One comment on that -- it could be anything from a HP unit circa 1950 onward. For instance if you're hearing this between 1K and 10K, that's because most oscillators had a switch for 1x, 10x, 100x of a frequency that was dialed in on the rotary control. Function generators were typically push-button and 1x, 10x, 100x was standard. Recording consoles and tape decks like the Technics RS-1520 or the Otari MX5050 (at least the 4track version I have) had switches for 1K, 10K tones (rotary on a Technics, pushbutton on an Otari). I've seen recording consoles with pushbuttons for 100, 1K and 10K and other tones. Older-school studios just used an external oscillator plugged into a slate input. Basically, the way I've always operated was never to set speed/pitch from slate tones. If you're lucky they'll give you an accurate 0-VU level and that's about it. Again, if you're lucky, you can use a scope and set azimuth from them (that's assuming they were recorded just before the program content was recorded, on the same deck, and the deck was azimuth-aligned differently between tones and program content -- not always the case). -- Tom Fine ----- Original Message ----- From: "Jim Sam" <[log in to unmask]> To: <[log in to unmask]> Sent: Thursday, January 27, 2011 1:58 PM Subject: Re: [ARSCLIST] Test tones circa 1978 I should add that I'm interested in this due to tape that was recorded at 7.5 ips, 250 nWb/m. The tone sequence is not standard, with tones changing abruptly as if a button was pressed, rather than a dial rotated. On Thu, Jan 27, 2011 at 10:40 AM, Jim Sam <[log in to unmask]> wrote: > All, > > Does anyone know how much test tone generators varied circa 1978? > > I know not to expect digital accuracy. For example, I would not > expect a 10.00 kHz tone, but how much leeway was there? +/- 0.25kHz, > +/-0.5 kHz, +/-1.0 kHz, etc.? > > Thanks, > Jim >