Moving from 120 VAC to 220 VAC operation on Krell monoblocks

I have a pair of Krell amps and I am running them at 240v. Had a pair of 12/3 240v 20A cables made. If nothing else it is cheaper to run. 222 is the switch configuration for 240v

Thank msalvatore for your input. Did you run your amps on 120 VAC/60 Hz initially? What were the improvements moving from 120 VAC to 240 VAC? Also you indicate that your switch configuration was 222. On which model of Krell amps?

I have contacted Krell and they say my switch combination is 122 for 220 VAC (previously was 212 for 120 VAC).

Daniel

Contacted Krell again and the setting for 240 VAC is 222. Thank you msalvatore for pointing out your settings. These seems to be specific settings for 220 VAC and 240 VAC. I initially asked the wrong voltage setting to Krell (220VAC). Special thanks to Mr. Bresnahan from Krell who was very supportive in answering these issues.

Just finished installing the 10 gauge dedicated circuits. This wire is a bear to work with. I used a core solid copper NMWU 10/2 (black sheeted cable). This cable is so stiff that it was trying to get out of the Furutech GTX-D (R) wire clamping system, when pulling/pushing the receptacle into the receptacle electrical box. Good thing I replaced the 2.5 inch receptacle electrical box for 3 inchers to allow proper wire slack length. Working on the main electrical panel was a breeze. I had my 240 VAC at the receptacles by the end of the day.

Today, I will need to modify the Krell for 240 VAC operation, cleanup the room and sit down with a nice cold beer. I will keep you posted on the results of all this work.

Daniel

I have configured  the Krell amps for 240 VAC operation but unfortunately the left monoblock amp did not have its stanby LED lit upon initial powering, while the right amp was behaving correctly. Krell amps have a breaker in the back to power the unit in stanby mode. If you want to listen to your system, you then need to power the front button. I did not push the front power button of the left monoblock to avoid potential disaster.

I had exactly 243 VAC at the output of both power cables. 240 VAC was entering both amps. Reconfigured power dip switches and put the power back to 120 VAC and both amps were working fine. Reconfigured for an operation to 240 VAC and still have the same issue on the left monoblock. Tried to power the left monoblock using the right channel dedicated power circuit and still had the same issue. In all likeliness, I have an amp which will not power up at 240 V...

Put everything back to 120 V and I can notice the improvements feeding power to the amps using 10 gauge wiring. First, the bass is massive compared to my original setup using 14 gauge. There is a level of noise/grunge which was previously unoticable on original setup that is now gone with newer setup. I also noticed an increase of ´thereness’. Recordings with massive orchestration have better instrument deliniation. Soundstage has expanded in width and depth.

Overall I am very happy with the end results using dedicted circuits with 10 gauge/120 VAC and could happily live with it, but somewhat disappointed that one of the Krell is not working at 240 VAC...I will contact Krell to do some basic troubleshooting and see if we can get things going. My guess is that there an issue with the power up/processing board at 240 VAC. 

Daniel