Sonique Hear My Cry Vinyl
Margorie Gomoran
As I venture further down the audio path looking to be named Emperor and ultimate ruler of the almighty Tweak Kingdom, I took a trip down VenHaus Street again. This trip led me to a cottage labeled OIMP. Hmmmm, I thought to myself... OIMP... that's a pretty bizarre sounding word. Well, OIMP ain't a word. OIMP stands for Oil Impregnated Metallized Polypropylene (cap).
If you weren't aware, Chris VenHaus has been cooking again in his audio kitchen. This time he has come up with a nifty little twist on an established capacitor recipe. Chris has taken a rather bland Metallized Polypropylene capacitor entre and added some serious flavor to it. As you guys who trip the light fantastic on tweakers road already know, a little while back Chris concocted one helluva great capacitor in the Teflon Film and Tin Foil V-Caps. Personally, I love 'em. I loved them so much I nominated them for the Tweak Product of the Year (2004). These caps were (and are) sonically stunning. They are a true delight for anyone's audio palette.
So now, we have Chris' latest entry into the capacitor cook off. This particular dish uses polypropylene as a dielectric which has been wrapped and lightly seasoned by thinly sliced aluminum foil (AKA as metallized). The poly is sauted in extra pure virgin olive oil (not really but its oil none the less). This entre comes with extra long, tinned OFC copper leads for ease of handling and finally, comes garnished with a shiny silver label with lovely red and blue lettering which is gently placed upon a unyielding brass case. This meal promises to provide a silky smooth presentation to the palette and auditory nerves.
But Seriously...
Of my two Korato preamps, my KVP-20 seemed to be the most likely of candidates to benefit from the OIMP V-Caps. The KVP-20 uses a pair of 2uF output caps in it's design. They are located at the outputs just before the RCA jacks. Fortunately, the Korato has plenty of room to accommodate the physically large size of the OIMP caps. Make no mistake, these things are huge and you need to make sure you have room to mount these before you order them. Granted, they aren't near the size of a true paper in oil cap but they due consume some serious acreage. You've been warned.
For me, the installation couldn't have been much easier. First, I took out the Solens that resided there previously. Then I installed a couple of those sticky backed, zip tie, hold down, anchor thingies... (OK, maybe one of you brainiacs out there can let me know what these damned things are called since Alzheimer's has obviously begun to set in). Then I installed the OIMP caps, soldered one end directly to the RCA jack and the other to a short lead from the circuit board. I did install a PVC sleeve around the exposed copper leads just in case. Better to have it there than get zapped (not there is any lethal voltage at this point in the circuit but it definitely looks better). Pretty simple and it took less than an hour to do.
OK, So Here Is The Standard Disclaimer
Like my Dad used to say, "If you play vagina, you are going to get fornicated." (or something like that). In other words, if you play with (potentially) lethal voltages, your gonna get shocked. Whether you live or not depends on your Karma.
Who knows, if you've led a good life, maybe you'll get off with a warning of an embarrassingly warm, moist stream that saunters its way down your leg ending up in your finely polished wingtips. On the other hand, if you've irritated people on a regular basis, hid behind pseudo-screen-names and cutesy little avatars, you might just graduate to the next level of consciousness. You may get to come back as simple one celled organism to teach you a lesson. Think of it, you get to start your perpetual journey all over again. Now that I think of it, go ahead, make my day. Just be sure to lick your fingers and stand in your bare feet on a concrete floor before you flip the switch to restart your preamplifier (or amplifier) without a variac.
In other words, if you don't have any experience messing about with high voltage tube gear, take your nifty new OIMP caps and your pre (amp or speakers) to local audio shop or guitar store. There should be plenty of nice technicians there that would be happy to separate you from a relatively small amount of your hard earned audio bucks.
Now Back To Our Regularly Scheduled Twitching Session
So I got the OIMP's installed without any hitches. I brought the Korato back up with my variac and all was well. No smoke, no sparks, no flames, life is good sometimes. I decided to plug it into my shop system and let it break in for a few days. I installed some old tubes so I wouldn't use up any more life on my Mullards. My shop system consists (usually) of a Rotel 981 amp, a Rotel RC-970BX pre, a vintage ADC 16/2R CD player and a pair of Infinity Qe speakers. Not too bad for a shop system. Other than the Rotel pre, the other pieces of gear are fairly resolute (including the ADC CD player).
Over the next week or so, I stopped in daily to hear the progress. Very unlike Chris' Teflon V-Caps, these are a breeze to break in. You immediately get a flavor of how they are going to sound. Over the next week you will hear them open up and become more refined. All in all, oh, about 200 hours should get you where you want to be with these caps. You really don't need to set them up in a different system for break in. You can easily live with them in your main system as they do their thing. Just expect the sound to be a bit closed and un-resolute at first. As time marches on, they get considerably better.
The Sound
Well, if you already know the sound of a Metalized Polypropylene cap like a Solens, Hovland, or MultiCap, you know that they can sound a bit hard and aggressive at times. Compared to Chris' Teflon V-Caps, the usual offerings of MP caps are extremely veiled. Here is where the OIMP caps shine. When I finally moved the KVP-20 into my 2a3/Lowther based system, I was simply amazed at the sound. The KVP 20 already had the Teflon V-Caps installed as coupling caps between the tubes. This alone was a sonically spectacular upgrade. Couple them with the OIMP output caps and it was like finding Audio-Nirvana.
These caps brought warmth to my system that was missing before. The strange part is we typically associate warmth (somehow) with a veiling of the sound. This isn't the case with these caps. The last thing these are is veiled. They allow tons of detail to come through while adding just the right amount of... something. Describing the sound of the OIMP's has been really difficult for me. These caps are very clean sounding. Though not as resolute as the Teflon V-Caps, the OIMP's allow a rich, full-bodied flavor to emanate from your favorite gear. A word I heard used by Bill Baker of Response Audio (one of the Beta testers) was 'texture'. Maybe that's a better way of describing their sound.
I'm not quite sure what the oil caps add to the electronic signal or if they add anything at all. Maybe it's distortion of some sort. Maybe it's sympathetic harmonics that are pleasing to our ears. Then again, maybe oil caps allow those harmonics to come though where a standard film cap doesn't, who knows. Maybe its similar to the difference between solid state and tubes where tubes have even order distortion and solid state de-emphasizes those same harmonics making it sound (subjectively) stripped of life. One thing is for sure, I don't have the gear in my shop to do a spectral analysis of what these caps do (or don't do) to the sound. The only thing I know is the OIMP caps sound far more lifelike than all of the other caps I've played with in these preamps.
I've had more than a few people come by and listen to my 2a3/Lowther-based system. Each of them knows it well. Each and every one of them was amazed at how much better it sounded after I upgraded to the OIMP V-Caps. The strange part to all this is that we were all pretty impressed with the sound of the system before the cap upgrade.
In the end, all I can do is trust is my ears. I've never put much faith in measurements, especially after the zero point infinity distortion ratings hailed by solid-state amps of yore. That and CD's with their 'huge dynamic range capabilities' and how new music is compressed and normalized to the point of having (maybe) 20db of dynamic range. We all know just how good those sounded don't we. To me, it's all about the music. If a cap brings me closer to the emotions I feel at a live performance such as the OIMP caps do, then I'm sold.
Do I have any complaints about the caps? It would be nice if they were smaller so I could improve the sound of even more of my gear. I doubt that's going to happen. It sure would be cool if I could find a way to installed these in my old HH Scott 299c though. I guess I could but I'd have to build an extended sub-chassis to house them.
Don't forget, these caps aren't just for tube amps and pre's. You can use these in your speaker crossovers, as bypass caps in power supplies in both tube and solid state gear or even in coupling situations as in a CD player (good luck fitting them in there). With a 600-Volt rating, you hardcore tube guys running 211's, 845's and other exotic beam tubes might just be able to use them too.
These caps really do make one heck of a difference. Depending on your system sound, these caps should work quite well. It seems that many current systems tend to be a bit on the lean side nowadays. You'll find that these caps will bring a system like that back to life. They bring just the right amount of texture to the sound without sacrificing any of the detail and bass or treble extension that we all love so much. If you are currently using caps like Solens, Hovland, or MultiCaps, plan on getting even more detail from your system. As I said earlier, the last thing these caps are is veiled. Will they be more revealing than a Teflon cap? Nope, but in concert with the VenHaus' TFTF Cap as it is in my Korato pre, it has become a spectaculaire sonique.
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