Differences Between H1 and H2 models

The H1 is the original design, which is well documented and in the public domain. PortaPack H2 is a modification based on the last, from an unknown origin (without public sources) with some upgrades:

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

Note: There are several H1 hybrid models, out there; some of them called the 2020 H1 Model including one or more of different enhancements and modifications as in: Bigger screen, charging circuit (and either the connector for a Li-Ion battery, or the battery itself also included), soldered head for speaker output, etc.

Audio

Both feature a headphone connector and the AK4951 AUDIO / CODEC IC (datasheet).

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:

H1

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.

H2

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

The AK4951 IC has been rotated by 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 mechanical switch, detecting the insertion of a male plug in it.

This is a non trivial difference, compared against H1 design where the speaker out pads are routed to the actual speaker out pins on the AK4951. On H2, the audio comes from the Headphones output pins of that IC.

Known issues

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

Power Supply

H1

There is no internal battery on your H1 PortaPack: You will need to power it up externally, from your computer or an USB powerbank.

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

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

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