Anyone else running field coil based speakers?

[dcathro]

53 minutes ago, andyr said:

 

Not as far as I am concerned!  

 

16Hz to >20kHz is my definition of 'full range' ... but if you don't listen to:

a. (pipe) organ music, and

b. classical piano or violin music

 

... you probably don't know WTF I am talking about.  

 

(I run Maggies - tweeters rated to 40kHz - with subs ... which greatly increase my enjoyment of:

• Bach organ music
• Yello, and
• reggae.)

 

 

So you:

a.  have a XO between your so-called "widebanders" and your tweeters

b.  don't have much HF delivery if you're already 6dB down at 20kHz, and

c.  you miss out on bass?

 

 

 

 

Sure, 40Hz to 15kHz is a good definition of where most of the musical frequencies reside ... but not to be able to hear a 16Hz (32' organ pipe) note means your enjoyment of Bach organ music will be severely degraded.    To say nothing of Yello!

 

 

 

Maybe you need to widen your horizons and listen to some 'box-less' spkrs - like, say:

• Maggie 30.7s
• or Maggie 3.7s plus a pair of good subs ... integrated well!

 

Andy

 

 

Andy,

 

What is your contribution to this thread on field coils?

 

I don't come onto your threads and tell you how much I hate Magneplanars.

 

But to answer your question, My speakers will go down to 30hz in room, and go out beyond my high frequency hearing capability.

 

I personally would rather have great dynamics, coherency and timing within the limited bandwidth than just have extension.

[dcathro]

11 minutes ago, springcreek said:

Andy

 

I don’t listen to much organ music, but I do listen to pretty much everything else and the Rullit’s do it all. And they make music come alive. 
 

I’ve never heard a sub I could live with, slow witted and dull. And it would be very difficult finding anything that keeps up with the Rullit’s. Maybe some of Oleg’s 15 inch field coils or some high efficiency drivers slot loaded. 
 

I have heard many big speakers over the years from Maggie's to Wilson’s, Evolution Acoustics MM7, plenty of big horns, etc, etc. Many of those systems were very expensive topping the million dollar mark. Some were good, like Mike Lavigne’s room in Seattle. But mostly they just sounded like hifi to me. None came close to doing what the Rullit’s do.
 

Sure adding some cone area would give greater scale and I might consider Oleg’s super aero 12s one day, but the aero 8 just sound so alive, so real, so dynamic, so present and so high resolution that I don’t really want for much. Other than some system tuning, some additional room treatment and building a mercury vapour field coil psu I’m kind of done. Just buying records. Though I would like to buy a Dava coil cartridge one day, not sure my Schroder could handle the cartridge mass 

 

To each their own, as long as it makes you happy 

 

Well expressed Andy!

 

Interesting that you have been to Mike Lavigne's room, one of the most out there rooms/systems on the planet. He spends more on footers that my system costs. How impressive was it?

 

I would love to hear your system one day.

 

 

 

[andyr]

8 hours ago, dcathro said:

 

Andy,

 

What is your contribution to this thread on field coils?

 

 

Directly about field coils - not much, David,  

 

I responded specifically to comment about your claim:

 

11 hours ago, dcathro said:

 

50hz to 15Khz is full range!

 

 

... which I regard as a misleading statement.

 

Andy

 

 

[dcathro]

11 hours ago, andyr said:

 

Directly about field coils - not much, David,  

 

I responded specifically to comment about your claim:

 

 

... which I regard as a misleading statement.

 

Andy

 

 

 

Andy, you responded to Springcreek's  assertion that his drivers were full range. My comment was a tongue in cheeks response to your assertion that 16hz to 40Khz was necessary.

 

I can completely understand that Andy does not feel the need to augment his speakers with a super tweeter and subs.

 

I have been running mini monitors for the past 18 months and I would not add a sub even although I was missing out on the bottom octave and a half. The subs would damage way more that they would add. If you don't understand that, we probably have very different expectations of what we want from our systems.

 

Cheers

 

David

 

 

[andyr]

23 minutes ago, dcathro said:

 

I have been running mini monitors for the past 18 months and I would not add a sub even although I was missing out on the bottom octave and a half. The subs would damage way more that they would add. If you don't understand that, we probably have very different expectations of what we want from our systems.

 

Cheers

 

David

 

 

And I fully accept your decision to miss out on:

• the lower octave and a half
• and the upper octave.

David, each to his (or her) own - your decision is exactly the same as those who don't augment their Quad 57s.  (The argument which is always used is that subs "can't keep up " with the electrostatics.)

 

Many Maggie owners make the same claim (Maggies are too 'fast') and yet a conductor friend of mine who had 20.1s about 15 years ago (then Magnepan's largest speaker - and therefore the one which delivered the most bass) said he needed subs to recreate the sound he hears when conducting an orchestra.

 

And all I can say is ... after listening to 3.X series Maggies (large but one size down from the 20.X series) for over 20 years, I am delighted with the extra enjoyment of Bach organ music - and Yello - that my sealed subs deliver.

 

Andy

 

[Azura]

David,  You asked 

"If I go with the Mundorf 33mH chokes at 0.84 ohms, and order a 35V transformer, I should have enough voltage that I can vary with a rheostat to get between 9V and 13V? If I  split the circuit as you have done, do I  need more volts, or is it just a matter of more amps?"

 

What is the specified current and voltage for one driver?  

 

martin

 

 

[dcathro]

21 hours ago, Azura said:

David,  You asked 

"If I go with the Mundorf 33mH chokes at 0.84 ohms, and order a 35V transformer, I should have enough voltage that I can vary with a rheostat to get between 9V and 13V? If I  split the circuit as you have done, do I  need more volts, or is it just a matter of more amps?"

 

What is the specified current and voltage for one driver?  

 

martin

 

 

 

Hi Martin,

 

They run between 6 and 12 volts, and 1 and 3 amps. I am running them close to 9 volts at just over 2 amps.

 

Would be nice to be able to vary between 8 and 12 volts.

 

Thanks

 

David

[Azura]

Perhaps easiest if you tell me what the resistance of one field coil is. Can you measure it  with a DMM?

 

martin

[dcathro]

On 22/10/2020 at 11:03 PM, Azura said:

Perhaps easiest if you tell me what the resistance of one field coil is. Can you measure it  with a DMM?

 

martin

 

Hi Martin,

 

I measured the field coil resistance at 4.6 ohms. 

 

Cheers

 

David

[Azura]

Using a 40V - 0 - 40V  5A transformer with 9% regulation and three Mundorf chokes ( one and then split with two in parallel) you get the below . I modelled it with hte FCs in parallel ie 2.3 Ohms load:

Here is a transformer that  would do the job:  

https://www.ebay.com.au/itm/2X40V300-TORTECH-40V-40V-300Va-Toroidal-Transformer-Primary-Voltage-240V-Ac/192614409912?hash=item2cd8b6a6b8:g:aQsAAOSwupVeCr9U&frcectupt=true

 

[Azura]

It is theoretically possible to wind 2 x filament windings of 2.2V 17A onto the torroidal core and remain within the 300 VA rating.  But better to get another transformer for the filaments.  

[dcathro]

10 hours ago, Azura said:

It is theoretically possible to wind 2 x filament windings of 2.2V 17A onto the torroidal core and remain within the 300 VA rating.  But better to get another transformer for the filaments.  

 

Thanks Martin,

 

Could I use the transformer listed here at 5V, 3A  - part number 266M2 ?

 

Thanks

 

David

[Azura]

For the filaments you need 2.2V 17A per filament.  If you could find a 5V centre tapped 17A transformer you could probably use it.  Minimum 100VA. Apart from the 110V hammond transformer I posted previously I doubt you will find one.  It will need to be custom wound. 

 

266M2

7.5

2.5V @ 3A

1.25V @ 6A

[dcathro]

20 hours ago, Azura said:

For the filaments you need 2.2V 17A per filament.  If you could find a 5V centre tapped 17A transformer you could probably use it.  Minimum 100VA. Apart from the 110V hammond transformer I posted previously I doubt you will find one.  It will need to be custom wound. 

 

266M2

7.5

2.5V @ 3A

1.25V @ 6A

 

So I either get a custom tranny wound, or I get the Hammond, Tortech and a step down.

 

To vary the output, does the resistance come before or after the Tungars? If the circuit provides 12.5 volts, and I want to run at 9 volts, then to drop 3.5 volts at 2.7 amps, with resistor at the end of the circuit I will need 1.3 ohms resistance, or before the tungars of around 8 ohms?

[Azura]

It would work in the AC or the DC circuit.  If you want to use an adjustable rheostat you would put it at the output. Perhaps with a cap after it for another smoothing filter. Ohms law but the whole circuit will come into it. 

 

The 1.5 R represents a 3 Ohm R on each leg. 

 

[Stump]

I will be running Tungar to run LM 555 and 597 tweeter. Took me a while to fine a used PR-22 which are no longer made.Will set up with DEQX HDP-5 and Amps before trying out the mono blocks..

 

[dcathro]

1 hour ago, Stump said:

I will be running Tungar to run LM 555 and 597 tweeter. Took me a while to fine a used PR-22 which are no longer made.Will set up with DEQX HDP-5 and Amps before trying out the mono blocks..

 

 

Wow, great setup!

 

What are the woofers?

 

I was trying to find a used PR22 for years, where did you get yours?

[Stump]

11 hours ago, dcathro said:

 

Wow, great setup!

 

What are the woofers?

 

I was trying to find a used PR22 for years, where did you get yours?

I didn't go with the field coil woofers but the RFC L15P530.Friend sourced the PR22 from Singapore. I could have gone with the new 3 way PR22 but like the exposed Tungar look.

[dcathro]

Thought I would bump this.

 

Anyone got into field coils recently, or heard any?

[klm]

I have a pair on order for delivery in September but until they actually land, I’m staying stumm in case it all ends in tears. Will be my first throw at those particular stumps.

[dcathro]

19 minutes ago, klm said:

I have a pair on order for delivery in September but until they actually land, I’m staying stumm in case it all ends in tears. Will be my first throw at those particular stumps.

 

Care to share the make and model?

 

I don't see how you can go wrong - I have never heard a negative story.

[klm]

50 minutes ago, dcathro said:

 

Care to share the make and model?

 

I don't see how you can go wrong - I have never heard a negative story.

Sorry, I walked under a ladder this morning, had a black cat cross in front of me and you want me to tempt fate again. 
If they arrive and sound like they should then I shall shout from the rooftops, should they go the other way, it never happened. I have faith in the manufacturer and we shall see in September if it is warranted.

[dcathro]

2 hours ago, klm said:

Sorry, I walked under a ladder this morning, had a black cat cross in front of me and you want me to tempt fate again. 
If they arrive and sound like they should then I shall shout from the rooftops, should they go the other way, it never happened. I have faith in the manufacturer and we shall see in September if it is warranted.

 

LOL 

[Analogsound]

8 hours ago, dcathro said:

Thought I would bump this.

 

Anyone got into field coils recently, or heard any?

I owned  Maxonic L-430EX woofer 10 years ago ( hard to find fully complete systems ) then I've been decided to sell it last few years ago
sound very fast and dynamic but it can't do deep bass at the low frequency than the Altec woofer, the mid-low soft is a bit compared with an Altec 416a 
my opinion: The field coil sounds amazing but not at all if you chose the wrong brand  or model
 

 

 

 

[dcathro]

On 10/03/2023 at 2:44 PM, klm said:

Sorry, I walked under a ladder this morning, had a black cat cross in front of me and you want me to tempt fate again. 
If they arrive and sound like they should then I shall shout from the rooftops, should they go the other way, it never happened. I have faith in the manufacturer and we shall see in September if it is warranted.

 

Did you ever get these, and if so have you kept them?