MEASUREMENTS: Fosi Audio TB10D [Upgraded Version] stereo amplifier (TI TPA3255 Class D). Ethernet is inherently "isolated".

 

Not much time this week to play with the toys as I'll be heading off on vacation for a few weeks. However, I did receive the Fosi Audio TB10D [Updated Version] (<US$80) above recently that I wanted to use as an inexpensive "utility" amplifier for various measurements and experiments. It's also based on the TI TPA3255 Class D chip amplifier; same as the AOSHIDA A7 recently reviewed.

As you can see in the unboxed picture above, there are no frills, just the amplifier and a 32V/5A power supply (same specs as AOSHIDA).

This is the "Updated Version" with improvements as discussed by the Cheap Audio Man back in late 2022. Presumably this update was released around September or October 2022. I see ASR measured this amplifier in September 2022 - not sure which version that was. I purchased this amp from the usual retail channels.

Due to the time constraints, I'll focus more on "core" measurements and compare especially to the AOSHIDA.

As We Hear It: Innomaker HiFi DAC Pro HAT review by Doug Gardner. And MQA is bankrupt; the end is here.

Arch,

I’ve been following along with your experiments using the Cosmos ADC and APU to test a variety of gear and I’ve put together a similar setup to do some measurements too. I’m sharing some results from testing I’ve done of the Innomaker HiFi DAC Pro HAT for the Raspberry Pi. I bought the DAC for US$89 directly from Innomaker for use in my home office.

My home office system is headphones only using the Drop THX-789 headphone amplifier fed by a Khadas Tone1 (Tone Board Generic Edition) DAC connected via USB to a Raspberry Pi 4 with display running RopieeeXL. Music playback software is Roon with Drop+Dan Clark Aeon X, Aeon Noire, or Drop x Sennheiser HD6XX headphones with PEQ settings from Oratory1990 to make the physical sounds. This setup gives me a clean and compact footprint with a touch screen for ease of use and objectively good fidelity per the measurements and reviews performed by you here on your blog and by Amir over at Audio Science Review. A drawback to this setup is that the Tone1, sitting in a separate box and with the USB and unbalanced audio cables, makes for additional clutter on the desk.

The Innomaker HiFi DAC Pro uses the same DAC chip, ESS 9038Q2M, as the Khadas Tone1 but, unlike the Tone1 Generic, is HAT compatible and has both balanced and unbalanced output. Balanced output is via two 3.5mm headphone jacks and unbalanced through a single 3.5mm output that can also serve as headphone out. I chose to use the balanced outputs. I assembled 3.5mm to XLR cables from spare Amazon cables I had on hand. No need for anything flashy on the cable front. If you don’t want to roll your own then you can buy 3.5mm to XLR cables from Innomaker’s Amazon store. It should sound like the Tone1, right?

MEASUREMENTS: Topping HS02 USB 2.0 isolator. (This works with the E1DA Cosmos ADC; and the Topping + Intona "double isolation" of DAC and ADC.)

Hey guys and gals, I must be a sucker for relatively inexpensive USB galvanic isolators. To be honest, this is mostly because I look for ways to lower noise on my measurement testbench, not that I'm concerned with the actual audiophile sound system these days! ;-)

Today, let's have a look at the recently released Topping HS02 USB2.0 isolator (currently ~US$100). This is an update to the previously reviewed HS01 last year. As you can see from the picture and specs, the box now has selectable USB-A/B connectors or USB-C. Isolation is not just applied to the in/out USB data connectors, but also the auxiliary power input with filtering which means the device could stay free of noise even if we plug in a power source with some noise in it. As usual, be mindful of power-hungry USB-powered devices which will require auxiliary power input.

Furthermore, Topping has improved compatibility now with the ability to negotiate USB2.0 low (1.5Mbps)/full (12Mbps)/high speeds (480Mbps). I can confirm that my low speed wireless keyboard dongle works fine.

The diagram showing the path of the data and power connections is relatively clear printed on top. Inside the box are a couple of pamphlets - the black one is the warranty card and Topping catalogue, and the white user manual. There's a short USB-A to USB-B cable in the plastic bag.