UTC O-10 "Ouncer" confusion

[nbnb]

Hi all,

Please excuse my noobness but just trying to get my head around this little transformer.

I recently inherited a few of these from a relative who passed away, and I was thinking it would be fun to make a simple Direct Box with the UTC O-10 ... however, I have a few questions that I'm hoping you guys can help with?

According to the terminal arrangements on the transformer, Primary is 6-8 and there are few choices for secondary.

I guess my questions would be:

1) For the signal coming from an instrument (bass guitar in this case), would the input go to pin 2 (if 200 ohms is wanted?)
2) For the outgoing signal to XLR, which of pins 6-8 would go to the XLR?
3) Since there isn't a ground listed on the outside of the transformer, is there a common pin that is used for ground?

Again, I am SO SORRY if this seems obvious to most, it's just confounding me at this point.

Here's a photo of the transformer, if that helps -

 

[Schmilsson]

Sorta, but the opposite.
The bass is high Ohm, so you'd wanna use the primary side for that. (Bass signal tip to pin 6, ground/sleeve to pin 8.)
Mic pre is low ohm, so you'd connect pin 2 to xlr-3, and pin 4 to xlr-2. xlr-1 goes to ground.

 

[nbnb]

Thank you so much!

This is incredibly helpful, and I appreciate you taking the time to clear it up for me.

 

[CJ]

you might try this hookup also, it would give you a bit more voltage at the output .

 

[nbnb]

Thanks, CJ -- if I'm reading the transformer correctly, that would give me 500 ohm at the output?

 

[dmp]

I just checked mine, output 1,5 (unbalanced), input 6,8 (xlr).
30k:500
I've experimented with different ratios and didn't hear any difference other than level.
You are feeding a line level balanced signal, so you want to step it down for the unbalanced out

 

[dmp]

Here's an old schematic by NYD. Like I said I think 30k:500 is fine, and I skip the pots.

 

[nbnb]

Thanks, dmp... this is super helpful. Definitely going to go with the 30k:500 now that you guys have mentioned it. That seems to make much more sense.

Cheers!

 

[dmp]

Whoops - I thought this was about a reamp. Now I see you want to do a DI, which is opposite. Earlier comments were right.

 

[CJ]

there is a UTC Ouncer 8 on this link.

https://groupdiy.com/threads/utc-transformers.74166/page-2
it is similar to the O-10 i do believe.

when you use the full winding on the 500 ohm side, you will be getting better flux linkage as the first section is nearest to the center leg of the core.

 

[Whoops]

You are feeding a line level balanced signal, so you want to step it down for the unbalanced out

DI BOX
Hi-Z unbalanced input
Mic Level Balanced Output