AT 0C9 ML II - Tone Arm mass optimistion

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DaveyW

AT 0C9 ML II - Tone Arm mass optimistion
« on: 18 Nov 2010, 01:36 pm »
Hi All,

Looking for a bit of advice on an avenue new to me.

My preferred LOMC continues to be the AT 0C9 ML II, the level of detail continues to amaze every time I go back to it.  :o
But I miss the more fulsome body and character that say a Grado RS1 or even a Denon DL-S1 provide.

I had an email from a fellow vinyl fan suggesting I consider increasing the mass of my tone arm (Linn Ittok II).
Over the Winter I'd like to have a dabble, but I know there's a huge range of different approaches.

I was hoping you could advise on the best approach/approaches I should take?

I look forward to any responses,
Cheers
Dave

neobop

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Re: AT 0C9 ML II - Tone Arm mass optimistion
« Reply #1 on: 18 Nov 2010, 02:47 pm »
Hi Davey,
I wouldn't think that would be the right approach, but you never know. My DL-304 seems to like med mass arms and compliance/VTF would indicate low mass arms. On the other hand, the OC9II has the same dynamic cu as the 150MLX or 440ML, but weighs around 8g. That would indicate a low mass arm for best results. In my experience, using arm mass to "tune" a cart in that way makes it sound kind of thick and sluggish rather than just having more prominent bass. I can't explain the DL-304, maybe the only way to know for sure is to try it. I would guess that adding no more than 2 or 3g at the headshell would give you a good idea. Your arm is already around 13g eff mass.

Have you exhausted loading options? I read in this very forum, awhile back, that a 20 ohm load was the answer. I assume that's going straight in. Unlike the 304, which got brighter with decreasing load value, the OC9II got more controlled up top rather than the bottom (I assume). If you haven't tried 20 ohms, IMO you should go there first. Let it settle in.
neo

orthobiz

Re: AT 0C9 ML II - Tone Arm mass optimistion
« Reply #2 on: 18 Nov 2010, 03:02 pm »
I know JohnChairGuy and I believe Wayner like to slather black goo on the arms occasionally. I think that increases mass and dampens it...I have no experience however.

Paul

Scottdazzle

Re: AT 0C9 ML II - Tone Arm mass optimistion
« Reply #3 on: 18 Nov 2010, 03:07 pm »
The AT OC9 MLII is a high compliance cartridge. I think increasing tonearm mass would be going in exactly the wrong direction.  If anything, the Linn might have excessive mass for that cartridge.

BaMorin

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Re: AT 0C9 ML II - Tone Arm mass optimistion
« Reply #4 on: 18 Nov 2010, 04:06 pm »
Hi Davey,
I wouldn't think that would be the right approach, but you never know. My DL-304 seems to like med mass arms and compliance/VTF would indicate low mass arms. On the other hand, the OC9II has the same dynamic cu as the 150MLX or 440ML, but weighs around 8g. That would indicate a low mass arm for best results. In my experience, using arm mass to "tune" a cart in that way makes it sound kind of thick and sluggish rather than just having more prominent bass. I can't explain the DL-304, maybe the only way to know for sure is to try it. I would guess that adding no more than 2 or 3g at the headshell would give you a good idea. Your arm is already around 13g eff mass.

Have you exhausted loading options? I read in this very forum, awhile back, that a 20 ohm load was the answer. I assume that's going straight in. Unlike the 304, which got brighter with decreasing load value, the OC9II got more controlled up top rather than the bottom (I assume). If you haven't tried 20 ohms, IMO you should go there first. Let it settle in.
neo

I need to chime in here a moment. I don't think the mass is the issue Davey is concerned about. I think he's looking to find a way to get the OC9 into a more full bodied sound similar to the "signature" sound of the Grado Sonata, etal.
Tracking and arm resonate levels don't seem to be an issue he's having......more so the "voicing". It is possible to enrichen the arm in certain frequencies through mass loading at certain points of the arm. Not unlike where a guitar string is struck. Plucking the E string at the 12th fret produces an 80hz note, plucking that same E string at the 22nd fret still produces an 80hz note, but it "sounds" thinner in body.  I believe proper damping of the arm tube at certain points can
produce a fuller bottom, by removing the enhancement of the upper registers.
I would be interested in how this would affect the 'crispness" of the upper mid through high treble regions the cart is known for.......if those frequencies are damped, could they be retrieved through a change in electrical loading?

Just a few of my thoughts on the matter

Marc

BaMorin

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Re: AT 0C9 ML II - Tone Arm mass optimistion
« Reply #5 on: 18 Nov 2010, 04:16 pm »
Another possibility Dave..........is give me exact dimentions of your arm board. Including total mass. Exact mounting points for arm base and arm holder. Thickness at arm base mount, and thickness at chassis mount.
hole sizes etc.

Wayner

Re: AT 0C9 ML II - Tone Arm mass optimistion
« Reply #6 on: 18 Nov 2010, 04:27 pm »
Adding mass to a tonearm of a modern turntable perhaps is not a good idea. I have done it in the past with vintage tables and have experimented with it on my Technics, but after awhile, you realize, as Neo stated, that the sound is muddied and sluggish.

Besides, weight seems to be the enemy of tonearms as it always lowers the resonance frequency, which may or may not give you more bass, perhaps just more rumble or make the woofers pump.

A resonance frequency of 10 with arm and tonearm seems to be the magic number, and while there isn't anything set in stone, in can be a direction pointer.

In the case of the AT cartridge, I believe across the product line, there is a 5db rise past the 10K point and because the frequencies are slightly "out of balance", the listener may perceive that the cartridge sounds "weak in the bass", and in fact relative to the exaggerated high end of the frequency spectrum, is.

I like the loading idea, as has been suggested, and I have a tool that I made myself that I can add virtually any load to a cartridge up to 100k. I suggest starting at something like 25K and go from there.

If you have things that are rattling on your tonearm like a counter weight, stylus guard, tonearm lock or perhaps the weight dial on your counter weight, plasticaly may help calm down these noises, which could be canceling out some of your low frequency retrieval, being out of phase (mechanically) with the cartridge.

When we say tonearm, it's an oxymoron, cause the last thing we want is to have a vibrating tonearm. That is why my Sony PS-X7 (with it's carbon fiber tonearm) is so incredible in information retrieval. It is simply quiet.

If that makes any sense.

Wayner

TheChairGuy

Re: AT 0C9 ML II - Tone Arm mass optimistion
« Reply #7 on: 18 Nov 2010, 05:01 pm »
I know JohnChairGuy and I believe Wayner like to slather black goo on the arms occasionally. I think that increases mass and dampens it...I have no experience however.

Paul

No goo on the arm for me, BoneDoc....only damping bits (and usually no more than 2-3 total).  It seems to fleck off just the right amount of energy trapped in the arm and turn it into harmless heat.

Each arm is treated by ear - but generally, more than this and it has consistently sounded overdamped (ie, dead sounding).

I do use a 1/8" wedge of modeling clay between Grado cartridges and headshell.  I have heard nothing but benefit from this on a variety of arms tried.

With a couple other cartridges, I didn't hear the benefit (except with the ADC XLM MkIII Improved)

I suspect it's because most of the other cartridge bodies already resonate at a lower preguency (ie, are better damped from the start) and the floppy and relatively weak Grado and ADC cartridge bodies benefit most from it.

That's merely semi-educated conjecture on why it works, of course

You can see the modeling clay application below on my Grado Gold1 with Longhorn mods and G1+ stylus below:



BaMorin

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Re: AT 0C9 ML II - Tone Arm mass optimistion
« Reply #8 on: 18 Nov 2010, 05:07 pm »

When we say tonearm, it's an oxymoron, cause the last thing we want is to have a vibrating tonearm. That is why my Sony PS-X7 (with it's carbon fiber tonearm) is so incredible in information retrieval. It is simply quiet.

If that makes any sense.

Wayner

To address the first part of this, The tonearm has to vibrate..where it does is critcal to the tone quality. As does a bow to a cello.

second part of this is a question.......what cart are you running on your PS-X7?
as mine was quite picky.

neobop

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Re: AT 0C9 ML II - Tone Arm mass optimistion
« Reply #9 on: 18 Nov 2010, 05:34 pm »
Perhaps mentioning the 304 was a red herring that should have been left unsaid. It, and the DL-S1 are the only carts I've encountered that behave the way I described. In my experience most LOMCs either keep the same frequency response when loading down or treble response is reduced somewhat. It is mostly dynamics vs focus that is effected. Maybe it's possible that those dynamics could be in the bass, yielding less bass. Apparently that is not the case with your AT. The preamp load is said to effect the suspension damping of the cart.

It might be counter-intuitive, but often reducing VTF will increase bass response. Bass calls for long cantilever/stylus excursions and this is not usually helped by increased VTF or arm mass. I'm quite familiar with your Ittock. It's a nice arm and I doubt if spurious resonances or vibration is the problem.

Which brings up another point, are you using a tranny or head amp or going straight into a high gain stage?

neo

Wayner

Re: AT 0C9 ML II - Tone Arm mass optimistion
« Reply #10 on: 18 Nov 2010, 06:56 pm »
To  address the first part of this, The tonearm has to vibrate..where it  does is critcal to the tone quality. As does a bow to a cello.

second part of this is a question.......what cart are you running on your PS-X7?
as mine was quite picky.

 The tonearm is designed to hold the cartridge, which picks up the  micro-vibrations and turns the mechanical engery into music, the tonearm  follows the cartridge (in a small respect) but it's job is to rigidly  hold the cartridge, so that it can do it's job. That is why folks at VPI  are now using internal arm damping material on their tonearms, that is  why REGA and SME have cast TAPERED arms, to reduce vibration  transmission, and other arm designers/manufacturers and doing the same  things, to stop vibrations from traveling up the tonearm, vibrating on  it's own resonance frequency and mudding up the mess.
 
 The Sony PS-X7 loves the Grado Gold1 (Longhorn) as well as the AT440MLa. Very quiet, very dynamic and not in the least muddy.
 
 Wayner

DaveyW

Re: AT 0C9 ML II - Tone Arm mass optimistion
« Reply #11 on: 18 Nov 2010, 06:57 pm »
Wow! I can't believe I only posted this up a few hours ago and already have so many responses  8)

OK lets put a few things to bed.

First up there's nothing spurious or essentially wrong, the cart sounds magnificent, but I suppose my recent exposure to Grado carts has left me yearning for the fuller bottom end (bass to vocals), yet retain the exquisite detailing

Re. amplification, I’ve tried 3 different SUTs (Ortofon, AT and Denon) and three active phono stages (Trichord Dino, Dynavector P75 and Project-Phonobox SEII)
The SEII has the edge in overall detail and taut crisp delivery, but all of these approaches delivered the same general tonal character. Slightly lean, but with a tight and punchy bass and mids a little thin when compared to say the Grado RS1.

I've also tinkered with loading (with both SUTS and Active stages).
Lowering the load down to 20 Ohms on the active stages made slight moves in the right direction, but at the expense of that airy openness. I do prefer it around the 100Ohm region.

I’ve also played with VTF, effects are very subtle though.

So do you think I’m wasting my time? I’m sort of getting the vibe “probably so”, but might be worth a little exploration?

If I was to proceed with damping/mass addition the real question for me is where to start?
Given the above, is it to load up the headshell with some form of putty or apply some damping along/around the arm tube?

I look forward to any further thoughts and general comments.

Thanks for all the contributions so far.
Dave

Wayner

Re: AT 0C9 ML II - Tone Arm mass optimistion
« Reply #12 on: 18 Nov 2010, 07:07 pm »
If you want to play around with some non-hardening modeling clay (aka "platiclay). I suggest using it sparingly and strategically, otherwise you will suck energy out of the cartridge. In many cases, this may retard the free movement of the tonearm (which is not to be confused with vibration) and this will have a negative effect on what you are doing.

I do feel that if you don't like the sound, to try another more compatible cartridge, rather then f'ing around with the arm.

Wayner

DaveyW

Re: AT 0C9 ML II - Tone Arm mass optimistion
« Reply #13 on: 18 Nov 2010, 07:30 pm »
Thanks Wayner
I'm currently quite happily spinning with a bit of Grado hybrid.
But I had a recommendation from someone who'd done this with the same arm and cart combo with positive effect.
Just wanted to get the forums thoughts on this before jumping in.
If the general belief is I'd be wasting my time I'll pop the whole thing on the back burner and keep on truckin' with the Grado.
Thanks for your thoughts on this.
Cheers
Dave

Wayner

Re: AT 0C9 ML II - Tone Arm mass optimistion
« Reply #14 on: 18 Nov 2010, 09:30 pm »
Dave,

There are also other considerations. TT mats are a big issue, IMHO, they may not change the cartridges low end, but the right one will help support the LP while isolating the platter from the LP, underneath. In other words, rigid enough to support the record, soft enough to isolate platter rumble. I think there are lots of systems that have sub-sonic problems with this. Tell-tale signs are woofer pumping. This sucks the energy out of the amplifier and because it is really out of the human hearing range, it is probably ignored. The fact is, it has a harmonic content to it that shows up on odd order harmonics. This, too will rob playback of bass energy.

Another factor is the tables base. I'm a believer in mass. My recent DIY, ARCom has a very heavy plinth, filled with plasticlay. It is inert and heavy. The payback is in spades as the table is dead quite, and the lowly AT440MLa mounted to it can squeeze out every bit of the performance.

The surface the table is resting on can have an effect too, but that, to a large degree is how loud you play your vinyl and the rigidity of the mount and the proximity of the speakers to the TT.

I'm sure you know this, too (maybe just for some of the newbies).

The moral to the whole story is that it is not just a few parts of the TT that contribute to the sound, it is the entire TT. Addressing parts of it, while ignoring others may lead to some incorrect tweaks and mislead conclusions. A path I've been lead down many times.

Happy spinning. BTW, the Grado Gold1 received "Editors Choice" award from the Absolute Sound for 2009, so I totally understand your passion for the Grado sound. On the right tables, they are very musical.

Wayner

BaMorin

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Re: AT 0C9 ML II - Tone Arm mass optimistion
« Reply #15 on: 18 Nov 2010, 10:38 pm »

Happy spinning. BTW, the Grado Gold1 received "Editors Choice" award from the Absolute Sound for 2009, so I totally understand your passion for the Grado sound. On the right tables, they are very musical.

Wayner

Just to bring you up to date Wayner........even though Dave and I are new to this forum, we're not new to Grado.........well Davey is kinda new I guess. It's taken me a year or so to corrupt him. :D  He's running a Z+ (potted body) with the MCZ stylus, He has a Red body with 8MZ stylus...along with several other ones he auditioned and downloaded into his files. (black through gold) He also had a Sonata-1 to play with for a period of time. I believe what he's looking for is to find a way to get the "Grado bass through midrange" out of his OC9......fill out those notes below 2khz I guess. 

Wayner

Re: AT 0C9 ML II - Tone Arm mass optimistion
« Reply #16 on: 18 Nov 2010, 10:56 pm »
Thanks BaMorin. To bring you up to date, I manufacture Grado Gold1 Longhorns for Audio by Van Alstine (as well as Green1s). We use 1000 cs liquid silicone on the coils to damped coil harmonics, much safer then potting (IMHO), but I think other then trying to tame some table flaws, changing the sound of a cartridge is almost futile. If the OC9 ain't doing it, I'd move on. I know others try to tweak cartridges or arms or something else, and they might be successful at taming some track irregulars, but trying to get more bass or less high end or smoothing out some mid frequency is a tough road to haul. I am making some suggestions, but in reality, I doubt they are going to do the trick. We must, however, encourage tweaking, that is how we advance the state of the play.

Wayner  :D

DaveyW

Re: AT 0C9 ML II - Tone Arm mass optimistion
« Reply #17 on: 18 Nov 2010, 11:11 pm »
I believe what he's looking for is to find a way to get the "Grado bass through midrange" out of his OC9......fill out those notes below 2khz I guess.

Possibly a bit of a Holy Grail :roll: But yes.

Thanks for your further thoughts Wayner.
Even though my LP 12 is well isolated, I've currently gone to the rather extreme tweak of moving the whole hi-fi into the adjacent room to the speakers to isolate it completely.
The plinth is well braced, but I've yet to add any form of incremental damping mass to the platters. Possibly something to try in the future.

OK OC9 arm damping on hold unless the tweakin' bug gets a hold again  :wink:
Cheers
Dave






BaMorin

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Re: AT 0C9 ML II - Tone Arm mass optimistion
« Reply #18 on: 19 Nov 2010, 01:00 am »

Possibly a bit of a Holy Grail :roll: But yes.

Thanks for your further thoughts Wayner.
Even though my LP 12 is well isolated, I've currently gone to the rather extreme tweak of moving the whole hi-fi into the adjacent room to the speakers to isolate it completely.
The plinth is well braced, but I've yet to add any form of incremental damping mass to the platters. Possibly something to try in the future.

OK OC9 arm damping on hold unless the tweakin' bug gets a hold again  :wink:
Cheers
Dave

Deer hide platter mat?   ( in my best "trunk monkey" grin)

neobop

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Re: AT 0C9 ML II - Tone Arm mass optimistion
« Reply #19 on: 19 Nov 2010, 01:47 am »
But I had a recommendation from someone who'd done this with the same arm and cart combo with positive effect.

Interesting piece of info there. If that is the case, perhaps you should give it a try. Nothing to lose and maybe it will work. If you have specifics from this person, then you know where to start. If not, try adding a little mass to the headshell. Maybe your loading results will change too, who knows?

I'm often amazed with results when tweaking a cart. Sometime they do the opposite of what's expected. Like raising the arm in the back and getting the mid-bass to come in.

neo