“Technics with the same style ‘loop’…”
Right…RS-1500, 1506, 1520 or 1700. I might not be popular for saying this, but that is a consumer machine all the way. And though the tape path might look like the same style as the 3M Isoloop, they are nothing alike. The Technics design is essentially the same as the X-10, just wrapped around in something that looks like the 3M closed-loop design. The Technics setup is at least adjustable as far as the pinch rollers go compared to the Teac/Tascam setup, but reading the service manual it looks like a relative pain to setup. Notice on the 3M there are no tension arms. There are two fixed guides upstream of and downstream of the capstan shaft. It’s bone simple resistor holdback and takeup tension but what more do you need? Because you actually have a true mechanical constant tension isolated closed loop design with no static guides inside the loop…actually no guides at all…the only mechanical noise is from the reversing idler which is a precision instrument in and of itself. 3M was after excellence with the design. You have to keep in mind instrumentation machines are recording and reproducing much higher frequency information that audio bandwidth, and low wow and flutter were essential. The only stationary things the tape touches are the heads inside the loop. There’s no scrape flutter idler. They didn’t need it. And while the Technics tension inside it’s loop depends on careful adjustments of the pinch rollers, the 3M design simply depends on positive contact of each roller with its associated contoured surface of the capstan shaft. Look at this:
That’s from the RS-1500/1506 brochure. The design is a bad facsimile of 3M innovation going back instrumentation machines from the 1950s. 3M Mincom translated the concept to their audio division with the M23 in the early 1960s. Technics introduced the RS-1500/1506 in the mid 1970s. But their “innovation” doesn’t carry forward the simple but elegant genius of the 3M Isoloop design, which depends not on any complex servo tension system…it’s mechanical constant tension…relay logic…not an IC in sight…all AC motors…and still out-performed the “professional” transport specs of the Technics machine a decade and a half earlier. No comparison. People will argue that point with me but you have to compare the specifications carefully, because Technics leads the reader with a typical percentage figure, but then following is a relatively massive +/- percentage swing which all equals more than the 3M spec, and the Technics spec is based on reproduce only of a precision test tape. The 3M spec clearly states it is the maximum amount…worst case…AND is the cumulative figure of tone recorded AND reproduced on the machine. It is the most real-world specification sheet I’ve ever seen in this area, and it is still much better than much more modern machines. The 3M machines were so innovative they didn’t even have mechanical brakes…that’s right, relay logic dynamic braking way back in the early 1960s. Sorry you got me started and I know you didn’t intend for that. It’s just the Technics machines were designed and built to sell and make money for the consumer market bracket. And they did well. But like I said it’s the X-10 tape path in a closed-loop format with some fortunate adjustability to the pinch rollers, but it’s a cylindrical capstan with symmetrical pinch rollers. And would be a pain in the ass to work on compared to a 3M machine. The 3M machines were designed and built for a professional market that disappeared a long time ago. And we’ve not even started talking about amplifier electronics. I don’t suspect you were thinking about reaching back out to the feller with the Technics, but I wouldn’t recommend it for your needs. If he’s giving it to you and you want to spend maybe $200-300 in parts and curse a lot getting it working you’d be able to sell it for a healthy profit. Those things sell for silly money to the audiophile market, which is why I say what I’m saying here is surely unpopular, because the Technics machines are very popular and sought after. For what they sell for I would take any Otari MTR series or Tascam 40, 50, or ATR60 series or BR-20 halftrack machines all day long over the Technics machines…I’d even take an Otari MX-5050 series halftrack over the Technics…reliable well-performing work-horses are the MX-5050 machines.
So…anyway…congrats if you read all that.
Let’s see what’s in your market…
