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Phono stage gain setting to match preamp and power amp capabilities

Hello All,  I have a Whest PS .30R phono stage, with adjustable gain settings.  My Audio Research LS-25 preamplifier also has adjustable gain settings (high 18db, medium 12db, low 6db; I have been using high at all times as I believe this is the best sound quality & "native" setting).  The Whest gain options are 43, 50, 55, 60, 65, 72.  It also has adjustable load settings of 100, 220, 470, 1k6, 15k, 47k.

The cartridge is Lyra Delos (Output voltage: 0.6mV@5cm/sec.) The power amp is an Audio Research VT100 (100wpc).  The speakers are Rockport Mira Monitors ( somewhat low sensitivity at 85 dB SPL/2.83 v)

The reason I am looking for advice here has to do with how much I have to turn up the volume control on the preamp up to get to the loud volume that I like to listen at when I am in my loud listening moods.  In order to get to the point of a dramatic concert style experience in my living room, when playing vinyl, I have to turn the preamp volume to the 3 o'clock position. Once I get the volume control this high, the noise floor (am I using the term correctly?) or background hiss increases audibly.  I do not get loud volume without that hiss.  Of course, when the music is full, you cannot hear it.  But when the music is lean, the hiss is there.

For the past year or so, I had the Whest set to 60db and 220 ohms.  I arrived at 60 because I didn't want to over amplify the signal in the phono stage and get more hiss.  But then I had to crank up the preamp volume.  Now I just set the Whest to 65, and as expected, the volume control on the LS-25 can be backed down a little.  I haven't had the chance to really listen critically or for long enough time to determine if the hiss has diminished.  But I will log the listening time soon.

Can you give me any advice on the proper way to set these options?  Should I go to full gain on the Whest and back down on the LS-25 volume control even further?  Or is a lower gain on the Whest a better way to go?  Also, can you help me understand the nature and source of the hiss I hear?  What is it, why is it there, and how do I get it to be 'inky black' as some reviewers like to say?

Thanks!
Mark
marktomaras
marktomaras OP
544 posts
 
To recap, some say lower the phono stage gain, and some say raise the phono stage gain.  Does anyone want to back up their argument with some supporting evidence?

Almarg, As for amplifier interference, I take it you saw my system photo. Is there anyplace on the rack where the amp would not interfere?  I ask this because the speaker cables are not long enough to have the amp anywhere other than in the center position.  The only option would be to put the amp on top of the rack, next to the turntable, or, reconfigure the shelf heights and put the amp on the bottom, with the preamps on the raised up center section.  If you think this is not adequate, then unfortunately, I don't have much of an option.  Of course, if I am looking for the source of the hiss, and that is it, I can put the amp on the floor in the middle of the room as I have some longer interconnect, but I think I will save that for the last test.

As for the ground loop, just so I understand properly, I disconnect my power conditioner from the wall outlet, plug in the cheater plug, and replug into the wall, and listen for a hiss change/reduction?  Is there any danger to my equipment for this test?

Thanks!
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almarg
9,670 posts
 
Can I turn the volume up, have the input selector on phono, and just listen with nothing playing?
Absolutely. In fact, that is what you should be doing. Additional noise that occurs just while a record is being played would be a function of some combination of the turntable, tonearm, cartridge, cartridge and tonearm adjustments, and the recording. And for a given playback volume would not be affected by the gain settings.
Some say lower the phono stage gain, and some say raise the phono stage gain. Does anyone want to back up their argument with some supporting evidence?
As I said, it’s hard to predict without detailed knowledge of the Whest’s design, and perhaps also without published measurements being available. But FWIW my instinct is that more often than not lower phono stage gain will correlate with better noise performance, **everything else being equal.**
If I am looking for the source of the hiss, and that is it, I can put the amp on the floor in the middle of the room as I have some longer interconnect, but I think I will save that for the last test.
Yes, I was just suggesting moving things for experimental purposes, to see if it makes a difference. So this sounds like a plan!
As for the ground loop, just so I understand properly, I disconnect my power conditioner from the wall outlet, plug in the cheater plug, and replug into the wall, and listen for a hiss change/reduction? Is there any danger to my equipment for this test?
No to both questions. Regarding the first question, as I indicated the cheater plug(s) should be placed on the power plugs of the phono stage and/or the preamp, to eliminate the possibility that a ground loop between those two components may be contributing. (Putting a cheater plug on the preamp’s power plug would also break a ground loop between the preamp and the power amp, although it doesn’t seem as if that is an issue here, since the noise is volume control sensitive).

Regards,
-- Al


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almarg
9,670 posts
 
P.S: Regarding the phono stage gain question, you may find the following thread to be of interest:

Gain vs. Volume

The bottom line, as stated in that thread by Atmasphere:
A simple way to look at it is to use the least amount of gain that you can to get the job done, as the more gain, the more can go wrong.
I am citing this in regard only to the phono stage in this case, however. Not in regard to the preamp, due in part to the examination of its schematic that I mentioned.

Regards,
-- Al

marktomaras OP
544 posts
 
Al, would you mind a brief phone chat with me? 

Thank you!
Mark
305-775-3020
oscar44
130 posts
 
I use a Whest and find that I enjoy the sonics with as much gain as I can use for a particular cartridge to have the resulting volume comparable when switching source from CD to turntable on my preamp.  I've gone as high as 65db with medium output MCs to great effect but when I go too high, it's obvious to my ears that I am overloading my pre-amp.  With your cartridge, I'd live with 65db and see what you think over time. I don't know your preamp but having owned two Whests now, I consider them pretty quiet. Maybe go to 72db just to hear what max gain sounds like too, it'll be a reference. MY guess is you'll be most happy at 65db on the Whest, and less volume on the preamp.
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