Varying hum on my VPI CLassic

[bsambo59]

All,
First, thanks for all the input from everyone on the Grado cartridge, I really appreciate it. The 1.5mV is indeed the right one for this TT.
I have read about this on a forum recently, but can't find it, so I will ask for any advice: I now have a light hum that increases the closer the tonearm and cartridge is to the center of the platter. It doesn't even start until you bring the tonearm over close to the platter and gets progressively louder if you continue to take the tonearm further in to the center. Is this due to lack of shielding on the VPI motor? Can anything be done to reduce this?

Thanks,
Sammy

[Alec124c41]

Have you tried reversing the plug in the socket, or is it one-position-only?

Cheers,
Alec

[bastlnut]

hallo,

looking into the issue of hum on the Classic.
it seems that it is not uncommen, but there is a solution that many ignore.
in the manual on page 8 it says.....

If you notice hum in the system, remove the interconnects and replace them with very cheap, standard VCR interconnects. These are well shielded and should eliminate the hum. If the hum goes away, get quality, well shielded interconnects.

this makes sense, and you have had some success with rerouting your cables.
maybe trying a mat will also help, and it may help the sound.
it is trial and error of course.

regards,
bas

[bastlnut]

hallo,

another question.....
are you using a mains filter for your system?

regards,
bas

[Ldg]

I have read about this on a forum recently, but can't find it, so I will ask for any advice: I now have a light hum that increases the closer the tonearm and cartridge is to the center of the platter. It doesn't even start until you bring the tonearm over close to the platter and gets progressively louder if you continue to take the tonearm further in to the center.

Hi bsambo59. Assuming a Grado (as per previous thread), hum pickup in certain Grado cartridges seems an unfortunate part of life's wondrous tapestry. I looked into why this might be, and formed an opinion that the specific Grado coil arrangement might be vulnerable to specific types of magnetic hum pickup. And to mitigate, one should avoid (or shield) sources of magnetic hum/interference, such as certain motors, lighting circuits etc etc. It's pretty well known, and seemingly fundamental, but no-one seems to talk about it. Seems unlikely to be cable/mains filter addressable or related as per BaS post. Pragmatically, you'll probably need to shield the motor to use that cartridge/TT combination sans hum.

HTH !

Personally, I hate hum.

[bsambo59]

After looking around the internet and seeing numerous cases of this happening with Grado carts on the VPI, I am convinced it is time to go with a cartridge that is shielded. I find it odd that with this many instances of this happening, that either Grado or VPI doesn't do something about this.
Any opinions on a cartridge for up to $1000 that is shelded and would be a good match for the VPI? Dynavector and Benz keep popping up as choices from others.
Hey, at 50 pounds, the VPI makes one hell of a paperweight in the meantime..........................

[bastlnut]

hallo,

before you give the Grado back, you can try and see if there is a fix.
many have used shielded interconnects and this solved the problem for them.
i know of other instances that a mains filter did clean up the electrical noise of a system with the side effect of solving almost all of the hum problems.
as per the VPI manual, try some shielded video cables that are shielded and see if this solves the problem.

if you want to switch cartridge anyways, a Dynavector XX2 or Benz Woody would be great.
athers to consider would be a Shelter or a ZYX.

regards,
bas

[Ldg]

I think it's bad advice to venture further on interconnects/filters etc, in this case, based on my own experience, and on what I understand to be the theoretical situation in play.

On other threads here I posted what seems to be fundamental differences in the magnetic arrangement of Grado cartridges. It's not so much a matter of cartridge screening, more of the magnetic arrangement versus other two-coil cartridge arrangements, IMO.

So most alternate MM/MI cartridges probably won't exhibit notable hum in this specific case, as I see it, no need to go looking for special screening.

HTH !

[bastlnut]

well, yeah, theories,
another bugaboo for me. its only a theory, only trying something will show you if it works or not.
in the US market, it is easy to try something and send it back if not satisfied.
shielded cables are a must with a Grado cartridge.
if the disturbance can come thru a platter from a motor, then it can come in from the cables that are not shielded.
much easier as a matter of fact as they go directly to the coils.

if changing the poling of the power cord can clean up disturbances of a transformer or motor, then a power filter can also make a difference.
dismissing a possibility just because of a theory is contrary to searching for a solution.
never try it, never know.

regards,
bas

[bsambo59]

I have some pretty high end shielded interconnects that I am using, but I thought I would give the cheap video interconnects a try. Same noise/hum and it increases as I move the tonearm towards and over the platter. It was worth a try and at least now we know that is not it.
I am back the issue being the design of the Grado and the need to go to a more shielded cart.
I am still thinking either the Dynavector or the Benz. I do see that VPI also offers a Dynavector 20X Special with a 1.0mV output. Any thoughts?

[bastlnut]

hallo,

i like the Dyna 20X, but never heard a 1,0mV version.
if you can, just go for the low output version that should be teh better for fine detail and dynamics.
unless you can not accomodate a low output MC.

i like the Grado sound so that i will find a solution or change equipment so i have the option of using one.
VPI seems to know of the problem, but do nothing about it.
who is a fault, VPI or Grado...the Chicken or the Egg?
Grado has made their cartridges so for decades, VPI and everyone knows it.
the only new guy on the block is VPI.

regards,
bas

[bsambo59]

Yeah, it amazes me that Grado and VPI keep selling this combo despite the issues.
I use a McIntosh MA-7000 integrated amp with a built in phono stage. I am a little leery of using the Dynavector with only a 1.0mV. Thanks to confusion between my dealer and Grado a couple weeks back, we tried the Grado Sonata with a .5mV and there wasn't nearly enough amplification. The 1.5mV Sonata currently on my TT has what seems to be the perfect amount of amplification.

If I remember correctly, Dynavector also makes the 20X in a 2.8mV........

[bastlnut]

hallo,

you will need a high ouput cartridge then.
the Dyna 20X is good, but the Grado does it for half the price.
you may want to look at the Benz Micro Wood you can swing it, if not the Glider.
Benz also makes a medium output MC with 0,8mV for valve phono stages,
so the Dyna is probably oriented similarly.
a Van den Hul would also be a good choice, and they have high output MCs too.

regards,
bas

[bsambo59]

But the Grado throws in the hum for no extra charge on this setup?

Is it safe to assume the Dynavector or the Benz is better shielded and has a much lower chance of hum??