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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 3rd Dec 2019, 12:02 am   #21
jamesperrett
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Default Re: Nakamichi bliss!

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Originally Posted by Radio Wrangler View Post
Back in the day, I was told that cassettes were better than open reel, because they had Dolby, 'metal tape', and all sorts of things.
Of course in the professional world there was Dolby A and then Dolby SR which were more sophisticated than the Dolby B, C and S that were used domestically. Tape formulations also improved in a different way, generally targeting higher output where reference levels could be up to 9dB higher than with older formulations.
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Old 3rd Dec 2019, 12:07 am   #22
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There tends to be an audible 'crushing' effect with cassette recordings that you don't get with R2R, though there is a lot of variation between different tape stocks even on the same machine. I assume it's a combination of slow tape speed, thin oxide coating and narrow track width.
Have you ever wondered why the frequency response of a cassette deck is normally quoted at -20dB relative to 200nWb/m? If you look at the response at 0dB it would look terrible with the high end drooping considerably. Cassettes can easily be driven into saturation at high frequencies.
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Old 3rd Dec 2019, 2:19 am   #23
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Default Re: Nakamichi bliss!

Like someone said about tuning engines, 'there's no substitute for cubic inches'
With tape, it's square metres per second. Anything that can be done to tart up a small format can be applied to a larger format, if there is any need.

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Old 3rd Dec 2019, 6:20 am   #24
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That's true. The specific need to record at 20db below reference was usually to avoid HF saturation and the misleading frequency response results that gave.
That was much more of a problem with slow speed recordings of which cassettes were an example. Open reel tapes at the same slow speeds had the same problem.

For cassettes, Chrome and then Metal came along which performed better than Ferric specially in the HF MOL saturation area. My 90's TDK tape reference book states detailed performance figures for their range of tapes at that time. MOL (saturation output level) at 10Khz for their TDK D tape was -8.5db and for Metal -1.0db ( both re 250nWb/m)

Many Tascam Portastudio decks performed quite well in the HF saturation department. They used double cassette speed (3.75ips) and "Chrome" (Type 2) tapes.
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Old 3rd Dec 2019, 7:43 am   #25
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Default Re: Nakamichi bliss!

It wasn't just the tape, the pole tips of recording heads could go too vlose to saturation and there was a compromise between hardness for wear versus saturation level of the pole material.

At higher tape speeds, on open reel machines there was also the opposite problem of engineering a long enough pole piece contact with the tape to get good LF response. There are two sampling aperture effects, the distance across the gap and the contact length of the pole pieces.

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Old 3rd Dec 2019, 4:07 pm   #26
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Default Re: Nakamichi bliss!

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With tape, it's square metres per second.
Or square metres per fortnight, if you don't like small numbers
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Old 4th Dec 2019, 12:28 am   #27
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It wasn't just the tape, the pole tips of recording heads could go too vlose to saturation and there was a compromise between hardness for wear versus saturation level of the pole material...
True, and some manufacturers like Nakamichi and Revox chose to stay with the softer head pole pieces for better fidelity even if it meant somewhat greater head wear.

This relates to Nakamichi's "pressure pad lifter" on its dual capstan decks. With the pressure pad now out of the way, the Nak heads wore more evenly and lasted considerably longer before head relap or replacement was needed. A pressure pad, especially when caked with tape muck can prematurely ruin a tape head. No surprise better designed open reel tape machines did away with the pressure pads, at least when the manufacture of tapes was improved to the point that omitting the pad was possible.

As far as I know though, Nakamichi was the only company to use the pressure pad lifter on cassette decks.

Interestingly, one company that I know of, Tandberg, used a softer material for the record head, but a hard Ferrite head for the repro head. I think I saw this on the TD20A model.
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Old 4th Dec 2019, 8:13 am   #28
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As far as I know though, Nakamichi was the only company to use the pressure pad lifter on cassette decks.
Agreed. I can't work out why Revox didn't do the same, given the quality of their dual capstan transport. Perhaps the head profile had something to do with it - they bought theirs in from Sony, I think.
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Old 4th Dec 2019, 10:55 am   #29
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Interesting. Yes I believe that machine was the first cassette deck Revox made, so not surprised if certain parts were sourced elsewhere. I'd thought not using the pad lifter might have been to do with Nak having copyrighted it.
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Old 15th Dec 2019, 2:25 pm   #30
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I remember encountering the Revox B710 cassette machine with its dual capstans in the presentation studios of BBC wales. All these were new in the early 1980's. A few more were scattered around music studios to provide soloists with copies of performances etc but all these machines, were constantly in and out of the service department and none provided azimuth compatability with another machine. The importer FWO Bauch swapped several machines out and when I visited the IBC(professional broadcast equipment exhibition) in the late 1980's at Brighton to see the latest toys, I was privilaged to see the new Nakamichi CR7E This thing had automatic line up, like the Dragon and all one needed to do was place a tape in it and press go. It then rolled in 30 seconds dropped into record and proceeded to record two tones, one low frequency and one higher several times, finishing with a motorised azimuth tweak after which it returned to the beginning and displayed (Ready) on the display. The stability of this machine was amazing and I was able to secure a trial of one from the importers B&W, I set it up with suitable pro pack, for balanced line working as machine three in the recording channel next to the concert hall in BH Cardiff and one day whilst recording a live Midday Concert to Radio 3 the stations Operations Manager walked in and said 'what is that cassette machine doing here'? I informed him it was on appraisal and that he was listening to it off tape! I then switched to tape machine 1 which was making the library recording and he then switched back to the Nak with the response 'good God' , why do the Revox machines not sound like this? I replied that with respect there was nothing wrong with rhe Revox that dropping in a Nakamichi transport would not cure! during the next few years all the revox cassette machines were phased out to be replaced with three headed off tape monitor Naks. Many of these, for an organisation of the BBCs' reputation, were very economical as they cost between 500 and 700 pounds including balanced line operaton wheras the CR7E needed a pro-pack, bringing the price to 1500. The servicing of these machines was easily performed by the engineering staff. The audio engineering department had a fleet of 55 Studer A80RC machines, in fact a complete cross section of Studer products including the venerable C37. If anyone gets to see one of those working it is a pleasure to see and hear for the sheer overall technical delight both mechanical and electronic. As a footnote to this ramble I was accidentally in the right place at the right time when the nakamichi CR7E, which I had on trial was offered to me by an ex colleague now trading in ex broadcasting equipment. He did not know its importance to my broadcasting life and when told said well you can have it for what I paid for it, 50. This was in 2008 and the machine was 20 years old and all that was necessary were the two rubber pinch rollers which were still available! Two years ago I believe B&W were still servicing all but the earliest Nakamichi product. I too have a lot of recordings made on this machine and I cannot say that I have noticed appreciable sonic degradation. I am however arranging to copy to computer and DVD. I wonder which format will be suitable for long storage?
Mike
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Old 15th Dec 2019, 2:50 pm   #31
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Default Re: Nakamichi bliss!

Excellent insight, thanks.
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Old 15th Dec 2019, 3:31 pm   #32
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The original B710s did give trouble in service - TS had a copyroom with twelve 710s, both Mk1 and Mk 2, and if memory serves the cassette hubs were replaced on all of them because the collet fixings slipped on the motor shaft. Shortly after this I bought a second hand Nakamichi MR-1 and was very pleased with it - and no doubt will be again once I have sorted out the mode-select motor.

I acquired both a B215 Revox and its professional sister, the Studer A721, some time later and these are undoubtedly better than the 710.

I have to concede, though, that should a CR-7 appear on my doorstep wanting a home, I wouldn't turn it away - to my mind it is the best all-round Nakamichi, without the excesses of the Dragon, although replacing the split-track head could be a headache.
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Old 16th Dec 2019, 11:16 am   #33
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I forgot , in my ramble, the best feature of the Nakamichi CR7E after the auto line up was the little black knob on the machine marked Azimuth! Tweaking this caused the display to change to a row of markers which were highlighted as one turns the control from centre, left or right. A small buzzing sound from inside the machine tells you that the head unit is being rocked by a tiny motor. If you place the monitor system in Mono you hear the HF peak as you steer through correct azimuth and back. The centre position for record is memorised so return to centre is always possible after listening to tapes made on other equipment. I wish I had a pound for every time I was asked by one of the wonderkinder of production "what is that strange swishing sound on the speech and music".
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Old 16th Dec 2019, 11:42 am   #34
Ted Kendall
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I forgot about that feature - it's the Dragon that chases its own tail with auto-azimuth on replay. Nice machine! Ignorance of azimuth errors didn't stop at producers, unfortunately - at an NPC which shall be nameless but is now demolished, I had trouble with a TA who couldn't understand why a splice out of line by 20 degrees went phasey. Actually, he couldn't even hear it when it was pointed out...

Last edited by Ted Kendall; 16th Dec 2019 at 11:51 am.
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Old 17th Dec 2019, 6:15 am   #35
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Default Re: Nakamichi bliss!

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I forgot , in my ramble, the best feature of the Nakamichi CR7E after the auto line up was the little black knob on the machine marked Azimuth!...
It could have been the best feature of a whole lot of tape machines, including most Naks, if only they had had it.

It's interesting that in the early days, Nak provided a record azimuth control (eg: NAK 700) but the much later CR7 had playback azimuth control. When transferring old cassette recordings optimally, a record head azimuth control, as per some high end Naks, is of course of useless.

For me a front panel play head azimuth adjuster, coupled with Nak's "pressure pad lifter" on the dual capstan models are the two most important features.

Of course the downside of any "front panel" adjuster is that adjusting it incorrectly can cause more problems than it solves.

Another perhaps little known fact is that cassettes recorded on simple single capstan machines can drift in recorded azimuth from start to end of a tape side, as the changing tape back tension can also change the recorded azimuth. If played back on the same type of machine the error may not appear but played on a dual capstan machine, while good in other ways, can introduce an azimuth error.

Here's my "poor man's" little black knob mod fitted many years ago to a humble Nak 480 but it can be fitted to many dual capstan Naks without change. Simple direct drive on the playback azimuth screw.
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Old 17th Dec 2019, 6:54 am   #36
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I forgot about that feature - it's the Dragon that chases its own tail with auto-azimuth on replay. Nice machine! Ignorance of azimuth errors didn't stop at producers, unfortunately - at an NPC which shall be nameless but is now demolished, I had trouble with a TA who couldn't understand why a splice out of line by 20 degrees went phasey. Actually, he couldn't even hear it when it was pointed out...
My impression is people find it much harder to notice audio faults than they do picture faults. Or at least the audio faults have to be a lot worse before they're noticed as a problem.

A related one seems to be excessively low expectations of "older" recordings. So, "Oh well, it's an old recording, what do you expect?" when often the old recordings are fine but they were transferred or processed inexpertly. The operators and managers can have no idea until an outsider notices the very poor quality of the digital files, and demonstrates what the tapes actually sound like compared to the inferior digitised copies.

Last edited by TIMTAPE; 17th Dec 2019 at 7:03 am.
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Old 23rd Dec 2019, 3:10 am   #37
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Default Re: Nakamichi bliss!

I'm constantly amazed by the ingenuity on here. I'd never have the knowledge or awareness to attempt such a thing, as I don't understand them enough to fiddle! Increasing the front-panel or user-accessible adjustments on gear where it's hidden is excellent.

I was delighted to discover in my 'Manual of the Ferrograph' that the makers expect the user to wire up plugs and attachments as a matter of course for certain recording procedures. They obviously hadn't considered the route of exorbitantly-priced yet very simple accessories!
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Old 23rd Dec 2019, 6:41 am   #38
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I guess back then, wages weren't as high relative to the gear so many had no choice but to build, often from kits, or modify their own gear. It's a different world now with much cheaper and mostly much better performing audio gear.

These days I only make custom mods when there's a real need for it and there's nothing else available, or buying that feature would be ridiculously expensive. I'm reluctant to buy a whole machine just for one inbuilt feature like a front panel azimuth adjuster.
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Old 23rd Dec 2019, 12:16 pm   #39
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Default Re: Nakamichi bliss!

A mod I did on a couple of cassette machines as a schoolboy was to replace the little preset pot on the back of the DC motor with a multiturn pot mounted on the front panel. This allowed me to practise my cello along with cassettes of the piano accompaniment.

N.
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Old 23rd Dec 2019, 1:37 pm   #40
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Interesting Nick. I made a similar mod on my Nak LX3.

As I was only using the deck for playback, I connected the speed control wiring to the existing front panel Bias Adjust pot, and for its new use relabelled it Pitch Control.

The Tape Type switch was also now redundant as it only affected record functions so I repurposed it to switch the new Pitch Control in and out of circuit.

When an adjustment is made often, placing it in easy reach makes sense.

Another small mod I made was on my Revox A700. There are times when the reel tensions need to be adjusted to play certain old tapes at their best. The A700 has two small PCBs under the front panel with trim pots only accessible with this panel removed. I drilled two small holes in the front panel, just above the trimmers. With a small screwdriver, each reel's tension in play can be adjusted without any dismantling.
A further development would be to make these adjustable via dedicated knobs on the front panel.

I just came across this short video of a Nagra/JBR playback machine. Note the dedicated azimuth adjuster and tape tension adjuster screw.

https://youtu.be/OiW6lDXtV0E
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