I asked the same question to Kingwa a few months ago and he had an opposite answer when using a regeneator. In this case a PS Audio P10. See my earlier post for reference. He recommended the R7 over the HE model calling it unnecessary in this situation.

Quick question about ACSS. The DI20 has a single ACSS output port. But the Master 9 needs 2 ACSS input cables, one per channel. What is the proper cable to use or is there a single end to dual end ACSS cable? I do not see one on the website under cables?

I have used the UE18+ Pro with the 4.4mm and 3.5mm ports. No hiss.

I second this opinion. As a preamp the A90 is lacking. Perhaps that is why Topping is making a dedicated preamplifier P90. It just is not nearly as good a preamp as it is an amplifier. But then again I bought a headphone amp first and a preamp option as a secondary option for flexibility if...

Bifrost 2 would be a better combo. Using all Topping was a bit fatiguing. Very clinical.

The A90 can handle the Abyss PHI without issue. With the Benchmark I would have the volume at 100% and it was still not enough. And this was after increasing the gain via the DIP switch internally. But the Abyss is a special case. Amps designed for it have 6 to 16 watts of power. I ended up...

The HPA4 did not have enough power for my Abyss headphones unfortunately. The A90 does on medium and high gain. Really too bad as I had the DAC3 HGC. It too didnt have enough power for the Abyss.

Currawong, have you had a chance to upgrade your Yggdrasil to the Unison USB and Analog 2 board? I was curious if the R7 is still an equivalent match sound wise in your opinion.

I too own the Mojo/Poly amd connect to the A90 via 3.5mm to XLR cable. Purchased on Amazon. Just be sure to notice the directionality of the cable. That data moves from the 3.5mm to the XLR.

You currently own two wonderful DACs with your DMPs. You are now choosing different amplification with the A90. Perhaps for more demanding headphones, like I have to. The D90 is the latest AKM chipset vs your SR15. Will you truly hear a difference in SQ? Honestly, I doubt it. But as...

Those cables will not work. You cannot convert your analog signal to digital with those cables. Those cables are for a DAP that already outputs digital via 3.5mm then goes into a digital input. But your players all use 2.5mm, 3.5mm and 4.4mm as ANALOG ONLY outputs. Only their USB ports are...

The D90 only accepts digital input(USB, coax, Toslink, AES and I2S), it ouputs analog to the A90 via RCA or XLR. Therefore you would directly connect your DAP to the A90 not the D90. Unless your DAP has 3.5mm Optical Out, which Astell&Kern products for example have, you are going about this...

I tried the, with my Phi CC. No problem driving them to loud volume levels distortion free.

I emailed Kingwa with that exact question. As I have the PS Audio P10. He said, that I do not need the HE versions. Just the standard R7 or R8 and etc for his product line.

I could not hear a difference between the two. But it was nice to have the 4.4mm and its extra surface area when using my UE18+ Pro.