New PL-L1000

[Pio1980]

I also have a '1000 for several years now. It is normally fitted with a Audio technica Microline MM tracking at 1.2g. I have a special headshell which is just a piece of bent aluminum on a standard plug. This makes the arm fairly light. My question is that i see a special counterweight on your machine which looks fairly massive compared to the stock one without the subweight which is what i am using. Can you detail more the advantages of this particular mod? Thank you

From the AK ad section for this mod system;
"This replacement rigid tonearm counterweight will fit Pioneer PL-L1000, PL-L1000A, Phase Linear 8000 Series II, and Phase Linear 8000A turntables.

The removal of the original decoupled counterweight and installation of my rigid design is a relatively straightforward 30 minute (approximately) job and comes with instructions. This kit comes with 3 different mass counterweights allowing you to use any cartridge/headshell mass combination you like, however it does require you to set the tracking force via an external gram scale. The many choices of reasonably priced and sensitive electronic scales on eBay tend to work well in my experience and should be a part of any turntable owner's toolkit.

The original counterweight design (like the majority of tonearm designs), uses an elastically decoupled counterweight for what is known as "dynamic damping". The purpose of dynamic damping is to theoretically increase the amount of damping control at the tonearm's fundamental resonance frequency. This is the infrasonic frequency that is hopefully higher than the majority of warps, but lower than the lowest desired audible frequency.

The problem with the real-world implementation of dynamic damping is that it rarely works as well as intended for the damping of the fundamental resonance, and it totally destroys any chance of the tonearm pipe enjoying the important benefits of a rigid coupling to a high polar moment of inertia mass at all frequencies higher than the fundamental resonance (the audible band).

So the purpose of this mod is to add a very significant amount of rigidly coupled mass into the roll and yaw plane of the tonearm. Since this design also places the counterweight as close to the pivot as possible, it reduces the amount of vibrational energy ingress into the tonearm from the environment via the arm pedestal as well as reducing vibrational energy ingress into the bearings coming from the cartridge.

The net result is a significant improvement in sound quality due to addressing a very important area of the turntable right at the source of the problem. Other tonearm mods done further downstream from the pivot bearings will have much lower effectiveness."

 

[carlvalle]

thats interesting to be sure. did you remove the gasket at the headshell mount also?
my counterweight is very close also because my arm is lighter. it would be interesting to try to see what the bandpass of the coupling is. i thought i measured my arm at 7hz but i cant remember. i have the thing sitting on a 24x24x1 block of granite, that sits on top of 4 of those gel filled arm rests for computers. There is no structure borne influence on the machine, but there can be acoustic feedback even with a record clamp. I also modded the table to add high quality pin jacks, a ground banana plug and three wire grounded ac. i have a service manual if you want a copy and i did trim up the photocells in the arm sensor just a bit. it has no deadband now. i also modded the feet with silicon o-rings. I lubed everything after cleaning with Mobil 1 euro. i am waiting for a copy of a test record, nothing i have can measure this monster. I really do think that this thing is the swan song turntable when properly cared for.

 

[Aerobat]

thats interesting to be sure. did you remove the gasket at the headshell mount also?
my counterweight is very close also because my arm is lighter. it would be interesting to try to see what the bandpass of the coupling is. i thought i measured my arm at 7hz but i cant remember. i have the thing sitting on a 24x24x1 block of granite, that sits on top of 4 of those gel filled arm rests for computers. There is no structure borne influence on the machine, but there can be acoustic feedback even with a record clamp. I also modded the table to add high quality pin jacks, a ground banana plug and three wire grounded ac. i have a service manual if you want a copy and i did trim up the photocells in the arm sensor just a bit. it has no deadband now. i also modded the feet with silicon o-rings. I lubed everything after cleaning with Mobil 1 euro. i am waiting for a copy of a test record, nothing i have can measure this monster. I really do think that this thing is the swan song turntable when properly cared for.

I've done similar mods and tuning on my PL-L1000, and I agree with you. Where are you located carlvalle? Do you have any photos of your rig?

 

[Pio1980]

The headshell ring is removed, yes. Plinth mods will be an eventuality here.

 

[carlvalle]

i am in st louis mo
i don't have many pictures, i will look and see what or take some
as far as modding the plinth, you can't add weight to the subframe unless you change the springs, and the top frame is pretty darn solid already. also i don't think you would want to change the mat, it is the nicest one i have seen and kind of heavy. i have a giant brass clamp and it's too heavy too. one other little mod i did, i put a piece of foam on the right side of the track to keep the carriage from slamming into the end on the right. seems to be something it does on return. i might need to check if my carriage rollers need some grease to damp the movement a bit. you have me motivated to recheck a few things

 

[Aerobat]

i am in st louis mo
i don't have many pictures, i will look and see what or take some
as far as modding the plinth, you can't add weight to the subframe unless you change the springs, and the top frame is pretty darn solid already. also i don't think you would want to change the mat, it is the nicest one i have seen and kind of heavy. i have a giant brass clamp and it's too heavy too. one other little mod i did, i put a piece of foam on the right side of the track to keep the carriage from slamming into the end on the right. seems to be something it does on return. i might need to check if my carriage rollers need some grease to damp the movement a bit. you have me motivated to recheck a few things

One of the items in the service manual is setting the speed of the carriage. It should take 5.5 to 6.5 seconds to return from the 7" position, which is pretty slow. Mine kind of bumps gently into the end.

 

[Pio1980]

You do know the rails have to be level for the system to work right, and they and the roller surfaces should be dry and free of any lube residue that could draw and hold dust and grit.

If you cleaned the thick gunk out of the rear guide roller and relubed it with thin stuff, that will affect tracking servo stablilty and control. The thick gunk is hysteresis (time constant) damping and necessary by design.
I use a rubber tape reel clamp for a record clamp, just lightly pressed onto the label. The spindle thrust bearing load was calculated, any more is out of spec and not good IMO.

 

[koseltri]

If you cleaned the thick gunk out of the rear guide roller and relubed it with thin stuff that will affect tracking servo stablilty and control. The thick gunk is hysteresis (time constant) damping and necessary by design.

I did this when I first got mine, thinking it was dried out (DUH!!!) and the tonearm turned into a rocket. I had to custom-blend new damping fluid (heavy silicone oil 'cut' with thinner oil) to get the speed back to normal.