I went and bought myself another prehistoric curio: an early 1970s Philips cassette recorder, model N2506:
My dad had one of these when I was pre-school age in the early 1970s. Even though I was very young I remember it well. It was his first stereo cassette recorder, used along side his Akai 1721L tape deck. At just one year old it developed really bad speed stability issues and after he failed to fix it over many wasted hours (even replacing every component on the speed-regulator board) it was broken for useful parts then skipped.
The seller advertised this one as spares or repair, in so far as it appeared to be visibly working but it was untested for audio because he had no cable to fit the DIN sockets at the back. He did however say that all the transport functions seemed to work, but actually they did not because unsurprisingly, the belts had perished. Someone had already replaced the main drivebelt with an elastic band, which certainly gave interesting audible results during replay. I replaced it with a NOS spare belt that I had previously bought for my ITT SL54 restoration (which ended up not needing a new main drivebelt). This cured the chronic wow & flutter issues caused by the elastic band. I remain in need of a new belt for the fast-wind functions that still do not work. I am on the lookout:
With the main drivebelt replaced and all the old goo removed with Autoglym Engine & Machine Cleaner, I cleaned and demagnetised the tape-path and listened again. It was instantly apparent that both the azimuth and playback-speed were out by quite a margin. It’s possible the azimuth had drifted-out over the period of 40 years, but the reason the speed was miles too fast is because someone who should have his tools confiscated had messed with the trimmer on the speed-regulator board for a reason that is now lost in time.
I reset both the azimuth and the speed using my Nakamichi DR-1 as a reference. Resetting the speed was not easy because the trimmer can realistically only be accessed with the case removed and with the unit sat on its face, which affects the playback-speed to start with. Time and patience won the day, as always.
With the mechanics sorted as far as I can without that one final belt, my attention turned to the unit’s cosmetic condition. Overall it wasn’t bad for a forty-year-old piece of HiFi. The Engine & Machine Cleaner made light work of cleaning the various stains, marks and residue from the alloy fascia, while everybody’s workshop favourite, 3-in-1 oil, worked wonders on the seventies-tastic wooden case, which miraculously has survived four decades with all its corners intact and no major scrapes or gashes.
If I were restoring the recorder to a condition that I’d be happy to describe as “full working order” for the benefit of someone else, I’d probably also replace the pinch-roller for piece of mind. However because this 'rolling restoration' is a labour of love purely for my own benefit, it would seem a bit of a wasted effort, because the original pinch-roller is still in good condition, having responded well to just a good clean. It’s likely though that I will be investigating the condition of the r/p head at some point, because even with the azimuth set correctly, playback of ferric tapes can still be quite muffled and indistinct, even those of the deck’s own recordings. (Playback of this deck's recordings on another machine are fine however. Most strange.)
Anyone interested in curious technology would surely appreciate some of the finer points of this deck’s engineering. For example the level-control fader on the top panel is not a rheostat or VR itself, instead it’s linked to an elaborate worm-drive that operates a traditional potentiometer located near the VU meter under the top panel. This principally prevents the fader becoming crackly with dust, which is a problem that would be worsened by the horizontal layout of the deck. Another interesting design-principle shared with other Philips chassis of this era (and earlier) is that the motor runs in reverse during rewind, necessitating some rather complex-looking leaf-switches near the motor to make it all work. Finally under the takeup-reel table is probably the earliest example of an electric autostop mechanism that I ever recall seeing. Brushes attached to the underside of the table wipe round a static metal disc with radial contacts on it, and when the table stops rotating (either because the tape has reached an end or because of a jam), the power is cut to the motor almost instantly. Clever stuff for its day, in my opinion.
Although this deck does not have Dolby noise reduction, it does have something called DNL (Dynamic Noise Limiter), which was Philips’ proprietary playback-only noise reduction system. To be honest it works surprisingly well.
I made a small video of the machine in the condition as it stands today, playing an excerpt from The Beatles Abbey Road CD that I recorded onto Maxell XL-II tape using an ITT SL837 (the Philips cannot record onto Type II tape). This video is mainly for the benefit of my dad so he can actually see one of these machines working properly!
Philips N2506 - Beatles Abbey Road Suite
If you read this far, well done. Statistically you are one of a seemingly-decreasing number of people who have a sufficient attention-span to read a blog of more than 500 words.
My dad had one of these when I was pre-school age in the early 1970s. Even though I was very young I remember it well. It was his first stereo cassette recorder, used along side his Akai 1721L tape deck. At just one year old it developed really bad speed stability issues and after he failed to fix it over many wasted hours (even replacing every component on the speed-regulator board) it was broken for useful parts then skipped.
The seller advertised this one as spares or repair, in so far as it appeared to be visibly working but it was untested for audio because he had no cable to fit the DIN sockets at the back. He did however say that all the transport functions seemed to work, but actually they did not because unsurprisingly, the belts had perished. Someone had already replaced the main drivebelt with an elastic band, which certainly gave interesting audible results during replay. I replaced it with a NOS spare belt that I had previously bought for my ITT SL54 restoration (which ended up not needing a new main drivebelt). This cured the chronic wow & flutter issues caused by the elastic band. I remain in need of a new belt for the fast-wind functions that still do not work. I am on the lookout:
With the main drivebelt replaced and all the old goo removed with Autoglym Engine & Machine Cleaner, I cleaned and demagnetised the tape-path and listened again. It was instantly apparent that both the azimuth and playback-speed were out by quite a margin. It’s possible the azimuth had drifted-out over the period of 40 years, but the reason the speed was miles too fast is because someone who should have his tools confiscated had messed with the trimmer on the speed-regulator board for a reason that is now lost in time.
I reset both the azimuth and the speed using my Nakamichi DR-1 as a reference. Resetting the speed was not easy because the trimmer can realistically only be accessed with the case removed and with the unit sat on its face, which affects the playback-speed to start with. Time and patience won the day, as always.
With the mechanics sorted as far as I can without that one final belt, my attention turned to the unit’s cosmetic condition. Overall it wasn’t bad for a forty-year-old piece of HiFi. The Engine & Machine Cleaner made light work of cleaning the various stains, marks and residue from the alloy fascia, while everybody’s workshop favourite, 3-in-1 oil, worked wonders on the seventies-tastic wooden case, which miraculously has survived four decades with all its corners intact and no major scrapes or gashes.
If I were restoring the recorder to a condition that I’d be happy to describe as “full working order” for the benefit of someone else, I’d probably also replace the pinch-roller for piece of mind. However because this 'rolling restoration' is a labour of love purely for my own benefit, it would seem a bit of a wasted effort, because the original pinch-roller is still in good condition, having responded well to just a good clean. It’s likely though that I will be investigating the condition of the r/p head at some point, because even with the azimuth set correctly, playback of ferric tapes can still be quite muffled and indistinct, even those of the deck’s own recordings. (Playback of this deck's recordings on another machine are fine however. Most strange.)
Anyone interested in curious technology would surely appreciate some of the finer points of this deck’s engineering. For example the level-control fader on the top panel is not a rheostat or VR itself, instead it’s linked to an elaborate worm-drive that operates a traditional potentiometer located near the VU meter under the top panel. This principally prevents the fader becoming crackly with dust, which is a problem that would be worsened by the horizontal layout of the deck. Another interesting design-principle shared with other Philips chassis of this era (and earlier) is that the motor runs in reverse during rewind, necessitating some rather complex-looking leaf-switches near the motor to make it all work. Finally under the takeup-reel table is probably the earliest example of an electric autostop mechanism that I ever recall seeing. Brushes attached to the underside of the table wipe round a static metal disc with radial contacts on it, and when the table stops rotating (either because the tape has reached an end or because of a jam), the power is cut to the motor almost instantly. Clever stuff for its day, in my opinion.
Although this deck does not have Dolby noise reduction, it does have something called DNL (Dynamic Noise Limiter), which was Philips’ proprietary playback-only noise reduction system. To be honest it works surprisingly well.
I made a small video of the machine in the condition as it stands today, playing an excerpt from The Beatles Abbey Road CD that I recorded onto Maxell XL-II tape using an ITT SL837 (the Philips cannot record onto Type II tape). This video is mainly for the benefit of my dad so he can actually see one of these machines working properly!
Philips N2506 - Beatles Abbey Road Suite
If you read this far, well done. Statistically you are one of a seemingly-decreasing number of people who have a sufficient attention-span to read a blog of more than 500 words.
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