Power Conditioner - Denafrips BIC500

Since 2016, an Equitech 1RQ (1000VA) Isolation transformer was used for whole system power conditioning. When the whole system moved to downstairs, the dedicated lines weren't installed, so the Equitech was used locally plugged into the wall.

With transformers, the amplifiers see the impedance on the windings, in this case 53 Ohms. People have argued that transformers restrict dynamics, and this relatively high impedance is one of the reasons. So to overcome this issue, the pre-amp and power amps are connected directly to the wall (until a dedicated line can be installed, just one of those other jobs 'to do').  A dedicated line has the impedance of the AC mains network which should be less by a factor of 10 compared with the transformer, so dynamics are certainly restored, can vouch for that.

The main issue with the Equitech, used locally, it transfers the harmonics from the load to the primary where it creates an annoying buzz. On no load, it's quiet, but after 12 hours or so on load it creates that hum, with the rattle or to U2, rattle and hum, either is distracting!

By chance, was looking at the Denafrips site, and way down the back of the pages is a model BIC500EU or US. This device is also a balanced output transformer (115-0-115) for 230V mains input, or 60-0-60 V for 120V systems. Denafrips only offer one model at 500VA which is plenty for source components. I agreed with the dealer that the transformer would not be suitable for the amps, so they remained plugged into the wall for now.

Description

Nothing much inside apart from the transformer, a small PCB which as a line iron cored choked with about 15 turns of Phase and neutral windings. There's a 0.1uF cap, VDR and suppression device for protection against high surge voltages, but not lightning. Outlets for EU use are four Furutech gold plated outlets (receptacles). Iknow they are since I bought the same ones for another project. and I guess also a Furutech line input jack which is shiny metal silver colour, so not gold. No on off switch or meter, that's it. Weight is 6kg 13lbs. Checked the wiring, seems to be in regulation, the output centre tap is earthed.  Output voltage symmetry is not bad at all, only varying by a few hundred millivolts (if the mains kept still it would be easier to measure).

Price: USD779, you go no wrong here with the price.

Audio performance

With AC power, the topology of the system plays an important role and trying to fit a conditioner in is somewhat tricky. Begone are power conditioners with chokes and caps, like from Furman. Monster, they don't fit audio, but certainly use them for IT equipment, printers, computers and so on.  The BIC500 only supplies source components, these are listed in my profile, but essentially:

SACD player

DAC

Lumin U1 (using the AES3 to the DAC)

FM radio

DAB+, Internet radio

Turntable

AC Power cables: Furutech Nanoflex 18

Out of the box, vocals have air around them, and placement doesn't drift. This is from the Travelling Wilburys 'You're not alone any more', Big O vocals are centre high, background vocals occupy a little right of centre. The recording is not exceptional, that's the point, if vocals can be placed accurately on an average recording, then an exceptional recording works wonders. And it does, with Veronica Swift 'How lovely to be a Woman' just above the speaker line and such articulation. Lady Gaga never ending power on 'Diamond Heart' doesn't drift, stays rock solid, once again above the speaker line. 

I'd say there's more front to back image, than with the Equitech, where it was a little more confusing. Tonally, much the same as before which is a good sign, good image is working noise reduction. Certainly at idle, there's no noise/hiss from the speakers.

No rattle and hum either. Very impressed!

Rear view

Interior view, Denafrips claim the transformer is theirs from in house.

The PCB is mainly for the input treatment, simple LC filter network on the primary.

Thanks for the great review.

i do have a 20a dedicated line and i use this onfilter EMI and RF filter.

https://www.onfilter.com/ac-emi-filters-af-series

The interesting thing is I can plug in a EMI meter to the wall outlet without the onfilter and it would show some 350mv of noise. If I plug the EMI meter to the onfilter to the wall, the noise meter goes down to like nil (like 15mv or something)

The sales contact recommended if I need more devices plug in, I can simply connect a simple power strip with no other conditioning to the onfilter, that seems to work just fine as I tested the power strip plugged into the onfilter and the noise meter also around 10-15mv…

an AC power line should have a 'source impedance' of well under 1 Ohm at the wall outlet.

an Equitech 1RQ (1000VA) Isolation transformer secondary won't be much higher.

There won't be much difference in 'source impedance' between an existing circuit and a dedicated circuit.

Wait.......

on a 230 Volt line a 1000VA load has an impedance of 53 Ohms.

7 hours ago, Speedskater said:

Wait.......

on a 230 Volt line a 1000VA load has an impedance of 53 Ohms.

Yes, that's right. if you want, you could bring it down some by working out the short circuit strength but for a puny transformer it will only last milliseconds anyway.

The 53 Ohms has nothing to do with the transformer.

It's what a 1000VA load's impedance is. (230 Volt line)

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A power transformer has two limitations:

Short term - core saturation

Long term - heat

an Equitech is a great transformer. That 1000VA is a very conservative rating.