Differences Between H1 and H2 models

Portapack H1 hardware represents the original design, which is well documented, placed in the public domain.

Portapack H2 hardware is a custom modification of the original design, made by unknown fans (which at this time are keeping their design notes / documents for themselves) including some upgrades:

• Bigger screen
• Different navigation buttons
• Internal battery
• Battery charging circuitry
• Better internal Speaker integration

Note: There is also an hybrid H1 / H2 model, called the 2020 H1 Model, which is an H1 but with a bigger screen.

Audio

At a glance, hardware-side, both models feature a headphone connector and the same AK4951 AUDIO / CODEC IC (You can get the datasheet following this link).

The AK4951 includes separate pins for speaker and headphone output:

• Pins 20 (SPP) and 19 (SPN) labeled as SPeaker Positive and SPeaker Negative (1W 8 ohm)
• Pins 22 (HPL) and 23 (HPR) as in (HeadPhones Left, HeadPones Right) (16 ohm)

Upon close inspection, several differences arise:

H2 Portapack audio

Portapack H2 circuitboard includes a connector header for easily adding an internal speaker.

The AK4951 IC is rotated 180º and placed more into the middle of the circuit board, allowing for the addition of an extra IC: The ChipStar brand CS8122S ultra-low EMI, filter-free, class-D amplifier, for driving the speaker output with up to 3W.

The speaker audio header is switched on/off by the headphone female connector, which includes the usual switch, detecting the insertion of a male plug in it.

H1 Portapack audio

Only the soldering pads for an internal speaker connector header are present. The speaker +/GND signals on the pad are routed directly into AK4951 pins.

NOTE: There is no extra amplifier IC between the speaker pad and the AK4951. The AK4951 includes a speaker amplifier capable of 1W, when powered @5v.

You can solder a laptop / tablet speaker in H1 speaker pads. In order to enable it, you will need to install MAYHEM firmware, where you can also configure under OPTIONS -> INTERFACE the addition of a SPEAKER button on your top status bar.

"Audio devil may be in the details"

Since the firmware is shared between H1 and H2, on Portapack H2 you end up powering up TWO speaker amplifiers: The one inside AK4951 IC, and the extra CS8122S one.

Power Supply

H1 Portapack

H1 Portapack design does NOT include any battery charging circuit, nor a provision for a power on/off switch.

Having said that, some enthusiasts managed to MOD their H1's by adding a standard usb powerbank management circuit board with the corresponding Li-ion battery and placing a manual power switch on their cases.

H2 Portapack internal battery

H2 includes an internal Li-Ion battery, standard battery charging / managment IC (located at the side of the speakerphone connector) and power switch.