How to reduce hiss with phono at high volumes?

[Dev_Steve]

Hi All

I’m looking into a STU, but I have two more questions that I’d love your guidance on:

1. When digging into the “white noise” issue, I actually disconnected the rcas to my turntable from the Expert Pro. Even without any turntable connected, the Expert Pro still had a lot of white noise. Is that typical?

2. Would power conditioning also help this issue?

Thanks, all! Your input has already been hugely valuable.

1. Yes, with inputs open there may even be a slight increase in the noise. If you have some RCA shorting plugs you could plug into the inputs you would see the minimum noise level of the phono amplifier.

2. The noise is mostly from the solid state devices themselves in the high gain amplifier. Some of the noise is probably attributable to the internal power supply to the phono stage, but if the power supply is well designed this would be very little. An external AC power conditioner is very unlikely to make any appreciable difference.

An MC step up transformer is going to be the best solution. With your cartridge I’d be looking at something like a 1:20 step up ratio.

I have found that the phono stage in the Devialet is quite susceptible to overload, there isn’t a great deal of headroom.

I found you need to be quite careful with the maximum signal settings in the configurator. I am using a 1:8 ratio step up Lundahl transformer, LL1933, with my Koetsu Black. I found that setting the MM stage at just above the maximum expected voltage from the SUT the phono stage was overloaded (the dB indicator in the display flashes orange) by some LP’s cut at quite a high level.

I set the maximum signal level to 50% more than the expected maximum from the SUT. Which means I need to increase the volume level quite a bit more when playing LP’s compared to a digital source.

So if you go down the SUT route then expect to do some experimentation with the input level. Of course this is quite easy on the Devialet as you can adjust the setting on the fly with an LP playing using the remote while viewing the phono settings menu in the display.



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This is great. I was thinking of going with the Ortofon ST-80 SE as I'm not really technically sophisticated enough to dig into the different details on more artisan options. My thinking is that given that Ortofon is putting out that particular transformer for its high-end cartridges, it should do the trick.


Admittedly this may be dumb question, but from my reading it sounds like you change the Expert Pro configurator settings to MM once you are working with the transformer. Is that correct?