Phono stage inquiry


I have an upgraded Whest PS.30RDT & when I increase the volume on the phono stage input when nothing is playing to a level not too far beyond my usual listening volume, I can hear a hiss. 
Should it be silent? Do any of you have this with your phono stage?

Thanks for your time. 
128x128infection
Like several of the others my guess is that the hiss represents normal behavior for this particular design, and for many other phono stages as well. However as Lew indicated we don’t have enough information, or familiarity with the particular phono stage for that matter, to be able to say for sure.

I see that for low output moving coil cartridges the gain of the phono stage can be adjusted via internal switches between 50 db and 72 db. Assuming you are using an LOMC you might find that changing the gain from whatever it is set to (probably in the direction of reducing it by a modest amount) can help.

Also, as Steve (Williewonka) said, different phono stages differ significantly in their noise performance. Like Bill (Bpoletti) I have found my Herron VTPH-2 to be totally silent, even when listened to in LOMC mode with my Stax electrostatic headphones firing directly into my ears and with the volume control on the Stax amplifier at max (which is way higher than I would ever set it to while listening to music). But that has been a source of constant amazement to me, and I would not expect the majority of phono stages to be similar in that respect, at least those having active input stages as opposed to transformers.

... with the hiss there’s also a mild hum
That could be due to a ground loop issue between the phono stage and the preamp. As an experiment, try temporarily putting a cheater plug (a 3-prong to 2-prong adapter) on the power plug of either component, to defeat the safety ground connection. That would break a ground loop that may exist between those components.

Also when I disconnected the XLRs from the Whest & increased the volume on the phono stage input I could hear my CD transport playing.

Assuming you are referring to XLR cables on the output side of the Whest that sounds like crosstalk within your preamp. Normal (albeit non-ideal) behavior for many designs, which is likely to be exacerbated when the preamp’s input is left unconnected.

Regards,
-- Al

Thanks again for the replies guys.


@lewm  it's interesting you say that because I have increased the gain setting to 100. Even though, I would have thought it should still be fairly quiet...


@almarg  here are the specs -

RIAA curve accuracy: 17Hz – 20.5Khz +/- 0.2dB or better

Frequency response: 5Hz – 62Khz +/- 1.0dB

Working band: 15Hz – 60Khz

MM Gain: 40dB @ 47Kohm

MC Gain 50dB - 72dB to suit all 0.15 – 2.5mV cartridges

Cartridge Loading 50ohm - 47Kohm in 6 steps

THD+N: 0.002%

My pre is a Wyred 4 Sound STP-SE stage 2... I have contacted EJ & asked about the crosstalk.



With all due respect I don't see how you could have increased the gain setting to 100dB (unless you modified the circuit) since it's only adjustable to a maximum of 72dB.
Dear @infection : No, certainly is not normal that hiss/hum you are experienced with your PS ( especially at that " moderated " SPLs. ) that even has a lower noise level than the top of the line Reference in Whest catalog. You unit must be totally silent by design.

So exist a problem in your unit that it's out of specs or contaminated from other audio system link. The hum could be a ground loop or maybe the orientation of the IC phono cable.

Anyway, exist a trouble down there.

Regards and enjoy the MUSIC NOT DISTORTIONS,
R.