Sweeping a bunch of transformers

[newhall]

So I have been sweeping a bunch of transformers I collected. I have been using rightmark audio analyzer. I am using a Behringer umc1820 interface. It sweeps two channels, one I just loop back just showing response of soundcard. The second I break out with quarter inch jacks with alligators. After awhile I found with experimenting with different loads I get good results.
I have found that transformers with high ratios like the high impedance as primary and low as secondary. I have seen that too high of load you get peak on high frequencys. I did not do any zobel networks.
I have this Adc out of a gates transistor line amp. Here is the best I could get. With this OT I could not get a very high signal with high impedance as primary. Result of too much resistance in windings?
So this is high as secondary. When done the other way I get massive bass loss and high peak above 10k.
So in the picture here is the low end squirrelyness the result of ringing?
My ratio on this OT is 1:5, or 150:3750.
Anyone ever mess with this transformer or recommend a project for it? Probably a cathode follower?

 

[newhall]

The primary, high impedance side is center tapped btw

 

[ruffrecords]

Out out transformers (OT) work best when driven from a low impedance.

Cheers

Ian

 

[newhall]

So are you saying put the 150 side on the plate or cathode (cathode follower) of an output tube instead of the 3.6k??

 

[newhall]

Or are you just commenting on hooking it up to sound card? Just clarifying for people

 

[newhall]

Now that I had my coffee. Yes that's why it worked better. Any have a comment on the jaggedness on the bass on the sweep?

 

[ruffrecords]

Or are you just commenting on hooking it up to sound card? Just clarifying for people

It is a general principle. Output transformers work better when driven by a low source impedance. So, say you have a 600:600 output transformer, it is likely to perform better when driven from a 50 ohm source rather than a 600 ohm one. In fact they perform best when driven by a negative impedance equal to the primary winding dc resistance. There are op amp circuits specifically designed to do this.

https://www.lundahltransformers.com/wp-content/uploads/datasheets/feedbck.pdf

Cheers

Ian

 

[newhall]

Thanks for that PDF. Interesting.