Jeff Rowland amp in unbalanced mode

Mordante - once it has input transformer it is truly balanced. Transformer has perfect common mode removal except for high frequencies where balanced input is defenseless anyway. To answer your question - Icepower datasheet for 200ASC (my Rowland 102) shows balanced input and I can see transformer inside on separate board.

Icepower switching frequency is too low (0.5MHz) to radiate and sharp switching pulses are filtered out by the output filter but nothing is 100% perfect and in addition there is still capacitive coupling. I would use common sense and for device that switches high currents at high speed I would use balanced cables with good shielding. My Rowland 102 does not even have unbalanced input - I respect Rowland's decision.

Kijanki, you hit the nail on the head, that is the exact reason for my question: the 201 hasn't got unbalanced inputs either, whereas I would like to use it with a pre-amp that has only unbalanced outputs. Nevertheless Rowland's manual mentions that unbalanced operation is possible with an adapter, so I am curious to find out if someone has tried this. Btw, thanks a lot for the link, Bob.

I can confirm that current JRDG amps are fully balanced in the input as well as in the output stages. According to Jeff Rowland, his amps put out an active signal on both positive and negative speaker terminals.

Hi Kijanki, have you considered adding a JRDG PC1 Power Factor Correction unit to feed your 102? I have heard that it is designed to enhance significantly its performance, but have not heard directly from anyone who has tried the PC1 on either 102, 201, or 501. PFC is already built into the Continuum 500 integrated, and the 312 amp. Guido

Guidocorona - There are two styles of class D output. One, like Icepower, uses single supply voltage and changes direction using mosfet full-bridge while the other style, like Hypex (Channel Island) uses two voltages positive and negative with mosfet half-bridge. First style sounds a little closer to tubes (even harmonics) but has half of supply voltage (DC) on both output terminals (doesn't bother me). Also bridging amps is not possible since it is already full bridge output. My small 102 has the highest bandwidth of the tree you mentioned and I don't listen very loud. I read your other posts on the PC1 and since you mentioned that my 102 is "eligible" I'm very interested. I have to upgrade speakers first (major expense) then I'll move to power supply. I'm sceptic about things like that, but I remember that at the beginning I was sceptic about interconnects and speaker cables - not anymore. Keep us informed! Is it expensive? I read review (AudioEnz) of 102/Capri and while Capri is better of two (exceptional) 102 is not bad, especially for the price.

Hi Kijanki, I looked for the Capri/102 review by Audioenz but could not find it. . . could you post the URL?
The PC1 is unfortunately not inexpensive, at $1500 list, but some dealers have sometimes offered a demo unit for quite a bit less. One good thing about it is that if you ever upgraded to 201 monos or 501 monos, the PC1 would serve there as well. Guido