The Grace Design m902 Reference Headphone Amplifier is equipped with an independent unbalanced stereo line output. As an option on new units, the m902 can be configured with a balanced stereo line output instead - called the m902b. In addition to new units, this option is also now available to existing m902 owners as an upgrade. The following document details the upgrade procedure. Please note: This does not provide balanced headphone outputs, only balanced LINE outputs for connection to power amps or powered speaker systems.

click here for RMA form

What does the m902 balanced output upgrade entail?

This upgrade replaces the existing unbalanced RCA line outputs with balanced ¼” Tip-Ring-Sleeve (TRS) output connectors. Internally the circuit path is updated to provide a high performance fully balanced output. Using the same high current output stage as our m906 and m904 monitor controllers, the balanced output provides the highest fidelity and is capable of driving longer cable runs effortlessly. Once the balanced upgrade is installed, the firmware in the m902 will be updated to the most current revision. Each m902 then goes through a 24 hour burn-in period, followed by a complete bench test and listening test.

Does this affect my warranty?

No. The transferable 5 year warranty on your unit is unaffected.

How much does the upgrade cost?

The cost for performing the upgrade, complete system testing and return shipping via FedEx Ground service for US customers is $195. International customers should contact us for additional upgrade details. Payment must be made in the form of check or money order (made payable to Grace Design) and should be included with your amplifier when it is shipped to us.

How long does the upgrade take?

Once your amplifier has reached our shop, the upgrade process typically takes 3 to 5 business days to complete.


What is the procedure for having this upgrade done to my unit?

To have the m902 Balanced Output Upgrade performed on your unit, simply complete the RMA form and include it along with your payment (check or money order made payable to Grace Design). Then ship your m902 to the following:

Grace Design Attn: m902 BU
4689 Ute Highway
Longmont, CO 80503


How can I check on the status of my upgrade?

If you would like to check on the status of your upgrade, you can call our shop at 303.443.7454 or email To track the status of your update most efficiently, please reference your m902’s serial number when contacting us.

click here for RMA form