DT990 600OHM (EX-) Owners Please Advice On DAC/Amp - Page 2

Originally Posted by Tyll Hertsens 


Basically a hybrid amp is one that seeks to gain the benefits of solid state designs with the benefits of tube designs. Solid state circuitry has the adantage of being more linear (less distortion) and better able to do a wide variety of functions at a lower circuit cost. For example a simple op-amp chip might take 5 or more tubes to accomplish the same thing, so a solid state amp could have a variety of tone controls, cross-feed circuits, balance and volume controls and still be relatively cheap to buy parts for and assemble. A tube amp has euphonic (plesant sounding) distortion that is very hard to replicate in a solid state design, but if a comlplex amp (one with tone controls, cross-feed, etc) is done with all tubes it would be expensive and it might have so much distortion contribution from so many tubes that it ends up being a mushy murk of sound. Following the above logic, it might make sense to build an amp that is a hybrid of solid state front end features with a lush tube output.

But, "hybrid" doesn't mean anything in particular in terms of circuit design. It just means that is a mix of two distinct ways of doing things with the intention of getting a bit of the best of both worlds. A Millet Hybrid has solid state front-end features and solid state linear output, with a tube stage stuck inbetween the front and back to lush up the signal. Pete Millett discovered a certain tube type that could run of voltages that are normally used for solid state electronics (+/-15V) and thought, "Hey, I can stick a couple of these handly little tubes in a solid state amp without having to build additional power supply circuits needed for the plate and filament voltages needed by most tubes." And Voila! a hybrid design. While it wouldn't be improper to call an amp with a solid state power supply with tube audio electronics a hybrid, it doesn't seem to me that the two are "mixed" intimately enough to call it that. But it wouldn't surprise me to find someone who would.