I don't know if this applies in other countries too, but here in the UK it's fairly common to see sealed new old stock police interview C90 cassettes selling in job lots for crazy low prices. The shells are nothing special, but they usually contain either Maxell UR or some flavour of BASF ferric tape stock. I've not made any frequency sweep measurements yet, but the batch of anonymous BASFs I picked up for just 67p each sound surprisingly good in a Pioneer CT-S450S with Super Auto BLE automatic tape calibration. Considering that anything similar costs around 5 times as much, they're worth a try. They also respond very well indeed to Dolby C or S with their anti-saturation and spectral skewing techniques specifically designed to combat the effects of tape saturation, so they can punch well above their weight if you have a well calibrated cassette deck with either of these noise reduction systems. Now, where did I leave that Fun Lovin' Criminals CD?
These cassettes have old police interviews on them? It would be more entertaining to listen to the tapes than record over them then! Last year a got three TDK AR-X 60 minutes, 1988 style, recorded on the A side only, in single channel mono, old radio reporter interviews that were archived. Superb condition for a few dollars each with cases and J-card inserts. I prowl around e-bay looking for such deals located in Canada. Lower shipping and not many US buyers interested for some reason. (My idea of a "good deal" has evolved somewhat and I am interested in acquiring more of the nice looking ones such as tdk ma-r and ma-xg. Nice meaning big open windows to view the tape and slip sheets without logo and letters. Plus the heavy metal frame is just plain cool. My reasoning is simple: So few are the titles of music I like... and would want to put onto cassette... may as well just get a few beautiful expensive nos tapes, right? For example: I have been busy since last Summer going through the top 100 charts from the 50's putting together "the ones I like". Then added in the 60's and re-discovered a lot of good ones that I heard last in the early 90's as a teenager listening to AM oldies stations. (All from way before my time but I like some of that stuff.) And yet, two decades of the most productive decades in music history... and I struggle to fill one 90 minute playlist with what I like. Now I am going back and obtaining the re-mastered high resolution file releases and analyzing in Audacity and soundforge. Surprising how many are re-released super loud and lacking dynamic range etc., Once this is all complete and the best of the best are selected, in a few more months, they are all going onto a nice TDK MA-XG sealed new old stock that awaits. Next project is a compilation of "Heavy Metal" which should... be put onto a worthy "heavy metal" TDK MA-R or XG tape I reckon. All madness and irrational and dumb but there ya go.)
They're new old stock so still factory sealed unfortunately. No crimes here! I tried the TDK AR-X when they first came out but they need a huge amount of bias to work correctly making them very over-toppy with a dip in the mid-range unless you have a deck that can do that, and many can't. If you can't get a reasonably flat overall frequency response then you'll never get Dolby B or C to track accurately. The downside of that being that you're stuck with a noise floor that's only around 2dB better than a TDK FE costing less than 1/10th as much as a NOS AR-X. One upside of the AR-X being the way it is is that not-so-good decks often have a hump in the mid-range and are lacking at high frequencies, so the AR-X could compensate for that to a degree by doing roughly the opposite and making a bad deck sound better. I can't find my original AR-Xs but will grab a used one and have another play if I can find one going cheap, but cheap ones are rarer than hen's teeth over this side of the pond. It's possible that the Super Auto BLE calibration on my Pioneer may be able to dial them in if I'm lucky. I do have a couple of ARs but they're a totally different formulation to the AR-X and perform very differently from what I've read, so I won't learn much from playing with those instead. I'm an electronics engineer who enjoys getting hold of schematics for hi-fi cassette decks and redesigning them to optimise a deck for one specific tape formulation that I can buy by the bucket-load. My reference deck is a blueprinted and custom-modified 3-head Teac V-1050 that's now flat within 1dB from 17Hz to 21kHz with a cheap TDK FE. That's up in CD player territory in terms of flatness. Once you get the frequency response that flat, all forms of Dolby NR track as close to perfection as makes no difference, so throw Dolby C into the mix and ferric tapes behave far more linearly than Type IV tapes can without it. It's noisier than using Type IV, but there's plenty of noise reduction with Dolby C anyway. If you're not familiar with what Dolby C does, here's an extract from the relevant Wiki page.. "In the region above 8 kHz, where the ear is less sensitive to noise, special spectral-skewing and anti-saturation networks come into play. These circuits prevent cross modulation of low frequencies with high frequencies, suppress tape saturation when large signal transients are present, and increase the effective headroom of the cassette tape system. As a result, recordings are cleaner and crisper with a much improved high-frequency response that the cassette medium heretofore lacked." https://en.wikipedia.org/wiki/Dolby_noise-reduction_system#Dolby_C The difference it makes in terms of high frequency performance with Type I tapes in particular is quite astonishing! I just wish the V-1050 had Dolby S as it is a big step up from C, but I do have 3 other decks that do, so I'll be looking into which one of those will be the best candidate for customising next. It'll probably be the Pioneer CT-S450S as I'm familiar with the IC it uses for recording EQ adjustment (it's the same device as used in the V-1050) and there's probably room for improvement to help it auto-dial in more accurately than it already does. It'll be fun experimenting anyway. I suppose it all comes down to what a person is aiming for; cassette recordings that have a specific sound to them depending on the tape they use, or a high level of transparency where they no longer have a specific sound. I'm aiming for the latter but on a budget. PS In the time I've been typing this, I've just won another job lot auction for the same kind of BASF ferric tapes in disguise (90 in total) and it's worked out at under 62p each this time! In UKland prices, that's a massive bargain!
AR-X are expensive and I wouldn't buy any nos sealed, having only these 3 used ones total and not that interested in collecting for the sake of collecting. I wanted to experience a variety of old "super tapes" and see what they sound like on the fully recapped and properly calibrated Nak ZX-7 I obtained last September. Good fun tuning in the azimuth and bias of each tape and pretty much every tape I try on it sounds beyond belief. And yes TDK FE is fantastic bargain bang for the buck.
It's an interesting conundrum trying to compare a ZX-7 (or many other Nak models) to decks from other manufacturers, as Nakamichi used less high frequency boost on recording and more on playback in the early days. This reduces the effects of tape saturation at high frequencies giving less "squashed" top-end. Nakamichi's 0dB level was also ~2dB lower than on most other decks from around 1983 when the shift to 250nWb/m for 0dB started to happen, so this worsened the effects of tape saturation on all decks that followed the new spec making Dolby HX Pro pretty much compulsory if you wanted to combat it. I'm a big proponent of never hammering meters up into the red on decks where the Dolby symbol is shown at -1dB on the meters (that's on 250nWb/m for 0dB decks) for this reason, as even most "modern" formulations don't handle it very well in terms of distortion. That's hardly surprising though when you consider that the original standard recording flux level for 0dB was 160nWb/m, so +3dB on a 250nWb/m deck is approximately equal to a meter-twanging +7dB on one of those! A few formulations that can handle it well are TDK SA-X, MA-R and MA-XG, although Maxell XLII and XLII-S come very close. With pretty much every other formulation you're ever likely to come across in the wild, sticking to sensible recording levels will pay you back with far cleaner recordings, especially if you're already using Dolby C or S where trying to squeeze every last dB onto the tape to improve signal-to-noise ratio becomes far less important anyway.
This forum is very accessible or susceptible to Google searches, by that I mean stereo2go will often come up in the top handful of Google search results for many cassette and walkman type related searches. (I didn't say all search results.) I read your intro and associated posts on the decades of experience you have in the electronics engineering side of "making a silk purse out of a sows ear" in terms of cassette decks and correcting poor design or low cost original component choices etc., So stereo2go forum would be another good place for you to put down some of your findings and upgrades to certain cassette decks. Because there is a good chance of such being found and read and being useful and thought provoking to many people out there. It would be educational to see some examples of enhancement possible by replacing components in such-and-such model decks where there was some bad design or oversight, thereby making such-and-such deck a very potent performer. Especially if there are any Nakamichi deck enhancements that are either fairly obscure or not well known about.
Thank you. The Teac V-1050 will likely be the first as I already have that one all typed up in a Word document, at least in terms of a parts list with brief descriptions at to why some of the changes were made. It shouldn't be too hard to write some accompanying text to go with it. I'll try to get round to doing that soon. I certainly wouldn't go messing with a Nakamichi beyond routine servicing and calibration, and I'm not particularly interested in owning one at the prices they sell for. If I win the lottery, maybe. Besides, my ears top out at 15kHz now and all of my mid-tier decks go way beyond that and have a flat enough frequency response and low enough distortion and wow and flutter for me to not care. Dolby S gives even a mid-tier deck a huge advantage over a deck that doesn't have it, so I'm perfectly happy to stick with those.
