Krell 700cx, and Tara cobalt A/C power cord.

Hi Audiolabryinth ,

I thought I'd share with you my experience using an aftermarket power cord with my Krell FPB300cx. As you know, the Krell CX line comes with a captive power cord set-up. Purely out of inquisitiveness, I cut the wall plug off the 300cx's captive cord and rewired a male C15 IEC adaptor to the end of the 300cx's captive cord (still keeping the same length of the captive cord - in case I needed to re-install the wall plug back). I then plugged in my Shunyata Research King Cobra CX (which is terminated with a C15 male IEC adaptor) into the Krell's captive cord.

To me, the improvements were so "significant" that I have been running this set-up for the last three years. In my experience, the improvements were across the frequency spectrum - even more low end slam (yes, even for a Krell!), smoother mid-range and highs. However, I would say the most significant improvement was a subjective "opening up" of this fine amplifier to become (finally) unrestrained! The translated effect of this was a more "holographic" soundstage (in my listening room). With the Shunyata King Cobra CX, the 300cx now "breathes" more freely and has a feeling of unreserved power - I feel just as a Krell should be!

I should also mention that I did some extended trialling of several other after market power cords on the 300cx (all of which I also own) including a Wireworld Aurora, PS Audio Statement (the original version) and a Shunyata Anaconda CX.

Of all these, the most synergistic match (for my system) was the Shunyata King Cobra CX on the Krell. Each of the fore mentioned power cords made a noticeable difference to the sound of the 300cx (and in all cases were an improvement over plugging in the 300CX's captive cord directly into the wall socket).

Given your 700CX's power draw, if you ever decide to experiment by wiring a male IEC adaptor into your captive cord, (the usual disclaimers/caveats apply - that it's at your own risk and that you understand wiring for correct polarity, etc.) I would strongly suggest a C19 IEC adaptor (which is a 30A high current version) and an equivalent high-current terminated aftermarket power cord of your choice.

I would be interested to hear your (or any other A’gon member’s experiences) if you ever decide to take this route on a Krell FPB series amp (with a captive power cord)!

All the best!

There are a couple of corrections I wish to make in my post above: What I meant to say was "...and rewired a "male" C15 IEC adaptor to the end of the 300cx's captive cord...I then plugged in my Shunyata Research King Cobra CX (which is terminated with a C15 "female" IEC adaptor) into the Krell's captive cord.".

Also, It doesn't appear that C19 IEC adapters are easily found in 30A versions, but there are 250VAC 20A versions available.

Audiolabyrinth, as you stated, my original preference was installing an IEC socket on the back of the 300CX, but the (metal) work involved in just cutting out the opening was beyond the tools I had on hand (the rear panel is about ¼ in thick)! The other alternative I considered is getting a back panel off an old FPB300, which has an IEC socket, but there are some panel layout differences, as my 300CX has cast inputs, etc. It was much easier to just wire in a male IEC socket to the end of the captive cord – just to see if there was a material and beneficial difference to the sound.

What I can’t explain (and will not attempt to) is my experience of the improvements brought by using a (suitable – i.e. Shunyata Anaconda CX in my case) aftermarket cord “in-between” the wall and the 300CX’s captive cord (regardless of knowledge to the contrary). In my system and room, the improvements were not subtle and outweighed any drawbacks of the additional length of running the 9ft (?) captive cord plugged into a 6ft. aftermarket cord. Hence my interest to see if anyone else with a captive corded FPB would find similar results by replicating what I did.

I should probably also mention that the wall socket I plug the 300CX (and my other audio equipment) into are PS Audio Power Point Premiers with an Oyaide WPC-Z Carbon Fiber faceplate and aluminium frame, connected directly to an isolated circuit breaker with high current, shielded in-wall wiring between the power socket and the fuse box. I’ve also got three-phase power in my house, with one phase purely dedicated to my music room. You would not think that these things make a difference (and perhaps not everyone may hear an improvement), but my experience is that they are cumulative and have (specifically) taken the sound of my Krell FPB300CX to another level! (I do have another standard wall socket next to the Power Point Premiers, connected to the same point in the fuse box, where I can easily plug in and hear the changes). Hope this gives you a bit more insight into my audio journey with the Krell FPB - Happy Listening!