Findings and short facts
  Here are some useful facts I discovered during the testing of my ES components. The full list of my ES components can be found here.
 
:: Bi-amping with two N55ES amps sounds much better than only one N55ES (mind you, those JBL Ti 5000 take a lot of power to drive correctly).
:: 2xN55ES in mono mode for LF and one N55 in stereo mode for HF did not give such good results. I guess mono mode sounds harsher than stereo.
:: There were 3 versions of the N55ES (AEP, for German market) - I describe my findings chronologically:
1.
7-digit s/n - 450XXXX, silver input jacks, cylindrical ES transformer (same as in N80ES),
2.
7-digit s/n - 450XXXX, gold-plated input jacks, cylindrical ES transformer (same as in N80ES),
3.
6-digit s/n - 50XXXX, gold-plated input jacks, square transformer.
:: 2xN80ES in stereo (bi-amp) mode provides the same results as a single N80. One N80 sounds much better than two N55 in mono-mode.
:: TA-E1000ESD preamp, despite having two digital processors, sounds very natural and is a bit noisier than the TA-E80ES using balanced connections.
:: TA-E80ES has better power distribution - it seems that the frequency response compared with TA-E1000ESD is very good at low volume.
:: TA-E80ES uses a different IR remote control code for volume control than do other Sony amplifiers.
:: SDP-EP9ES uses a different IR remote control code for volume control than do other Sony amplifiers.