MCH-K38 front panel buttons and LED lights

The buttons on the front panel are toggle on/off switch. 

Power button:  Red means Standby and Green means power on.  No Light means AC power switch off.

Channel 1 ~ 8, Red light means the source is set to XLR and Green means the source is set to RCA.  No Light means the channel is turn off.

The light in between 1 & 2, 3 & 4, 5 & 6, and 7 & 8 are Mono indicators.  Red light also means the source is set to XLR and Green means the source is set to RCA.  No Light means the channel is turn off.  The mono channel can be toggled on/off with channel 2, 4, 6, & 8. 

Please make sure to press the buttons to turn on the channels.  Since our stereo lights are very small LED on the button top, so it might be easy to miss if its put inside the rack.

Where can I find a Turn-On trigger cable for MCH-K38

It is not included as an accessory. If you need it, please contact your distributor or dealer. You can't use any generic 12V trigger cable.

What some of the amps have the same power rating at 8 and 4 Ohms ?

There is two side to a coin. The truth is that the amp is capable of more power than the spec suggested. So if 4 and 8 Ohms are specified at 100Wx2, that means the power supply is a 200W PSU. And we are extremely conservative about our power rating (we provide conservative RMS rating, not peak power). A customer reported 180W for IDA-8 because he is using just one channel to do the measurement. So, if IDA-8 is in a bigger case, and we put in a 300W PSU, you will see a higher rating. In reality, you get more than 100W per channel from the 200W PSU, because not both channels are driven at the same time.

Why don't we put in a bigger PSU? Each model is designed for specific product position and adding more power will certainly increase the cost and size of the product.

Can the amplifier's speaker terminals be used as source inputs (e.g. to REL Subwoofer) ?

In some applications, the speaker outputs from the power amplifier are used as source signals for devices such as REL sub woofer. For such application, usually the receiving devices should have DC offset blocking capability because some amplifier by design has floating ground (DC offset) on the speaker outputs. 

The following models have no DC offset on the amplifier speaker outputs and the negative terminal is also the ground:

NuPrime STA-9, MCH-K38, IDA-16

The following models' speaker outputs can not be connected directly to sub woofer input:

NuPrime Reference 20, ST-10, IDA-8