Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!linus!decvax!microsof!uw-beaver!tektronix!tekid!tekig1!gregr From: gregr@tekig1.UUCP Newsgroups: net.audio Subject: Re: How my ears are built (and a question) A reply Message-ID: <1192@tekig1.UUCP> Date: Wed, 6-Jul-83 19:10:36 EDT Article-I.D.: tekig1.1192 Posted: Wed Jul 6 19:10:36 1983 Date-Received: Fri, 8-Jul-83 09:46:48 EDT References: <1211@tektronix.UUCP>, <618@hou5e.UUCP> Lines: 51 You asked why various high end preamps sound different when auditioning them with a phono cartridge at an audio solon...? The answer to this question has been explained very well over the years in audio publications (Audio, others). The major difference is in the way the preamp loads the cartridge. Preamps have widely varying input capacitances which moving magnet cartridges are very sensitive to. (Other complex loading problems also exist and RIAA equalization errors are possible but these are second order effects in well designed and usually expensive preamps.) It is ABSOLUTELY necessary to adjust the input C for each preamp tested to be the same as all others being tested. Since most preamps allow no adjustment or only very coarse adjustments (100 pf steps or so) this must be done with add-on capacitors either internally (best) or externally (rather poor). Different cartridges have different sensitivities to C variations. (I suspect this explains the tendency for subjective reviewers to proclaim that one cartridge is better than another because it allows differences between preamps to be heard. In fact there probably is no correlation between C sensitivity and sound quality.) Notice that we are comparing preamps here and adjusting for equal C for each preamp with ONE cartridge. If the object is to compare cartridges we should use ONE preamp but adjust it for different C values for each cartridge tested. Again this is ABSOLUTELY necessary because each cartridge produces its optimal performance with a particular capacitive load. (This easily explains why certain cartridge-preamp combinations sound better than others.) Also note another related problem due to capacitance. If tonearms (or integrated tonearm-turntable combinations) are to be compared they will have widely varying cable capacitances depending on length and cable type. Therefore to compare tonearms the capacitances must be made equal, but to compare cartridge-tonearm combinations the C values should be optimized for the particular cartridge used. If you think this sounds like a lot of effort to compare differences in the way components sound --- your right! Accurate comparisons between components is virtually impossible in a store regardless of how friendly the salesman is. Notice that I'm not even talking about scientific testing i.e. double-blind controlled statistical testing. Even if you are a "golden eared audiophile with perfect sensory memory and nothing to prove" you still can't make valid tests when you overlook (re don't understand) how components work and their sensitivities. Oh yes, do cartridges and speakers sound differently? Of course, they are electromechanical with widely varying designs and measureable performance differences. Do preamps sound differently? After very time consuming, controlled testing I believe so. But very subtle differencs when testing problems like above are corrected. The problems, defects, and variations of the electromechanical elements will mask virtually all of these differences when the preamp setup is correct. Equalizers however are a completely different story .....