Annoying Sibilance Problem

The phono stage is built into the preamp and can be swapped from MM to MC. The specs from the manual are as follows:

MC - 125mV for 0.5V output from source unit
MM - 125mV for 0.5V output from source unit

The input impedence for line-in is 47K Ohm +/- 5%

Signal to noise ratio - 97dB

The total empiricists "I never liked math guide" to phono stages first asks if you just changed your phono stage. second do you run it through a big tone mellow line stage after that.Which helps as foil.
I switched away from an all tube ARC pre with phono to a cheaper SS Graham Slee Amp 2 using a H.O. Dynevector 20 X m.c.. I only did this because the ARC had a noise floor at eye level and it had the kind of gain that could not be tamed. The new one is SS and while supremely quiet and toned up by a two 6SN7 line stage (Great rich tubes) I had the AE line stage hot rodded. As it broke in the sibililants became unbearable. I hung with it and depending on the record it has calmed down considerably with brake in. The voices aren't nearly as bad as massive collections of orchestral strings blaring out the high octaves. I May have to go back to work if I don't get bailed out. Then I will by an SLP-05 and use a separate a boulder phono.

I had a Grado master that had the same problems. Sent Cartridge back and tech made an adjustment and helped some what. A nice older gent. I upgraded tonearms from Rega 600 to Graham 2.2 and isuue was greatly diminished. However still there. The Grado was spectacular in some respects. Ironic it had an uncanny ability the reproduce the female voice when no sibilance was present. I remember one annoying track in particular "Radar Love". Gone to a Benz L2 and sibilance not a problem.

The specs for the phono stage make no sense? Is there any chance that you are running into the MC input or your preamp is set for MC gain internally? How high is your volume control set ? Is it possible that you're phono stage is overloading?

Hi Doug,
you say:
>>> ... there's nothing wrong with that Allison Kraus LP. <<<
Thank you for sharing that. I had a suspicion this COULD be the case. Certainly my system is not up to it (last track on side 2) in the current state.
Now it looks like I have found my 'Test-record' for this problem ---. Other than these two tracks I'd mentioned all sounds very nice otherwise.
Would you please share the other two 'tricky' LPs mentioned, it might me a good challenge to tackle those.

Hi Silvergsx,
you state:
MC - 125mV for 0.5V output from source unit
MM - 125mV for 0.5V output from source unit

That spec sounds impossible for the MC...

that 125mV looks like the overload spec. for MM and even high at that, see below.

An example could look like this:

Gain: 40 or 60dB @ 1kHz (i.e. MM or MC)

Input Overload: >100mV @ 1kHz, 40dB gain
>10mV @ 1kHz, 60DB gain

Greetings,
Axel