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Interesting Doug. As I pointed to, here I find that tuning balance with the R/L gain stepped attenuators I put in the CSP3 (if needed), can be slotted in for the big sound field easily, and it works across recordings. When it gets there, it is wild, like the already great soundstage just opens up and expands into a magically enhanced sound space with subtler content and differentiation throughout. Your experience makes me wonder if this is a smaller adjustment than dual attenuators on Steve's amps, which would support the smooth potentiometers experience being better for you. Anyway, thanks for your input.
Not having experienced dual potentiometers, I do like that once system/room stereo is balanced, gain settings for me are all about refining stereo gains together for system/room, and optimizing sound on various recordings. I have not noticed my system showing need for more than this to adjust sound stage. Once the system/room is balanced right, soundstage seems right across the board. But based on your experience, I can see how balance could be another tuning tool per recording. And though not costly, "tuned up" smooth potentiometers, I agree, Steve's do sound good.
On filthnoise's question about pre stages, I grabbed my ZStage from my other system and replaced my CSP3 with it.
All components are modded for speed, fine resolution and lucidity except the Zstage, and just a heads up, but this makes the ZStage better than how I remember it with all else stock, and it alters my impressions.
DAC
ZBIT (originally set a 1/2 half gain for this test, wanting to get DAC voltage closer to "normal" RCA out levels)
ZRock2 (not far above unity but doing its thing on highs and lows using the B setting)
ZStage
Simple Wave 300B (wide open, no attenuator)
To max this amp out before notable distortions, at these settings, and with a nice Zaerix Mullard 12AT7, higher gain compared to 12AU7 stock, the ZStage needs to be at about 90%. On first impressions it sounds quite good. However, for me this near-max pre-stage gain is usually not optimal, typically liking them less than maxed individually. For gain tuning between stages, I seem to prefer the sound when no stage is past maybe 70-80% and usually less... seems to me spreading the gain that the amp gets around between stages is where I find more optimal complex sound.
Sounds really good, not as richly complex and complete in subtleties as with my CSP3, but quite good with pretty great clarity, body, dynamics, space and balance.
Playing some, I found I prefer the sound with the ZBIT ±1-2 o'clock, which puts the Zstage at maybe 70-80% for my amp to reach max volume before distortions (depending on recordings). This higher gain from the source seems to stress the ZStage a little less, while bringing up dynamics, density/body, lucidity, etc to levels I prefer... all else the same, the even better sound perhaps being one I could work pretty easily with if I did not have the CSP3. I need a lot of time working with different recordings and settings to determine something like this conclusively, but it sounds really good on 1st perusal in this setup.
So... a consideration, the output voltage of your phonostage may not make or break it, but would likely effect the optimal tuning potential of this setup. At some point, a lower voltage source could set up noticeably less benefits in gain tuning than with a higher voltage source, and/or, it could get to where you are unable to reach full volume, perhaps important if on volume edges for system/room and listening preferences. For gain riding, I like to have some usable ranges for each stage, better able to tune dynamics/density/clarity/hit and all.
In this setting though, ZBIT ±1:30, ZRock2 maybe a notch above unity, and ZStage ± 70%, this is about as loud as this amp can go without notable distortions, and it has relatively neutral balances and headroom to gain ride from.
Now, to test this setup, I am listening to a recording I know will push things at max volume "before distortion." It reminds me of the thin edge that can come from gain riding, especially since for me, pushing edges is seductive, as it seems the sweetest lucidity comes with gains near edges. This "edge" is based too on recordings, variable to say the least. A setup can seem good, but then not so good with powered up recordings. This recording is quite dynamic, full, and complex, with big hits, and some distortions intentional in the recording (think fuzz box), so a decent test for me. It is Bugge Wesltoft-Henrik Schwarz-Dan Berglund "Trialogue."
With the above settings, I was noticing a fine distortion that might not go away easily from reducing gains at high listening levels. I was thinking perhaps it was from the ZStage itself in this particular setup, bringing up memories of having to turn down my player software with a DAC that had high output in order to solve subtle distortions when I was using only the Zstage as an additional stage for gain tuning. So I pulled the higher gain 12AT7, and put in a nice "RCA" Mullard 12AU7. Adjusting the ZStage gain up a little to compensate, so far that seems to have solved that niggling subtle distortion from this particular recording.
This presents a potential challenge from using gain stages.... how well they match up, and how hard they push each other, especially if you prefer the edge sound, or need it to get satisfying volume. And over time, the more stages I add together, the more having some flexibility and headroom with each stage for overall gain tuning becomes important.
Last, is hum/buzz. I am working it pretty hard just now, so I am sensitized, but since I got my new amp, along with some utility power changes, the hum increased here. It was even audible at times at the seat without music, under maxed conditions, and with my movie source setup, which is noisier than my audio setup. And the work I have done got it under relative control, enough not hear it unless close to the speakers most of the time, and having everything pretty cranked up. But still I would prefer none.
The utility power change made voltage more stable on our road, but increased variable hum, so I figured this was a good chance to go over everything and fix it as best I can. And the new 300B amp, guessing it is probably contributing from increased transformer fields from it's massive transformers (relative to my Torii), and from being "wide open," so amplifying noise before it more. On investigation though, I found the 300B is almost completely silent fed directly by the ZBIT/DAC only. Then the CSP3 pretty cranked added some, but still pretty quiet.
So I figured the 300B being wide open, and the CSP3 set high, both would be amplifying ZRock noise, the only stage left in this noise evaluation. I verified this switching in and bypassing the ZRock2... bypassed there was almost no noise. So I started working on it with noise in mind, taking it as far as I can for now, and with pretty good success.
More experiments to come, but if I turn up things near max, what noise is left is most times pretty mild, and the ZStage in the place of the CSP3 is about the same... Usually, my ear 1-2 feet from to the speaker, I can pick up noise, but sometimes less, sometimes a little more, seemingly with grid shifts??? But where I was going... Here, gain stages cranked up near, or at max, and after noise, reveal noise proportionately more in perception for me. It seems something like the last 10-20% on the attenuator punches up perceived noise in my current system. But when all is good, I love using a variety of gain stages.
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Adjusting Volume with two knobs? (Read 2229 times)
