Question regarding MC cartridge loading vs high frequency response

OK guys. I need help from the vinyl experts here as I have a bit of a system-related mystery going on. But first, some backstory.

There have been a couple very recent system changes that may be playing a role in this scenario. First, I just switched from an old stereo transistor power amp (Proceed HPA 2) to a new pair of tube mono blocks (Bob Carver Crimson 350)--my first tube components. Second, I just finished using my Dr. Feickert alignment tool for the first time as I wanted something more accurate than the Technics overhang gauge. (I used the Stephenson alignment.)

Now, today when I played vinyl for the first time after these two system changes took place the treble output was far hotter than what it had been before. (System is a Technics SL1200 G/Lyra Kleos MC cartridge feeding a Parasound JC3+ phono pre via Shunyata Research Zitron series Cobra cables--Music First Audio Baby Reference passive preamp) I hadn't changed the phono pre loading (100 ohms). The tube amps do have a brighter presentation than the rather dark sounding Proceed amp, but not nearly enough to explain what I was hearing.

Wondering what was up I first checked to see if the change in cartridge setup had also changed the tracking angle, and sure enough the arm was tilted slightly tails up. So I dropped the back of the arm down to level. That did improve things somewhat--especially in the bass--but the treble was still too hot. The good news was the high frequency output was clean as could be, vocalists were dead center and there was no treble splash to either side. There was just too much of a good thing going on.

I then went on the internet to explore cartridge loading. I came away with the impression that dropping my loading from 100 ohms to something lower will reduce the treble output somewhat, and, of course raising the loading above 100 ohms will increase the treble output. (FYI: I set to 100 ohms based on Michael Fremer's review of the Kleos.)

My question to anyone out there who wishes to respond is.....do I have it right? If so, how much do I need to drop down from 100 ohms to even out the top octave to octave and a half (approx. 5 kHz and above)?

Also, what could have caused such a dramatic change in my vinyl playback? It sat around unused for about a month. That couldn't possibly be the cause could it? Honestly, I'm at a loss.

Anyway, thanks Hoffman Forum members for the assistance.

 

I’m no expert but I have owned the JC3+ and while nice, I found it leaned toward a brighter, drier presentation. Add that with the Lyra (which I have never heard, only read about) which supposedly leans bright, and this combination puts you where you aren’t feeling satisfied. The gear is wonderful, but together (along with the amps, cables, etc) they just may not give you the sound that you are seeking.

As for loading in the JC3+, I have found that it does change the sound, but very subtly. I can’t imagine that loading on its own can give you the change you’re seeking. But at the end of the day what do any of us really know? I recommend tweaking your loading and listening, it’s the only way to truly see.

Good luck, I hope you get it sorted out to your satisfaction.

 

I would check the sound of a cd or digital file to see if those play with an exaggerated treble also. It may be a mismatch between your passive preamp and the tube amps. You vinyl setup might not have anything to do with it.

 

I based the loading on my cartridge based on a review of similar gear to what I bought. I forget the loading that was recommended in the review. While I think it was a good starting point, probably saved me a lot of time getting to my final setting, the settings weren't even close to what I ended up with. I'll tell you this, the recommendation in changing the settings were found to be opposite of what found. The suggestion was to increasing the loading and I found that decreasing the loading was better. I'm not sure why that was, probably room dynamics. But it's what happened. So, try things at different setting and see if an improvement happen with a change. I'll state that a single increment in the loading may not be noticeable so keep incrementing until you actually hear a difference and determine if it's better or worse. You can always go back to previous settings. The way I see it is that you bought the gear to you bought to have the flexibility to tailor the way your system sounds, so you should at least become familiar with the settings. You can read stuff on the internet, but at the end of the day, you're the only person on the internet that's going to listen to your system.

 

I would agree with trying different settings, although I also agree that that should not produce the results you mentioned.
If there is a 47k ohms option, try listening to the cartridge completely unloaded to see if there is an even brighter sound. If it does not produce that effect, then that eliminates the cartridge loading as a culprit, since not loading it at all will bring out the best - or worst - in the musical presentation.

 

If I read this right, the Kleos is not new, you just redid the install with the Feickert? I am not familiar with your table, but are you sure you're using the same tracking force as before?

I am not familiar with Lyra cartridges (in the sense that I have never owned one), but I think they may sound somewhat similar to Sumiko's top-end products (lots of detail and top-end extension). Sumiko goes out of their way to state that the best sound from their cartridges will be obtained with a negative rake angle (tail down on the tonearm). So I think lowering the back of your arm has you on the right path. Just make sure after you do so that you dial in your tracking force again accordingly.

As far as loading, it seems I read before that Lyra is somewhat unusual in that they seem to make a bigger deal regarding capacitance for their offerings than most other manufacturers of moving coil cartridges. You might look into this...it may help. Then again, maybe you're just now hearing what a Lyra cartridge is supposed to sound like now that you have it all aligned properly?

 

I'm curious where you see that recommendation? I'm not sure how much of the design and manufacture they control these days, but still seems odd they would design and build a cartridge that wasn't optimally aligned with a level tonearm at the recommended tracking force.

 

It's in the lengthy set-up guide for the Blackbird cartridge.

 

Yea OK, I didn't see it there except for the recommendation on where to start the VTA adjust process (they say it doesn't work going from above, not sure why), but no biggie, I was just curious.

 

Here's the excerpt:

 

Ah ok, I see that now, an addendum at the end of the azimuth section, still seems odd that they wouldn't fix it in subsequent designs. Also realize this is the same manual supplied with the previous elliptical stylus version, the one I downloaded from the site is dated 2003, you would think that a new stylus and cantilever may necessitate new instructions to optimize setup.

Anyway, thanks, I missed that drawing showing an apparent preference for the -1.2 deg setting of VTA.

 

please list every change of hardware since the cartridge sounded neutral.
FYI loading with lower resistance usually brings down the top end but Lyra carts are somewhat unusual- it is based on cable capacitance and loading combinations. check your manual and find out the capacitance of your cables.
For VTA aim for a dead level top of headshell, in the groove.

 

The electrical impact of cartridge loading on frequency response with a moving coil cartridge is negligible.

Because moving coil carts are so low in inductance, the resonant peak of the circuit formed by the cartridge inductance, cable (and phono stage) capacitance and phono stage resistance is always up in the radio frequency range. The peaking of the circuit is miles above the top octave, and changing those R, C and L values a little bit here and there aren't going to moved that resonant frequency into the audible range.

If the phono stage doesn't like radio frequency ringing, and the ringing is inadequately damped, things can seem brighter and harder with a lighter resistance load , but you're probably not actually effecting top octave performance, and you won't encounter that kind of change with every phono stage.

If you get to some extreme levels of resistance loading -- where the resistance load on the cart is nearing the internal impedance of the cart -- you'll start to have voltage loss that could give you a kind of softer sound. More insertion loss is not a great thing especially in a signal chain where you're trying to boost a very low level signal.

Lyra has an almost absurdly specific resistance load recommendation for that cart -- 95.3ohm ~ 816ohm. But it is a 5.4 ohm internal impedance cart, so, I guess if you want to try a heavier load on the cart you could, now to say 60 ohms. But if you're hearing a change in the sound after changing the amps and the cart alignment, I'd look to the amps and the cart alignment as the source of the difference, not the phono cart loading, which hasn't change and is in the specified range.

I don't know if you have any other source besides vinyl in the system, but I'd definitely check other sources to see if your issue is actually related to anything in the phono signal chain or more relating to the amp change.

Two things on the amp change -- first, I don't know if you're going balanced or unbalanced, but presuming unbalanced, you've gone from an 11k ohm load on the passive pre to a 100k ohm load. That could have an impact on frequency balance depending on the nature of the output impedance of the passive pre. (You could actually be getting considerable less insertion loss now with the higher impedance load of the tube amps, that could make things sound hotter certainly.)

Also you've gone from solid state amps with presumably very low output impedances to tube amps with a relatively high, 1.7 ohm output impedance. I don't know what speakers you're using but, depending on the impedance curve of the speakers that change in amp output impedance could also be having an impact on frequency balance.

I'd check the phono performance against other sources before trying to do all kinds of things like operating the phono change out of the recommended range trying to change sound elsewhere in the chain.

 

Thanks for the input guys. More info...

The tube amps definitely do have a brighter output in the top two octaves or so. Particularly, in comparison with the rather dark sounding Proceed amp that was in the system just before them. The Carver units are also amazingly clean up there, and they throw those highs out into the room like you'd hear from real cymbals. They are also highly resolving. The soundstage layering I'm getting with these things is the best I've experienced. And hidden little details in the various mixes are making themselves known. This is with both sources.

Regarding the Lyra cartridge, it has about 35 to 40 hours on it so far. So maybe more break-in time is required here--particularly now that my setup is more accurate as my realignment with the Dr. Feickert tool was successful. My turntable is now doing a much better job of tracking difficult albums. ( That was money well spent.) I experimented with loading and ended up back at 100 ohms. Dropping lower did not lower the treble.

As far as the passive preamp goes, it uses attenuation transformers and is immune to the cable length/resistance problems that afflict other passive attenuators. I'm still using a balanced cable to link the preamp with the Carver amps. I may experiment with a set of single ended cables to see what change that may bring.

Finally, now that I've played a wider range of recordings I'm finding the (comparatively) more forward nature of these amps to be both a blessing and a curse--depending on the recording in question. I was enraptured with the sonics I was hearing when my CD of White Winds by Andreas Vollenweider was playing. Absolutely the best I have ever heard that recording sound. The way that certain elements in the mix just hung suspended in the air, and the delicacy of the treble when various chimes and bells were struck just had me spellbound. Also, some of my older rock recordings seem to like these amps. The old MFSL CDs of Procol Harum's Broken Barricades and Robin Trower's Bridge Of Sighs gained new life. Again, a lot of that had to do with the better soundstaging and resolution. The sparkle on top didn't hurt either.

However, there were also some sonic flies in the ointment. Lateralus by Tool--a recording that could never be described as warm and fuzzy--came off as too brash and clinical. Am I hearing the truth for the first time? Having said that, even with this album I was getting info I hadn't heard before. Maynard was certainly more intelligible. Also, my old LP of Steely Dan's Gaucho came off a bit cold, and those layered stereo background vocals with the hot Ssss had nowhere to hide. Again, not a warm and fuzzy recording to begin with.

Finally, I don't know what roll break-in plays with tube amplifiers, and these are brand new. It could be that I just need to live with these for a few months before I make any decisions. It could be that both the Lyra cartridge and the amps need more hours of play with all kinds of recordings. It certainly is a different sound I'm hearing compared to what I'm used to. Maybe that's the biggest problem. Personal bias.

 

Also, in regards to the tube amps, I've yet to try using a different tap (I'm on the 4 ohm tap now), and I've not messed with the tube bias either. I'm currently at 100 mA and may try raising it up a bit. The Magico loudspeakers I use are rated 5 ohms with a 2.8 ohms minimum specified in the bass. (I found a review on the web that measured a 2.3 ohm load at 76 hz. So I may try the 2 ohm tap.)