Field Coils for Audio Systems

I remembered I just bought an infrared for custard, so I fired it up this morning. The numbers weren't bad, but it also didn't feel nearly as warm as it did yesterday (house was about 77 yesterday).

The case of the PSU was 107. The field coil housing was 85 or so. But definitely felt cooler to the touch than it had.

I'll measure again tonight.
 
I remembered I just bought an infrared for custard, so I fired it up this morning. The numbers weren't bad, but it also didn't feel nearly as warm as it did yesterday (house was about 77 yesterday).

The case of the PSU was 107. The field coil housing was 85 or so. But definitely felt cooler to the touch than it had.

I'll measure again tonight.
Is that Celsius or Fahrenheit? You'll want to check the infrared on that; I'm assuming the latter since you were using it for cooking. If so then those temperature are nominal.
 
Is that Celsius or Fahrenheit? You'll want to check the infrared on that; I'm assuming the latter since you were using it for cooking. If so then those temperature are nominal.
Yup, f. So yeah really pretty fine. I would guess the field coils were more around 100 last night but we shall see.

Ok the hunt for the most magic continues since I don't think that's it .
 
I remembered I just bought an infrared for custard, so I fired it up this morning. The numbers weren't bad, but it also didn't feel nearly as warm as it did yesterday (house was about 77 yesterday).

The case of the PSU was 107. The field coil housing was 85 or so. But definitely felt cooler to the touch than it had.

I'll measure again tonight.
How was the custard? :)

If you want a try an epic custard recipe look up "Australian Women's Weekly Baked Custard". An Aussie staple since the 1960's.

LPG
 
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I did order the Coleman regulator kits and have them sitting in my soldering box. I've had a lot going on and finishing that project isn't going to happen anytime soon.

Zayin Audio is making me 2 custom adjustable voltage SupraRegs for my AC-Xs. This is a double leap of faith as I haven't seen let alone listened to a system with a Zayin Audio SupraReg power supply and it's a custom job.

I'll report back once I get it and have some time on them.
 
How was the custard? :)

If you want a try an epic custard recipe look up "Australian Women's Weekly Baked Custard". An Aussie staple since the 1960's.

LPG
It was for ice cream :)

I'm looking to sell some of my ice cream in my food truck but I usually do raw eggs and make the best damn ice cream, it's been a bit of a job to get a recipe I like without raw eggs
 
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I did order the Coleman regulator kits and have them sitting in my soldering box. I've had a lot going on and finishing that project isn't going to happen anytime soon.

Zayin Audio is making me 2 custom adjustable voltage SupraRegs for my AC-Xs. This is a double leap of faith as I haven't seen let alone listened to a system with a Zayin Audio SupraReg power supply and it's a custom job.

I'll report back once I get it and have some time on them.

Please do report back. I now have two new pairs of field coil drivers sitting waiting for me to build the Coleman's, and I just don't find the time. It's new for me this kind of diy so I can't just whip them up.
 
Can you explain to me what current I should set if I have a constant current power supply?

I have Supravox 380 exc speakers. https://www.supravox.fr/en/products/copie-de-380-2000-lc-haut-parleur-de-grave-95db-8-ohms-1

The manufacturer specifies 9-12V 2x5A.

Currently, I have the power supply set to 11.26V.
I don't see them supplying the ohm rating of the field coil so we could calculate the current needed to supply the same voltage.

If you have a multimeter, and can measure the field coil resistance, we could calculate your current needed to achieve your 11.26V.

With a CCS I would recommend having a voltmeter installed within the new power supply you can see what you are feeding it.
 
Can you explain to me what current I should set if I have a constant current power supply?

I have Supravox 380 exc speakers. https://www.supravox.fr/en/products/copie-de-380-2000-lc-haut-parleur-de-grave-95db-8-ohms-1

The manufacturer specifies 9-12V 2x5A.

Currently, I have the power supply set to 11.26V.

Hi,

If you measure the impedance of the field coils, the current will be between 9/R and 12/R. The value can be determined by measurement and by ear. That is when you have both a measured and subjective smooth response.
 
At higher voltage you get more current flow, the Qts of driver sinks.
When you use it in a openbaffle It's a bad decision you loose some in the deep bass.
In a box, it sounds better; the magnetic strength increases; more control; better impulse processing.
Exsample at 6.0 volt qts 0.9 at 11volt qts 0.5 are values to illustrate
P.S
Qts 0.15-0.4 for horn
Qts 0.5- 0.767 bassreflex/ closed
Qts 0.8- 1.2 openbaffle
 
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Pmax 14 volt × 5Amp = 70watt coil
R= u x u/ power
R= 14x14/ 70 = 2.8 ohms
I=u/r
11.26volt /2.8 ohms= 4.02 ampere
Assuming the maximum voltage/current (14 volts and 5 amps) of the excitation coil. No guarantee.
P.S
in which type of loudspeaker is the supravox used?
 
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Pmax 14 volt × 5Amp = 70watt coil
R= u x u/ power
R= 14x14/ 70 = 2.8 ohms
I=u/r
11.26volt /2.8 ohms= 4.02 ampere
Assuming the maximum voltage/current (14 volts and 5 amps) of the excitation coil. No guarantee.
P.S
in which type of loudspeaker is the supravox used?

It’s highly unlikely to be dissipating 70watts. The 5amp is the recommended ps to not have it maxed out. If I had to guess it’s probably 25-35watt dissipation at max voltage.
 
OK guys, thank you very much for your help. I learned a lot and many things became clear to me.

Yesterday, I measured my field coils.
The resistance of a cold field coil is 3.4 ohms.
The resistance of a field coil heated after an hour of playing is 3.8 ohms.

The values on the laboratory power supply are:
cold 11.52V 3.308A and 38.21W, hot 11.52V 2.983A and 34.47W.

The power supply is not calibrated and shows a slightly different voltage than my multimeter, which I used to measure the resistance.
 
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It’s highly unlikely to be dissipating 70watts. The 5amp is the recommended ps to not have it maxed out. If I had to guess it’s probably 25-35watt dissipation at max voltage.
You were right, I prefer the old drivers anyway, Telefunken, Siemens LL high voltage, low current. The older Fertin 18" ran at 60 watts.
helix_to_heaven.jpg
 
OK guys, thank you very much for your help. I learned a lot and many things became clear to me.

Yesterday, I measured my field coils.
The resistance of a cold field coil is 3.4 ohms.
The resistance of a field coil heated after an hour of playing is 3.8 ohms.

The values on the laboratory power supply are:
cold 11.52V 3.308A and 38.21W, hot 11.52V 2.983A and 34.47W.

The power supply is not calibrated and shows a slightly different voltage than my multimeter, which I used to measure the resistance.

I like how you measured them cold and hot!

Realistically, these numbers are close enough for you to use as a reference for the CCS power supply. Set theCCS at 3amps to achieve 11.52V once warmed up.
 

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