Right…a DP3T switch means double-throw, three or triple-throw. Basically 2 independent sets of common “outputs” if you will, each with three selectable inputs.
If it was me I’d install jumpers. You’re wanting to easily switch the speed, I get it, but machines that are designed with this sort of selectable speed functionality typically also have multiple EQ adjustment pathways to match the speed change. So a machine that’s designed to operate on different speeds has multiple EQ adjustment pots, sets for each speed. In your case, since the MS16 is designed to be setup and operate at one speed (whether it’s 7.5, 15 or 30ips), and it has only one signal path per channel (one set of EQ adjustments), any time you change speeds you’re going to have to recalibrate the whole machine. So just keep that in mind. No matter how convenient you make it to switch speeds, you’re still going to have to go through the entire calibration procedure, whereas a machine designed to be quickly switched would have the separate EQ trimmers for each speed, and you would do a full setup for each speed, and then could easily switch between the speeds and each would be calibrated. The head profile and trim range of the adjustments on the MS16 were designed for 15ips. And that’s where it sounds best. It has great frequency response at 15ips…well over 22kHz…and that’s at 0dB +/-3dB. At 30ips the LF head bump is all wrong and you *may* improve HF performance, but how usable is another 2kHz of bandwidth when you’re already well over 20kHz? Yes there would be some improvement in s/n ratio, but if you’re using the dbx this is really a moot point. And if you’re not using the noise reduction, people seem to be fine with the dynamic range when the machine is setup to take advantage of +9 or higher class tape. Real-world reports indicate you lose the bottom-end at 30ips on an MS16, which is what you’d expect since the doubling of the tape speed shifts the response curve up an octave. If the -3dB point at the low end is 40Hz at 15ips, it will be 80Hz at 30ips. No thank you. You might be able to get some of that back using the LF repro EQ, but, again, the heads were designed for 15ips, so the gap and profile are not going to allow same performance at 30ips as at 15ips. And your tape time is cut in half/tape cost doubles. 7.5ips might be interesting…probably has a wicked low-end, but the bump might be in the wrong spot. HF performance is probably okay…maybe out to 18kHz or something? But the s/n ratio will worsen. If I had that machine I’d probably only use 7.5ips if I wanted to save on tape costs…and, I’d expect to be dependent on using the dbx, and then if I wanted to run it where it’s designed to run, at 15ips, I’d be grumbling at having to recalibrate. It’s a 15ips machine and performs well there.
The 58 and MS16 have the same amp card assembly. The design was a complete departure from anything Teac had done before, and it was introduced with the 58. It is not garden-variety at all. It is a DC servo design that mitigates DC offset minimizing the need for coupling caps in the signal path…similar to the Jensen twin-servo design…discrete front-end…it’s really pretty slick. And more costly to manufacture. The signal path sound and character on a tape machine comes from the head design and the amplifier electronics. The heads on the 58 were also a departure and next generation tech. The design carried all the way through until the ATR80 series, so includes the 38, MS16, 48, and ATR60 series. The difference between those machines I just listed is the amplifier electronics. The 48 is the only other one that is even close to the 58/MS16 design, but it is already a value-engineered departure from the 58/MS16 design…still discrete front-end, but the servo design is gone in favor of a more garden-variety design that incorporates and is dependent on coupling caps to mitigate DC offset. The ATR60 series takes a further step away and does away with all the discrete front end except for the first stage with the 2SK68/2SK70 dual transistor, and then right into an opamp. Jack Endino talks comparatively about the MS16 and ATR60 series…you can find the page if you do a web search…noting the MS16 actually sounds good…and he’s comparing a bunch of different machines and different formats. It’s a good read. But he shares his opinion the ATR60 series is noisier and just didn’t sound as good…which was curious in his notes because the heads are the same, and the tape path is extremely similar…well the amp circuit is why. He also talks about 15 vs. 30ips.
So all this is to say do what you want, experiment however you want, but the MS16 has a unique signal path, and it wants to eat at 15ips, and that’s where I would use it.
