Help with getting obscure transformers to destroy signal again

[hoyahelper]

Hey all long time lurker here

I got a strange one for you!

Now im a bit of a novice but also like to throw things together and see what happens. I got these Prahn Danish transformers (cant find any info anywhere on them) on Tradera (swedish ebay) and decided to just do a simple passive stereo box and see what it sounds like. The result was this. There is also a reference of what the sample i used sounds like not going through the transformers.



The box they came in said they were 447 ohms so I Assumed sending a line level through that made them distort and thats what made that very destroyed sound. But went to use them today and now they sound like example two in the link provided. Not sure what could be the reason - could it be electrical (ground loop?) or maybe just the behaviour of the transformers?

just wanted to see if anyone has experienced this before and might have any ideas.

Thanks very much!

edit - ignore the broken cables - tip for input ts jack was soldered to one winding and tip for output ts jack was soldered to other winding. Ground bypasses transformer altogether

 

[scott2000]

Look like some kind of radio coils..

 

[gyraf]

IF transformers for radio?

 

[hoyahelper]

Could be IF transformers!

the gray screw things are caps to windings - not sure if that constitutes it as an IF transformer

If it is an IF transformer - does anyone know why the way it affects the audio signal might change? Could it be to do with radio frequencies?

 

[ruffrecords]

If it is an IF transformer it will have practically zero effect at audio frequencies. Some IF transformers had a built in detector diode so maybe this is causing the distortion.

Cheers

Ian

 

[hoyahelper]

Thanks Ian! I think you may be onto something with the diode clipping! Will test that out and see what happens!

 

[hoyahelper]

Hey all! So i figured it out

turns out there was a ground hum in the signal path which was in a feedback loop as the box was plugged into a patch bay - the hum feedback looped seems to cause some kind of major diode clipping modulation to the signal - hence the sound!

now ive learnt all about diodes and clipping - thank you all for your help!

 

[abbey road d enfer]

the gray screw things are caps to windings

They are the magnetic core (or part of it). Looks like they can be rotated for adjustment.

If it is an IF transformer - does anyone know why the way it affects the audio signal might change?

Transformers are designed for a nominal frequency range, power xfmrs for 50/60 Hz, audio xfmrs for the audible range, IF xfmrs for much higher frequencies (typically ca. 460kHz for AM, 10.7 MHz for FM)
When used outside its nominal trequency range, the result is limited response, in your case, utter lack of bass.

Could it be to do with radio frequencies?

No. Just inadequacy.

Anyway, I think the way you have connected them is wrong.

 

[CJ]

mini transformer used in overdrive stomp box>

https://aionfx.com/project/isotope-amp-overdrive/

 

[ward]

the tychobrahe octavia has a transformer too.... personally I like the whacko nature of this stomp box

 

[ruffrecords]

mini transformer used in overdrive stomp box>

https://aionfx.com/project/isotope-amp-overdrive/

Plenty of third harmonic that way. Good for instant power chords.

Cheers

ian

 

[abbey road d enfer]

the tychobrahe octavia has a transformer too.... personally I like the whacko nature of this stomp box

In the tychobrae, the xfmr is not intended for distortion/saturation, it's there to produce two out-of-polarity signals that are full-wave rectified. The intent, as the name implies, is to produce essentially second-harmonic, otherwise known as one octave up.
Of course, rectification also produces a lot of higher-rank harmonics.
The advantage is that the processed signal's envelope is a rather decent image of the input (within limits).

 

[CJ]

Langevin transformer with overloaded primary was responsible for Grady Martin,s early fuzz bass, hard to duplicate the partially open coil,

 

[abbey road d enfer]

Langevin transformer with overloaded primary was responsible for Grady Martin,s early fuzz bass, hard to duplicate the partially open coil,

That someone has found this sound to be pleasant illustrates perfectly the perversion of artistic directors...