New cartridge for Jelco SA-750D

[dbxdx5]

Thats a good place to start, do you have a shot of the tonearm+cart+stylus as it's playing, from the side? Eyeballing might give us an idea of whether the arm height needs to go up or down.

I'll take a pic during the week and circle back.

 

[dbxdx5]

I would use the Shure with the brush up. Then use the fluid arm damping. Using both is too much dampening! I would use the Jelco arm dampening for every cartridge. I have fluid dampening on my SME 3009 arm, every cartridge sounds so much better!

Just realized I didn't reply to this. But thanks for the point about overdoing the damping. I plan to do as you suggest and try both damping approaches individually.

 

[bobins08]

Just realized I didn't reply to this. But thanks for the point about overdoing the damping. I plan to do as you suggest and try both damping approaches individually.

You might pick up some surface noise with the brush that you don't with the fluid.

It will be interesting to hear your results.

 

[dbxdx5]

Thats a good place to start, do you have a shot of the tonearm+cart+stylus as it's playing, from the side? Eyeballing might give us an idea of whether the arm height needs to go up or down.

I tweaked the arm height to get it as close to parallel with the record as possible.

 

[jkilla]

I tweaked the arm height to get it as close to parallel with the record as possible.

How about a photo focusing at the headshell + cart + stylus? , it is more important than the arm tube level

The adjustment of the arm height ultimately is to affect the stylus rake angle and the vertical tracking angle. It's just that the changes have to be done at a macro level (arm height) to influence the micro level stuff (stylus rake angle and vta)

 

[dbxdx5]

How about a photo focusing at the headshell + cart + stylus? , it is more important than the arm tube level

The adjustment of the arm height ultimately is to affect the stylus rake angle and the vertical tracking angle. It's just that the changes have to be done at a macro level (arm height) to influence the micro level stuff (stylus rake angle and vta)

Yep, that makes sense. Here's a different shot.

 

[jkilla]

Yep, that makes sense. Here's a different shot.

Assuming the shot is as level as we can see, I think the headshell/cart is just a little "tail down", perhaps raise the arm height ever so slightly up.

Play a track with punchy bass and adjust by ear.

If the bass still seems kinda "blurry and flabby", raise the arm a tiny amount and listen again. If the bass seems "thin and lifeless", you've raised it a bit too far.

Oh the joys of vinyl :yes::scratch2:

 

[dbxdx5]

Assuming the shot is as level as we can see, I think the headshell/cart is just a little "tail down", perhaps raise the arm height ever so slightly up.

Play a track with punchy bass and adjust by ear.

If the bass still seems kinda "blurry and flabby", raise the arm a tiny amount and listen again. If the bass seems "thin and lifeless", you've raised it a bit too far.

Oh the joys of vinyl :yes::scratch2:

Ha. Yes, the "joys" are manifold.:thmbsp:

I think the headshell is more parallel than it appears in the picture. I did some listening yesterday, and the sound was as good as I've heard with the SAS stylus. That's probably partly due to using the damping oil in the Jelco; there was no horizontal movement of the cart during playback this time.

 

[bjlefebvre]

Thanks for posting the chart. I'd only read the effective mass of the 750s was about 21gr but that is with a 6.5gr cartridge. An EM of 13gr +/- opens the door to a bunch of carts my Audio Technica ATP-12T can't handle with its EM of 21gr. And it is great I can get a reasonably priced 10" version.

Sorry to resurrect an old thread, but if that is the correct arm mass, this means that the JELCO 750D should be able to handle my Empire carts that have a recommended VTF of ~1.25g, correct?

 

[AvFan]

Sorry to resurrect an old thread, but if that is the correct arm mass, this means that the JELCO 750D should be able to handle my Empire carts that have a recommended VTF of ~1.25g, correct?

There have been follow up threads on the Jelco 750's effective mass and many folks don't believe the numbers provided by Jelco (EM in the 13 to 14 range) and believe the EM is around 21gr. If you searched for this thread I suggest you look for more recent ones that describe why some folks feel that way and draw your own conclusions. My only experience with a heavier arm is an Audio Technica ATP-12T that has an EM of around 21gr. I don't have any experience with Empire cartridges but a VTF of 1.25gr would seem to indicate a compliance around 20cu and so probably wouldn't be the best match for a heavier tonearm. It might work if the Jelco 750 is mid mass. The Vinyl Engine calculator is a good first pass analysis tool.

 

[bjlefebvre]

Thanks. Will dig around further.

 

[marcmorin]

There have been follow up threads on the Jelco 750's effective mass and many folks don't believe the numbers provided by Jelco (EM in the 13 to 14 range) and believe the EM is around 21gr. If you searched for this thread I suggest you look for more recent ones that describe why some folks feel that way and draw your own conclusions. My only experience with a heavier arm is an Audio Technica ATP-12T that has an EM of around 21gr. I don't have any experience with Empire cartridges but a VTF of 1.25gr would seem to indicate a compliance around 20cu and so probably wouldn't be the best match for a heavier tonearm. It might work if the Jelco 750 is mid mass. The Vinyl Engine calculator is a good first pass analysis tool.

I've mounted 2 of those arms and a Jelco 250SA on the later model ARs, all shod with either a AT 440 OOC or 440 MLa Tracked the carts at 1.4 gr. got resonate peaks in the 9hz range. So, I'm thinking that these are well below the 21gr listed in the chart.