Hammond or Triad?

[ALL212]

If using a choke is there a difference that should be noted that would determine which to use?

Triad C-7x vs. Hammond 158M.

Triad 90 DC m/a, 10 H, 270 ohm
Hammond 100 DC m/a, 10 H, 262 ohm

Hammonds are almost twice the price. 

 

[johnsonad]

In my limited experience, neither transformer measures anywhere close to the listed value in resistance. I've both and the build quality or at least finishing is better for the Hammonds.  I noticed no difference when used as intended.

 

[Chris65]

Triad is made in China, Hammond in Canada, which probably accounts for the price difference.
I also echo Aaron's comments.

 

[mcandmar]

I found the same as Johnsonad says when i had them side by side.  They are probably all made in China anyhow, as i found when i recently ordered a second Hammond power transformer.

 

[Chris65]

Hammond source some small power transformers from China (like yours), but as far as I'm aware all Audio transformers/chokes are still made in Canada.

 

[Paul Joppa]

I have not bought a C7-X in a long time, but they have been built in several places over the years. When the Paramour first came out, they were built in Mexico and done the old-fashioned way, layer wound with paper between each layer - this reduces the stray capacitance, improving high frequency performance as a plate choke. At some point they switched to regular bobbins, and (IIRC) later they were clearly made by Hammond without attribution.

The C7-X comes up often, because it is widely available. But since the layer winding was abandoned, I know of no special reason to stick with it over others with similar specs.

 

[ALL212]

I think in most cases we're replacing the 270 ohm 5w resistor.  How far off of 270 ohm can we be and still function according to spec?  These things are +- 20% IIRC.

 

[Paul Joppa]

It's not very sensitive. At 70mA, a 270 ohm resistance will drop 20vDC, which is much less than the usual 300-400v in a power supply. I would not even bother to calculate it as long as the resistance is between 150 and 400 ohms.

 

[ALL212]

Bought one of each for comparison:
Triad comes in at 245 ohm
Hammond at 188 ohm (measured 3 times to be sure)

Hammond packaging - very good.  Triad packaging, non-existant.
Triad has tinned ends, Hammond does not.
Triad reasonably close to advertised value.
Hammond...WTH??

 

[mcandmar]

Hah my pessimistic prediction was true, they are made in China now  :

Here are the two i have in stock,  Hammond 11.9H 192r, Triad 14.2H 244r

 

[ALL212]

For the Hammond it gets worse...

Triad 10.2 H
Hammond 5.3 H

I'm wondering now if I have a mislabeled choke from Hammond?

I'm going to return it - or try, and see what happens with the next one.

 

[Paul Joppa]

How are you measuring inductance? It is a function of the applied AC voltage, AC frequency, and  the DC current. You will usually get a small measurement if the applied AC voltage is small (<10v?) and/or the frequency is high (>120Hz).

 

[ALL212]

I've got an LCR meter.  I'm assuming it works ok.

 

[Paul Joppa]

That was my guess - these meters often use 1kHz tones at a fairly low voltage. Fine for air-core crossover coils, or for RF chokes, but not as relevant for power supply or plate-load inductors.

 

[ALL212]

Paul - does that mean I shouldn't trust it for measuring the chokes?  It appears close on the Triad but way off on the Hammond.

 

[Chris65]

I have a cheap LCR meter, & both the Triad C7X and the Hammond 158M (made in Canada) measure close to 10H.

 

[Paul Joppa]

Paul - does that mean I shouldn't trust it for measuring the chokes?  It appears close on the Triad but way off on the Hammond.

I would not trust it for measuring chokes that will go into power supplies or plate loading chokes. There is no reason not to trust it for crossover and RF measurements.

The point is that iron-core inductors have a substantial variation over the range of voltages and frequencies, so any single measurement is only valid under similar conditions to the measurement.

 

[braubeat]

if you really want to get into it you can get an LCR meter that checks at various frequencies and then apply current with a constant current source that has very high impedance. this would give useful information but not the whole story.

michael