[bapcha]

Quoting from the Bryston Cubed series brochure

"Quad-Complementary topology improves linearity
to a new standard of accuracy while virtually
eliminating aggressive higher harmonic distortion
byproducts. Quad Complementary eliminates
crossover distortion by improving transistor
matching and reduces capacitance in the output
stage by a factor of four which improves transient
response and bandwidth"

The topology described above has been used in integrated circuits since the 1960's. It is referred to as a "common centroid layout" - and the reasons for its use are the same as stated above (and other factors like process variations). I am not putting down Bryston's efforts (I have been a loyal customer since 1994)

Has anyone else here compared the SST line with the Cubed line of amps?

Thanks!
Bapcha

[James Tanner]

Thanks for your email.

Although the description of Quad Complementary sounds similar to the common centroid layout, the latter is a process used in integrated circuit op-amps in their differential input stages to gain better matching and sometimes lower capacitance.

It has to do with geometry and generally does not refer to complementary pairs. It was first used in around 1971, I believe. It also normally is used in MOSFET input stages.

I have not seen the use of Quad Complementary output stages, either before or since Bryston pioneered it, in any other products.

Thanks for your interest, and for your loyal support for over 20 years!

Best regards,
Chris Russell
Bryston Ltd.

[CanadianMaestro]

Didn't Bryston earn a patent for the Quad C ?
If so, that is solid proof that it was not previously used in other gear.
 

[bapcha]

It is not that hard to get circuit design patents. If a circuit design is both elegant and effective, variants will be sold 50 plus years after the fact. Case in point is Dave Fullagar's 741 op amp.....

Most circuits are not unique, but a variant/a variation on an existing theme

Bapcha

[CanadianMaestro]

If the Quad-C presents a significant advancement (in SQ etc) over past designs, that's likely good enough.