will
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Every so often the question of CSP “transparency” comes up. It is an interesting question, and I have found that it is not black and white.
My front end is really good, so the characteristic qualities from the CSP3 are not used as “a fix,” but as a system enhancement tool. Once tuned in a revealing way, the OTL “factor” is to me very compelling, though conditions, tastes, and setup effect everything so nothing is an absolute given.
From reading the Forum, I guess “transparency” and “revealing” are as much or more a requirement for me as they are for most folks. Toward this end, I have found that the CSP3 sound can vary pretty wildly, from relatively colored and veiled to quite revealing. In the pursuit of “real” sound, I have explored this a lot, adjusting and tuning everything in my system to the end of natural, “alive” sound. With some effort I have been able to gain the beauty of well-implemented OTL and gain riding without meaningful sacrifice to transparency...listening now, I would say the opposite in fact.
In this simple circuit, every design choice can be heard, including how we end users continue the design. Just one tube choice can make it darker or brighter….more or less revealing...more or less present and live …..faster or slower…..also effecting extension, nuance, warmth, spaciousness, textures…..But there are three tube positions, input and output cables, vibration control choices, power cleaners, power cords, and fuses….individually and collectively these all can increase or detract from the feeling of “transparency” of the pre.
The adjustment pots take it further. Determined by the balance of volume levels chosen for tubes in each position (including the OTL effect being stronger or subtler) these alone can change our overall balance and tone quite a lot.
Then there is how we balance the CSP balance in the whole system/room sound with the influences of the amp tuning, determined by how the amp and preamp gains balance.
Discussing “transparency” or lack thereof, the above points to how many things can effect our sound depending on how we choose to “sculpt” the tone, density and balance of the CSP3 in a system.
And it is clear that adding a circuit and cables to the signal path, all else being equal, absolute transparency is reduced. But Steve's voicing seems designed for transparency that is a bit warmed up for musicality, and based in part upon quality tube availability and prices. I think this “by-design” leaves leeway for tuning (or not) depending on our preferences…including increasing or decreasing “transparency.”
The questions become: does the character of the CSP3 have potential benefits for our musical enjoyment in our given setting; is “absolute transparency” the best for music, especially with varied recordings; is our baseline sound (before the CSP3) “in fact” “transparent” [many of us prefer warmth and even masking to make a system more comfortable by using tubes, cables, sources, etc that are colored or less transparent on purpose. Starting at the beginning, many good sounding sources tuned to sound “warm” or “analog” can be relatively colored. Or popular tube examples... 6N1Ps, or more subtly, American Amperex 7308s impart color and masking that many consider a good balance for musicality]. Finally, we can usually choose cables, tubes, feet, fuses, etc to heighten transparency in the CSP3 and/or amp to better accommodate the addition in the signal path, and without overall sacrifice of things we associate with “transparency”...micro detail, texture, spaciousness, speed, definition, air, close and broad ambient information, etc.
Then, if we compensate for transparency losses, how we approach volume between the CSP3 and amp matters relative to “transparency.”
I found that using the CSP3 traditionally as a volume control, with the amp at a set level was not for me. In this case, volume changes from the CSP3 also increase or decrease the tonal characters it imparts in balance relative to the tonal qualities the amp imparts, not least of which, the CSP3 OTL effect. When the CSP3 is stronger in the balance, the tone will have more density, and at lower volume, the overall tone will be more lean.
My Torii MKIV, being relatively even in presentation quality at various volumes within the range I tend to use it, I prefer to set up a range I find tonally optimal for the CSP3, and use the amp as primary volume. Then I can push the CSP3 a bit more to increase density of leaner recordings, or reduce it a bit in the blend to open too dense recordings, a primary benefit of the CSP3 OTL circuit for me. With “gain riding” I can adjust the tonal signature of various recordings, and being pretty particular, this is a big deal for me.
I find the OTL qualities difficult to describe. Lon suggests "compression" sometimes, and I agree, but think of it is a very particular “compression.” How we adjust the OTL (output transformerless) tubes adjusts how much the signal is “compressed.” By design, this quality can be tuned to taste to help find OTL “magic” that best suits a system/room. But looking at it carefully, in a very revealing system, especially if we have sensitives to signal density, or relative to how it effects the tonal range with various room and system anomalies, it can be trickier. The more we drive the output tubes, the more of the OTL "factor" we will hear, creating a denser, more powerful signal across the spectrum. So things like midrange hardness anomalies from the system/room can be amplified if we push the CSP3. But at the same time, the signal can be improved in many areas, being cleaned up by running through the right OTL tubes. So it all depends on a lot of things.
To me, this OTL "factor" sounds like it smooths, consolidates and cleans the signal, and can be a powerful, or relatively subtle effect depending on settings and tubes. Working on the whole signal, it effects all aspects…. tonal density across the spectrum, definition (and associated inner spaciousness), texture, smoothness, and dynamics, at least within a range. The “color,” or lack thereof, this imparts depends on caps, tubes, cables, etc; on tube pot settings and master volume, and more.
Whatever the sound preference, I think the most “transparent” way of using the CSP3 depends on using it with a relatively narrow master volume range while using the amp as primary volume.
The output pot settings influence the level of driving the output tubes, and therefore the OTL effects, but also adjust the tonal balance based on more or less of the chosen output tube's sound. Aside from the OTL effect, adjusting the input pots, and the output pots, increases or decreases each in the balance, allowing optimizing the tonal values of the tubes used in each position. And the rectifier effects both the input and output notably, some rectifiers more dense/dark, some more open/bright, some leaner, some more or less dynamic, more or less extended...and so on...
I like to adjust the CSP3 to be more open/spacious and the amp, also revealing, but a little warmer. Inevitably the amp and CSP3 will sound a little different, and this can be exploited to help us tune them together with an overall sound we like while contributing a nice complexity.
With my Tranquility DAC (very transparent), and Jupiter caps, I like the CSP3 OTL pots past center to pull the CSP3 lucidity, and very importantly, using open/revealing tubes and cables to allow this without excess density. This does three things. The open/revealing settings can mitigate “transparency” reduction from having added more parts into the signal path; with the CSP more open, increasing the CSP3 volume in the balance can increase density without excess darkness and thickness; starting with settings for open neutrality in the CSP in the middle of the chosen volume range, we can easily shift it leaner or denser to help balance different recording qualities by “gain riding.” By turning it up a little, and the amp down a little, we can emboldening leaner recordings. And likewise, the amp higher, and the CSP3 lower, can open up a too dense/dark recordings.
With the CSP3 pots balanced to tastes for the tubes and OTL effect, and the master volume range set to balance best with the amp, then a relatively narrow range of adjusting the master volume can do this work without notable divergence from the sound we have chosen for the CSP3. With careful tuning, this can facilitate the CSP3 “magic” and gain riding while being relatively neutral and transparent.
For me, in this very revealing system/room, it was not easy to integrate the CSP3 with transparency. But I got there. And burnin is really important here. Now if I pulled the CSP3, the amp alone would likely be a little too warm. But since they are always in together, I tune them together as if one amp.
Though I think less transparent and revealing sources could limit the potential, I can comfortably say that with the CSP3, my system/room, the sound is not limiting in transparency... it is very revealing...present, natural and “real” sounding, a sense of players in good rooms the objective. And perhaps as important as anything to me, it is adjustable to better bring out different recordings.
Current Settings: My CSP3 has jupiter caps and is well seasoned. The settings lately are: an early 60s IEC labelled PCC88 input (sold as Mullard made but they look like Telefunken) with the pots set at 8 or 9; a pair of early 60's Valvo E88CC gold pins as outputs (pots at 6 or 7), and a 50s Fivre GZ32. The master volume range is from about 12 o'clock to 2. ICs are DIY VHAudio silver recipe. From the Tranquility DAC...24 gauge wire and KLE Absolute Harmony RCAs, and CSP3 to MKIV...28 gauge wire and the third best KLE Silver Harmony RCAs. The power cable is a quiet, revealing, and friendly PI Audio cable made for the Tranquility DAC for which I added a ground wire and Furutech pure copper ends. The fuse is a HiFi Tuning silver with a WA fuse chip.
In the MKIV I am running Mazda labelled Phillips GZ32 with double bottom D getters, British made 75C1s (OC2), 59 CBS labelled Siemens ECC88s, Sylvania labelled OB3, and Tungsol 6L6Gs with a Synergistic Research Red fuse.
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