UTC HML-40 Transformers.... What to do

[abechap024]

Hello,
I got some HML-40 transformers that are used as high pass filters, They high pass at 40 hz so my idea is to just use them as regular transformers, Except they only have 3 terminals...I'm assuming they have the grounds tied together - what a not good idea! Anyone have any experience cutting these things open to untie the grounds ... or any other ideas?
Thanks
AC

 

[emrr]

if those are what i remember, they do not qualify as transformers.  simply inductor/cap networks.  i think you will only destroy some perfectly fine 600 ohm high pass filters, and not gain any transformers either. 

 

[abechap024]

hmmm ok, well thats good to know... why would they use an inductor in just a HP filter? just curious....
AC

 

[emrr]

Was the traditional passive approach for any sort of EQ at the time; steeper cut-off I believe.  Is there a diagram on it?  I think the HML unit I have shows the internal connections.    From memory this hi pass type is inductor to common, series cap on the hot signal, inductor to common.    Whether you ground the common is up to you. 

 

[CJ]

be aware that the caps inside those things can be very old and leaky.

and no way to get at them.



Not!  ;D

 

[abechap024]

hmm so any ideas on something interesting I coudl use them for (besides the high pass action)? mybe an eq or something? maybe convert them into a flux capacitor?
thanks
aC

 

[emrr]

I would use them as intended all day long, on a ton of different sources.  I'm not sure they are good for much else, other than selling to someone who wants them for what they are. 

 

[analogggman]

Bump thread.

Do you just wire the neutral and ground to the common, and hot to the in, and hot to the out? Best to just use mono jacks with one of these?