V25 controls with OLED display

The following information is for Tortuga Audio preamps based on the V25 preamp controller with the OLED display. If you have an earlier model that uses the original 7-segment display, please consult the menu for a separate section on V25 control with 7-segment display.

The Apple Remote #

The Apple remote has only the 7 controls buttons as shown below. These are adequte for common control actions like turning on, muting, adjusting volume etc. More complex control actions require menu driven interaction between the remote and the visual OLED display. Apple Remote - OLED Display

The OLED display #

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The OLED display is a 256×64 bit high contrast white-on-black graphical display. It works interactively with the Apple remote to allow more complex controls than are possible with the Apple remote alone. Being a graphic display, the OLED can display a wide range of text, numbers, lines, and images. These capabilities are used to good effect to enable the user to easily configure and control the V25 preamp controller and V25 based preamps.

OLED display - channel balance

The V25 control scheme #

The V25 control scheme is shown in the diagram below. The left hand column shows the control menu tree (list) items. These menu items are shown on the OLED display as the user scrolls up and down the menu list.

The following is a summary of how the control scheme works.

  • You wil spend 99%+ of your time in volume control mode (the pink box)
  • You press the Menu button to turn on the preamp on if it’s off
  • When the preamp is on you press the Menu button to access the control menu list
  • The OLED display is a window into the control menu list but only a single menu list item is visible at any time.
  • You scroll up and down the control menu list using the raise/lower buttons on the remote
  • If you pres the Menu button when already viewing the menu list, the controls revert to the default volume control mode (the pink box) – (kind of like the “escape key” on a computer)
  • Pressing the Center button on the remote while viewing a menu list item will activate that item’s respective control action
  • The most common example: to turn off the preamp
    • Press Menu – exits volume control action (pink box) and displays Volume menu item
    • Press Raise – scrolls up to the Off menu item
    • Press Center – activates the control action to turn off the preamp

drawit diagram

The control menu shown above is the current control menu as of firmware version 220 released on February 27, 2018. Preamps with earlier firmware will differ slightly from this menu.

Prior to the version 220 firmware release, there were separate Calibration (Cal) and Impedance (Imped) menu items.

Description of controls #

Each menu item and control action/view in the control scheme diagram shown above are described in the accordion list below. Click on any control topic to expand and read. 

Control  items below that indicate (menu) in their name relate to the navigable menu tree diagram above and are shown on the OLED display. There are controls items below that are not directly associated with a menu item or which do respond to control inputs from either/both the remote control or encoder knob. 

  • The V25  goes through a 5 second boot-up process each time power is applied.
  • No controls are active and nothing is displayed during the boot-up process. 
  • At end of boot-up the OLED screen will briefly display a turtle (a “tortuga”) which then fades to black.
  • The V25 is now turned off and in standby mode ready to be turned on and operated normally.

The V25 can be turned on 2 different ways as follows: 

Remote Turn On:  #

  • Briefly press/release the Menu button on the Apple remote

Encoder Turn On:  #

  • Briefly press/release the encoder control knob/push-button on the front panel.

When the preamp turns on you will see the words “Tortuga Audio” briefly displayed and then fade to black followed by the display showing the default volume control display. After any delays (depends on preamp model) the preamp will then unmute and the volume will ramp up to the level it was at when last used but in no event greater than the Max Volume setting which is user adjustable via the menu.

The V25 can be turned off two different ways as follows: 

Remote Control:  #

  • Navigate to the Off menu. 
  • Then press the Center button to execute the turn-off process. 

Encoder Control:   #

  • Press/hold-in the encoder control knob/push-button on the front panel
  • Hold in for between 3 and 5 seconds and then release

During the turn-off process the volume will ramp down to zero, the tortuga will appear briefly on the display and then fade to black. At that point the preamp is turned off and in standby.

Volume is adjustable 2 ways in the V25: 

Remote Control:   #

  • Navigate to the Volume menu item. 
  • Then press Center button to switch preamp to volume control action/view
  • The volume control/action view is the default control  action/view for routine operation of the preamp. 
  • Press Raise/Lower buttons on the remote to increase/decrease volume
  • Holding down the raise/lower buttons will cause the command to repeat 
  • Volume level is shown numerically in center of the display

Encoder Control:  #

  • Turning the encoder clockwise/counter-clockwise will raise/lower the volume.
  • Note that the preamp must be in volume control/action view for this to work. 

Summary of the information, controls and related options available in the volume control action/view. 

  • Volume level will dominate the center of the view with large numerals.
  • Volume can be displayed either as Steps or dB. This can be changed via the Vol Units menu item.
  • Adjust volume using the raise/lower button on the remote or by turning the encoder to the right or left.
  • Channel balance adjustment is enabled in this view by default. Adjust channel balance using the left/right buttons on the remote. You can’t adjust channel balance with the encoder.
  • Channel balance adjustment is shown by numbers to the right or left of the volume level indicating the number of steps of adjustment.
  • You can adjust channel balance up to 20 steps right or 20 steps left. Each step is appoximately 0.6 dB.
  • You have the option to change the display mode in this control/view to change input instead of balance adjustment. Please refer to the Vol Display menu item for details on changing this.
  • If you opt for Input Selection instead of Channel Balance, the left/right buttons will change inputs instead of adjusting channel balance.
  • If you opt for Input Selection instead of Channel Balance a separate new menu item labeled “Balance” will be enabled. Please refer to “Balance” menu item for details.
  • Press the Menu button to escape back out to the “Volume” menu item

Volume muting is NOT an item on the control menu per se but since it’s such a commonly used feature it gets its own section here. 

You can mute/unmute the preamp with either the remote  control or the encoder.  

Remote Control:   #

  • Press the Mute button (lower right hand corner button to toggle the mute state
  • When muted the preamp’s volume will ramp down to zero 
  • When unmuted again the preamp will ramp volume back up to its prior setting

Encoder Control:  #

  • Briefly press-in/release the encoder push button to toggle the mute state 

Channel balance control is available 2 different ways in the V25. 

Volume control action/view (default):   #

  • Navigate to default volume control action/view  (see Volume control for details)
  • Use Left/Right buttons to adjust channel balance left/right
  • Balance adjustment steps are shown to the left or right of the current volume. 
  • No balance adjustment values are shown when balance is neutral (zero).
  • This is the default method to adjust balance

Balance control action/view (optional): #

  • Navigate to  the Balance menu item (not present by default – must be enabled)
  • Press Center button to enter Balance control action/view
  • Use Left/Right buttons to adjust channel balance left/right
  • To enable the Balance  menu item please see Vol Display menu item for details. 

Input switching is available 3 different ways in the V25.  #

Input control action/view (default): #

  • Navigate to  the Input menu item
  • Press Center button to enter Input control action/view
  • Use Right/Left buttons to  immediately switch to next higher/lower input number
  • Alternatively, use Raise/Lower buttons to tentatively select next higher/lower input.
    • Press Center button to execute switch to new input selection
    • Volume will ramp down to zero, input gets switched, and volume ramps up again.  

Volume control action/view (optional – needs to be enabled):   #

  • Navigate to default volume control action/view  (see Volume control for details)
  • Use Left/Right buttons to immediately switch to next input 
  • Current input shown in upper left corner of display
  • To enable this input switching control mode please see Vol Display menu item for details. 

Encoder knob:  #

  • Press/hold in encoder push-button and while pushed in turn knob right or left to switch immediately to the next higher/lower input number. 
  • Release encoder push-button when desired input has been selected

The Display control provides for both Brightness adjustment and display Timeout adjustment from a single control action/view. 

Display brightness adjustment: #

  • Navigate to  the Display menu item
  • Press Center button to enter Display control action/view
  • Use Raise/Lower buttons to increase/decrease display brightness
  • As you change brightness level the level number itself will actually change brightness while the rest of the info on the display retains the original brightness
  • Press Center button to lock in the new brightness level  

Display timeout adjustment:    #

  • By default the display timeout feature is disabled (set to off). 
  • When enabled, the display will turn itself off when the timeout timer times out. 
  • You can adjust the timeout period from 5 to 120 seconds. 
  • Navigate to the Display menu item
  • Press Center button to enter Display control action/view
  • Use the Right/Left buttons to increase/decrease the display timeout period
  • When you decrease the period to less than 5 seconds the timeout feature turns off
  • The display shows the timeout period as you adjust it. 
  • When the timeout feature is disabled the display shows “Off”

The Imp/Cal control provides for two interrelated features: adjusting input impedance and initiating calibration of the LDRs. These are both accessed through the same Imp/Cal menu item. 

Impedance adjustment : #

  • Navigate to  the  Imp/Cal menu item
  • Press Center button to enter Imp/Cal control action/view
  • Impedance setting #1 is fixed by default and cannot by changed
  • If the current impedance setting is labeled “Locked” that means it requires calibration
  • Used the Raise/Lower buttons to navigate through the impedance settings. If 2 or more settings have already been established, moving between them will literally switch the impedance of the preamp to the setting/level number shown on the display.
  • An unused impedance setting is labeled “Off”. 
  • Use the Right/Left buttons to increase/decrease the impedance level of the current impedance setting
  • Press the Play button on the remote to initiate calibration of the currently selected impedance setting/level.   

About “Locked” Impedance: #

  • When an impedance setting/level is marked “LOCKED” it means that setting/level combination has not been through calibration or even if it had been previously it now requires calibration be performed.
  • When the current setting/level is marked “LOCKED” you will not be able to switch to another setting including even the default setting #1. A “LOCKED” setting demands resolution before moving on. 
  • There only 2 ways to resolve a “LOCKED” setting. 
    • #1 Run calibration
    • #2 Reduce the impedance level to zero which effectively disables that specific impedance setting and allows you to switch to another setting. 

Running calibration after a Reset: #

  • The reset process  destroys all attenuation tables for all impedance settings including the attenuation table for the default #1 impedance setting.
  • After the reset process is completed, the user MUST put the preamp through 2 cycles of calibration at the default setting #1/20k.
  • Some versions of the firmware may do this automatically but the user should ALWAYS check if the impedance/cal status says ** LOCKED ** which indicates it needs to be run through calibration.

Initiating calibration:    #

  • Navigate to the Imp/Cal menu item
  • Press Center button to enter Imp/Cal control action/view
  • Press the Play button on the remote to initiate calibration of the currently selected impedance setting/level. 
  • When calibration is initiated the display will change to the calibration status display. 
  • When calibration is complete the preamp will return to the volume control action/view. 
  • Press the Enter button to interrupt and quit calibration at any time if you don’t wish to wait for the cycle to complete. 

The # (number of) Inputs control allows the user to adjust the number of inputs that the preamp can switch between. The V25 can accommodate up to 6 inputs. #1 input is always the first input. If only one input is enabled it must be input #1. Enabled inputs must be sequential and can’t be skipped.  

# input adjustment : #

  • Navigate to  the #Inputs menu item
  • Press Center button to enter #Inputs control action/view
  • Use  the Raise/Lower buttons to adjust the number of inputs available or desired. 
  • If “1 input” is selected then all the input related menus and controls will become disabled and in the case of a menu item will no longer appear in the menu list. 

The Vol Units control allows the user to view the volume in either step number (default) or in units of dB (decibels) of attenuation.  

Changing the displayed volume units: #

  • Navigate to  the Vol Units control  menu item
  • Press Center button to enter Vol Units  control action/view
  • Use  the Raise/Lower buttons to toggle between Steps and dB 
  • Press Center to lock in volume display units and return to the default volume control action/view. 

The Vol Max control allows the user to adjust the maximum allowable initial volume associated with any of the following events: 

  • When preamp gets turned on
  • When input is changed.  

Changing the max allowable initial volume: #

  • Navigate to  the Vol Max control  menu item
  • Press Center button to enter Vol Max  control action/view
  • Use  the Raise/Lower buttons to adjust the value between 1 and  the maximum step available in your preamp.  
  • Setting Vol Max to the maximum volume of your preamp effectively defeats any protection provided by this feature.  

The Vol Display control allows the user to select how certain controls work in the volume control action/view. There are 3 options to choose from as follows: 

Changing the Vol Display option: #

  • Navigate to the Vol Display menu item
  • Press the Center button to enter the Vol Display control action/view
  • Use the Raise/Lower buttons to select the desired option
  • Press the Center button to lock in the selection and revert back to the default volume control action/view

Option #1 – Balance (default): #

  • Selecting Balance means that the Right/Left buttons within the volume control action/view will be used to adjust channel balance

Option #2 – Input: #

  • Selecting Input means that the Right/Left buttons within the volume control action/view will be used to switch inputs
  • When  selected this also causes the Balance control menu item to be added to the list of menu options. 

Option #3 – Input & Phase Reversal #

  • Selecting Input & Phase Reversal means that the Right button within the volume control action/view will be used to switch to the next input
  • The Left button within the volume control action/view will be used to toggle Phase Reversal on the balanced inputs of certain preamps that are especially equipped with the Phase Reversal feature. 

The Version info menu item provides information only. There is no control action associated with this menu item.

  • Navigate to the Version info menu item
  • Press Center button to access the version info view showing the following information:
    • Model: the model number of the V25 based product 
    • Hardware: the hardware version of the V25 controller board
    • Firmware: the version number of the current firmware
 

Reset control allows the user to do a factory reset of the preamp controller. What this means as a practical matter is that it erases all the LDR calibration data and related impedance settings. You then have to run calibration (twice) to rebuild the attenuation tables for the default #1 impedance setting. All other impedance settings are lost. All other control options are reset to factory defaults. 

Please note that Reset is not a panacea or “go to” remedy for resolving problems with your preamp. 

  • Navigate to the Reset control menu item
  • Press Center button to access the reset control action/view
  • To initiate Reset press the Right button on the remote 5 times. Note the press count on the display. 
  • Once reset is initiated it can’t be stopped. 
  • If the unit is turned off or powered down before reset is completed it will resume or start over when next powered up. 
  • When reset is completed the controller will revert to the default volume control action/view

Remote pairing is a procedure to pair your V25 based preamp with a a specific Apple remote. Each Apple remote has an internal ID number between 0 and 255 (256 possible IDs) that it transmits with every command it sends. The V25 will only respond to commands from the one remote/ID number it is paired with. The pairing process teaches your V25 the ID number of your remote. It will then ignore the 255 other Apple remotes with a different ID number. 

The Apple remote ID numbering scheme allows you to own multiple Apple products each responding to a different Apple remote in order to avoid conflicts. For this to work each product must be deliberately paired with a remote with a unique ID number. The Tortuga Audio V25 is no exception. 

Here is the remote pairing procedure:

  • First, the V25 preamp must be turned on
  • Press/hold in the encoder knob/push-button for 20+ seconds
  • When the display changes and indicates the unit is in pairing mode, release the encoder
  • Then press the Center button on the remote. This should complete the pairing process and the preamp should revert to the default volume control action/view. 
  • Repeat the above process if the V25 still does not respond to the remote.
 

LDR3000T | warm up delay #

The LDR3000T Tube Preamp has a visible 10 second warm up timer which will count down from 10 seconds when you turn it on. During this warm up period the tube heaters will turn on and stabilize. When the timer hits 0, the tube plate voltage is switched on, the preamp’s output is unmuted, and the volume then ramps up to its previous setpoint.

We recommend the user avoid making any additional control inputs while the warm up timer is running.

LDR300 | buffer output delay #

The LDR300.V25 Buffered Preamp has a built-in 10 second delay (not visible on display) which disconnects (mutes) the preamp output for 10 seconds each time power is connected to the preamp. The same 10 second delay happens again each time the preamp is turned on. Therefore you may notice that even though the OLED display indicates the preamp is no longer muted after turning it on, the 10 second buffer output delay timer may still be running keeping the output muted. This is normal. The buffer output delay is there to protect against bumps and pops during power/turn on/off transitions.

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