OLED display module #

The OLED display module is a high contrast, 256 x 64 pixel, white-on-black, graphic OLED (Organic Light Emitting Diode) display with a 3.12 inch (diagonal) screen. The OLED display was released in June 2018 for use with Tortuga Audio’s LDR.V25 (“V25”) LDR preamp controller board including all V25 versions of Tortuga Audio preamps. With release of the OLED display we discontinued using our earlier dual 7-segment displays. V25 based preamps with the earlier 7-segment displays can be upgraded to the OLED display by upgrading the firmware and adding a jumper across 2 pins on the V25 board.

OLED display module - with cables

OLED display module - front view

3 versions #

The OLED display exists in 3 versions (A, B & C) with C being the most recent. The relevant similarities and differences are as follows:

    • All three use the identical underlying OLED display
    • Physical differences are solely in the attached adapter board used to interface with the preamp controller board.
  • Version A uses a parallel communication interface.
  • Versions B and C both use a serial SPI communications interface.
  • All versions use the same 14 pin OLED header connection and ribbon cable.  
  • Version A interface board had an additional 10 pin header that is absent from versions B and C.
  • The only difference between B and C is the location and orientation of the 14 pin header.
  • Version A OLED displays will only work with Version A V25 preamp controller boards
  • Versions B and C OLED displays will both work with either Version B or C V25 preamp controller boards.

OLED display assembly #

The OLED display proper is only one part of an OLED display assembly as shown above. The display assembly components are each described below.

OLED display module #

The display module itself is a glass OLED screen attached to a green rectangular circuit board with a 20 pin interface header and mounting holes in each corner. A custom adapter board is mounted behind the main circuit board via the 20 pin header. The adapter board has a 14 pin header for connecting the OLED display to the preamp controller board via a ribbon cable. The adapter board also serves as the mounting point for the IR receiver module and for connecting the encoder module. All signals for the IR receiver and encoder are now routed back to the preamp controller via the single 14 pin ribbon cable.

OLED ribbon cable #

The OLED cable is a 2×7 IDC ribbon cable that runs between the 14 pin V25.J9 OLED header and its corresponding 14 pin OLED.J2  header on the inter board of the OLED Display Module. The ribbon cable carries the following signals:

  • 3.3V power
  • Ground
  • SPI display select
  • SPI clock
  • SPI data
  • IR receiver
  • Encoder leg A
  • Encoder leg B
  • Encoder push button
  • Reset
  • Data/Command

Please be careful to make sure the red stripe on the ribbon cable is on the same side of each header that has a white dot the circuit board. 

Encoder/IR cable #

Version A used a second 2×5 IDC ribbon cable to carry encoder and IR receiver signals.  This cable ran between the 10 pin V25.J3 header and the its corresponding 10 pin OLED.J3 header on the adapter board of the Rev A version of the OLED display module.

Versions B and C do not use this cable.

Encoder module #

A rotary encoder module (with integral push button) interfaces to the preamp controller board through the OLED display module. The encoder takes the place of a conventional front panel manual volume control knob. It also provides additional functions such as muting, power on/off, and input switching.

Encoder cable #

A 4-wire encoder cable connects the rotary encoder module to the 4 pin OLED.J4 header on the display module adapter board. The pins are labeled EA, EB, ES & G on both the OLED interface board and the encoder module. This cable is used in all versions of the OLED display module.

IR receiver module #

The 3-wire IR receiver module interfaces to the preamp controller board through the OLED display adapter board. It is soldered directly to the OLED display adapter board. The 3 pins are keyed such that the IR receiver module can only go in one way naturally. The IR receiver must be positioned such that it looks out into the room through the front panel as must the OLED display itself.

OLED interface with V25 controller #

The interface between the OLED display module and the V25 controller board is shown below but without the actual cables present. The boards shown below are both version A boards respectively. Versions B and C differ in that there’s only the one interface cable going to the J9 OLED header on the V25 and no J3 cable.

Note the 4 pin header for attaching the encoder cable. Also note the IR receiver soldered to the adapter board.

V25 controller & OLED display connections

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