I don't want to shatter your illusions, but I hadn't seen the inside of the AP310 yet and I had to laugh when I saw the picture of the circuit board on Audiophonics.
If you take a look at the boards of devices from the two major Chinese manufacturers, you'll notice a very strong similarity in terms of layout, circuitry, components, materials, etc. So the board probably comes from one of these manufacturers, which wouldn't be unusual.
The L70 is very similar to the AP310 in terms of construction. In both devices, the balanced inputs are debalanced, and then the volume is adjusted. In the AP310, this is done via the two-channel MUSES72320 chip, while in the L70, this is done via the relay-based volume control. This probably makes no difference, although I personally prefer the relay-based volume control, as the Muse chip could introduce noise.
After the volume adjustment, if the balanced output is used, the signal is rebalanced on both devices. I don't think there's any difference in sound between the L70 and the AP310. The L70 has proven to be absolutely transparent in testing (all measurements in the top range) and in use by many users. The AP310 could only be better or have an advantage if the L70 had limitations.
As you can see from this example, a balanced HPA, like the L70, is usually a completely normal preamplifier with an additional headphone amp attached to one of the outputs, nothing else. Essentially, the design is no different from other preamplifiers, whether they cost €500 or €30,000.
But you also get an excellent HPA for the price.
As a preamplifier, the AP310 looks to me to be a well thought-out and well-built device with a very good price/performance ratio. A review by Amir would be interesting.
All of this is just for information, also for other users who read this.
