0% Interest for 24 Months! Learn more »
(800) 222-4700
  • Español: (800) 222-4701
Cart
June 2017 Giveaway

Sweetwater Forums [Archived]

After 15 years of great discussions, the Sweetwater Forums are now closed and preserved as a "read-only" resource. For discussions about current gear, check us out on Facebook, YouTube, inSync, and our Knowledge Base.

Need pinout of Behringer OT-1 isolation transformer (or schematic of unit using it)

tubino

I need the pinout of the OT-1 transformer, and cant' find it anywhere! If I could get a schematic of any Behringer equipment that has that transformer, that would also work.
Here's the deal: I bought a used DI 4000 at a good price with the idea that I would cannibalize the OT-1 transformers to use in a DIY preamp-active crossover. Basically I want to have them to break ground loops when needed, at the output. I guess I was expecting two leads in and two leads out (like the Jensen 1:1 isolation transformers in the Iso-Max units), but these things have many leads! It would be very cool if the DI 4000 buttons for -20db achieved that by using different taps on the transformer (!), but that seems too good to be true. And yet...
Anyway, tracing the leads to make sense of the units is harder than it sounds. I'd be very grateful for a sheet on the units.
January 28, 2011 @02:02pm
TimmyP1955

Are they 1:1 transformers, or are they typical of what's in a DI? If the latter, they are not what you want to use as an isolation transformer, owing to the change in signal level.
January 29, 2011 @11:42pm
tubino

Are they 1:1 transformers, or are they typical of what's in a DI? If the latter, they are not what you want to use as an isolation transformer, owing to the change in signal level.

Huh. That's a good question. I don't now what is typical of a DI... I just know that these are called isolation transformers in the Behringer propaganda, and they claim good specs for freq response. And I popped the cover on my DI 4000 and saw an abundance of leads... It seems plausible to me that they could be 1:1 AND have additional taps on primary and secondary to provide gain / attenuation. Sure wish I had a schematic for the DI4000...
In the meantime I went ahead and bought a Jensen Iso-Max unit that I trust has excellent frequency response, and I also posted the question to the Behringer folks at their site, and they promise an answer in 1 business day, so by Tuesday maybe I'll know something.
January 30, 2011 @01:52am
TimmyP1955

The IsoMax has 1:1 transformers. DI transformers commonly have about 20dB of gain reduction I think (you can find this info on the Jensen site).
February 3, 2011 @12:32am