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Adcom GFA-535 ii listening review or: Never meet your heroes


Active Member
Feb 21, 2021
I take it you didn’t document this experiment? Because there‘s a paucity of documented tests replicating your results. If you heard a difference under properly controlled circumstances it was likely obvious in the measurements (e.g. huge variance in impedance matching, frequency response, distortion or output).

Sorry, no. Other than I bought an amp that - over repeated trials, I statistically preferred more than others. It could measure worse or different. I don't know. I could just pick it out reliably. I wasn't trying to prove anything other than that I would only be willing to buy something that I could reliably discriminate (and prefer) from other things. Otherwise just buy the least expensive. And the one I bought was one of the least expensive. And I wasn't trying to prove anything with my post (I am entirely on board on using objective measures) other than some amps do sound different from others - for all sorts of objective reasons - and I didn't have a test bench more much else besides a SPL meter, so double blind listening with repetitions was the only way to make any decisions besides price. As one poster said, amps can sound different for all sorts of reasons - all measurable - and they do interact with preamp output, speaker impedances etc. so one can either model it all with an appropriate array of measurements or, failing that, do careful double blind listening with matched loudness and many repeats of every condition. Then analyze the data. I think you took me wrong in trying to claim magic subjective differences. I entirely agree it was in the measurements - I just didn't have a way to make them and they weren't readily available (pre-internet, etc.) I have no idea if modern solid state amps vary much from one another or not - the debate seems to continue as to whether some measurement differences manifest as audible differences or not. In such cases, good double blind, otherwise matched listening experiments might be the answer. Maybe we need someone Amir to set up a lab for that sort of testing - but it would require having people send in multiple pieces of equipment to compare. So 1) get measurements; 2) test whether they matter (sometimes it will be obvious, but other times, we would need to test). Cheers!
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