Visit to Audiophile Bill to hear his horns project

[Audiophile Bill]

Pulled the trigger on custom Dueland Cu-Sn CAST caps based on a bunch of research. Thank you to the members who commented above. Will take 8-9 months to ship, but these speakers have already been a 6 year ordeal, so what’s another 8-9 months?!

Take a look at this spare pair of voice cones that I just received for the RCA1428/1443. These are basically impossible to find. How do they look after ~80+ years?! They don’t make ‘em like they used to!
Compared to modern drivers, what stands out? The size and shape, I bet. Anything else?

View attachment 85190

oh my - they are gorgeous.

Is the cone a phenolic impregnated cloth / fabric of some sort. Voicecoil is large and the diameter of the coil wire looks large.

Have you a photo of it assembled?

 

[Audiophile Bill]

Well from the sublime above with Surge’s RCA to the ridiculous.

Here you will see finally had the time to assemble one of the field coils for testing:

 

[Zeotrope]

Bill has the beautiful shiny new version!

Here's how the phenolic cone on the RCA looks when it's mounted. Behind it is about 50lbs. of copper wire.

 

[spiritofmusic]

Well from the sublime above with Surge’s RCA to the ridiculous.

Here you will see finally had the time to assemble one of the field coils for testing:

View attachment 85192
View attachment 85193

Bill, i just KNOW that mutha is gonna sound spectacular.

 

[Solypsa]

geez guys all this unobtanium ( new or old ) is just a tease!!

 

[cal3713]

I just wanted to comment on what a pleasure this thread has been. Thanks Bill & Spirit. Not many places in the world where DIY, experimentation, and all-out-assault get combined... and fun to find out that many of my discovered preferences and solutions (Duelunds, pure silver wire, DHT SETs, and hell, even WAGO lever clips) are already in use by the participants -- and I know I didn't find out about them from you all.

Given all that overlap, I'm sure I can trust the ears in here... a very rare find. Thanks.

 

[Audiophile Bill]

I like connectors. These ones are from the company Amphenol. Yes they are expensive military certified connectors, but honestly not much more than Speakon etc let alone the “high end” brands.

 

[DasguteOhr]

I like connectors. These ones are from the company Amphenol. Yes they are expensive military certified connectors, but honestly not much more than Speakon etc let alone the “high end” brands.

View attachment 85286

Amazing quality for exsample external power supply tube amps.
Nothing is better?
100% operational safety regardless of whether it is snowing or raining

 

[cal3713]

I like connectors. These ones are from the company Amphenol. Yes they are expensive military certified connectors, but honestly not much more than Speakon etc let alone the “high end” brands.

View attachment 85286

Amazing quality for exsample external power supply tube amps.
Nothing is better?
100% operational safety regardless of whether it is snowing or raining

Haha. Exactly. And I've already got two on my dht preamp power supplies (one for each tube/channel)!

 

[dcathro]

Well from the sublime above with Surge’s RCA to the ridiculous.

Here you will see finally had the time to assemble one of the field coils for testing:

View attachment 85192
View attachment 85193

Hi Bill,

They certainly do look serious!

Interesting that AER, like Supravox, use those cheesy brass binding posts. I have purchased some Cardas copper posts to replace mine in the future.

Have you been able to listen to the raw driver (not mounted) yet? Can you hear any differences

Cheers

David

 

[Audiophile Bill]

Hi Bill,

They certainly do look serious!

Interesting that AER, like Supravox, use those cheesy brass binding posts. I have purchased some Cardas copper posts to replace mine in the future.

Have you been able to listen to the raw driver (not mounted) yet? Can you hear any differences

Cheers

David

Hi David,

This weekend all being good!

cheers

 

[Zeotrope]

Guys, let's talk about field coil Power Supplies - I just switched from constant voltage lab supplies (which I've been using for years), to unregulated (for the high voltage midrange) and constant current (for the low voltage upper bass woofers) from Wolf Von Langa.

Wow!! I’m really surprised at how much of an improvement the new power supply has made!
The difference is much more profound than I expected. Vocals sound more relaxed and less strained than I’m used to. When I decided to upgrade from my Lambda constant voltage lab supplies, I was doing it mainly to eliminate noisy transformers and for aesthetics. I had learned that constant voltage supplies are not recommended for field coil speakers; but I had no idea the difference would be so profound - it’s as if I upgraded the entire speakers. Imaging is also more focused, especially at different frequencies. For example, a guitarist who sings is now centered; previously, the guitar notes would be slightly un-centered relative to her voice.

Bottom line: if you are using constant voltage supplies, you are missing out!

This one powers all 4 drivers: 2x Midrange (110V) and 2x Upper Bass (12V)

 

[Solypsa]

Interesting. Will be looking to learn more here, especially 'why'....

 

[Zeotrope]

The best explanation I’ve found comes from Audio Feast (https://www.theaudiofeast.com/field-coil-psu)

Field coil driver acts like an audio transformer:
Primary winding = voice coil
Transformer core = field coil magnet circuit
Secondary winding = field coil

When the audio amplifier puts a signal into the voice coil, it will come out on a field coil. It will impact voltage on the field coil.
Closed loop field coil power supply responds to the signal and tries to put the voltage back to the original.
Virtually the music amplifier and closed loop field coil power supply fight each other.

If we have a closed loop audio amplifier, things can get more complicated.

 

[Zero000]

I like connectors. These ones are from the company Amphenol. Yes they are expensive military certified connectors, but honestly not much more than Speakon etc let alone the “high end” brands.

View attachment 85286

Proper connectors.

Been using connectors of that type (and much bigger with more pins) on and off for decades.

Commonly used to connect bespoke black box computers of various sorts in aerospace and defence.

They can sometimes be a bit of a bitch to undo but I doubt you will experience that.

I've used them typically during the software/hardware integration phase of flight controllers/autopilots/engine electronic controllers/missile guidance systems/bomb detonators etc etc etc LOL.

 

[Audiophile Bill]

Guys, let's talk about field coil Power Supplies - I just switched from constant voltage lab supplies (which I've been using for years), to unregulated (for the high voltage midrange) and constant current (for the low voltage upper bass woofers) from Wolf Von Langa.

Wow!! I’m really surprised at how much of an improvement the new power supply has made!
The difference is much more profound than I expected. Vocals sound more relaxed and less strained than I’m used to. When I decided to upgrade from my Lambda constant voltage lab supplies, I was doing it mainly to eliminate noisy transformers and for aesthetics. I had learned that constant voltage supplies are not recommended for field coil speakers; but I had no idea the difference would be so profound - it’s as if I upgraded the entire speakers. Imaging is also more focused, especially at different frequencies. For example, a guitarist who sings is now centered; previously, the guitar notes would be slightly un-centered relative to her voice.

Bottom line: if you are using constant voltage supplies, you are missing out!

This one powers all 4 drivers: 2x Midrange (110V) and 2x Upper Bass (12V)
View attachment 86329

They look really nice - what is the price of the WVL constant current supplies?

 

[Zeotrope]

Ultimately, I didn’t go with Audio Feast, since they (oddly) don’t really allow for the voltage to be adjusted. I say oddly, since they talk about the importance of finding the sweet spot of voltage output, yet don’t have a design that allows for fine tuning of output!

I also have not heard of needing mono supplies (1 per driver) - I know that Jeff Jackson for example said it doesn’t make a difference if you’re powering all field coils from 1 transformer or not, and clearly WVL doesn’t think it matters (or they wouldn’t do it).

 

[DasguteOhr]

For high voltage field coils with low current, I would always use power supplies that work with tube rectification. no recharging tips like diodes can bring harshness into the sound.
for field coil with low voltage and high current, a power supply with a sieve chain capacitor choke,capacitor ,choke, capicitor which can bring a similar effect.
Like that

Making of a Field Coil Speaker, Part 2: FC PSU

Hi! Part 1 of this series about the development and building of a field coil speaker system showed the first trial for a bass cabinet and...

vinylsavor.blogspot.com

 

[Zeotrope]

For high voltage field coils with low current, I would always use power supplies that work with tube rectification. no recharging tips like diodes can bring harshness into the sound.
for field coil with low voltage and high current, a power supply with a sieve chain capacitor choke,capacitor ,choke, capicitor which can bring a similar effect.
Like that

Making of a Field Coil Speaker, Part 2: FC PSU

Hi! Part 1 of this series about the development and building of a field coil speaker system showed the first trial for a bass cabinet and...

vinylsavor.blogspot.com

Perhaps, and I don’t know enough to comment, other than to say that there is no 1 best solution. Besides, I can’t stand Thomas Mayer and would never give him my money, so I don’t care how good his products are.

Also, for my drivers, tube supplies require mercury vapour. I have a pair, but I don’t use them due to the dangers of mercury vapour rectifiers.

 

[DasguteOhr]

was only intended as an example of how to build it nothing more. there are enough providers