Wiring a Decca tonearm

[OLLY]

Can anyone help in which wires pair up on this Decca tonearm. About time I tried it out after gathering dust for about 15 years.  

[VanArn]

There are several models of Decca pick-up arms; a picture would help for starters. The original  arm for the FFSS cartridge  was exclusively built for the slide on head. The colour coding used for that model was as follows:- Left channel, red wire.

                Right channel, green wire.

                The shield wire is a common return  ( ground ) for the  left and right channels.

[OLLY]

.What about the yellow wire.  From what I  know it is FFSS tonearm

[VanArn]

Definitely the original Decca FFSS arm , circa 1958 and later. The yellow wire  I believe , connects to pin 2 of the rectangular contact block at the business end of the arm. I am not sure about its use other than that Decca  also supplied a 78RPM and  mono LP  cartridges and this connection may have been fitted to suit  these models.  You can verify  all the connections with a multimeter.  Looking at the  contact block from the front, the left contact ( pin 1 ) is the red lead that is by Decca's wiring standard, the left channel. Pin2 is not used. Pin 3 is the shield cable and it is the  common  ground return for the left and right channels. Pin 4 is the right hand channel and is connected to the green wire.

 In the supplied photo , pin 1 is at the top of the contact block.

Edited April 19, 2020 by VanArn
additions.

[OLLY]

Thanks for your help 

[OLLY]

Paired up red and shield, green and yellow to RCA outputs. Not a sound.  Where did I go wrong.

[pwstereo]

Red = Left centre pin

Green = Right centre pin

Shield = Ground connection for both channels

 

Red RCA socket gets Green wire to centre conductor

White RCA socket gets Red wire to centre conductor

Both RCA sockets get the shield to their outer connectors.

 

I'm assuming you'd have Red and White RCA sockets on the turntable and want to maintain the usual Red is Right standard that stereo follows.

Edited April 23, 2020 by pwstereo
Spelling

[VanArn]

The Decca FFSS uses  a sum and difference matrix system and it is a three wire connection arrangement; not four. The shield wire is the common  ground return.   The red wire is  the 'hot' left channel and the green  wire the 'hot'  right channel. The internal pick-up wire  leading out from the bearing pillar base should be anchored to a tag strip  ( or terminal block )  near the base of the arm with an allowance for free play so that it does not impede the arm movement.  The interconnecting lead to your amplifier will  need the earth shields joined together at the tag strip and you will have to connect the inner wires to the red  and green wires of the Decca cable at the tag strip. I would expect your interconnecting lead to be colour coded , red for the right channel and white for the left channel. The Decca FFSS  was very susceptible to hum and it was common to find  a Strepsil  or  tobacco tin fixed over the tag strip.  The yellow wire should not be connected to anything at this stage.  I believe it connects to the junction of the horizontal movement coil and the two vertical movement sensing coils in the case of the stereo pickup and of course just the horizontal coil in the case of the mono  only versions. Connecting the yellow wire to an RCA outer shield would short out the mono signal component, the sum component, therefore no output.

 

Edited April 23, 2020 by VanArn
addition

[OLLY]

Really appreciate the comments. I will retry possibly over the weekend and let you know how it goes. I have seen tracking weight variations of 2 grams to 5 grams so I will start at the lower end and work my way up until I feel it is where I like it best. 

[VanArn]

3.5  gm was the tracking pressure for the Decca stereo cartridge. The original stylus is  a half  thou. inch radius  nude diamond tip and this had a tendency to bottom in  the groove of many  early stereo recordings.  It also developed  wear flats after only a few hundred hours of play and a check of  condition of the stylus under a microscope before using it would be  advisable to avoid damage to your discs. 

[OLLY]

Thanks, will do. 

[OLLY]

Just checked the stylus with an eye loupe and it looks like it has flattened out on the sides.  I will set it up and have a listen on an old unwanted record just to make sure I have it correctly set up.  Once that's done I will have to decide what I'll do with the tonearm as it was originally mounted to the Garrard 301 which I doubt will ever be put back into service as I prefer the Commonwealth Electronics 12D/3.

[OLLY]

Is there someone in Australia that retips these Decca cartridges.  If so what would be the cost to have one done.

[VanArn]

 The Garrott Brothers  were the go to people  many years ago and you could try to have the company that took over from  them,  rework the Decca for you. Decibel Hi Fi would be the first people to contact.  Unfortunately, it is an expensive process.

You should consider that the  vertical tracking angle of the MK I  cartridge was around zero degrees and this suited English Decca and Telefunken recordings using the original  Teldec stereo  cutting head. Years after the introduction of  stereophonic discs , a 15 degree standard was used as a compromise to improve results with the different makes of cutting heads that were  then in use. The later standard of 20 degrees came into use when it was discovered that the actual  cutting angle differed from the  set cutting stylus angle. I would only  use the Decca as a mono cartridge providing you have a collection of early (mono)  vinyl  as it excels in playing these. and have  it tipped with an elliptical diamond.

Edited April 24, 2020 by VanArn

[OLLY]

Got about 1000 78's which I could use it for but I would still need to have it re tipped which I'm not sure I would want to do as I am happy with my setup at the moment.

Looks like it might be time to sell it as it is.  Any idea as to what it's worth listing it for.

[Batty]

This thread made me think about rewiring one of my Hadcock GH228s, a previous owner has used RTV to seal the end of the armtube, I have no idea how far it goes in, but that is the end of that project.

[OLLY]

just wired up the Decca FFSS for the first time in about 50 years and my initial thoughts are that this cartridge (Head) leaves me wondering how much better it could be with proper SRA, mounting distance and a new stylus. So much more punch than my AT15XE at the same volume levels left me sort of shocked that it has so much potential.  From what I had read I sort of expected some hum but it's dead quiet.  Maybe I will resurrect the Garrard 301 after 20 years and pair it up to the Decca as it once was.  I have some serious decisions to make so I will be checking out the costs that I will be up for next week.

 

 

[Ian McP]

plenty of info on the more recent versions of the classic Decca cartridges

https://sublimelistening.com/london_cartridges.html

https://theaudiobeatnik.com/london-decca-reference-cartridge-review/

 

[audiofeline]

A poster on this thread https://www.vintage-radio.net/forum/showthread.php?t=83479  (from 2012) indicates that

"John Wright, who formerly worked at Decca and who, along with a partner, bought the rights to the Decca designs when Decca's owner shut down the Special Products division, still builds the current London cartridges", and does repairs to the original carts.  It could be worth contacting him for more advice.

 

And looking at various comments on the internet suggests that the Decca carts are quite exceptional, and definitely worth the time/money to restore.  The early carts were mounted on the Decca arm, and SME adapters were also available for other arms. 

 

[Graceman]

Also a huge amount of Decca discussion (256 pages) here:

 

https://www.lencoheaven.net/forum/index.php?topic=545.0