VTL TL5.5 Series II unity gain hometheater

I just checked the specs, and the usual culprit for this is low input impedance, but 50k Ohms is exactly standard.  

So stupid question but are you sure you got the right receiver outputs??  There are are 3 different sets of L and R outputs in a receiver, the main, the main surround and rear surround.  It’s possible you are using the wrong one’s, or have disabled them.  Try using the center for one of them, see if the output suddenly appears. 

Another alternative, of course, is to try one of the main preamp inputs.  If that works well enough the problem is probably in the surround processor switch circuit. 

Thank you Eric for your response, 

Yes I did checked again I am using the right receiver outputs front L and R I was using the processor with the VTL TL2.5i and has no problem with it is strange.

Thanks again

I have read the user manual for the VTL TL5.5 Series II Signature preamplifier. Is it possible that the input selected for "Mon/Proc" is currently in a "lockout" mode, and therefore must be unlocked before any settings can be done?

Page 15

Connect the Surround Sound Processor to the preamplifier.

To take advantage of the processor unity gain loop capability, connect the Front Left and Right outputs of your home theater preamplifier processor to the left and right channels of any input on the preamplifier, and set that input for Unity Gain by holding the Mon/Proc button and pressing the button for that input simultaneously. 

Volume setting indication changes to UI and mute LED blinks. If there is no reaction to the front panel unity command then the unit is in lockout mode and must be unlocked before setting. Unit is in muted mode and volume does not change from unity gain.

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Re-enable Input: To re-enable the input. 

While the preamp is in Power-on mode, select the input you wish to re-enable and hold down the Mute button at the same time.

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4. User unlocks Programming Lockout (During power-up only) (Front panel or RS-232
port)
Programming lockout is to lock all programming functions so that they are not able to be accidentally re-set to some unintended setting during normal operation. (To make a system change requiring re-programming, lockout is unlocked and then re-locked after making the change.)

Hi imhififan, 

Thank you for your responses, yes I did all that locks and unlocks programming with no lucks, sound from L and R came out but extremely small even those I adjust my processor all the way max but nothing changed. Pulling my hairs out of this one on my TL 2.5i have no problem but on the tl2.5i you don't have to program the unity gain, the only thing I can think of maybe I need to use xlr cable from preamp to amp to take advantage of the fully balanced of the tl5.5 current using rca single ended. Also I noticed the gain for each input on the tl5.5 is very low I have to turn the offset for each input up so my volume control sound reasonable (volume usually set at 50) each input offset set at 40. I also adjusted the gain from low to normal of the preamp without any luck.