Now I would love to connect the notebook's headphone socket to an old "PHILIPS SOUND PROJECT ZU7 66 RH 891 Stereodecoder" Hi-Fi set (looks like this one: http://www.busby.co.uk/public/images/sa ... 018/68.JPG). These old high-quality Hi-Fi sets are frequently being thrown away or sold for a few dollars, probably because people don't know how to connect their modern devices to them.
The only way of getting external audio into this machine is an old socket labelled "TAPE". You can see it on the left side of this: https://www.radiomuseum.org/images/radi ... 672903.jpg foto. I have identified this as being a 5/180° DIN connector socket (see https://en.wikipedia.org/wiki/DIN_conne ... alog_audio).
Marginal note I: I'm not quite sure why the socket is for five pins. Maybe the Hi-Fi set features both "tape in" and "tape out". I wouldn't know what the fifth pin is any good for, however. https://en.wikipedia.org/wiki/DIN_conne ... alog_audio mentions "Screen/return" as a function for pin #2. I have no idea what this is supposed to be.
Marginal note II: As far as the connection cable quality is concerned, I've heard that it's important to use a "balanced audio" quality whenever possible.
Anyway, my main question is: How can I safely connect the notebook's headphone socket to the Hi-Fi set's "TAPE" socket?
AFAIK "headphone outputs" provide a lot more power than expected by any "tape in", and the impedance is be wrong. (I'm assuming that "tape in" is the same as "line in". Please correct me if I'm wrong.) To my knowledge, these old machines don't like receiving too much power and the wrong impedance and have a tendency to get broken if they do.
My impression is that there might only be two ways of achieving the adjustment needed:
- Use something similar to the Automatic volume limiter system (AVLS) that can be found in some headphones. Seems that in the professional audio world there are systems called "Direct Input units" ("DI units", cf. https://en.wikipedia.org/wiki/DI_unit) that might do the job. Don't know if that is exactly what would be needed - does anyone know? An example for a DI unit is the "ZDirect Professional Passive Direct Box" by U.S. company ART (http://www.artproaudio.com/product/zdir ... irect-box/).
- Let the operating system (MX-17.1) tell the notebook's sound D/A converter never to exceed a certain amperage, and/or voltage, and never to go below a certain impedance. Don't know if MX-17.1 can talk directly to the D/A converter in order to achieve that.
Any input on this topic will be greatly appreciated.