Field-coil TSD15 & RCA 73B lathe turntable

[BTH K10A]

I just love this guys style, no bling just an eclectic mix of top quality vintage professional equipment. :)

Seems to be a home made field coil conversion of an EMT cartridge with battery for power. Certainly a lot cheaper than an Io Ltd ;)

PiDdntAceXU#t=64/

[Barry]

Just what is it about field coils? Why should they 'sound' any better than permanent magnets?


As an aside, have a look at this (and read the comments posted!)

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A bit like watching paint dry - and an appalling demonstration of the capabilities of an EMT 930st, despite the correct use of the EMT suspension cradle.

[BTH K10A]

Barry

Whilst field coils may seem a retrograde step, their abandonment in favour of permanent magnets was a cost decision and not for quality reasons. There seems to be an acceptance that alnico sounds better than ferrite and other newer types of magnets in speakers, and those that have tried field coil speakers feel they sound better than equivalent permanent magnet versions. Those lucky to have listened for a field coil Io against a PM version have similar findings. Whether this is down to the lines of flux or some other factor I don't know but I find the concept intriguing.

The 930 in the video is using a DU 397 Multiconverter than enables the phantom three phase RC network and the felt brake to de dispensed with and the speed controlled by altering the mains frequency.

http://www.emt-profi.de/b-seite03cc.htm

I have a number of TBM records but not this one so I can't comment on how it should sound.

[Ali Tait]

The field coils I've heard have all sounded wonderful.

[Barry]

Barry

Whilst field coils may seem a retrograde step, their abandonment in favour of permanent magnets was a cost decision and not for quality reasons. There seems to be an acceptance that alnico sounds better than ferrite and other newer types of magnets in speakers, and those that have tried field coil speakers feel they sound better than equivalent permanent magnet versions. Those lucky to have listened for a field coil Io against a PM version have similar findings. Whether this is down to the lines of flux or some other factor I don't know but I find the concept intriguing.

The 930 in the video is using a DU 397 Multiconverter than enables the phantom three phase RC network and the felt brake to be dispensed with and the speed controlled by altering the mains frequency.

http://www.emt-profi.de/b-seite03cc.htm


Me too - I'm also intrigued as to why AlNiCo magnets should sound better than the rare-earth magnets: after all flux is flux.

Some time ago I looked into the DU 397 speed control for the EMT 930. Took it no further as I was, and still am, perfectly happy with my 930 'as is'.

Regards

[Dominic Harper]

Although I have not as yet played around with the concept of a field coil cartridge, I can say there will be more to this than you would imagine.
Choice of wire used for the coils, plus size of wire, coil former material, cantilever material and length, coil former shape, damper material and size, tie wire material and size, and finally tip profile all influence how a cartridge will perform. Each part and how it is designed all impact on one another,
thats without getting into impedance and output!

[YNWaN]

The field coils I've heard have all sounded wonderful.

Most of the field coils I've heard have sounded quite coloured - though they have been in horn loaded cabinets which is more likely the cause. My point being that it's not easy to separate one aspect from another.

focal make some very modern field coil drivers. In their case the emphasis is more on being able to adjust the electrical damping of the driver.

[Ali Tait]

Most I've heard have been on OB's. Forget the name, but a friend had a set that were 70 years old and sounded great.

[BTH K10A]

What are probably the best speakers I've ever heard are a home brew 2 way with an 18" bass unit and a compression driver, both of which have field coil magnets.

[Marco]

I just love this guys style, no bling just an eclectic mix of top quality vintage professional equipment. :)

Seems to be a home made field coil conversion of an EMT cartridge with battery for power. Certainly a lot cheaper than an Io Ltd ;)

PiDdntAceXU#t=64/

Interesting, Andy, but the music is bloody awful! :eek:

Marco.

[Barry]

Forgive the thread drift, but lovers of tone controls, might like to consider the addition of EMT's 240 "electronic bathroom" reverberation control to their system:

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[BTH K10A]

Interesting, Andy, but the music is bloody awful! :eek:

Marco.

Agreed, but the RCA Lathes are nice when used as mono turntables.

[BTH K10A]

This guy seems to have a monopoly on 73b's if the last pic is anything to go by.


http://ameblo.jp/lajazzaudio/entry-11488626633.html

Type 73-B
Type： Dual Motor Idler drive turntable
Platter：17.5 inches(44.5cm)
Cycle: 33、78
RPM： 1800
HP: 1/150
Power(Hz): 60/50hz (MI-11825/MI-11826)
Power(Volts): 105 - 125 volts
Power(watts): 90 - 145watt

Dimension: approx. W31 3/4" x H20" x D22 1/4"
Weight(Platter): approx. 61 lbs.
Weight(Total weight): approx. 280 lbs

[pure sound]

It'd be interesting to see more closely how he's incorporated the field coil within the magnetic circuit & if he is still just using the stock pole pieces & yoke. A PP3 battery isn't going to last too long either!