I have no idea but I found this looking for specs.
The 355 was introduced as a more versatile replacement for the older 399; as such, it was the only Stereo Preamp-Tuner product ever produced by Scott.
As a Tuner/Preamp (similar to the older 331-series) the 355 had no basic power amplifier section like the 399 Receiver. Instead the 355 provided a cathode follower, line-level, preamp out --
Just add the basic power amp of your choice, usually a Scott Type 208, but Mac's and Dyna's were also popular choices.
The 355 added true FM-MPX stereo reception utilizing the 350/335 decoder design, incorporating the "Stereo Guide," 6AV6 tube indicator.
As "Simulcast Stereo" was becoming obsolete, the 355 was the only Scott AM/FM tuner to share a (very rare) common circular tuning dial. Scott engineers cleverly resurrected the 300/320 tuning gang, but thankfully left the more complex dial-cord string and slide-rule dial inventory untouched.
To accommodate a matching power amp;
Scott offered the optional, 208 Power Amp; a modular piggy-back, design derived from the 7591-based 299-C amp. All audio connections, accessory AC, and antenna jacks were top-mounted on the shortened chassis, to facilitate the matching 208 "piggy-back" package.
6-tube, Pre-Amplifier section:
(4) 12AX7 - preamps
(1) 12AU7 - cathode follower
(1) 6CA4 rectifier
5-tube, FM Tuner section:
(1) 6BS8/6BQ7 - FM RF amp
(1) 6U8A FM mixer
(3) 6AU6 (shared w/AM)
5-tube, MPX section
(1) 6AV6 (6GX8) ("Stereo Guide")
(1) 6BL8 - MPX
(2) 12AU7 - MPX
(1) 12AT7 - MPX
2-tube, AM Tuner section:
(1) 6BA6 AM RF Amp