MTH Proto Sound by QSI verse PS 1 and PS 2

Kris, I don't know the precise details of them, but PS-1 used QSI for sound. These did not have any command control (DCS) functions but the sound was a major break through at the time. They were basically conventional engines with a cool sound system. PS-2 was the beginning of command control for train operation.

Steve

The QSI Set up was three boards sandwiched together.  MTH had there version made as a 2 board set.  QSI evolved with great amount of conventional options such as the ability to assign ID and Road Names to the engine controlled by a sequence of bells and whistles.  MTH does not have that capability as they transitioned into PS-2 full command control.

Sounds and basic features of PS-1 and QSI are the same.  Most MTH boxes say QSI but it is MTH production version.  If an engine has full QSI system, it was either a different manufacturer or owner upgraded to QSI for those extra conventional features.  QSI system is no longer supported.  MTH system is, as parts still available, though no longer being manufactured.  G

QSI products were sold to MTH or could have been licensed in an agreement with MTH, I don't know the details. QSI shows up in other brands of engines as well, the two that I can think of are Weaver and Williams.

QSI is not an MTH thing but PS-1 is strictly MTH.

PS-1 is a sound system and not command control but may have one or two other features such as remote control of the coupler device.

Lee Fritz

QSIndustries offered the first successful electronic reverse unit (E-unit) around 1983, followed by plug-in circuit board sound systems.

MTH adapted QSI systems in 1994. I purchased a Premier Southern Ps-4 from a Forumite (20-3006-1; 1401) made that year. The last two lines of Features on the box end flap state, "Protosound (TM) Digital Sound Package Designed by QSI [QSI herald with a small yellow lightning bolt on a black background]."  This system has basic sounds.

As posted above, MTH and QSI added features quickly, including Passenger Station Announcements (PSA) and Freight Station Announcements (FSA), remote control of couplers, and a host of others.

QSI products offered the best operation and sound systems available. As PhillyReading posted, lots of them were installed in Weaver and Williams locomotives. They were designed to fit Lionel postwar locomotives. The reverse board was wide enough to keep the plastic sides of a Lionel postwar Geep from moving inward. Art Boynton of QSI had a table at York for years.

As I suspected, the system in my Ps-4 worked with my ZW but not with newer transformers. I contacted MTH as well as J and W Electronics. MTH Parts brought a circuit board from a RailKing Southern Ps-4 to York, and Wayne Renga (J and W) installed it. Now I can use newer transformers that produce "pure" sine wave AC. Other transformers produce "chopped" sine wave AC. QSI products are designed for Lionel Electrical Operating Standards [postwar transformers]. "Chopped" sine wave AC will damage or destroy them, though they may run at first.

PS-2, designed by MTH for DCS [command control], superseded PS-1.

The term "PS-1" was coined [here on the Forum, I think] to identify these earlier systems after PS-2 was introduced. "PS-1" was not printed on MTH boxes. "ProtoSound by QSI" was.

Protosound features were accessed by turning track voltage up and down [but not off]. That seems tedious now. But back then it was state of the art. As GGG posted, locomotives could be assigned their own ID, then another ID for multiple-unit consists. They could run independently of other locomotives that would not start until they were "called." MTH added a PROGRAM button to Z-4000 transformers to make that process easier and faster.

QSI and PS-1 systems are designed for conventional operation. But they incorporate many features of command control.

Dear gentlemen

Thank you for the information this exactly what I was looking for on this topic. Thank you for the quick education and time line for the QSI (PS-1) and PS-2.