Some designs without output transformers ( OTLs ) were produced by Julius Futterman in the 1960s and'70s, and more recently in different embodiments by others.
32.
The Williamson amplifier was of symmetric push-pull design and used negative feedback and a specially designed output transformer to produce lower levels of distortion than previous designs.
33.
When the original Marshalls came to the U . S ., Unicord's engineers were concerned that the output transformers could not reliably handle the full output.
34.
The 1?5 Vibrasonic, like the 4?0 Concert-Amp, featured a larger interleaved output transformer designed to minimize distortion and maximize clean headroom in the output stage.
35.
Solid state designs can be manufactured without output transformers and are therefore immune to speaker-dependent impedance mismatches and other transformer effects which alter the system spectral response.
36.
Vacuum tube push pull amplifiers usually use an output transformer, although class A ( i . e . neither device is driven to its non-conducting state ).
37.
The main problem with these designs is constructing output transformers able to sustain the plate current and resultant flux density without core saturation over the full audio-frequency spectrum.
38.
From early on his career, beginning in 1979, Vaughan received technical assistance from C�sar D�az, who began by replacing and tweaking the output transformers on his amplifiers.
39.
The isolation that could be created by each transformer is defeated by always having one leg of the transformers grounded, on both sides of the input and output transformer coils.
40.
Introduced in the Mark II-B was the Simul-Class power amplifier stage, which combined tubes running in class A and class AB through the same output transformer.
