Parasound JC1's vs. Sim Audio W10

Cadougie - there are a couple of reliability things that could use improvement, mostly in older used JC-1's. Parasound is aware of these and some of these have been improved in the newer versions. I'm surprised that you had problems with a recent amp - perhaps it was from an older build lot.

I resolder all of the power transistor solder joints because some of these are not good in the older amps. The open-frame pots used for the bias adjustment seem to drift (or the other components drift), and finally, the inrush limiters do not have a lot of margin, so I use higher current versions. Once these things are changed, it is a very robust amp. I have had mine for several years and use it every day.

Dennis - I have had and still own some NGF (no global feedback) amps, the CODA's. They are very sweet on the highs, but the JC-1's left them in the dust for detail, particularly with mods. The new Coda's are definitely better, because they are using better parts now (I heard them at CES). However, the Bass control of the JC-1's is hard to beat. NGF designs will never be capable of this. You really need NGF to get bass control and pristine, sweet highs are possible with it as well.

Sean - I used to have the same opinion about amps with global negative feedback. This is why I own amps such as the CODA's. I still like them, but I found that it is possible to get the same speed, liquidity, focus and air of these non-feedback amps by doing the right mods to well-designed amps with feedback, namely the JC-1's and the HCA3500. And you get the added bonus of great bass control due to the feedback, which results in extremely low output impedance.