Dual 1237 cartridge mounting

[shacky]

When mounting cartridge to standard Dual cartridge mount I know the VTA is set for 3rd record. So using a spacer between mount and cartridge would help correct geometry for single play. I do use the changer function but would never put more than three albums on and usually only two.

Using the washer like spacers that come with mounting accessories moves the body of cartirdage away from the mount which is what I want but also reduces the area of contact between the cartridge and mount. So it won't be as solidly connected to the headshell. Unless I could fabricate shims the sames size shape as the top of cartridge - which I don't think I'd be good at doing.

So my question is - how important is it to have the cartridge solidly/rigidly connected to headshell?

 

[OvenMaster]

Technically? It's vital to have full contact, otherwise there's the possibility of unwanted resonances or perhaps excessive microscopic flexing. I think.
Does the cart top have full contact with NO spacers? Adding spacers or Blu-Tac as filler also increases mass.
If you look at the underside of the tonearm directly behind the headshell, you should see a screw attaching the headshell or mount to the arm. To get at the screw, you have to take the platter off and put a screwdriver up through one of the chassis holes in order to loosen it and to move the shell up or down. The bad part is that there's no markings or scribe marks to guide you. Here's an example from a 721 showing what the heck I'm saying.
Tom

 

[Fred Longworth]

Unfortunately, as you add spacer washers to get the height correct -- and thus the VTA -- it becomes easier for the cartridge to "rotate" forward or back slightly, causing a vertical tracking angle problem!!!

The cure for this is to make custom shims out of cardboard. Give them a broad footprint, so that the tendency to rotate and develop a zenith error is eliminated.

Hope this helps.

Fred Longworth

 

[NoTransistors]

I was just considering posting findings regarding similarilar thoughts.

I have found that when I first mount a decent cartridge [on any of my Dual decks], it usually sounds good. Then, in an effort to improve the sound, I unscrew the cartridge, put a blob of Blu-Tac on top, and replace the screws, tightening until the Blu-Tac oozes out. Never sounds as good.

Never.
Never.
Never.

Moral of the story: Sometimes a little bit of resonance is good for the soul.

Seth
Forever Analog

 

[shacky]

Thanks Fred! And Tom - I'll check but I don't think the 1237 has this adjustment.

I recently tried a Shure M91ED in place of Ortofon F15 MkII and the difference was stiking. I was wondering if some of the benefit came from mounting the Shure directly without spacers where I had placed the 3 washer spacer on the Ortofon to get what I thought was proper height. I think the spacers made the cartridge too "loosely" connected.

Will try Ortofon without spacers to see if it improves by comparison.

Jim

 

[Detailman]

Instead of spacers you might try adding a flat record under the mat.
This will also change the vta with a lot less ag factor.

 

[ozmoid]

Instead of spacers you might try adding a flat record under the mat.
This will also change the vta with a lot less ag factor.

Very good idea! There are lots of .50 donors at the thrift to sacrifice, too. You could even build a collection of different thickness albums to get more accuracy. Stick 'em down with blu-tac if the mat slips.

 

[shacky]

I like the record under the mat idea only this is a 10.5" platter. I'd have to somehow cut the record.

I couldn't go to sleep without trying the Ortofon without spacers. I think it did tighten up the imaging. There was such a difference I was getting disappointed with the NOS Ortofon upgraded with F/FF elliptical stylus. Stanton had recomended this to me last year and it really is a nice cart.

NOt being an expert (yet) I'd say the Ortofon is more neutral with deep soundstage - wonderful midrange. The Shure is brighter making hi's and lo's a little punchier - good for classic rock.

I need to find another Dual cartridge mount to make changing back and forth easier. I broke my backup - broke the connector off green wire. And I had been getting some hum with that mount. Any way to put new wires on these old Dual mounts?

Jim

 

[Detailman]

As far as being a 10.5 in. platter, ok if it sticks out some cause you are playing a 12 in. record.

Good question about repairing the headshells. I tried to repair one where I had a similar problem and destroyed it.
William Thacker on Epay is good to do business and has nos stock for Duals and seems to be about the least expensive around.
I bought a couple extras a while back and it does make it easier if you like to tinker.