Hi Lowrider,
What phono stage are you using? And how long is your phono cable? I'm wondering if load capacitance, which is affected by both of those things, could be a contributing factor. Rega doesn't seem to specify a load capacitance recommendation for the cartridge, but their own MM phono stage has a specified input capacitance of 100 pf, which can probably be assumed to be in the right ballpark in combination with typical phono cables and cable lengths.
Also, perhaps additional breakin is needed?
Best regards,
-- Al |
Thanks, Lowrider. Before you give up on this cartridge, here are some further thoughts:
I took a look at the manual for the Linn Axis, which is written based on the presumption that a Linn Akito tonearm is being used. It appears that the arm has a calibrated VTF (vertical tracking force) dial on the counterweight, which should be initially adjusted such that it reads zero when the counterweight is set such that the arm "floats" (i.e., it does not have any downward or upward force). That should be done with "bias" (antiskating) set to zero. The counterweight is then adjusted to the desired VTF.
VTA (vertical tracking angle) is set by loosening a hex screw on the base of the arm, and raising or lowering the height until (as recommended in the manual) the arm tube is parallel to the record surface. It can be and ideally should be fine tuned from there by listening.
Are those the procedures that you followed, and if so what tracking force did you end up with?
Also, I note that the manual recommends setting the bias/antiskating dial to the same value as the tracking force. That kind of recommendation has often been made by turntable manufacturers, but is completely ridiculous IME. If that is what you have done, try setting it to half that value, and fine tune from there by ear.
Concerning my earlier comments about load capacitance, given the three foot length of your phono cable, and the 100 pf input capacitance of Rega's own MM phono stage (which would presumably be a suitable match for their cartridges, in combination with the capacitance of typical lengths of typical phono cables), I suspect that neither setting of the 0/150 pf switch on your preamp would introduce a great enough incompatibility to account for most or all of the symptoms you have described. But it's probably still worth opening the preamp and trying the other setting, as that could conceivably help to some degree.
Best,
-- Al |
Can anybody tell me Raul's Agon "handle" or a link to the MM thread and I'll get back to you soon. Rauliruegas. Stand back before clicking, though. It's over 11,000 posts! We'll understand if your intention to "get back to us soon" turns out not to be practicable :-) Best regards, -- Al |
Manitunc, if you were familiar with Lowrider's posts you would realize that when he says "all my LPs are top class," presumably referring to those he has used in assessing the new cartridge, he knows whereof he speaks.
Also, there are many digitally mastered classical LPs that provide excellent sound quality. Many (although certainly not all) of the 1980's Telarcs, for instance, some of which I recall Lowrider mentioning that he owns.
Regards,
-- Al |
Lowrider, I see what you are referring to, on page 6 of the manual for the Perseus. It makes no sense to me, though, that they would provide a 0/150 pf selection for moving coils, and no capacitance selection for moving magnets. So I'm not sure that the info shown in the manual is correct. It might be worth your while to open up the preamp, and change the capacitance setting to the opposite of what it is at now. And while you're at it, make sure that resistance is in fact set to 47K, and that gain is set to 45 db and not 65 db. Hmmm. Come to think of it, the 45 db MM phono stage gain + 15 db line stage gain of that preamp is pretty high for use with that cartridge, which has a specified output under the standard test conditions of "6.8-7.2 mv." Is the harshness and thinness particularly or mainly evident on high volume peaks? Best regards, -- Al |
I can't say what the answer to Q1 is, without being familiar with the sound of the particular recordings. Re Q2, if load capacitance differs considerably from what is optimal for a particular MM cartridge, in either direction (too high or too low), it will profoundly affect the upper treble, quite possibly the lower treble, and perhaps even the upper mid-range. It is very conceivable that a severe enough mismatch could cause massed strings and brass to sound harsh and thin.
Typical MM load capacitance recommendations tend to be in the area of 100 to 300 pf, or in a few cases as much as 500 pf or so.
Load capacitance will affect LOMC sonics to a MUCH smaller degree, and in indirect ways that involve how the phono stage responds to ultrasonic and RF frequencies. So as I said, despite what the manual seems to say it doesn't make sense that the preamp design would provide a 0/150 pf switch for LOMC's, but no selection for MM's.
The "0" position, btw, will not really be 0 pf. It will be some presumably fairly small number corresponding to the intrinsic input capacitance of the preamp, while the 150 pf position will be 150 pf greater than that. And the capacitance of the phono cable will add significantly to that total.
Repeating my earlier question, how long is the phono cable?
Best,
-- Al |
Doug, thank you kindly. My comments are as follows:
First, as I know Doug realizes there are two different test standards against which rated cartridge outputs may be specified. If I recall correctly that can produce a disparity of +/- 3 db between ratings that are provided by different manufacturers. 3 db corresponds to a voltage ratio of 0.707, so it is possible that the output of the Rega cartridge, nominally rated at 7 mv, is no different than the output of some other manufacturers' 5 mv cartridges.
Second, early on in this thread I had asked "is the harshness and thinness particularly or mainly evident on high volume peaks?" My understanding is that the answer was "no." Therefore I agree with Onhwy61 that the problem is unlikely to be related to phono stage overload.
I also inferred from the answer that the combination of cartridge output and system gain and sensitivity structure is not such that the volume control has to be operated excessively close to the bottom of its range. "Excessively close" meaning that volume adjustments might become overly coarse, and/or that the two channels might tend to get out of balance.
Assuming that my interpretations have been correct, I don't think that the relatively high output of the cartridge is an issue at this point, although if you were to change to a different cartridge it would be preferable to select one having a significantly lower rated output. Which shouldn't be hard to do, as I am not aware of any other cartridges rated as high as 7 mv.
If you'd like further commentary on the overall gain structure of your system, let us know what amplifier and speakers you are using, and what your listening distance is.
Best regards,
-- Al |
