Connecting input transformer for 1290 mic pre

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Robotski
Posts: 4
Joined: Sat Jul 14, 2018 2:28 am

Connecting input transformer for 1290 mic pre

Post by Robotski »

I have built two JLM Audio 1290 macro mic pre kits and have the VTX 102 003/OEP262A3C input transformers for them, but I didn't order
the "go between plus kits" since I don't need either phantom, pad or phase reverse for these.
I've got small PCB's to mount the transformers on, but haven't found any info regarding the wiring for connecting these before the preamps or if any resistors or other components are needed.
Can I just strap these in front of the mic pre's? How do I wire them?

Cheers!

/T.

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Joe Malone
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Re: Connecting input transformer for 1290 mic pre

Post by Joe Malone »

Robotski wrote:I have built two JLM Audio 1290 macro mic pre kits and have the VTX 102 003/OEP262A3C input transformers for them, but I didn't order
the "go between plus kits" since I don't need either phantom, pad or phase reverse for these.
I've got small PCB's to mount the transformers on, but haven't found any info regarding the wiring for connecting these before the preamps or if any resistors or other components are needed.
Can I just strap these in front of the mic pre's? How do I wire them?

Cheers!

/T.
Yes easy just wire as below and no other parts are needed for loading etc as they are already on the 1290 module.

PRI side
S1 is +in pin 2 of input XLR
F2 is -in pin 3 of input XLR
LInk pins S2 to F1

SEC side
S1 linked to S2 is +in to 1290 module
F1 linked to F2 is 0v
Also take Mu Can shield pin to 0v as well.
Joe :-)
JLM Audio
Capturing Audio without Injury

Robotski
Posts: 4
Joined: Sat Jul 14, 2018 2:28 am

Re: Connecting input transformer for 1290 mic pre

Post by Robotski »

Thanks for this info Joe!
And with "0v" you are referring to the 0v to the left of the "IN" on the 1290 PCB?

And I just ordered two VU buffer circuits in the webshop!

/Tomas

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Joe Malone
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Posts: 2069
Joined: Wed Jan 24, 2007 11:35 pm
Location: Brisbane, Australia
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Re: Connecting input transformer for 1290 mic pre

Post by Joe Malone »

Robotski wrote:Thanks for this info Joe!
And with "0v" you are referring to the 0v to the left of the "IN" on the 1290 PCB?
Yes correct
And I just ordered two VU buffer circuits in the webshop!

/Tomas
Cool :-)
Joe :-)
JLM Audio
Capturing Audio without Injury

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