Alon, re the question you posed just above, I think that the Coincident Statement Phono Preamp, with the apparently optional line-level input, is one to consider. I have no experience with it, but I have seen its sonics praised highly by other members. It meets all of the requirements you specified in your post with the exception that it does not have a fixed output. Obviously, though, you could determine a setting of its volume controls that would be optimal for use with your headphone amp, perhaps even the max setting that would essentially remove its volume controls from the signal path. It does provide two sets of output jacks, btw. There is no remote, though, and the separate dual mono volume controls may or may not be to your liking. Its 66 db overall gain seems to me to be a good match for your 0.4 mv cartridge and the relatively high 36 db gain of your amplifier. Good luck on your quest! -- Al |
Outstanding, Alon! And I must add that it's always a pleasure to read your witty posts. I take it that your preamp has both MM and LOMC phono stages. The manual seems to imply that the version of the preamp it is based on can optionally have one or the other, but not both, although it mentions the existence of an early version and a later version of the preamp. Also, I'm wondering what gain setting you are using on the transformer. As you no doubt realize, the gain of the transformer will be a key determinant of the loading seen by the cartridge. You might find this thread to be of interest. As you may realize, the load impedance that is optimal for a given cartridge can be expected to differ when a SUT is used, compared to when the cartridge is driving an active gain stage. As to why the apparent breakin phenomenon occurred, I haven't the slightest idea. My initial instinct would normally be to suspect that something unrelated was adversely affecting the sound during the first couple of hours, such as the warmup state of the equipment, or out of the ordinary AC line voltage or noise conditions. But the methodology you described would seem to have eliminated those kinds of possibilities. Best regards, -- Al |
03-25-12: Alonski
It seems clear and obvious (well, now) that "direct" is not possible because with any outboard or built in phono stage, one would need a volume control and additional circuitry to control the downstream amp, in essence, you need a line stage for this to work whether it's part of the Steelhead or VAC is irrelevant. FWIW, and I have no familiarity with the Steelhead, my take on this is that it is not irrelevant. The functionality of a line stage is needed, somewhere, but if that functionality is implemented to a high standard within the same component that provides the phono stage functionality, investment of a given number of $ can potentially provide better results, since those $ are only paying for one component instead of two (plus an extra pair of interconnect cables). Also, while a pure phono stage (lacking line stage functionality) will not incorporate a volume control mechanism, it still has to include circuitry to drive the line stage and the interconnect cable between the two components. The requirements for that circuitry will not differ greatly, if at all, from the circuitry that would be required to drive the power amp, and the corresponding interconnect cable. So the two-box approach means having an additional buffer/driver stage in the signal path, compared to the one-box approach. Obviously, those potential advantages of the one-box approach may or may not be realized depending on the specific components that are involved, system synergy, listener preferences, etc. In your particular case, my feeling is that what you previously proposed is likely to be well worth exploring: Replacing an amazing preamp that has a really good built-in phono stage, with an OUTSTANDING phono stage that allows me to go direct to my VAC amp for best LP sound (which is what I care about most) and would accommodate my CD player with what would probably be a very decent line stage input. So in essence, it's a preamp with its main focus on vinyl.
One more benefit to this is that I could sell my VAC pre to offset some of the cost of the new phono stage. Best regards, -- Al |
Alón, congratulations! That is exciting indeed.
A note of caution, though. Although the chances of a problem occurring would seem to be very remote, I personally would never connect the output of a component capable of supplying upwards of 2 volts or so into the input of a component that is designed to receive and process millivolts or less. Especially one as special and as expensive as this.
Yes, the CD may be designed to cause the player to output a suitable level, but things can go wrong. The player can fail abruptly in unpredictable ways, or go berserk. AC power can drop out, or flicker off and on, causing the player to briefly do who knows what.
As I say, chances of a problem occurring are very small. But I would take NO chances with a component as special as this one.
Best regards,
-- Al |
Bill, that looks to me like an excellent suggestion. You appear to be referring to the "KAB PreconLP Inverse RIAA Level Converter." It appears to be a purely passive device, using resistors and capacitors to divide down the signal level and also provide inverse RIAA equalization.
The only slight caveat I see is that when inputting to the preamp's LOMC inputs I would make sure that loading is set to 100 ohms, as opposed to a value that is much higher (e.g., thousands of ohms). Apparently the device relies on that loading, in conjunction with its own output impedance, to divide down what would otherwise be MM levels to LOMC levels.
In this case, though, even that concern is pretty much eliminated by the fact that the highest value load setting that is provided on the preamp for the LOMC inputs appears to be 470 ohms. That value would still reduce what would otherwise be MM levels by a substantial amount, probably something like 10 db (about a factor of 3 in voltage) according to my calculations.
Best regards,
-- Al |
Alón, yes, that is exactly what I am recommending that you do NOT use. Everything they say in the paragraph you quoted is essentially correct, but no matter how well the CD may be engineered for the particular purpose it cannot control what the PLAYER may do in the event of malfunction, momentary AC power dropouts, etc.
I believe that the moving coil section of the preamp employs a transformer at its input, which would be designed to handle signal levels measured in microvolts (millionths of a volt), and miniscule amounts of current. Misbehavior of the player, caused by the kinds of (admittedly unlikely) events I mentioned could easily put voltages across that transformer that are a couple of thousand times or more greater than those amounts. As well as overloading and stressing circuitry in the preamp that is downstream of the transformer.
Using the KAB device Bill suggested, you would use a conventional CD of your choice, and those risks would be eliminated.
Best regards,
-- Al
|
Alón, re your three questions:
1)As you may realize, regardless of whether other interconnections in the signal path are balanced or unbalanced, and regardless of whether the two components in question are internally balanced or not, having a balanced connection between them will reduce susceptibility to ground loop effects (both low frequency hum and high frequency buzz); will reduce susceptibility to noise pickup in the interconnects; and in some cases will reduce cable effects and cable differences. On the other hand, none of those things may be significant issues in a given setup. And the balanced vs. unbalanced alternatives will call into play different interface circuitry in the two components, and which may be better will depend on the particular designs.
So what I would suggest is asking Kevin for his opinion and/or trying it both ways.
2)Hard to say what minimum amount of separation would be ideal without having intimate knowledge of, and hands-on experience with, the particular design. Sounds like another question for Kevin.
3)I use shorting plugs (not caps) on unused RCA inputs in my system (not on outputs, of course, which should not be shorted). I doubt that they make any difference, but I suppose it is remotely conceivable that they could reduce noise pickup on unused inputs, that might to a small degree couple into the signal path. IMO caps are unlikely to accomplish anything more than keeping out some dust particles. Other opinions may differ, of course.
Best regards,
-- Al |
