Thanks for the tip! I got a price match from Apos Audio right away, and made the A90 purchase through them. Apos provides free priority shipping and a 2nd year warranty. They got my SMSL DA-8s to me in three days flat from Shenzhen China to the US (I paid extra for express shipping). Great customer service, I must say.If anyone is looking at picking up an A90, Amazon has them on sale for 15% off right now at $424.99.
Khadas has a weak grounding plane. It's basically its weak point. Most don't get any problem, but if noise finds its way in you get the situation you now have. source: https://blog.jdslabs.com/2018/11/jds-labs-atom-amp-official-release-benchmarks/#comment-22949I noticed an issue I'm having with the A90. Whenever my GPU gets loaded heavily, aka while gaming there's a mild static electricity style noise in the background. The noise is present even if I turn the volume on the amplifier down to zero. If I change the gain setting, the amplitude of the noise changes accordingly. If I unplug Khadas toneboard from my PC the noise stop. I never had this issue using the Atom and 789 in the same setup with the same cables. My PC has a high quality PSU and a 3080 GPU. I tried using different USB ports and the noise still remained. I'll try higher quality USB C cable going to the Khadas dac, and a USB noise filter (iSilencer by iFi)
My A90 ordered from Apos Audio arrived yesterday from Shenzhen, courtesy of the free priority shipping that Apos provides. Fabulous engaging detailed sound, I notice faint plucked strings like background harps, while listening with Focal Elex and HiFiMan Ananda. The A90 is a tremendous achievement by John Yang and Topping. And thanks to Amir for his thorough review. Though I dare say the L30 is an even bigger achievement considering the tighter budget constraint.My A90 arrived last night after ordering it on Amazon's Prime days - very quick delivery for free shipping and 15% off! Paired it with my D90 for my home office use and after one day of listening to music all day and playing a few video games, it's definitely a keeper. Using it both as a headphone amp with a pair of Beyerdymanic Amiron Home with a balanced cable, and as a preamp to drive a pair of Presonus Sceptre S8s.
It's ground loop. Are you using XLR?I'm trying A90 with a SMSL Sanskrit 10th MKII and its picking up the same noise from the GPU and PC in general. Quite sad.
I know its probably more the DAC's fault for not filtering the USB signal, but still annoying. Gonna try USB filters tomorrow so see if these help.
Yep. Try XLR.Using a Mogami RCA cable, I also tried Monoprice RCA cable
Alright I thought it was m300 mkii. Sorry.None of the interfaces I have for this PC have XLR outs (Khadas Toneboard and SMSL Sanskrit 10th MK2).
I have a Motu 8a that I use for measurements, but I would rather not dedicate a big interface like that to a setup in which I only need a two channel DAC. I was hoping a simple DAC like one of these would suffice.
Which power switch do you use? The one on the back or on the front.I noticed my A90 could intermittently produced pop sound while turning on. When that happened, there was no click sound from the relay. Should I worry?
The front switchWhich power switch do you use? The one on the back or on the front.
Yeah. You should worry about it.The front switch
Thanks, I'll contact the distributor and see what are the options.Yeah. You should worry about it.