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Non-Smoking Man
23-02-2017, 16:06
Many moons ago I owned a Decca Blue; that gave way to a Gold, which was sold on to a friend.
Some months ago the Decca, worn out, found its way back into my posession. What to do with it?

I have a tidy number of mono 7" singles (300). and about 200 mono albums (jazz and classical) so I plumped for a retip and mono conversion.

One of the considerations I bore in mind with monoing a Decca was that many of its problems stem 'in the vertical' - monoing involves removing the vertical generators, (or at least disconnecting them) so I reasoned that the Decca might behave itself a bit better in mono.

John Wright (Mr Decca, or should I say 'London') returned my old Decca Gold newly retipped with a Paratrace ie line contact stylus, and it was fitted to my Wilson Benesch Act .5 unipivot arm on a TD124.

Results are very good - no mistracking at all and a fine sound straight away.

Known to you all on here (and to me) Tom (Montesquieu) also has a TD124 not 15 minutes drive from me which opens up the possibility of me unbolting my armboard with the aforementioned arm and cart and installing it on Tom's for comparison with his Miyajima mono (s) - he must have collected about 3 or 4 by now..lol..

Jack NSM

Wakefield Turntables
23-02-2017, 16:09
Interesting post. I've been thinking about getting a mono cart for a long time and I love Decca carts :eyebrows:.

Non-Smoking Man
24-02-2017, 11:57
Interesting post. I've been thinking about getting a mono cart for a long time and I love Decca carts :eyebrows:.

Mono-ing and retipping comes cheaper than a stereo retip because John Wright explained he doesnt have to recalibrate for stereo. I paid £258 delivered.
It has followed an AT33PTG and betters it. Ive had a Cadenza Blue in the system and I would put the Decca somewhere between the Blue and the AT.

I used to think Deccas needed arm damping but mine is very happy in a Unipivot (Benesch Act .5 (see above).

Finally, Deccas' construction makes them a good bet for a retip because they dont have rubber suspension which can wilt over time.

Jack

Wakefield Turntables
24-02-2017, 19:15
I have a completely re-worked DECCA maroon with best diamond John had to offer. I've used this on a SME3012 arm and a nice sound was had at Rexton towers.

Barry
24-02-2017, 21:59
In a strange way, Decca cartridges are perfect for monophonic playback. This is because the first Deccas were mono only, employing a coil and toroidal magnet generator that sensed only the lateral (horizontal) motion of the record groove. With the advent of stereo, two more magnet and coil assemblies were added. The three generators are arranged as a 'sum and difference' configuration, to provide a signal output from the left- and right hand-walls of a stereo record groove.

However whilst the compliance in the lateral plane of a Decca cartridge is very good (~ 30cu), owing to the 'cantilever less' design, the compliance is quite poor in the vertical plane (~ 6cu). But if one is only interested in the playback of monphonic records, this does not really matter.

To do the job properly, one needs to connect to the lateral generator only. And this is where things become interesting. Connection to the lateral generator only, requires connections to be made to the centre contact on the cartridge body and to the 'test' tag laying below it (this tag is the common connection of the three generators). This means the usual plastic connector and mounting bracket cannot be used; the cartridge needs to be mounted in either a 'Deccapod' or a 'GB' mounting block, and also connection to the common test tag will be tricky. But if you can do it, you will have converted a stereo Decca cartridge into a true mono cartridge. You can also then experiment with the electrical loading of the lateral generator, as was done with the Decca 4RC.