Rowland PC1 PFC on Capri pre early findings


I have just re-inserted a Rowland PC1 Power Factor Correction (PFC) device in my system 1 hour ago. It is feeding a Rowland Capri preamplifier. Previously Capri was powered directly by a Purist Anniversary PC plugged into an AC wall outlet. Now the Purist is powering the PC1, while the Capri is being fed 384V Direct Current (DC) by the PC1 through a small Rowland supplied pigtail looking somewhat non-denominational. The PC1 is designed to increase the operating efficiency of the device that it is applied to and to eliminate capacitor charge ripples caused by AC. It was deliberately designed for high current Rowland, and not for the Capri pre, although the Capri is compatible with it without any changes of jumpers etc. . .; this means that what I am doing here is purely an experiment limited in scope to the Capri.

I have been playing only 1 CD on repeat this far: Nora Jones 1st CD, so my findings are just very early surfacy impressions. PC1 seems to have extended the frequency range top to bottom; bass appears to be further defined with greater authority/punchiness/control; imaging appears to have acquired enhanced focus. . . this means that Jones's head actually seems more contained, centered, and perhaps slightly smaller than before; instruments are more localized in the 3 dymensions; stage is wider/deeper; there are more harmonic 'bristles' or texture and a more evident leading edge in small transients from percussion instruments. I am perhaps perceiving a very slight increase in sybilants and a slightly more forward presentation. . . but the PC1 is not at all broken in. I will document further observations as the PC1 breaks in and I play other CDs.

One more potential variable is the Rowland-supply power pigtail to the effect of the PC1 on the Capri. Would an upgraded DC pigtail have any audible effect?

For your info, The PC1 can be applied readily to the Rowland Continuum 250 and Capri without any setup changes because these devices have autosense multivoltage power supplies. the 102, 201 and 501 amps require some alteration in fuse setup. The Concerto products require both a fuse setup change and a change to internal jumpers. PC1 is not applicable to JRDG 300 series amps nor to the JRDG Continuum 500 integrated, because these devices already incorporate PFC circuitry. Note that the PC1 is NOT a general purpose power conditioner and is not compatible to any arbitrary device/brand. I have no information about applicability of PC1 to older Rowland amps. It is likely not compatible with amps and pres from other manufacturers . . . so do not try wild experiments with the PC1 without consulting and approval from your dealer, JRDG and the manufacturer of your amp/pre. The PC1 retails for $1500. It is available from Rowland dealers like Soundings HiFi of Denver (Co) (303) 759-5505.

The rest of my currently active configuration consists of: Teac Esoteric X-01 Limited, Rowland 312, Vienna Mahler v1.5 speakers. Capri+PC1 is currently in use instead of my ARC Ref 3.
guidocorona
04-13-08: Mr_bill
Mr Guido,
Great findings and keep sharing!
Does anyone know if the new Continuum 500 will have analog power supplies for the amps like the 300 series or the switching supplies like the 501's?
Thanks,
Bill

As far as I know new 312 and new version of 301 monos use switching power supplies. They both use PC1 PFC internally.
Branimir, you are correct, spoke to JRDG today. 300 series rowland amps implement some form of regulated switching power supply fed by a power factor correction circuit (PFC). In answer to Bill, Continuum 500 also has switched and regulated power supply, but -- if I understood correctly -- its PFC circuit has much greater capacitance than that built into 300 series amps or in external PC1 unit. . . .
I have tried two different power chords on PC1 this far:
1. Cardas Golden Reference -- Reasonably extended, but oddly enough, sounding slightly dry, without the low level detail nor the staging I am seeking.
2. Purist Anniversary -- more extended at both ends, with a greater degree of low level detail and sense of space. Also more authoritative than Cardas Golden Ref and with greater harmonic complexity -- some may call this more 'organic'.

This finding is consistent with my experience of the same two PCs directly on the Capri, prior to inserting the PC1 in the chain. This is all together quite curious, because the Capri draws only 6W, yet it appears to benefit from the exceedingly hefty Anniversary.
Please note that I also used the Purist anniversary as my standard chord of choice on the ARC Ref 3, where I prefer it slightly over the Shunyata Helix Anaconda Alpha.

Next, I intend to test the effect of a Shunyata Anaconda Helix Alpha on PC1 and will report results here.
Some more data/info trickling in from JRDG. . . estimated break in for Capri as well as for PC1 is at least several hundred (500?) hrs. As Capri draws only 6W, real breakin time for PC1 may actually be longer than 500 hrs. Capri output impedance is 40Ohms. JRDG also estimates that Capri performance is maximized in a fully balanced environment. G.
Yeah, I just talked to Rod about my anticipated Continuum 500, expected by month-end. Rod's saying that 1,000 hours is what to really expect for complete burn-in. It'll sound good right off the bat, but improve substantially as it burns in more and more. I'll just leave it on continually and drive the speakers at low levels when no one's around.

Hopefully in May I'll be able to travel down to JRDG in Colorado Springs to see how they put it together.

Dave