CSvax:Pucc-H:ad0@pur-ee.UUCP (09/26/83)
A few years ago I purchased an HY400 power amp from Gladstone Electronics. This is their bipolar amplifier module. Delivery time was very reasonable, as was price ($99.95). I have been using it for part of a sound reinforcement system for a rock band, and have had no complaints with it. It requires a +/- 45 v power supply to operate. Specs: (as listed by the mfg.) Output : 240 watts into 4 ohms Total harmonic distortion at 20 Hz .01% at 1 KHz .01% at 20 Khz .09% S/N ratio better than 100db Freq. resp. (-3db) 15 Hz to 50 KHz They also make lower power amps, and since I bought mine they have come out with similar FET amplifiers. Also, two HY400 can be bridged together for 480 watts of power. Please forgive if this sounds like an advertisement. I have no affiliation with this company whatsoever; I just thought these amps worth mentioning. Andrew J. Thomas ...pucc-h!ad0
emrath@uiuccsb.UUCP (09/27/83)
#R:pucc-h:-30900:uiuccsb:5700012:000:760 uiuccsb!emrath Sep 27 02:39:00 1983 I'm a tad skeptical about that 240W rating (into 4 ohms) from a +/-45V supply. To get 240W rms into 4 ohms, you need 43.8 Volts (and 10.95 Amps) 0-peak at the output. Even assuming you could get a +/-45V supply to do this, I doubt very much that the output stage could deliver something like 10 amps with only 1 volt drop. I realize that this was a manufacturer spec, but did it say that you can run these at higher than 45V, in fact must, in order to get the 240W? The 480W output from a bridged setup is more plausible, since if an amplifier is voltage supply limited (not current supply limited and not thermal limited), then two amps bridged will put out four times the power of a single amp. For that, your supplies would have to put out 15.5 Amps peak.
ray@utcsrgv.UUCP (Raymond Allen) (09/29/83)
Actually, although I don't know what is inside an HY400, it is possible for a common-collector output stage (the kind usually used in power amps) to swing to within ~0.7 volt of either supply voltage. This is assuming that whatever is driving the output stage can provide a driving voltage that, itself, can swing to either supply voltage. Ray Allen utcsrgv!ray (416) 978-5036