Sometimes at louder parts and volume peaks of a vinyl there is a noticable distortion. This distortion is independant of the volume level of the pre.
I am now searching for the reason. The output of the Koetsu Black is 0.4 mV. So it is in the range of outputs a Superline Standard is build for (0.1 mV to 0.5 mV). Do you think that the distortion is caused by the amplification in the Superline because the output of the Koetsu is on the upper end of the compatibility range of the Superline?
I run the Superline with 100 Ohm and 4.7 pF. When I try a higher resistance or a lower capacity the distortion gets more noticeable.
Im not able to test a Superline E. But perhaps that is the right Superline to choose for a Koetsu Black. Does anybody has experienced a Koetsu Black with a Superline Standard?
I had no issues with an Urushi Wajima feeding the regular Superline and it should be able to handle the Black as well. Are the issues only while using the Superline and how old is the Koetsu? I have had tracking problems with mine, caused by its aging suspension.
I would naively assume that if Naim says 0.1 to 0.5, then 0.4 should be fine.
Have you had this combo for a while and was the distortion always the same, or is the distortion new? Or you cannot tell as it is all new?
And for the price of the Koetsu Black, don’t they have an opinion? Or the dealer (PhonoPhono?)
FWIW, PhonoPhono write on their website that the Black is very sensitive to VTA and should only be used on arms with a VTA adjustment that has 0.1 mm steps. So not a Rega. At the same time, of course, Rega says that VTA adjustment is generally unnecessary and a psychological condition rather than a technical one (they are not mincing words in the Rega book). You choose 
My SPU Royal N started distorting high levels but only on the right channel. When I took it off the arm I found the cantilever was no longer straight, not bent but skewed, you couldn’t see it when mounted. I’d been wondering if the bias was enough, looks like I found out.
I recalled that Richard uses a Black with an E, also on a Rega. See the discussion in the following thread. Notice the apparently inconsistent info regarding its output:
Yes, I have used my Black with a Superline E (not on a Rega, but on other decks). I don’t think there were any issues of this kind, but hard to say for sure as I also decided the Black was in need or a rebuild, which I haven’t had done yet.
Ah OK, sorry for confusion
I have tried different heights of the tonearm. Now I am using a 0.5 mm spacer. After installing the spacer the sound was a bit more forward. For me it sounds better than without a spacer. But with or without the space the distortion issue is the same.
It have called my dealer and he will make a visit to get the reason for the distortion. And it is not PhonoPhono.
My Black is about five years old. So it should not be an issue of age.
Yeah, I did not intend to say that the VTA and the distortion are related. It was just one of these funny hifi contradictions.
For the distortion, I still don’t know if it started suddenly in a system that worked before, but I guess it will be best if the dealer sorts it
Try the opposite; lower resistance or higher capacitance.
Hans
I have tried exactly this: lower resistance and higher capacity. In this case the distortion gets less noticeable but it does not go completely.
Then its unlikely to be the loading or the gain. Have you cleaned the stylus? I get a similar response sometimes when the stylus isn’t clean. Other possible reasons are tracking issues, which may appear if the cartridge isn’t properly aligned, or damages to either the cartridge, Superline or cabling.
Good luck.
Hans
How about a bit more VTF, what are you using?
I have tried different VTA. Koetsu suggests up to 2. I have tried a little bit more and less, but the distortion was not influenced by this. Now I am using 1.95.
After trying different capacities, resistances, VTF and Antiskating I have lifted the tonearm with a 2mm spacer. Before that I used a 0.5mm spacer. Although the cartridge has no more a 90 degrees angle to the platter the distortion is mostly gone!
So the problem seemed to be solved. I am happy! Thanks for all your hints!
Glad you are enjoying the spacer with your Rp10 and Koetsu. I used and use still spacer for my Lyra carts and Rp10 and now P10.
It’s definitely something to do, even if Rega thinks is against their philosophy.
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