Please help with compliance and effective mass

[planarboy]

Hello,
I have no idea how to guage an arms effective mass.
I have a Michell RB300 with Pete Riggle endstub and counterweight, the tube has been sandblasted, and I have stuffed foam up in the tube.
This was all a year ago and seriously I was just screwing around with it with no knowledge, modding cos it looked good, ya know?
I have lead sinkers drilled stuck to the bolts at the vertical pivot, someone told me this increases mass in the horizontal plane, I can weigh the lead if anyone wants to help me. They are about 10 grams each.
Now I'm getting a DL103 and I need to learn how to match this carts compliance to the effective mass of my arm.
Do I really just need a heavier counerweight, should I do the compliance mods I see online to the cart, should I make the cart heavier.
I have no idea, it's time to get serious about all this.
Also would a Supex SD900 Super 2 be a good match for a rega arm , is it possible to mod the two together for a happy marriage?
Don't worry about money, I can always sell my rocket powered skates.
It is my mission to learn and make these things work together properly. I still buy all other carts throughout the year and use and enjoy them too.
But I wanna be a 103 head, if they are that moddable, such fun, what a hobby.
Thankyou,
dave

[tedr]

It's a case of figuring out where to start I think, and I don't know how much you know already, but here's an attempt to answer your questions.

compliance is a quantity that applies to your carts and stylus, you can look it up in the technical specification that comes with your cart. A small number means it is stiffer and will need more tracking weight to play loud without mistracking. A bigger compliance number means the stylus is mounted in a softer suspension, it will play at lower tracking weights without mistracking. Observe the recommended tracking weight range for the cart and don't exceed it you can do permamnent damage. Lower tracking weight is good, less wear of the groove by the stylus.



effective mass is a quantity derived from the tonearm and headshell masses and is stated in the tonearm technical specification.

In your situation I would go back to the stock setup and get that setup correctly before trying to improve something get it set up how it was intended by the makers and see how you like the sound.

Personally I like Technics TTs they have the setup made very easy, interchangeable headshells and calibrated adjustable tracking weight and antiskate make set up really a pleasure to do and it can be done quickly.

Does thois help?

[tedr]

PS

you might also ask these questions at vinylengine forum

http://www.vinylengine.com/phpBB2/index.php

[planarboy]

Hello.
Tedr, I did post this exact thread in vinylengine.
To the guy above, thanks for the tips, erm, soon I will be getting a stock RB250 to put in a plinth I am making and selling...I might just own it for 6 months and do a whole lot of experimenting...it would be hard to get my RB300 back to stock, so, I will have a stock arm and a mod arm.
Should help me.
Low compliance=stiffer suspension
and vice versa...thankyou
I always thought low compliance was better..different things suit different situations. ??
The compliance mod I see that can be done to the DL103, err...soundsmith, I think, do it, and all I read about potting with epoxy, does this all mean lower compliance after the mods?
Oh sorry, the guy above is also tedr.
haha

[Nanook]

have a look here

also look here, Wally's explaination

simple math.

[planarboy]

Hello nanook, I've talked to you before.
I have that test record, thanks for the links, the wally one doesnt work though.
dave

[Nanook]

planarboy, look here

when you click on the script it takes you to a pdf. The link in this post takes you to the thread.

stew

[planarboy]

...that link works.
Oh my god, that is the worst before/after weight loss picture ive ever seen (an ad down the bottom) Whats that guys effective mass. I wonder if he wobbles at a certain frequency due to his own footfall...hahahahahahaha.
Now scroll back up and read again...
dave

[Nanook]

Oh my god, that is the worst before/after weight loss picture ive ever seen (an ad down the bottom) Whats that guys effective mass. I wonder if he wobbles at a certain frequency due to his own footfall...hahahahahahaha.

I didn't see any image, I'll take yer word for it.

Yes planarboy, our paths have crossed here before. Hope the explanations are suitable for the cart/mass compliance and that they answer your questions.

As far as mods to the DL103, I believe a good one is to remove the cart from the body. I saw a video on youtube on how to do it.

As mass increases, resonant frequency drops, and conversely, as mass decreases, resonant frequency increases. It all depends on your arm and cartridge as a system.

I'm assuming you have an RB300?

stew

[planarboy]

...I was in the mood for a laugh.
I still have my RB300, yes