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I think I know the problem andhow to fix

I read the manual and I think I know what the problem is ... your Wyred STP SE preamp is an active preamp ... it has a power cord .. a transformer .. a diode bridge and power supply caps ... this makes it an active preamp ... Wyred misleading calls it passive because it has "no additional gain' ... it should actually have been referred to as an active preamp with unity (zero) gain ... your Wyred is not a true passive preamp ... it just does not provide any additional gain added to the source's signal

In a true passive preamp it is the source that is driving the signal and the extra set of ICs at the output of the passive preamp to the amp through the passive preamp's volume control and why when you said "Passive Preamp" members assumed that the source was doing the driving and not the Wyred preamp ... because they thought as you indicated it was a passive preamp ... but it's not

Because you said "Passive" some members felt it was a true "Passive Preamp" and lacked the drive to push/drive the signal from the source through the Wyred's volume control and out the second set of IC's at the preamp output to the amp ... but that is not the case

The Wyred is an active preamp that has the ability and takes complete responsibility of driving the output ICs and can do so because it has a power supply and is active ... it just doesn't provide any additional gain from the source's signal and none is needed

Most modern system have enough gain from the source to drive the amps and no additional gain is needed but the preamp does provide the needed current to drive the second set of ICs at the output after the volume control

So far so good it's working as intended ... but I think I know what your problem is .. bear with me

The Wyred preamp is also "Buffered" meaning that the XLR outs do not see the impedance that the RCAs outs are connected to ... that's very good and a excellent feature

In a un-buffered preamp when you hook up an XLR out and a RCA out at the same time ... the preamp sees the input impedance of both devices (amps) that the XLR and RCAs are connected to and actually interprets the combined input impedances of both load devices ... amps ... as half of what they actually are ... lets say both your main amp and sub amp have a input impedance of 50K ohms each ... a un-buffered preamp will read that as 25k ohms ... not good because it's low-ish

That's an outstanding preamp as it is active with no gain and buffered so each output ...XLR and RCA only sees the particular load (amp) that they are connected to instead a of summing the input impedance loads of both amps

So what's the problem and how do you fix it

Some how you turned on the home theater by pass circuit which is truly passive and meant as a pass through only for HT configurations

I told you I read the manual ... how to fix

The very first thing is to turn the volume way down on the sub amp so you don't blow the subwoofer after you correct the HT bi pass .. then following the specific instruction below for turning the HT bi pass on ... reverse it and turn the HT bi pass off

Again ... TURN THE SUB AMP VOLUME DOWN FIRST ... and then turn the HT bi pass off ... if you can't figure it out ... Call Wyred ... I'm sure they can walk you through it

From the Wyred manual


To properly set up the HT-Bypass feature you must complete the following. Make sure the unit is powered up, but in the off position. Press in and hold the input up and down buttons while simultaneously pressing the power button (volume knob). The display should come on in the setup menu. Press input up or down until you find a screen that says "HT Bypass". Once "HT Bypass" is selected, push the MUTE button. This will select the HT Bypass mode, and allow for assignment. Now rotate the volume knob to turn HT Bypass on and select the input desired for this operation. ((NOTE: Make sure you select the correct input in the set-up. If the input is incorrect, and a signal is applied to that input when selected, the source will be playing VERY LOUD.)) Now press the power button again to exit the set-up menu.

You can access the selected HT Bypass input any time by pressing the HT button on the remote, by scrolling through the inputs on the front of the unit or on the remote, and also by using the remote trigger input. Using the remote trigger input will automatically configure the preamp for use with an HT system, and also power up connected amplifiers via the trigger outputs.

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