In Reply to: This is too good not to share to share with your buds. posted by Michael Samra on April 14, 2017 at 23:58:57:
In 1999, Sony developed their reference CD/SACD player SCD-1. Here is how the audio amplifier of this machine looks like:
Balanced audio voltage signal converted to unbalanced by mix op-amp. Mixed signal amplified by two op-amp voltage stages, followed by two op-amp line amplifier stages, followed by discrete transistor buffer, providing RCA output of 2 Vrms at 600 Ohms. For XLR output, this unbalanced signal is converted into balanced by yet another op-amp stage. The signal path from DAC to XLR goes through 6 op-amps with the total open loop gain of 1,400 (!) dB, for 12 dB of closed loop gain. Everything is DC-coupled so as to avoid capacitors in the signal path, but it ends up with electrolytic caps to XLR outputs.
Surprisingly, it sounds pretty good. It sounds even better though if the whole thing is replaced with a single differential stage using two tubes and a line output transformer.
This post is made possible by the generous support of people like you and our sponsors:
Follow Ups
- Another EE joke - sser2 12:02:00 04/15/17 (3)
- RE: Another EE joke - Michael Samra 16:49:04 04/15/17 (0)
- RE: Another EE joke - Triode_Kingdom 15:02:35 04/15/17 (1)
- RE: Another EE joke - Michael Samra 16:51:18 04/15/17 (0)