2. amps-preamps
  3. 134861-2089

Moving from 120 VAC to 220 VAC operation on Krell monoblocks



Just read an interesting article from MBL regarding audio benefits for operating power amplifier at 220 VAC on dedicated electrical circuit. http://www.msbtechnology.com/faq/how-to-wire-your-house-for-good-power/
 
Also read on the Gon that Dan d’Agostino has voiced the sound of the FPB amp series by operating them at 220 VAC. 

I currently own a pair of Krell FPB-350 MCX monoblocks which operate on 120 VAC dedicated circuits (14 gauge wire). Contacted Krell and they indicated dip switch positions for operating the amps on 220 VAC. The MBL paper suggests to wire 220 VAC dedicated circuit using 10 gauge wire to reduce electrical noise and amplifier modulation of electrical circuit.

While the theory seem to be valid and before rewiring my dedicated circuits, I would like to have some Krell amp owners comment on the benefit of going to 220 VAC operation for those who have performed the mod.


128x128dasign
dasign's avatar
dasign OP
201 posts
 
Hi Chris,

You're my favorite philisopher :-)

*****************
The Canadiens are in hockey hell rigth now...

Daniel
msalvatore
5 posts
 
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
dasign's avatar
dasign OP
201 posts
 
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
dasign's avatar
dasign OP
201 posts
 
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.
dasign's avatar
dasign OP
201 posts
 
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
More to discover