I have been working on my near vintage dream system for about 12 years now .The one that I could not afford at the time.You know the drill.
2 each 200c signature amps SN#0710 and 0711, silver face,with warning labels, one was marked high ,one low. Not factory labels.The only difference I can see is one has black rack handles,the other has bronze rack handles? Question?, any reason to believe there is any internal differences and are these early or late in the production cycle?Units do have a little relay noise, but not enough to be an issue They are working great.
1 each PS Audio 5.5 Preamp with external power supply.Question?Would I use the AC or the DC inputs at the amp??? and why? Any simple way to test before hookup?
I am currently using a SoundStream C-1 preamp at the AC inputs with a GCPH phono and DPL3 /stage 4 dac, Things are working fine.
(I did have an issue with a Bryston preamp in the wrong input and I don’t want to repeat that, but I can’t recall ac/or dc inputs?
I recently restored a PS Audio 5.5 Preamp (really love that thing - it’s my main source now) and think I have an answer.
Nearly ALL power amps have a capacitor-coupled input stage which protects the amps and speakers from excessive DC Offset from upstream. I think PS Audio added the DC feature without this coupling to create a “purist” option, expecting a low/no offset calibrated preamp would be connected to it, therefore delivering a “pure” signal path.
The 5.5 has a user calibratable DC offset adjustment at the end of the phono stage so I believe they designed the 200c for a pairing like this since they are contemporary units. To adjust the offset, simply take the lid off, short the phono inputs and in straight wire mode put a sensitive DC voltmeter on the output and adjust the trimmer pot for each channel to 0 VDC. That’s it.
That said, this is a feature in pursuit of perfection at the cost of safety, so be careful as if your sources aren’t perfectly calibrated you could blow up your amp, speakers or both! Even with my tuned 5.5 I would use the AC inputs.On the other hand, you only live once!!