Newbee,
I think it’s time to change your handle to old pro!
+1. Excellent suggestions by Newbee!
Interestingly, but probably inconsequential, is that the unused CD input has a little hum to it at full volume, whereas the other inputs do not. This is just a little side note.
That sounds like normal behavior. It can be expected, especially with high impedance inputs such as those provided by your preamp, that small amounts of noise and/or hum will be picked up by unconnected inputs. Although it is essentially a non-issue, if you wanted to get rid of this hum you could purchase RCA shorting plugs from one of several eBay sellers who offer such things, and insert two of them into the RCA jacks for that input while setting the input mode to single-ended for that input. Or you could insert those shorting plugs as stated, and also jumper pins 1 and 3 together on the corresponding XLR connectors. Doing that would eliminate the hum regardless of whether the input mode is selected to be single-ended or balanced.
Regarding the more significant issue, I understand that noise is clearly audible at the listening position in phono mode when the volume control is set at max. But based on what has been said I’m somewhat uncertain as to how loud and how objectionable the noise is at the listening position, with no music playing, when the volume control is set to the highest position you would normally set it to when listening to music. That is really what matters.
In that regard, these two statements in update 2 appear to conflict:
I lowered the gain on the phono stage from 55 to 50db. The theory is that I can turn the volume high without much issue on the preamp. I did this, and indeed, with the lower gain on the Whest, I had to raise the volume quite high to get a loud experience, but I was not maxed out.
50db is working, though I am still at the top of the volume control.
As I say, what matters is the noise level, as perceived from the listening position, when the volume control is at the highest setting you would normally use.
Also, to be sure it's clear, keep in mind that phono sources are inherently much more susceptible to noise issues than both digital sources and non-phono analog sources (e.g. tuners), due to the vastly lower signal levels that phono cartridges put out, compared to other sources, and the vastly higher gains those signals are subjected to compared to the outputs of other sources. Any noise introduced to or generated by the circuitry at or near the input of a phono stage, and/or subsequent amplification circuitry within the phono stage, will be much greater in relation to the magnitude of the signal at those points than the same amount of noise would be in relation to the magnitude of a signal provided by other sources.
But if this noise does in fact occur to an objectionable degree at the listening position at normally used settings of the volume control, and you have not been able to reduce it to acceptable levels after trying various phono stage gains, it would seem that you’ve probably isolated the issue to the phono stage. Which is surprising, given its reputation for quiet performance and given the not particularly low 0.6 mv rating of your cartridge.
Although I’d feel more confident in that conclusion if shorting plugs were placed on the inputs of the phono stage when the turntable is disconnected, rather than leaving its inputs unconnected. Assuming you don’t have any shorting plugs on hand, though, what might be worthwhile would be re-assessing the noise with the turntable disconnected and with the phono stage’s input loading set to its lowest possible value, which I’ve seen indicated as being 50 ohms. And for that matter, let us know what loading choice you’ve been using with the Delos.
Any suggestions on a super quiet phono stage?
The Herron VTPH-2 ($3650) which I purchased not long ago is incredibly/totally/absolutely silent in my setup with the 0.5 mv cartridge I am using, as well as being wonderful sonically (see the many comments that have appeared here about it in past threads), as well as providing much more versatility than the single gain setting of the ARC phono stage you mentioned. And Keith Herron is an absolute treasure to deal with.
Best regards,
-- Al
