August 23, 2009

Power Grab, RGPC Isogray vs Torus Power RM8A

Richard Gray Power Company's range of Isogray compatible products. Note the 400 Pro and the Substation side by side, 2nd & 3rd from left.

More PLC pow-wow time! This is getting exciting. Two PLC so close in technical execution and price range, yet can represent "clean power" sound so differently.

The RGPC Isogray system, is the ultimate power line conditioning solution in it's product catalogue. It is made up from a unit of RGPC Substation(price, RM$13K+) isolation balanced transformer and a unit of RGPC 400 Pro(price, RM$4K+) choke parallel transformer. In this review, I'll just have to pit the RGPC Isogray against my resident Torus Power RM8A(purchased price, RM$18K).

The RGPC Substation, powering my power amps and the RGPC 400Pro. Note the grey adaptors for NEMA-5 to UK spec BS13 amps plug on power cord. I used the very decent stock power cord supplied for the RGPC 400 Pro, but was told by Odiosleuth that sound quality can be improved if a better power cord was used instead.

You connect the Substation to the wall supply, use it to then split A/C power supply to your power amp(s, if mono block) plus connect to the RGPC 400 Pro to feed your source and pre amps.

The RGPC 400 Pro, supplying clean power to my CDP, turntable, phono stage and pre amp.

In practice, RGPC uses a two stage treatment system by two smaller transformers, where else the Torus Power approach is to use one very massively over sized transformer for the job.

Which is better? I know, I had previously proclaimed that the Torus Power is the best PLC you can buy at the moment. Can RGPC grab that title from today?

To start, I must confess that due to the way the plugs and cabling in my system are set up for the Torus Power, i.e. UK spec BS 13amp plugs, I had to use power adaptors with the RGPC in use. So there's a certain "contact " disadvantage to the RGPC in this comparison, just in case, if you're the type who are anal about this sort of things! I know Odiosleuth is, He!He! So you can read and interpret this review with a pinch of salt.

With that declaration out of the way, let start rolling! At first listen, I thought the Torus Power offered an overall darker impression of musical proceedings compared to the RGPC Isogray, however, that doesn't mean the latter is bright either. It's just,.....well, let's say, a little shinier, more varnished by comparison. I think the RGPC "signature" high frequencies reproduction contributes to this impression. By comparison, there just seems to be a little spot lighting of the upper frequency spectrum, always. I must stress however, the highs were never grainy nor splashy. Another area where the RGPC is easily distinguished from the Torus Power is the bass. The RGPC's bass just exhibited better slam, tighter control but extended just as low. I would rate both the RGPC and Torus Power's mids to be equally matched, except, due to the slight spot lighting of the highs, the vocalist's mouth will be more focused, versus the more solid density body of the Torus Power. When playing violin solo pieces, the RGPC would highlight the bowing string's attack over the woody resonance and decay of the instrument body that followed. I felt the Torus better balanced between the strings and the woody body of the violin.

Subjective evaluation of the back ground noise floor was equally quiet between the two, but perhaps due to the darker nature of Torus Power, I thought it did had a minor advantage. Staging and imaging of the RGPC seemed more sculpted and tightly arranged, the imaging outlines very clearly drawn out, giving the impression of a very focused subject thru an optical sonic lens. The Torus Power had a softer edge imaging presentation, with the sound stage seemingly less tightly managed, yet at the same time can seem more organic by comparison. Yeah, I know I sound very contradicting, but sometimes that's the way it is.
If at first listen the RGPC seems to scale dynamics and transient better. Upon closer inspection, that's not the case, the Torus is just very slightly more laid back in that respect. With the RGPC Isogray, vocals hang on the same plane as the speakers, followed by instruments layering behind. The Torus Power does the same thing, but with the vocals starting from the speaker's back wall.

Both RGPC and Torus Power made my system sound equally transparent, with superb retrieval of subtle spatial cues and minor recording details stood out well from the background music mix. I found that even though both gave a different account of the same musical proceedings, I could in fact happily lived with either PLC solution. I have found both to be equally musical on an emotional level, i.e. listening with your heart.

The RGPC Isogray's performance ran so close to the Torus Power, that only by preference, I could call the winner. You're welcome to disagree with me as I am sure that in the context of some other system, the RGPC Isogray may indeed prove to be the preferred PLC solution. In practice, try before you buy is still most relevant when shopping for PLCs.

In summary, I found the technical performance of both PLCs to be equally accomplished. However, for sound quality performance in the context of my system, I still have a slight preference for the Torus Power's sonic characteristics. From my own opinion at least, the Torus Power retains it's title for now.

However, Odiosleuth confessed to me that music became less enjoyable since the RGPC Isogray left his system in the past few days, and has been bugging me to return the RGPC Substation to him again for further possible investigation of merging it with his Shunyata Hydra 8! Do look out for the exciting follow up on the matter from him in the near future.

Your choice between the two could very much boil down to the final two factors that'll swing in either way. First of which, I think most plug anal audiophiles with very high end power cords would sway towards the RGPC Isogray equipped with NEMA-5 power receptacles for superior plug contact. The other factor would invariably boil down to price, and favourable trading terms, if applicable.

I know of many whom liked what the Torus Power did for their systems, but just couldn't get over the UK spec BS13 amps receptacles that came with it. It is for these folks, the RGPC Isogray offers so close in terms of performance, if not better, but also a non issue for the NEMA-5 receptacles fitted.

RGPC products are sold by CMY Audio & Visual, contact John Yew, tel: 03-21439406

Torus Power is sold by AV Designs, contact James Tan, tel: 03-21712828

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