HX3.7 Installation Manual

HX3.7 Mainboard

HX3.7 – Preliminary Draft

The improved, highly integrated HX3.7 mainboard will be available by end of 2024. It replaces the current HX3.6 mainboard and should be compatible with most existing installations. It offers 4 channel DACs and better audio amps/filters, full Leslie speaker control circuits and an effects insert loop with additional ADC between internal tube amp and internal rotary simulation. This allows separate use of the rotary simulation for external musical instruments as well.

HX3.7 does no longer offer "legacy" button/switch inputs (like Panel16) and classic analog drawbar inputs (old green DB9/DB12 boards). Instead, it relies on I2C bus interfaces on external panels (like Preset16, Extern16 or VibratoSwitch) and analog scanning MPX bus circuits as found on PTX, ANX, DBX9 and DBX12 drawbar boards. For existing OEM installations, we will offer an interface (LegacyBoard) providing connectors for legacy hardware (see below).

However, we strongly recommend I2C bus (PANEL I2C connector, for buttons/switches/LEDs) and MPX bus (ANLG MPX, analog scanning for pots/drawbars) circuitry as this greatly reduces wiring effort. Refer to our DBX, ANX and PTX schematics for MPX bus interfacing (using 74HC164 shift registers and 4066 analog switches) and Preset16/VibSw schematic (using PCA9554A and PCA9555 port devices) for I2C bus interfacing. All newer drawbar boards for HX3.5 and up (colored black) are compatible with HX3.7 ANLG MPX bus.

All I2C-bus based Preset16, Preset12-2 and Extend16 boards are compatible with HX3.7, they do not need the LegacyBoard. For connection of a vibrato rotary switch, we offer the small HX3.7 VibratoSwitch board which has its own I2C circuit onboard. It connects to PL31 PANEL I2C bus.

Common Features with HX3.5/HX3.6

• Same firmware and same FPGA sound engine
• Same PCB size, same mounting holes
• Same location of DC, USB, audio and MIDI connectors
• MenuPanel/Preset Bus Connector (I2C)
• Analog MPX Bus for newer DBX, PTX and ANX boards
• Auxiliary MIDI out, Fatar scan and pedal scan connectors

Omitted Features

• No onboard drawbar inputs
• No onboard button/switch inputs
• No ExtensionBoard connector (Leslie control and headphone amp circuit integrated on board now)

Additional Features

• All ExtensionBoard features integrated
• Integrated 11-pin Leslie control, ExtensionBoard pinout on 14-pin box header PL1
• Additional DAC, outputs for plain organ and pedal signal, total of 4 audio output channels
• Headphone amp
• Improved DACs and audio amps/filters
• Insert loop (mono effects insert between tube amp simulation and rotary simulation)
• 3 onboard MIDI connectors (2x IN, 1x OUT), MIDI OUT may alternatively be mounted on JackExtension
• Onboard audio output jacks may be jumpered as L/R mono jacks or stereo L/R and stereo headphone jack
• Additional output signals and effect loop input available on 16-pin box header PL2 and 3-pin wire-to-board connectors
• JackExtension PCB available for additional MIDI and audio input/output jacks, same jack location as old extension board

MIDI output jack may be mounted on mainboard (new hole for connector necessary) or custom JackExtension board (old location of MIDI OUT connector) alternatively. Note: JackExtension board may be customized for OEM use as it only contains passive components (jacks, optional level potentiometer).

Preparing HX3.7 for First Use

Commissioning is carried out in the same way as for the HX3.6 board. However, note the different header designations for HX3.7. Of special interest are sections HX3.6 external digital inputs and HX3.6 external analog inputs; read this carefully. Disregard sections concerning internal analog and internal digital inputs, vibrato rotary swich, ExtensionBoard as these are not applicable to HX3.7 mainboard.

Headers/Connectors

HX3.7 Components/Connector placement (also avalable as PDF, see on our Documentation and Update Server)

HX3.6 Mainboard connectors
PL1	External 11-pin Leslie connector (optional)
PL2	HX3.7 JackExtension Board (optional)
PL3	Stereo audio output; mid = GND
PL4	Plain organ/pedal audio output; mid = GND
PL5	6,3mm jack audio output right or headphone L/R (see JP1/JP3)
PL6	Stereo headphone output; mid = GND
PL7	6,3mm jack audio output left or stereo L/R (see JP1/JP3)
PL8	External EFX loop audio input; mid = GND
PL9	DC input, 5V (JP4 set) or 9..12V/500mA, plus on center
PL10	MIDI IN1 DIN connector
PL11	DSP PROG (debug, do not use)
PL12	MIDI IN/OUT for XB2 kit
PL13	FPGA JTAG (debug, do not use)
PL14	Fatar/matrix scan board (FatarScan2)
PL15	MIDI IN2 DIN connector
PL16	DC input/ouput, 5V/500mA max.
PL17	DC input, 9..12V/500mA
PL18	Shift register scan board (Scan16, Scan61 or Bass25)
PL19	MIDI OUT DIN connector (optional)
PL20	Aux MIDI output for MAG, TTL level (optional)
PL21	MenuPanel LED outputs with MIDI scan driver, sustain and cancel inputs (active low) for other
PL22	MCU ARM Cortex M3 Debug (do not use)
PL23	USB jack (MIDI over USB, updates)
PL24	SD card adapter (optional)
PL25	FT800 graphic display (optional)
PL26	4-pin connector USB (debug, do not use)
PL27	6,3mm jack rotary control footswitch
PL28	Serial interface for FTDI cable (debug/Editor)
PL29	Bluetooth or WiFi module (optional)
PL30	6,3mm jack swell pedal (FC-7 compatible)
PL31	I2C bus (menu panel, button/switch boards)
PL32	MPX bus (DBX drawbar, PTX pot and ANX boards)
PL33	3-pin connector rotary control foot switch
PL34	3-pin connector FC-7 compatible swell pedal

Connectors not used may be left open.

Rotary Connector

Box header PL1 carries signals for an external 11-pin Leslie. Pins 1 to 11 are wired 1:1 to a 11-pin Amphenol socket. For old 9-pin Leslie installations, small 5V relays may be needed as some Leslie speakers use negative switching voltage. Three 5V relays (common coils to +5V pin) may be driven directly from 11-pin control outputs 6, 7 and 8.

PL1 Leslie 11pin Connector
Pin	Funktion
1	Rotary audio channel (organ), to pin 1
2, 3, 10	Stationary audio channel (bass pedal), to pin 2 resp. 3 and 10
4	Audio ground, to pin 4
5	Common ground for control signals, to pin 5
6	Leslie Power On (MOSFET switches positive voltage to ground, active low), to pin 6
7	Leslie Fast (MOSFET switches positive voltage to ground, active low), to pin 7
8	Leslie Slow/Run (MOSFET switches positive voltage to ground, active low), to pin 8
11	Leslie +30V supply (clamping), to pin 11 (optional, may be left open)
12	Additional analog Gnd output, not connected
13	Additional digital Gnd output, not connected
14	Auxiliary +5V supply output for relays if needed
R12 R33	Trim pots control rotary and stationary levels on PL1

JackExtension Connector

HX3.7 JackExtension board

Box header PL2 carries audio signals for additional jacks, MIDI out signal and footswitch inputs (active low = connect to ground) for sustain/sostenuto functions.

PL2 Extension Jacks Connector
Pin	Funktion
1	Headphone Left
2	Headphone Right
3	Ext Out L (plain ORGAN signal)
4	Ext Out R (plain PEDAL signal)
5	Ext In L (Effect Loop Input, mixed to mono)
6	Ext In R (Effect Loop Input, mixed to mono)
7	Sustain Footswitch
8	Sostenuto Footswitch
9	MIDI OUT (-, DIN pin 5)
10	MIDI OUT (+, DIN pin 4)
11	Efx Jack Insert Switch (open when inserted, Gnd when not)
12	Vcc +5V
13, 14	Analog Ground
15, 16	Digital Ground

Note: A small board will be available which makes installation of additional HX3.7 connectors easier. HX3.7 JackExtension will be used in futute 19" rack expander. It replaces the former HX3 ExtensionBoard. HX3.7 JackExtension connects to HX3.7 PL2 and only carries passive/mechanical parts for convenient wiring. For OEM applications, JackExtension may be customized to existing chassis layouts. A MIDI OUT connector may be mounted here instead of mainboard.

Jumpers

HX3.7 Mainboard Jumper
JP1/JP3	PL5 jack function, headphone (both in HDPH position) or rotary R (both in R position)
JP2	Analog Gnd (Probe Connection), both pins
JP4	5V DC input on PL10/PL12 (wall wart connector) if jumpered, otherwise 9..12V if open
JP5/JP6	MIDI IN2 +5V phantom supply for bass pedal if both present
JP7	Config Disable (do not use)
JP7	FPGA config disable (debug, do not use)
JP8	Power supply +5V over USB (can cause noise, default open)
JP9	Digital Gnd (Probe Connection), both pins
JP10/JP11	Select Hammond (HAMD position) or Yamaha FC7 type swell pedal
Default jumper setting: JP1/JP3 in R position, JP10/JP11 in FC7 position

Note: HAMD position of JP10/JP11 swaps tip and ring of PL30 jack. This may also applicable for some other brands (CASIO etc).

Digital Inputs

Connectors and jumper locations of Preset16-2 board (new version)

As stated above, HX3.7 does not provide any digital button inputs. Instead, additional Extend16 or Preset16 boards may be used for tabs, buttons and switches. Connection of digital controls (tabs, buttons, switches) to HX3.7 is made in the same way as for HX3.6 external digital inputs. Old Panel16 boards may not be used without HX3.7 LegacyBoard (see below). For default tab functions, use Preset16 or new Panel16-I2C jumpered to group #2 address $62 instead.

Board Addresses for Digital Inputs
Input group	0	1	2	3	4	5
Bus address	$60	$61	$62	$63	$64	$65
Jumper on Preset16, Extend16	JP1, JP2, JP3 closed	JP2, JP3 closed	JP1, JP3 closed	JP3 closed	JP1, JP2 closed	JP2 closed
Note	Fixed addresses for old Preset16 (Upper 0, Lower 1) or Preset12-2 (both)		Extend16 or Preset16 Used by LegacyBoard	Extend16 or Preset16 with address jumpers	Extend16 or Preset16 with address jumpers	Extend16 or Preset16 with address jumpers
Button-Funktion	Button #0..#15	Button #16..#31	Button #32..#47 (former "onboard")	Button #48..#63	Button #64..#79	Button #80..#95
Button top left or first input	#0	#16	#32 (PL25 Pin 1)	#48	#64	#80

The number of a specific pushbutton/switch results from the group base number (16 * group/board number) plus the specified offset. So for the board with address $63 the first input would be 16 * 3 = 48.

Please note: Input group #2 ($62) was assigned for the 16 button/switch inputs on the HX3.5/HX3.6 mainboards in the past. This address may be assigned now to any Preset16/Extend16 board as long as no LegacyBoard is used. However, HX3.7 LegacyBoard (see below) occupies input group #2 on fixed address $62. Do not assign a board address twice.

Analog Inputs

As stated above, HX3.7 does not provide any analog control inputs. Instead, additional DBX9/DBX12, PTX4 or ANX8 boards may be used for drawbars and potentiometers. Connection of analog controls to HX3.7 is made in the same way as for HX3.6 external analog inputs. For compatibility with existing installations, you may consider the HX3.7 LegacyBoard (see below).

HX3.7 VibratoSwitch

HX3.7 VibratoSwitch

HX3.7 does no longer provide a header for vibrato rotary switch connection. New HX3.7 VibratoSwitch board provides a 6-way rotary switch as well as an interface circuit for I2C bus on PL31. It is connected in the very same way as other button/switch interface boards (Preset16, Extend16, MenuPanel).

The HX3.7 VibratoSwitch board is not needed when using the HX3.7 LegacyBoard (see below) as this provides its own vibrato switch circuitry.

HX3.7 LegacyBoard

HX3.7 LegacyBoard

As HX3.7 does no longer offer legacy analog and switch inputs, the HX3.7 LegacyBoard will be available to connect existing passive switch/button boards like Panel16 (2x8 = 16 inputs, two 10-pin headers), analog drawbar controls (2x12 = 24 inputs, two 16-pin headers) and a 6-way rotary vibrato switch (10-pin header). The LegacyBoard is not needed for new installations using the MPX bus/connector (all DBX/PTX/ANX boards). LegacyBoard PL1/PL5 connect to HX3.7 PL31 PANEL I2C and PL32 ANLG MPX box headers. Route-through box headers (PL4/PL10) are provided for both, allowing easy daisy-chaining to MenuPanel or additional input boards.

Connection to analog and digital controls to HX3.7 LegacyBoard is made in the same way as for HX3.6 internal analog inputs and HX3.6 internal digital inputs:

• Connect old-style drawbars, old DB9/DB12/DB9 MPX drawbar boards or potentiometers to PL2 ANLG UPR and PL3 ANLG LWR of HX3.7 LegacyBoard
• Connect old Panel16 or buttons/switches to PL7 and PL8 of HX3.7 LegacyBoard
• Connect vibrato rotary switch to PL6 of HX3.7 LegacyBoard

Please note: On HX3.7 LegacyBoard, the internal analog inputs PL2 ANLG UPR and PL3 ANLG LWR are emulated by external analog MPX inputs (starting at param #5024 in HX3 Editor). Analog input assignments #5000 to #5023 do not exist on HX3.7, even with LegacyBoard connected.

Optional PL9 control output is available on OEM request (not populated on standard HX3.7 LegacyBoard).

The LegacyBoard is not intended for new OEM designs which should use the I2C and ANLG MPX bus instead.