Wide-Bandwidth 1:1 Output Options

[Recording Engineer]

Beside the obvious Jensen, what are some excellent options for an extremely-wide bandwidth, extremely-high maximum input level, 1:1, 600ohm:600ohm line output transformer?

 

[vintagelove]

Beside the obvious Jensen, what are some excellent options for an extremely-wide bandwidth 1:1, 600ohm:600ohm line output transformer?

If you can pick up any of the Mci 400/500 console line transformers that float around used fairly often, they're ridiculously good. Here was a post by an ex mci employee. I never measured the extent of the frequency response myself, but I know they pass anything in the audible spectrum flat at +28db without a problem. I tested that much myself.

Btw, there may be a pair still for sale in the black market here.


"The output transformers MCI used used the bifilar winding technique. They will handle a level of +30 dbm with no problem. The frequency response is flat to approx. 1 mhz, with a -3db point at 3mhz.; I know this as I measured several myself. The transformers were manufacture3d by Southeastern Transformer Co. in Miramar,
Fla.; they are no longer in business.

I know this as fact as I ran console checkout at the MCI factory when we were shipping the 416 consoles; later I was service mgr. for the MCI dealer in Nashville, before opening my own business there."

 

[ruffrecords]

You would need some serious inductance to be flat down to one milli Hertz (1mhz).

Carnhills will take +30dBu.

Cheers

Ian

 

[Recording Engineer]

A friend has been very slowly designing a stereo mic preamp with around 100dB of tube gain (Can anyone say fuzz bass?!) for himself, myself, and a friend. The goal is no more than that, satisfying only ourselves, but we’d like to use available transformers or purchase a small bulk of custom ones to his specs. (as he did with the input transformers), should any more preamps be built down the line for any reason.

The guy that did the custom input transformer order is long retired and did a single prototype of the custom output transformer, used in the single-channel preamp prototype. Unless we can find someone to do low-quantity custom order, we’re going to have to settle with something off the shelf.

After the prototype, he made a single gain-stage preamp with an MCI transformer. Indeed, it is an amazing output transformer!

 

[scott2000]

This place was mentioned favorably in the past.

https://www.heyboertransformers.com/

 

[CJ]

big M for Mega, yes.

who needs anything past 100 KHz?

note that there is a tradeoff in the quad-filar designs,

as the transformer goes from an inductor to a capacitor, there will be a huge phase shift, but at 100 Khz does that matter?

 

[TheJames]

as the transformer goes from an inductor to a capacitor, there will be a huge phase shift, but at 100 Khz does that matter?

My dog thinks so. The bats were the most offended by it.

 

[CJ]

my brother just got a new 100 wat ham radio transmitter.

says it is messing with all the5 G phones,

i don't see how, maybe harmonics,

 

[Recording Engineer]

Thanks guys.

He has had a commercial brick & mortar audio electronics repair business for 35-years with the same guys on the bench the entire time. He hasn’t been on the daily-grind bench since he started it, but he and his wife run it all. If he ever had the time, he’d be a great contributor to this community, but he’ll never retire.

I view his design-perspective as audiophile without audiophoolery, classic-rock dirty, and over-designed with practicality.

I think the audiophile and over-design sides are where the MCI impresses.