Trimax Transformer Help

[mac]

Hey everyone,
I am still trying to come to terms with audio transformers, specs etc. Can someone help me to understand the info on the front of this trimax transformer. I have four of them from four older units with huge VU's on the front of them called "Extended Range Volume Indicator" units made by LM Ericsson.

So Primary is posts 1 & 4 at 30,000 ohms and secondary is posts 5 & 8 at 7500 ohms.

How to consider a use for these??  Impedence seems all wrong for mic input or output transformers for mic pre building.

cheers,
Mac

 

[emrr]

good for bridging line level input to 1 or 2 tube grids; tube limiter or bus amp input.  Might work as PP low current output to line (with careful DC balance adjustment), assuming you can get away with a 7.5K output Z, which you probably can.  Hey, it's less voltage loss that way!

 

[mac]

Hey Doug, thanks heaps for your response. I am trying my best to understand your reply. I think I need to learn a lot more about this topic. So far in my DIY builds I have pretty much just followed recommendations for input and output transformers. And have only done some minor experimentation.

Can you recommend some good reading resources to learn ? - particularly in terms of your suggested uses - input for tube limiters, or other tube circuits.

Thanks again, Mac.

 

[lassoharp]

If a Pultec clone interests you, you may be able to use these as the interstage transformer.  That circuit uses a 1:2 step up in that position.  Looks like you have a CT on the 30K winding.