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Still got the capacitors?

For a long time, some of us are gripped by passive parts' sound qualities. And all this time, we are faced with the opposite tribe, trying to convince us that it is a waste of time and money – "the passive parts have good technical parameters, and hence they all sound the same", they say. The other tried to be smarter, investigating more tricky technical parameters, such as dielectric absorption or leakage current, trying to associate capacitors' sonic properties with such parameters.

And decades later, I still have two "problems". The first is, I can easily hear the different capacitors sound different, and second, I am still not aware of any firm relation between their sound and any known technical parameter, either. And that is why I am still spending my time and money buying and listening, to find the ones that simply sound the best.

As time goes on, some capacitor types however also become obsolete, which makes this endeavor somewhat frustrating. Especially if you have to manufacture the product in series.

At the time I started to design the A20, my favorite power supply reservoir capacitors, Panasonic HA, which I used in the Model A, were already obsolete for a couple of years. However, I stashed some quantity, so I could keep using them also in the A20. Yet, it was definitely the time to look for the parts that can replace, or hopefully (eehhh….) even improve on them.

So I looked at the major vendors' stocks and got myself several samples of every capacitor that can be a possible replacement. And checked them in the A20. Not all the caps I tried here were the same capacitance and rated voltage, and although performance may vary a bit with capacitance and voltage, I believe the fundamental sonic properties they showed are intrinsic to them as such. The results are as follows, with caps listed in the alphabetical order of manufacturers.

Cornell Dubilier SLPX – They are open, and boast the instruments coming from everywhere, from left or right, or above or below. So you might perceive this as a "huge stage", but no instrument has any focus.

Elna Tonerex – More open and more sparkling than Panasonic HA, still smooth, although on a bit velvety or grainy side (or it is "emphasized texture", it is Elna, finally). Or it can be defined as a rich tone, although again on the bit bright side. A second best focus (no "harmonics arriving before the fundamental" feeling), not pinpoint like Panasonic HA but fine enough for long term listening.

Kemet ELH – Despite the decent resolution and superior ability to draw the height of the soundstage, a somewhat mid-fi impression. Probably due to a modest dynamics and unconvincing tone.

Nichicon LKG – A bit more open, and a bit more dynamic than Panasonic HA, although with not that precise focus and coherence.

Nichicon LKS – A variation on the LKG type of sound. (Nominally, it is Nichicon’s LKG miniature.) Apparently a bit more smooth. Still not that precise focus as HA.

Nippon / United Chemi-con SMH – Initially hardest to determine, but there was no real focus and no real stage. And dynamically not the best.

Panasonic HA – Smooth yet defined. Absolutely the best focus, with a feel of "organic spaciousness" that no other cap equals yet. My long time favorite, as said unfortunately discontinued a few years ago. Panasonic did not offer any replacement.

TDK Epcos B41231 – Fairly smooth yet open, but, although the positioning is not bad, somewhat out of phase feeling. Lacks attack.

Vishay 256 PMG-SI – Well ordered and coherent. At one moment I thought these might replace HA, but they did not. Relatively similar to Nichicon LKS. Good caps.

So, with A20 I quietly proceeded with Panasonic HA. With A21, since its output stage includes practically dual mono supply, I expected some things, such as soundstage and positioning, to be different. Hence I repeated some experiments with A21, using again some of the parts above, and adding some more too. And things again were not simple. More on this in the next post.

So, in the A21 caps experiments there were some newcomers, and let's meet them first.

Rubycon USC – The most captivating on the first listening. Very three-dimensional (spacious + focused) and defined, with extremely high resolution, and very dynamic presentation, from deep bass to the open highs. The midrange is liquid, however a bit pronounced, with a hint of microphonics, which got me a bit nervous in the longer listening terms.

Rubycon MXG – It is also distinctive, in a similar way to the USC, but to a lesser degree, so with a certain sense of being more calm / neutral / natural. It is however also less authoritative and with a less convincing soundstage.

Vishay 056 PSM-SI a.k.a. MAL2056 – Vishay's new product, and it is pricey, but it was the first one that made me think if Panasonic HA, as good as it was, was a bit too dark. In other words, made me believe the cap can be correct in all areas, but more open, even though this Vishay is not too bright either, in fact I am not sure if it does not lack something in the most upper end. But generally, its tonal colors are just seductive and rich, and the resolution is outstanding, too. As said, no obvious shortcomings either, apart from not having the highest soundstage, meaning it is positioned mostly in the bottom half of the room – you have to decide yourself if things have to sound this way or not.

At this point I certainly preferred Vishay 056 PSM-SI, but for the above said reasons, I had to try some previously tested caps in this environment too. The remarks below are the outcome of multiple checks done by swapping the caps forth and back.

Nichicon LKG – In the A20 it was not very distinctive but it was good, and in the A21 it was again very good. Somewhere between Vishay 056 PSM-SI and Rubycon USC. A tiny bit less airy than 056 PSM-SI, but more lush and involving, still being enjoyable and seductive at that. Not having any actual shortcoming, it is quite open, and hence a bit less forgiving regarding its environment. That is why I tried again also Nichicon LKS.

Nichicon LKS - Although having a more smooth balance at the first listening, in the midrange it appeared more mechanical / less expressive than LKG.

Elna Tonerex – Very similar to LKG, with a slightly different tone and positioning (that is not easy to describe). Eventually, I found Tonerex less involving in comparison.

I am not sure if the reasons are visible from the above, but I narrowed my choice between Nichicon LKG and Vishay 056 PSM-SI. In this final turn, I settled on Nichicon LKG, for being musically more expressive.

In the next few days I plan to give another try also to the Vishay 256 PMG-SI (I bought previously only one pair). And that is where I will draw the final conclusion regarding the A21 (I still have a week or two to decide about this part).

Participants in these experiments gathered for a photo are below, click on the picture will bring it hi-res.


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