Mission 774 Original Tonearm

[Spider27]

Hello,

 

I recently got Mission 774 original tonearm out of curiosity because I heard that this is a good tonearm and versatile. However, I found that there are some odd things about this tonearm and would love to get some advice and recommendation if possible to understand fully about this tonearm to use.

 

1) Empty well in the base of the tonearm (photo attached)

Is this where damping fluid to be put? If so, it does not touch any area of toneam armtube or bearing.

How does this damp the tonearm?

 

2) Damping Paddles

I believe that there are meant to be 3 of these in a set and I only have 2 (small and large I believe and missing medium). I checked manual and could not find where and how to use this with.

Anyone know how & where to use this paddle for?

 

3) Counterweight

This is first time see counter weight has very soft yellow foam inside where threaded tube goes in. What is the purpose of this foam? Does it make any difference comparing with solid counter weight that most of modern turntable comes with?

 

4) RCA connector (with weird red & white cables)

This is where I found that disappointing to see given its reputation. The connecting area where 4pin thingy with RCA cable look very messy. I attached photo. Is this normal?

The white solid core cable wrapped around cooper shield from interconnect cable and terminated with screw ring. And there is red cable without termination. 

 

Have I understood correctly that red cable is ground cable from tonearm and white cable is chassis ground cable? 

The red cable is very short so I do not think that I can connect to phonostage ground connection and white cable...Ah... No idea what to do with it.  

 

 

Any feedback and suggestion would be greatly appreciated. Thank you.

Edited January 15, 2020 by Spider27

[Herbyj]

Hi Spider

 

The Mission 774 is a very good tonearm, I have one and have been using it for years.

 

There is a guy on Ebay in the UK  called XTC, he makes new paddles, counterweights, arm tubes etc etc for the arm. He is away at the moment so I can't put up a link to any of his Ebay auctions.There is also a lot of info on the internet about the arm, just do a search.

 

The trough is filled with silicone and the paddles dip into the silicone to damp the arm. The different thickness of the paddle provides different amounts of damping. Depending upon your cartridge, different amounts of damping sounds best. Some cartridges may sound best without any damping.

 

You are missing one of the paddles.

 

The counterweight has a yellow foam which decouples it from the arm tube but this foam deteriorates over time. I replaced mine with a heavier one from the XTC in UK when I went for a heavier arm tube.

 

That arm tube looks like it's been butchered, they have not done a very good job of putting a new connector onto the arm tube. You really need to re-solder those connectors or get both male and female plugs to replace the ones that you have. Sometimes the arm tubes come up for sale too.

 

Also, Johnnie at Audio Origami in Scotland knows a lot about these arms, sells the silicone and other parts too.

 

Hope this helps.

 

Herby

 

 

 

 

[audiofeline]

The RCA connector looks like a real dog's dinner.  The four wires on the tagstrip should correspond to the 2rca plugs, I'm assuming that the white is the +ve signal and the green is the -ve.  Check with a continuity tester.  As the short red wire appears to be connected to one of the green wires, I would guess that this may have been used to ground the tonearm.  A check on the manuals on VE suggests this is not part of the original configuration.  The white cable with the circular connection would probably be an earth.  Check if it's connected to the shielding on the rca lead, or if it has a free wire with the two rca's. 

[Spider27]

4 hours ago, Herbyj said:

Hi Spider

 

The Mission 774 is a very good tonearm, I have one and have been using it for years.

 

There is a guy on Ebay in the UK  called XTC, he makes new paddles, counterweights, arm tubes etc etc for the arm. He is away at the moment so I can't put up a link to any of his Ebay auctions.There is also a lot of info on the internet about the arm, just do a search.

 

The trough is filled with silicone and the paddles dip into the silicone to damp the arm. The different thickness of the paddle provides different amounts of damping. Depending upon your cartridge, different amounts of damping sounds best. Some cartridges may sound best without any damping.

 

You are missing one of the paddles.

 

The counterweight has a yellow foam which decouples it from the arm tube but this foam deteriorates over time. I replaced mine with a heavier one from the XTC in UK when I went for a heavier arm tube.

 

That arm tube looks like it's been butchered, they have not done a very good job of putting a new connector onto the arm tube. You really need to re-solder those connectors or get both male and female plugs to replace the ones that you have. Sometimes the arm tubes come up for sale too.

 

Also, Johnnie at Audio Origami in Scotland knows a lot about these arms, sells the silicone and other parts too.

 

Hope this helps.

Herby

 

 

Thank you so much.  I will contact XTC to get medium paddle since it is the one that is ideal for typical MM cartridge I believe.

 

The photo with cables are not actually armtube but RCA cable with 4pin termination with 2 weird looking ground cables.   H

 

ere is armtube photo attached.

 

I re-read multiple times on operation manual and also refer to your comment and I think that I figured out the paddle installation. Can you confirm if I did correctly referring attached photo?

[Spider27]

1 hour ago, audiofeline said:

The RCA connector looks like a real dog's dinner.  The four wires on the tagstrip should correspond to the 2rca plugs, I'm assuming that the white is the +ve signal and the green is the -ve.  Check with a continuity tester.  As the short red wire appears to be connected to one of the green wires, I would guess that this may have been used to ground the tonearm.  A check on the manuals on VE suggests this is not part of the original configuration.  The white cable with the circular connection would probably be an earth.  Check if it's connected to the shielding on the rca lead, or if it has a free wire with the two rca's. 

 

I took close look at both tonearm 4 pin male connector and RCA cable female 4 pin connectors and here is finding.

 

Tonearm Male 4 pin connector

 

1 - Green (Right channel -)

2 - Red (Right channel +)

3 - White (Left Channel +)

4 - Black/Blue (Left Channel -) 

 

RCA Female 4 Pin connector

 

1 - Green (Right Channel -)

2 - White (Right Channel +)

3 - White (Left Channel +)

4 - Green (Left Channel -)

 

5 - Red short wire is also soldered to #4 and unterminated.

6 - White short wire is wrapped around RCA copper shield and terminated with thin donut shape plate.

 

Question is what to do with #5 and #6. Does anyone have any idea?  

 

Edited January 15, 2020 by Spider27

[audiofeline]

#5 (the short red cable, also connected to the rca -ve) could have been connected to the tonearm to address a ground hum problem.  I would de-solder it, and connect it if your have a hum and grounding the tonearm to the -ve signal fixes the hum. 

The white cable connecting to the rca cable shielding won't do anything if it's connected to the chassis.  Connecting it to one of the signal -ves (the green) might provide some extra shielding, as would connecting the other end to the ground point of your amp (and not connecting the circular connection labelled #6).

 

I would suggest de-soldering the short red wire, and not worry about the white #6.  Install the tonearm.  If you have any hums, you can then start to trouble-shoot using some of the ideas above.  It's easy to do the trouble-shooting, get a length of insulated wire and touch the two ends to different things.  If the hum stops when the test cable is connected between two points, you can then make the connection permanent.  As this wire won't carry any signal, it can be any insulated wire.  Hopefully you won't need to do any hum trouble-shooting. 

 

[Spider27]

10 minutes ago, audiofeline said:

#5 (the short red cable, also connected to the rca -ve) could have been connected to the tonearm to address a ground hum problem.  I would de-solder it, and connect it if your have a hum and grounding the tonearm to the -ve signal fixes the hum. 

The white cable connecting to the rca cable shielding won't do anything if it's connected to the chassis.  Connecting it to one of the signal -ves (the green) might provide some extra shielding, as would connecting the other end to the ground point of your amp (and not connecting the circular connection labelled #6).

 

I would suggest de-soldering the short red wire, and not worry about the white #6.  Install the tonearm.  If you have any hums, you can then start to trouble-shoot using some of the ideas above.  It's easy to do the trouble-shooting, get a length of insulated wire and touch the two ends to different things.  If the hum stops when the test cable is connected between two points, you can then make the connection permanent.  As this wire won't carry any signal, it can be any insulated wire.  Hopefully you won't need to do any hum trouble-shooting. 

 

 

Thank you very much and very well noted.

 

All of tonearm that i have used so far have ground wire that is to be connected to ground connection at phono preamp. Isn't this arm also need ground wire to be connected to the phonostage ground wire connector?

 

The reason for asking is that the RCA does not have separate black ground wire similar to Rega tonearm and I believe that Rega tonearm is ground to left channel wire? 

Edited January 15, 2020 by Spider27

[wen]

i had this arm on a Linn i once had, fantastic tonearm with multiple options to change to suit cartridges, used a Sonus Blue MM, ADC ZLM MM, Ortofon SPU classic N MC, ortofon 2M Bronze MM, Ortofon 2M Red MM, the arm was modified from standard which ruined it's inherent characteristics and versatility

[Spider27]

I am thinking to mount Shure M95HE cartridge which states that tracking force to be 0.75~1.5g. I guess that middle ground around 1.2g would be ideal. If so, should I use medium one or small paddle?

[wen]

i cut my medium paddle in half, suited the Ortofon SPU to a T, ran this cartridge the longest

[Telecine]

6 hours ago, Spider27 said:

I am thinking to mount Shure M95HE cartridge which states that tracking force to be 0.75~1.5g. I guess that middle ground around 1.2g would be ideal. If so, should I use medium one or small paddle?

The manual for the  Shure M95HE cartridge states:

400 Hz - 24 cmlsec

1,000 Hz - 33 cmlsec

10,000 Hz - 19 cmlsec

 

At 1 gram tracking weight.

 

Use the medium paddle.
 

Edited January 15, 2020 by Telecine

[audiofeline]

10 hours ago, Spider27 said:

...All of tonearm that i have used so far have ground wire that is to be connected to ground connection at phono preamp. Isn't this arm also need ground wire to be connected to the phonostage ground wire connector?...

You only need the ground wire if you have a hum (an "earth loop").  If you don't have any hum, you don't need it.  It depends on your system and wiring if you will need it or not.  Sometimes connecting the earth wire will create an earth loop/hum! 

[Spider27]

Made medium paddle using 1mm thick wire.  Found below spec from web.

 

Dimension A = rod length attaching to arm
Dimension B = rod length vertical
Dimension C = rod length - bottom stub
Dimension D = diameter of steel rod

 

Large damping paddle =
A = 15mm
B = 15mm
C = 5mm
D = 2mm

 

Medium damping paddle =
A = 15mm
B = 15mm 
C = 5mm
D = 1mm

 

Small damping rod =
A = 15mm
B = 12mm
C = 2.5mm
D = 1mm

 

[Spider27]

5 hours ago, audiofeline said:

You only need the ground wire if you have a hum (an "earth loop").  If you don't have any hum, you don't need it.  It depends on your system and wiring if you will need it or not.  Sometimes connecting the earth wire will create an earth loop/hum! 

Thank you. I took the white short wire out of RCA cooper shield which does not serve any purpose. And used heatshrink tube to make it a bit neater on messy area.  And, figured out what the red cable is for. It is ground wire to be connected to one of the mounting screw based on manual.

 

[Spider27]

Hope above info helps any novice like me who try to use Mission 774 tonearm for the first time. 

[Spider27]

Does anyone know what the exact mounting distance for the tonearm? 

Mounting template says 8 9/16" which is 217.5mm. However, I found that other forum sites mention 215.4mm.

Since this tonearm does not have overhang adjustment, I guess that it needs to be exact..

[Telecine]

The Vinyl Engine tonearm database says 215.4 mm. Another site quotes 215.4 mm as the manufacturers specification. I would go with that.

 

The tonearm length is adjustable.

[audiofeline]

The distance is in the manual, downloadable from VE.  It is written on a diagram in the first few pages.  I can't recall what it was, but 215.4 sounds right (I remember thinking it was less than 220). 

[Spider27]

This is the mounting template from VE site. The distance is 8 9/16" which means 217.5mm?

[Telecine]

It is a mystery. Check the manual.

[audiofeline]

Page 4 of the manual states 215.4mm from pivot to spindle. 

[Spider27]

Thank you. I usually go for mounting template which I thought more accurate since manufacturer pays more attention for measurement on mounting template. However, almost all of other resources indicate 215.4mm so mounting temp might be an error. I will try both to see which aligns better with protractor. 

[Capone]

So my original Mission 773 cart was beyond repair (economically)

So im after some suggestions for a cart to suit these original Mission 774 tonearms, its mated to a Linn LP12, around the $500-$600 range 

Im not biased if its MC Or MM

And 2nd hand is always an option

For future reference at this stage until funds build *Rock,Grunge,Blues)

Cheers

PS- @Spider27 keep us informed on how yours is coming along

[shailesh]

Garrott p77 (and higher models)

[Capone]

Update from my Mission 774 adventure, Arm was rewired by Audio Origami. I got rid of the dreaded Red plug & made an offboard RCA junction box .Also upgraded to an underslung brass counterweight, with extra weights for future cart upgrades , this gets rid of the original Yellow goop one. Next i will be playing with the dampening paddles .