tape Head to (mono) Reel-to-Reel.

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Adding a 3rd Tape Head to (mono) Reel-to-Reel.

Postby Elephone » Thu Aug 22, 2019 5:27 pm

Hi. I've got a few old clunky reel-to-reel machines that I like to use purely for effect sometimes but re-aligning the taped audio with the original digital audio is a real pain, as obviously the tape stretches after rewinding, etc.

Clearly, I'm not trying to achieve a professional tape sound here, merely experimenting with the more manic effects of my old valve Philips EL3542 which is in excellent condition.

So, I want to add an extra tape head, temporarily at least, to bounce back to my DAW in real-time. I realise there will still be DAW alignment issues, but I'm really just looking to minimise this.

I thought I might use a Sony solid state mini reel-to-reel tape machine I have. The head and its wire connections are very accessible on the Sony, so it seems like the best candidate, especially since it takes 3" reels and since the Philips is valvey enough!

So I suppose I can simply extend the wires of the Sony to reach the Phillips and place the head against the tape in some makeshift but stable fashion.

This is the bit I'd like some advise on: How close to the Phillips' head can I place the Sony head? I've seen some 3-head tape machines with record & play heads right next to each other, but these might be specially made to allow that.

Are there any other things I might want to consider before going ahead with this (i.e. apart from not being silly)..? It's just a bit of fun (at least).

Thanks :)
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Re: Adding a 3rd Tape Head to (mono) Reel-to-Reel.

Postby Hugh Robjohns » Thu Aug 22, 2019 6:00 pm

Elephone wrote:...re-aligning the taped audio with the original digital audio is a real pain, as obviously the tape stretches after rewinding, etc.

I hope not! You've got some major transport tension problems if it does! What I suspect you probably mean is that the capstan speed drifts a bit between recording and replaying, resulting in a sync drift when you relay it into the DAW.

So, I want to add an extra tape head, temporarily at least, to bounce back to my DAW in real-time.

I very much doubt that's possible in that particular Philips machine. The heads mount onto a plate that also supports the pinch roller arm and various others bits and pieces, and there isn't provision -- or space -- to easily mount an extra head... let alone the additional electronics required. And it would seem a shame to mangle the machine if it's in good nick.

So I suppose I can simply extend the wires of the Sony to reach the Phillips and place the head against the tape in some makeshift but stable fashion...

Good luck with that! The head alignment is critical if you want reasonable performance and quality and there's nowhere to mount an extra head satisfactorily on that Philips machine and expect it to stay aligned... And while remoting the head from the Sony would be reasonably easy, you'll need specialist tools, test tapes, and test gear to get it reinstalled and aligned correctly again...

If I were you, I forget the notion of bodged DIY and look out for a semi-pro three-head machine on the second hand market. A Revox A77 / A700 or B77 / PR99 would be ideal, or one of the Tascams, perhaps... or one of the hi-fi machines like an Akai 4000 variant or Sony... there are plenty to choose from and they come up reasonably often...

Or maybe better still, borrow or hire one, just to see whether the whole palava is really worth it. :-D

How close to the Phillips' head can I place the Sony head?

Far enough away that it isn't affected by the record head's magnetic field... probably at least as far away as the existing head is from the erase head. And the cabling back into the Sony's electronics will need to be shielded because the head will produce a very small signal from a fairly high impedance, so interference could easily be an issue.

But I really don't rate your chances of getting the head correctly aligned and stable enough to get anything like a decent replay. Tape head alignment is difficult and fiddly enough when you have the correct pivoted mounting points and all the right alignment tapes and test gear... doing it with a remote head on a wire wedged into a machine that wasn't designed to take a third head is likely to be farcical... and I doubt the fun will last long...

I expect Mr G will be alone shortly with a useful second opinion as he has far more experience of working on vintage domestic tape machines than I do.

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Re: Adding a 3rd Tape Head to (mono) Reel-to-Reel.

Postby Folderol » Thu Aug 22, 2019 6:08 pm

To add my 2d...
I generally like to encourage experimentation, but in this case I'd say your chances of success are just about zero, and you'd end up with less than you have now.
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Re: Adding a 3rd Tape Head to (mono) Reel-to-Reel.

Postby Kwackman » Thu Aug 22, 2019 6:15 pm

Hugh Robjohns wrote:If I were you, I forget the notion of bodged DIY and look out for a semi-pro three-head machine on the second hand market. A Revox A77 / A700 or B77 / PR99 would be ideal, or one of the Tascams, perhaps... or one of the hi-fi machines like an Akai 4000 variant or Sony... there are plenty to choose from and they come up reasonably often...

There were some cassette 3 head machines too which might be a bit cheaper if you would find the audio quality acceptable? I had a Tascam one in the 80s, and I think NAD made them too.
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Re: Adding a 3rd Tape Head to (mono) Reel-to-Reel.

Postby hobbyist » Thu Aug 22, 2019 6:49 pm

Elephone wrote:Hi. I've got a few old clunky reel-to-reel machines that I like to use purely for effect sometimes but re-aligning the taped audio with the original digital audio is a real pain, as obviously the tape stretches after rewinding, etc.

Clearly, I'm not trying to achieve a professional tape sound here, merely experimenting with the more manic effects of my old valve Philips EL3542 which is in excellent condition.

So, I want to add an extra tape head, temporarily at least, to bounce back to my DAW in real-time. I realise there will still be DAW alignment issues, but I'm really just looking to minimise this.

I thought I might use a Sony solid state mini reel-to-reel tape machine I have. The head and its wire connections are very accessible on the Sony, so it seems like the best candidate, especially since it takes 3" reels and since the Philips is valvey enough!

So I suppose I can simply extend the wires of the Sony to reach the Phillips and place the head against the tape in some makeshift but stable fashion.

This is the bit I'd like some advise on: How close to the Phillips' head can I place the Sony head? I've seen some 3-head tape machines with record & play heads right next to each other, but these might be specially made to allow that.

Are there any other things I might want to consider before going ahead with this (i.e. apart from not being silly)..? It's just a bit of fun (at least).

Thanks :)

Don't know what machine you have but none of the several that I owned would the adding of a head have been feasible at all.

You would have to get it into the tape path without causing problems.
I cannot envision that being done without problems. That path was designed for smooth flow and correct contact to the heads.

And you would need to add the proper electronics to amplify and tweak the signal to send to your DAW. Again where would those go and how would you install them. Iffy even if you used a second transport.

Seems easier to tap into the existing record head amplifier output and then send that back to your DAW than to add a head to do it.
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Re: Adding a 3rd Tape Head to (mono) Reel-to-Reel.

Postby Hugh Robjohns » Thu Aug 22, 2019 6:52 pm

I've had a thought which might be a better solution for your experimentations. It's a bit old-school Radiophonic workshop/tape concrete... but it can be done successfully with some care...

So, perhaps a better way of getting real-time replay would be to arrange your two tape machines side by side, and then find a way to loop the tape out from the Philips record machine and over to the Sony for replay -- or vice versa. Source spool on one machine, and take-up spool on the other.

That way, you don't have to wreck anything, the tape guides will maintain the tape-head alignment (hopefully), and the time delay between record and replay will remain constant.

The way you arrange the machines will depend on how easy it is to extract and insert the tape in the respective machine's tape paths, how best to maintain the appropriate tape tension across the heads (particularly in the replay machine), and how the machines react to not having a take up spool in place! Just make sure both machines are set to run at the same speed, and watch out for tape loops when starting and stopping them!

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Re: Adding a 3rd Tape Head to (mono) Reel-to-Reel.

Postby Elephone » Thu Aug 22, 2019 7:01 pm

Hugh Robjohns wrote:What I suspect you probably mean is that the capstan speed drifts a bit between recording and replaying, resulting in a sync drift when you relay it into the DAW.

Okay. Surely there's also some 'give' in tape, even if it's a few fractions of a mm. Every time I've tried to realign audio tape and cassette with the digital original, the tape recording has always been longer, so I assumed it had been very slightly stretched.

Hugh Robjohns wrote:I very much doubt that's possible in that particular Philips machine... let alone the additional electronics required..

Right. Additional electronics? The Sony machine will convey the signal to my DAW while in record mode. I got the idea from watching this video and thought it might be doable:

https://youtu.be/mYgbaCv5nKQ?t=371

Hugh Robjohns wrote:And it would seem a shame to mangle the machine if it's in good nick.

I wasn't going to do anything irreversible or damaging.

Incidentally, I do actually have two Phillips EL3542s and also a spare Phillips EL3542 tape head. So, I could temporarily connect the spare head to one Phillips machine via long wires while leaving it in place. I just thought the Sony would be easier and less noisy.

I could also pass the tape through both machines (like people did to create long tape loops) but with one on record, thereby leaving the heads as they are, but I suspect the tape would become out of alignment as it would with <<RW and playback in DAW.

Obviously I don't expect professional results, in fact, the reason I want to sync it better is to mix it with the digitally recorded original, especially to get some 'fizz' in the hihats. I suppose I could use Recycle to chop up a normal bounce and and then synch it by using tempo, but I don't use click tracks so the original audio isn't metronomically in time.

Thanks for the advice. It was just an idea.
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Re: Adding a 3rd Tape Head to (mono) Reel-to-Reel.

Postby Elephone » Thu Aug 22, 2019 7:08 pm

Hugh Robjohns wrote:I've had a thought which might be a better solution for your experimentations. It's a bit old-school Radiophonic workshop/tape concrete... but it can be done successfully with some care...

So, perhaps a better way of getting real-time replay would be to arrange your two tape machines side by side, and then find a way to loop the tape out from the Philips record machine and over to the Sony for replay -- or vice versa. Source spool on one machine, and take-up spool on the other.

That way, you don't have to wreck anything, the tape guides will maintain the tape-head alignment (hopefully), and the time delay between record and replay will remain constant.

The way you arrange the machines will depend on how easy it is to extract and insert the tape in the respective machine's tape paths, how best to maintain the appropriate tape tension across the heads (particularly in the replay machine), and how the machines react to not having a take up spool in place! Just make sure both machines are set to run at the same speed, and watch out for tape loops when starting and stopping them!

H

Ah! Actually, I think there is way to do that without the 'play' machine running or without it driving the loop, so it just feeds through driven by the 'record' machine. I'll look into it. I wouldn't be able to do that with the Sony as the 'play' machine, unless perhaps I can with the casing removed. The reels fit inside a compartment with a door.
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Re: Adding a 3rd Tape Head to (mono) Reel-to-Reel.

Postby Elephone » Thu Aug 22, 2019 7:29 pm

hobbyist wrote: Seems easier to tap into the existing record head amplifier output and then send that back to your DAW than to add a head to do it.

How would the head pick up anything from the tape while it's recording?

I know that a good three head machine would be better. Apparently combined record and play heads are a compromise, since recording and playing are different processes that can be better achieved with separate heads for each role.

I did actually want the archaic sound of the Phillips, but without the bouncing back and chop up job.

Cheers!
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Re: Adding a 3rd Tape Head to (mono) Reel-to-Reel.

Postby Elephone » Thu Aug 22, 2019 8:19 pm

Incidentally... I forgot to mention that I also wanted to do it to make a tape delay effect by getting the audio to feedback into the machine.

Actually, in this regard I'm not too bothered about the delay being at a particular speed to match original audio because I probably can easily splice it quickly enough digitally and then synch the loops to a DAW tempo (e.g. triplets) to the desired tempo to create delays (and loops). That is, the effect doesn't require the exact alignment that mixing digital and tape recordings would.

If you think I'M crazy: https://www.youtube.com/watch?v=GTe3Gy8uff8
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Re: Adding a 3rd Tape Head to (mono) Reel-to-Reel.

Postby James Perrett » Thu Aug 22, 2019 9:50 pm

Now if you had an old Brennel or Collaro based machine it would be much easier as these tended to have spaces for additional heads. Unfortunately your Philips machine isn't really the best machine for exploring the creative uses of tape as there isn't much space around the record/play head as far as I remember.

I think Hugh's second idea of using two machines with the tape threaded to bypass the capstan in the first machine so that the speed is controlled by the playback machine would be most likely to achieve workable results although the sound quality will be nothing like as good as can be achieved by a proper studio machine.

The tape speed will vary, even with the best machines, and the only way to eliminate the sync issues is to use timecode and sync the word clock to the timecode generator/reader - but that's starting to become far too complex for this sort of experimentation.
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Re: Adding a 3rd Tape Head to (mono) Reel-to-Reel.

Postby Tim Gillett » Thu Aug 22, 2019 11:15 pm

It seems to have been pretty well covered so far. Far, far easier to use a standard 3 head machine than go down the modding path. For a special project I added an extra play head and preamp to an already 3 head deck, and for another added a custom erase head for tighter editing. This year I temporarily installed a special play head to a Revox A700 for optimal playback of some early 50's Soundmirror live recordings on paper tapes. All worked well but then I had the experience and it was worth it to the paying customers. Repairing tape machines is beyond most people let alone custom mods... Have you tried a tape emulation plugin? Or even a guitarist's distortion effect pedal which uses an overdriven transformer? I repaired one of the latter for a customer a while ago and was impressed with the tape like harmonics it seemed to produce.
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Re: Adding a 3rd Tape Head to (mono) Reel-to-Reel.

Postby Elephone » Fri Aug 23, 2019 3:38 pm

Tim Gillett wrote:Have you tried a tape emulation plugin?

Thanks yes, these are fine for the more professional tape effect.

Thanks
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Re: Adding a 3rd Tape Head to (mono) Reel-to-Reel.

Postby ef37a » Sat Aug 24, 2019 6:21 am

I agree with Hugh et al, not a practical proposition.

"Replay head output on long wires" ! Doomed to failure, you will pickup all the hum and RF in creation plus, if you want replay whist recording, some form of bias trap will be needed.

The actual replay electronics is the really easy bit. NE5534/LM4562. I am sure Google will find you a circuit for the EQ.

Dave.
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Re: Adding a 3rd Tape Head to (mono) Reel-to-Reel.

Postby James Perrett » Sat Aug 24, 2019 12:33 pm

ef37a wrote:The actual replay electronics is the really easy bit. NE5534/LM4562. I am sure Google will find you a circuit for the EQ.

One of the first pieces of electronics I ever built was a three transistor tape playback circuit for a Brennel tape recorder. The circuit diagram came from the 1972 Henrys Radio catalogue but I think they had taken it from one of the Mullard data books.
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Re: Adding a 3rd Tape Head to (mono) Reel-to-Reel.

Postby ef37a » Sat Aug 24, 2019 2:35 pm

James Perrett wrote:
ef37a wrote:The actual replay electronics is the really easy bit. NE5534/LM4562. I am sure Google will find you a circuit for the EQ.

One of the first pieces of electronics I ever built was a three transistor tape playback circuit for a Brennel tape recorder. The circuit diagram came from the 1972 Henrys Radio catalogue but I think they had taken it from one of the Mullard data books.

I am sure somewhere in my loft James I have a nomograph by Miniflux giving very detailed design data for head amplifiers and several circuits. Must brave the spiders and have a look for it before I get too creaky to get in there!

Dave.
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Re: Adding a 3rd Tape Head to (mono) Reel-to-Reel.

Postby Elephone » Sat Aug 24, 2019 9:24 pm

ef37a wrote:I agree with Hugh et al, not a practical proposition.

"Replay head output on long wires" ! Doomed to failure, you will pickup all the hum and RF in creation plus, if you want replay whist recording, some form of bias trap will be needed.

The actual replay electronics is the really easy bit. NE5534/LM4562. I am sure Google will find you a circuit for the EQ.

Dave.

Thanks. I have done this with a Walkman cassette player head (extended on wires) to rub along strips of tape stuck to card, a few years back.
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Re: Adding a 3rd Tape Head to (mono) Reel-to-Reel.

Postby ef37a » Sat Aug 24, 2019 9:35 pm

Elephone wrote:
ef37a wrote:I agree with Hugh et al, not a practical proposition.

"Replay head output on long wires" ! Doomed to failure, you will pickup all the hum and RF in creation plus, if you want replay whist recording, some form of bias trap will be needed.

The actual replay electronics is the really easy bit. NE5534/LM4562. I am sure Google will find you a circuit for the EQ.

Dave.

Thanks. I have done this with a Walkman cassette player head (extended on wires) to rub along strips of tape stuck to card, a few years back.

Ok but, low impedance head for transistors and no stonking great mains traff about!

Dave.
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Re: Adding a 3rd Tape Head to (mono) Reel-to-Reel.

Postby Elephone » Thu Aug 29, 2019 6:18 pm

ef37a wrote: Ok but, low impedance head for transistors and no stonking great mains traff about! Dave.

Thanks! That's why I presumed it'd be easier than it most likely is. I'll probably try the 2 machine method.
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Re: Adding a 3rd Tape Head to (mono) Reel-to-Reel.

Postby cyrano.mac » Sat Aug 31, 2019 4:34 pm

Ditch the EL3542...

Get something like a UHER if you want to experiment with tape. These have a removable tape carrier. And the heads are available too. New. Not cheap, but hey...

You can pick up a mono UHER for next to nothing. Replace belts. Again, available new. Not even expensive. Clean and lubricate. The chassis and capstan flywheel are built like a tank. And they're all exactly the same. Except for the electronics, but even these are interchangeable.

I'm amazed even the NOS tape carriers show up on evilbay quite often.
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