I’ve been playing around with different parafeed and interstage coupling caps this year and have settled on a combination that works for my tastes: V-Cap ODAM and V-Cap CuTF (no affiliation). The CuTF (copper foil and Teflon dialectric) are well known and well regarded, so I won’t say anything about them other than that they are, to my ears, excellent, and they are pricey.
The ODAM caps are new to the market (released end of May this year). ODAM stands for “oil damped advanced metallizedâ€. What follows details my experiences with and impressions of them.
TL;DR version: great sound in a small, easy to install package.
The ODAM caps may be of particular interest to Bottleheads because, besides sounding great (to my ears), they are (1) small, and (2) less expensive than copper or silver foil caps. Their small size is a standout feature. Copper and silver foil caps are huge and heavy, and can be challenging to install in amps with limited free space. Case in point: I installed 3.3 uF Audyn True Copper Max caps in my SII-2A3. They measure 63mm x 60mm (approx. 2.5 in X 2.5 in). I didn’t want to rebuild or modify the wood base that I’d already finished with copper sheet cladding. To make the caps fit, I ended up removing the MourQuiet attenuators and input selector switch, and moving the power on/off switch to the rear of the amp (in retrospect, I probably could have left the power switch where it was). Even with all that front space of the amp cleared out, the Audyn caps barely fit. Had I used ODAM caps, which are lighter and smaller, I could have installed them with no modification to the amp layout: a 3.3 uF 630 VDC ODAM measures 1 in X 1.9 in.
Were it not for the small size of the ODAM caps, I likely wouldn’t have tried them, on the assumption (which I now think is very wrong) that a “metalized†plastic cap couldn’t compete with copper or silver foils. In my SII-45 amp, I previously had Clarity Cap CMR (metalized polypropylene) as parafeed and interstage coupling caps (4.7 uF and 0.1uF). The CMRs lived up to their name and gave me more “clarity†(detail), but to my ears sounded sterile and lifeless. I eventually added 4 X 0.1 V-Cap CuTFs, 2 as bypass caps for the 4.7 uF CMRs and 2 as replacements for the CMR interstage coupling caps. I’ve mentioned the sonic results in other threads. Suffice it to say that I was very happy with the CuTFs (and still am).
After adding the CuTF caps, I greatly preferred my SII-45 over my SII-2A3 for all music except strings. The 2A3 amp did a much better job on violin and cello. In comparison, the 45 amp was great for string resonance and emotion, but something about the leading sound of bow on string was off: too much resonance without any sharpness. The relative superiority of the 2A3 for strings only increased when I added Duelund 0.01 uF bypass caps to the Audyn parafeeds and CuTF 0.1 UF caps as couplers, and later swapped in EML 2A3 mesh tubes in place of JJ-2A3-40s. With those changes, the SII-2A3 rivalled the 45 for all music. The EML mesh tubes brought about half the “magic†I heard in the 45 but, together with the Audyn/Duelund/CuTF combo, with greater detail and “realismâ€.
I figured the bottleneck in the SII-45 amp was the 4.7 CMRs. Problem: the only way to make 4.7 uF Audyn copper foil caps fit (or any other foil cap) would be to add 2 or more inches to the base. So I decided to try ODAM caps instead: 2 X 2.2 uF ODAMS with 1 X 0.22 uF and 1 X 0.1 uF CuTFs, for a total of 4.7 uF. It was tight, but I managed to fit them all in the stock position without any mods to the layout (Yes, I know I have too many “bypass†caps – I will try removing the 0.1 CuTFs sometime in the near future).
V-Caps take a long time to break in and stabilize. On my first listen after installing, everything sounded washed out and flat. There was no bass and no dynamics. This was expected as I previously installed CuTF caps in both the SII-2A3 and the SII-45 and knew I was in for a wild ride while the caps were breaking in. But after 100+ hrs of burn-in, the 45 amp started to sound stellar. It equalled the 2A3 amp for detail and dynamics, but with much more “emotion†and “depthâ€. I don’t know how to describe the sound: it just sounded really good and immersive to me.
After another 50+ hours of burn-in, I find the 45 amp superior (for my tastes) to the 2A3 in every respect. Now when I compare the 45 amp to the 2A3 amp (for strings and everything else), the 45 is the more detailed and dynamic and “realisticâ€. In comparison, the 2A3 amp sounds a bit congested, with an exaggerated or forced sounding leading edge.
So, if you’re thinking about trying different caps and don’t want to modify the amp layout or base (or even if you do), you might want to consider ODAM caps. I’ve only listened to them bypassed by CuTF caps, so I have not experienced how they sound by themselves, but my guess is that they sound very good and will make a great match for your favorite flavor of bypass cap. Of course, as always, the usual caveats apply: YMMV, system/component synergies matter, etc.
Of potential interest to Beepre owners: Chris VenHaus, owner of V-Cap and VH Audio, plans to release a 10 uF 250 VDC ODAM cap later this year. I plan to replace my 10 uF Clarity Cap CMRs with them.
I am so pleased with the ODAM/CuTF combo in my 45 amp that I have rejigged my plans for my upcoming Kaiju build. Prior to learning about the ODAM caps, I picked up a pair of enormous Miflex 10uF 600 VDC copper foil and oil caps b/c come hell or high water I wanted the sonic benefit of copper foils in my Kaiju. To make them fit, I had planned to make a new and larger chassis. But after hearing how the ODAMS/CuTFS compare to my Audyn/Duelund copper and silver foil combo (even with CuTF coupling cap), I’ve made the hard (on my wallet) decision to go with 3 X 3.3 uF 630 VDC ODAMs bypassed by 0.1 CuTFs as parafeed caps instead (When I asked him, Chris V said he had no plans to make a 10 uF 600+ VDC ODAM cap). As a result, I no longer need a bigger Kaiju chassis.
Now the question is what to do with these preposterously large 10uF Miflex caps? Can anyone tell me if the Jagers use 10uF caps in the x-overs? If not, I need to find these things a new home.
Cheers, Derek
