Annoying Sibilance Problem


Ok so here's the scoop.

I've got a Grado Gold mounted on my Technics SL1200 and everything sounds wonderful, except on some recordings I get some pretty nasty distortion on hard T sounds and S sounds in vocals. It's not on every record but when it's there it's very apparent. I can't imagine the records are the problem as some of them are new, but I do not have another table/cart to test that right now.

The funny thing is if I swap the preamp over to mono the distortion is pretty much gone. Any ideas why it's doing this? Any help would be greatly appreciated.
silvergsx
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
Axel, I'm merely going by what it says in the manual that came with it. I'll shoot the company an email today and see if that's a typo and try to get more information on it.
Axel,

My #1 most challenging/torturous LP for reproducing clean high frequencies:

‘Les Plaisirs de la Renaissance’, Deller Consort, Harmonia Mundi, HMU 963

That Allison Kraus record is difficult because her closely miked voice and its echoes present waveforms at high frequencies that are very close together (in time). Many systems can't avoid mushing them together, which usually sounds horrible. The Deller LP is more difficult for several reasons:

1. Deller's voice is much stronger. Bigger amplitudes challenge the tracking ability of the cartridge, the ability of the phono and other amplification stages to avoid slewing distortion or overload, the ability of the power supplies to resist being modulated by the signal and the speed and non-distorting cababilities of the midrange and tweeter drivers.

2. Deller is doubled and/or harmonized by an alto recorder, an instrument whose rich and tight harmonic structure is also difficult to reproduce. When he and the recorder hit/hold the same note or harmonically related notes, keeping the two voices separate is a severe challenge.

3. Unlike Krauss, both Deller and the recorder actually know where the notes are. ;-) Pitch stability from the TT is super-critical.

4. The recording was made in a stone hall - nicely authentic but intensely echo-ey, with multiple and extended reverberant decays.

5. One of the most challenging tracks was placed on the inner grooves (on side 2), adding smaller modulations to the challenges.

Other Deller Consort recordings would probably present similar difficulties. Keeping all these strong, closely related high frequency waveforms clean and separate is a terrific challenge. I've have other Deller recordings on CD so I know it can can be done. The trick is to do it from an LP, with its richer and more complete harmonic structures.

As Jaytea described for himself, it also took me four years of work (and a lot of money) to be able to play this LP cleanly. It's one of the first I play to test any new component or tweak because it is so unforgiving, and so satisfying when all is right. :-)

Another tough challenge in a similar way is the 'La Boheme' on Decca/London with Renata Tebaldi. On any 'La Boheme' Mimi's first big solo comes near the end of side 1, where tight inner groove modulations make the problem we're discussing more challenging. The Decca recording was also made in a sonically rich acoustic (though not stone, thank goodness!), which brings echoes into play again. Tebaldi's voice is of course more powerful and pure of tone than any pop/jazz singer, which adds amplitude and the need for tonal accuracy to the challenge.

If you can get through side 1 cleanly (which took me 2-3 years) don't congratulate yourself yet. The big crowd scenes and multiple voices on side 2 are more difficult for some components. It's a never ending battle. :-)
Hells Bells, great stuff!

Doug, now you mentioned one that I actually have, and I know EXACTLY what you say.

+++ Another tough challenge in a similar way is the 'La Boheme' on Decca/London with Renata Tebaldi. On any 'La Boheme' Mimi's first big solo comes near the end of side 1, where tight inner groove modulations make the problem we're discussing more challenging. +++

I have the 'wide silver band', -- so much the better. I have made some progress in getting that 'improved' but not perfect for sure. That groove made me send a re-tipped Dorian two times back to the re-tipper. It got better, but also never really 'right'. That Tebaldi soprano could crack glasses, I say.

Thank you for your most helpful detail,
Axel