Field Coils for Audio Systems

[spiritofmusic]

Like a surgeon handling a brain or heart, I would think Lol.

 

[dcathro]

My new motors are ready for shipping hopefully tomorrow. It took a little extra time as I had some custom thread made on the permendur pole so I can use any manner of phase plug that I make depending which driver I use.

View attachment 79471

Wow, these look great, Bill!!

Can I ask, who has made these for you, and what were your specifications for the design of them?

 

[spiritofmusic]

I believe Bill asked if he could have the best, and only the best. And then got the best.

 

[Audiophile Bill]

Wow, these look great, Bill!!

Can I ask, who has made these for you, and what were your specifications for the design of them?

They have been made for me by a fabulous Russian engineer that I have come to know. The specs were originally configured / conceived for AER drivers.
I asked for a couple of tweaks including the special permendur pole threaded pole piece to allow me to use any phase plugs of my design. Normally the AER motor poles are flat with no plug. The face plate is also drilled to allow flexibility of frames from various manufacturers.

 

[Audiophile Bill]

I believe Bill asked if he could have the best, and only the best. And then got the best.

To be fair they are a no holds barred and absolutely sumptuous build. Milling permendur is a pita as is solid billet Armco iron like that. Unfortunately he won’t build any more because it was too much work / hassle with complexity and machining.

 

[dcathro]

To be fair they are a no holds barred and absolutely sumptuous build. Milling permendur is a pita as is solid billet Armco iron like that. Unfortunately he won’t build any more because it was too much work / hassle with complexity and machining.

So yours will be unique! Fantastic.

I will be looking forward to following your adventure!

 

[dcathro]

They have been made for me by a fabulous Russian engineer that I have come to know. The specs were originally configured / conceived for AER drivers.
I asked for a couple of tweaks including the special permendur pole threaded pole piece to allow me to use any phase plugs of my design. Normally the AER motor poles are flat with no plug. The face plate is also drilled to allow flexibility of frames from various manufacturers.

Bill,

Does he have a website, or is there any information on his work?

Thanks

David

 

[Audiophile Bill]

Bill,

Does he have a website, or is there any information on his work?

Thanks

David

Hi David,

No website or online information afaik. Possibly there is on Russian site that i am not aware of.

Best.

 

[the sound of Tao]

To be fair they are a no holds barred and absolutely sumptuous build. Milling permendur is a pita as is solid billet Armco iron like that. Unfortunately he won’t build any more because it was too much work / hassle with complexity and machining.

Amazing, you’re really going with the flow on this Bill.

There’s much involved!… looks like an adventure just getting it fitted and everything settled in… then exploring the outcomes of varying/fine tuning voltage… is the plan still to use an off the rack lab power supply to explore the effect on the power to the fc initially.

Also is re-fitting with the field coil magnet something that you’d be able to feasibly come back from if you ever wanted to try the stock AER fixed magnet back in again. Just perhaps to re-confirm the differences down the track some time once you’ve got your bearings on the field coil… or do you feel that you just need to move ahead to do the custom psu either way. Just that part will be a story in itself.

You’ve got so many choices, figure it will all unfold for you along the way… this is such a great adventure, thank you… love it!

 

[Mister E]

Anybody here ever listened to Oleg Rullit's Super Aeros?

And regarding field coils, let's not forget ESD Acoustics from China.

DRAGON-ESD Acoustic

FIVE WAY SYSTEM

www.esdacoustics.com

 

[morricab]

To be fair they are a no holds barred and absolutely sumptuous build. Milling permendur is a pita as is solid billet Armco iron like that. Unfortunately he won’t build any more because it was too much work / hassle with complexity and machining.

So, no comparisons......how will we deal with this on WBF?

 

[Audiophile Bill]

Amazing, you’re really going with the flow on this Bill.

There’s much involved!… looks like an adventure just getting it fitted and everything settled in… then exploring the outcomes of varying/fine tuning voltage… is the plan still to use an off the rack lab power supply to explore the effect on the power to the fc initially.

Also is re-fitting with the field coil magnet something that you’d be able to feasibly come back from if you ever wanted to try the stock AER fixed magnet back in again. Just perhaps to re-confirm the differences down the track some time once you’ve got your bearings on the field coil… or do you feel that you just need to move ahead to do the custom psu either way. Just that part will be a story in itself.

You’ve got so many choices, figure it will all unfold for you along the way… this is such a great adventure, thank you… love it!

Hi Graham,

I am fairly laid back on such matters.

I had been looking for field coil motors of good quality and suitable for Lowther for at least 4 years now. I never managed to find any that suited what I was after so when this opportunity came along I didn’t even think twice especially since they were developed alongside AER frames.

I am not sure what experience you have with full range drivers but buying vintage Lowthers and others one has to be pretty well versed in removing the frames, cleaning the air gaps, and realignment. It is part of the journey when one acquires them because invariably the gap will have picked up some detritus on the way. It is quite fiddly and needs a very think spanner to get adequate room to manoeuvre the bolts. I learnt all this stuff about 4 years back and feel very comfortable with it all now. As such refitting the permanent magnets is no problem for me.

On the power supply you got it - plan is to use variable lab power supply in order to measure, listen and land on where I enjoy the drivers most in my system. I will then make something much more “special“ as the final supply.

I am glad that you and some others take a modicum of vicarious pleasure in my mad adventures. Certainly I find it great fun. As I said elsewhere - this is an itch I had to scratch. The best way to learn about such matters properly is to get stuck in with them at home and get involved.

Best.

 

[the sound of Tao]

Hi Bill,
I’ve probably got just not enough experience at this end and have only heard mostly off the shelf solutions plus some modest exploration myself so that is why it’s great to be able watch you go through it all with your build. It is an opportunity for me to learn much and that is a very big part of the draw for me.

I work in design so the process is for me comfortable… especially thinking about multiple iterative approaches and allowing process to flow and develop, but it’s more the specific technical aspects that leave me hanging on the edge of my seat at times

I do have a quite clear vision of what I’m pursuing though and feel a good connection to where you are going. That’s why it’s so appreciated at this end. Yours is very bespoke and different and personal journey and that is its great attraction.

 

[bonzo75]

Clear vision of where I am going. The last time I said that I was graduating on campus without any work experience

 

[the sound of Tao]

Clear vision of where I am going. The last time I said that I was graduating on campus without any work experience

Ked I hate to tell you but you don’t get to see where you are going to end at the start… it just becomes clear when you realise you’ve already raced past it

 

[Audiophile Bill]

Anybody here ever listened to Oleg Rullit's Super Aeros?

And regarding field coils, let's not forget ESD Acoustics from China.

DRAGON-ESD Acoustic

FIVE WAY SYSTEM

www.esdacoustics.com

Not heard the Atelier Rullit’s but would love to. Apparently meant to be one of the best in this category.

Best.

 

[spiritofmusic]

Field coil horns seems like the inner sanctum of the secret society. A bit like the Batcave having a cellar.

 

[morricab]

Hi Graham,

I am fairly laid back on such matters.

I had been looking for field coil motors of good quality and suitable for Lowther for at least 4 years now. I never managed to find any that suited what I was after so when this opportunity came along I didn’t even think twice especially since they were developed alongside AER frames.

I am not sure what experience you have with full range drivers but buying vintage Lowthers and others one has to be pretty well versed in removing the frames, cleaning the air gaps, and realignment. It is part of the journey when one acquires them because invariably the gap will have picked up some detritus on the way. It is quite fiddly and needs a very think spanner to get adequate room to manoeuvre the bolts. I learnt all this stuff about 4 years back and feel very comfortable with it all now. As such refitting the permanent magnets is no problem for me.

On the power supply you got it - plan is to use variable lab power supply in order to measure, listen and land on where I enjoy the drivers most in my system. I will then make something much more “special“ as the final supply.

I am glad that you and some others take a modicum of vicarious pleasure in my mad adventures. Certainly I find it great fun. As I said elsewhere - this is an itch I had to scratch. The best way to learn about such matters properly is to get stuck in with them at home and get involved.

Best.

I simply avoided Lowthers as i found them too shouty and when you see their breakup in the highs it is easy to know why. The only way i heard them work was with the whizzet removed as in Horning speakers, which I like. I am not sure how AER managed to avoid this without resorting to multiple whizzers like Cube Audio but their measurements suggest they figured it out. Voxativ seems to have at least partially overcome this as well. That said, i haven't heard a single driver whose treble i could live with. I hear some breakup on all of them (even the AERs I have heard at shows). Based on comments about your system, perhaps you have done something that could convince otherwise...

 

[dcathro]

I simply avoided Lowthers as i found them too shouty and when you see their breakup in the highs it is easy to know why. The only way i heard them work was with the whizzet removed as in Horning speakers, which I like. I am not sure how AER managed to avoid this without resorting to multiple whizzers like Cube Audio but their measurements suggest they figured it out. Voxativ seems to have at least partially overcome this as well. That said, i haven't heard a single driver whose treble i could live with. I hear some breakup on all of them (even the AERs I have heard at shows). Based on comments about your system, perhaps you have done something that could convince otherwise

My position is similar.

I have heard and enjoyed Lowthers on many occasions, but did not feel that I could live with them. I have been curious about the Voxativ and AER, and also the Feastrex.

I chose to go with Supravox widebander because there is no wizzer and therefore I felt that I could integrate a tweeter and have a smooth
response.

Will be watching with anticipation on how Bill's experiment goes.

 

[tima]

J

Just talked to him on the phone.

Do you or Ralph (@Atmasphere) know the Web address for Classic Audio Loudspeakers?

It does not appear to be:
http://classicaudioloudspeakers.com which redirects to

Classic Audio Loudspeakers

There's a page there but tjat shows only a box with a blue border and no content.