Better LDR Passive Preamp Sound

Tortuga Audio has developed an improved software based LDR control algorithm that greatly improves on our already highly regarded LDRx Passive Preamps.

Key aspects of this new “HiZ” (high impedance) control algorithm include:

• Substantially increased input impedance with a nominal 10k  (+/- 1k)  ohm impedance floor
• Improved sound including better dynamics, musicality and sound stage
• Compatibility with a much broader range of audio sources and amplifiers including many low impedance amps
• Retains the same colorless clarity, transparency and unveiled high resolution that our LDR Passive Preamps are already known for
• Entirely software/data driven design improvement
• Can be retrofitted into currently owned LDRx Passive Preamps
• Includes control compatibility with the Apple Remote

Click Here For More Technical Info on the HiZ Upgrade

Does This Upgrade Apply To My LDR3x? 

The HiZ upgrade only applies to LDR3x boards purchased prior to November 1st, 2013.

If you ordered an LDR3x between November 1-15, 2013, chances are good your board already has the HiZ upgrade included since we delayed shipments during this period to make sure recent orders were shipped with the HiZ installed.  Contact us at info@tortugaaudio.com if you’re in doubt or have any questions if the upgrade applies to your board.

All LDR3x units shipped from November 15th, 2013 onwards include the HiZ software.

Ordering The HiZ Upgrade

You have the choice of doing the upgrade yourself or having us do it for you.

Option #1 – Do It Yourself: If you do it yourself, we will ship you a new HiZ microcontroller chip with the upgraded software that is specific to your LDR3x board based on test data we have on file for your board. The cost for this option is $32.

Option #2 – We Do It For You: If you want us to do it for you, you’ll need to ship your board back to us. Upon receipt we will not only install the HiZ chip, but we will also retest your board and update the HiZ firmware with up to date test data, and then send your board back to you. The cost for this option is $52.

Lost Test Data:  In the event we no longer have the original test data for your board, your only option is to send your board back and have us do the upgrade. It’s highly likely that we do have your board’s original test data but in the event it’s either lost or corrupted we will advise you that your only option is to send in your board. In this event, we will not charge the additional amount for option #2 or rebate you the difference if you already paid it.

Shipping:  Shipping is included in the price for domestic US customers. An additional shipping charge will be applied during checkout on all international shipments.

Replacing The Microcontroller Chip

To implement the HiZ upgrade you will need to replace the existing PIC18F4550 microcontroller chip in your LDR3x board.

The chip is readily identified since it’s both the largest component in the board and it’s also the only component that is socketed and removeable.

To remove the chip simply use a small screwdriver, insert it between the chip and the socket at end of the chip that doesn’t have the little black transistors next to it. Then gently pry the chip out.

Take the HiZ upgrade chip and carefully align its pins with the socket holes. It’s absolutely critical that you make sure the chip is both pin/socket aligned and that the end with the small notch in the chip is facing the right direction. The notched end should be facing the end that has the “U5” label next to it on the board. Once properly aligned, gently press the chip into the socket. DO NOT force the chip in if it resists. If it resists, check the pin alignment with the sockets. A little patience and finesse go a long way. Once the chip starts to go into the socket, press if firmly in place to make sure it’s fully seated.