KGUSS Topping A90 Discrete NFCA Headphone Amplifier Pre-Amplifier 6.35mm/4.4mm Balanced/4-Pin-XLR Headphone Output R2R Relay Volume Control (Black)

I recommend and endorse this preampI was looking for a preamp that had a ladder network type volume control. Preamps that have these types of volume control have channel to channel matching that keeps the center image in the same spacial position when you change the volume. Once you find the listening sweet spot, it stays there and doesn't change when the volume or gain is changed. (regular potentiometers have a tendency for the center image to wander which moves the sweet spot to off-center and that sweet sound starts to disappear).The sound quality for the Topping is top notch. It had a nice, smooth, clear and transparent sound that controlled the sound stage wider than the speaker positions and can maintain a focused image that projects several feet into the listening room and far behind. Reviewers also think this is a great preamp - you can see measurements and comments for example at audiosciencereview. This preamp has an excellent value for the money.This preamp holds its own even when compared to preamps over $2000 (I listened and compared the Topping to a few of those). I also compared this preamp to Pro-ject, Cambridge, Schiit, and others. The other preamps I listened to weren't as smooth and transparent and one of the competitors had poor focus and a "haze" that filled a space about two feet around that existed between the two speakers - and it was always there even at low volumes.Using 48kHz (CD) sample rate music. Input source through balanced connectors with main amp driven by balanced output and stereo subs driven through RCA connection. Other gear used = Magnepan, Parasound, Pass.

The A90 Discrete is an upgrade in price only from the original A90 amp. Even worse is the "HiFi College" seller! I thought I was buying this thing from Amazon and it turns out that Amazon actually sells very few products that they support after the initial return/refund period. After three months the product began creating faint snaps, crackling, and popping sounds. After a month of trying every possible combination of power glitch solutions, I tried my old reliable SMSL SP200 amp and it worked fine. HiFi College told me I would have to ship 0the A90D to China for "testing and inspection" at my own expense ($90 USPS). I had purchased a second A90 Discrete from Apos Audio two months later and it began failing after two months after the High gain setting achieved less gain than the Low gain setting. After 23 days I finally got a RMA from Apos and returned the second A90D to San Diego. I paid $15 for shipping a replacement unit that I am currently awaiting. The low cost/high performance of all the Chinese audio devices (Topping, SMSL, Gustard, etc.) is impressive as long as they work. DO NOT PURCHASE ANY OF THESE DEVICES THROUGH AMAZON!!!!!

This thing completes my little stack. Balanced sound output is just exceptionally detailed across the full range. Hypnotic, arresting detail. I’ve gone back and listened to so much familiar music again just to hear it from this and discover new detail. Tons of classical, jazz, classic rock.This did fail on me once, after a few months or so. The seller was responsive and arranged quick return / replacement. Normally the failure would bug me. But the sound quality is just so great. This thing is the precious.My alternate amp is Schitt Magnius. It is not comparable. Categorically blurrier sound. To be fair it is a solid amp on its own. It is just not remotely as good. I went through the musical equivalent of heroin withdrawal without my discrete Topping A90.I’ve got a Singxer SU-6 DDC feeding a Gustard R26 DAC behind this, and either Monoprice 1570C cans or 7hz Timeless IEM in my ears (both are planar magnetics). Balanced XLR from DAC to amp, XLR / TRS to ears. If that doesn’t mean anything to you it is enough to know it is a decent high detail chain all around the amp. I imagine this would not sound as good in a weaker stack, as it would only expose things you do not want to hear.

Only good while it works. Sound quality and features on this product are great. I can not recommend anyone getting this product due to my experience with it becoming bricked and dead twice. It died the first time after 6 months of use and was sent back to China for warranty repair. Got it back and it was fine for one year before it died again.Turn around time from receiving the RMA shipping label and getting it back home was about 2 months (Oct 7 to Dec 4)Good:Sound qualityRemote controlPre outsXLR Inputs and outputsFeels solid / metal constructionR2R volumeBad:Gets really hotWill not last long termno dedicated front power button (has a multi-function button for turning off, but mess up and you changed a setting, turn off by remote possible as well. So better than many others but still want a dedicated power button in front)long turn around for warranty work

This review is for the regular Topping A90; not the discrete. This amp's main duty is to serve as a preamp down to a balanced subwoofer then to a pair of Mackie studio monitors. To my largely untrained ear the sound is cleaner compared to my Schiit Magni 2 Uber that handled these duties before. So much cleaner in fact that the price is justified by just this. I plugged in a set of Moondrop Arias, Denon AH-D2000 headphones, and a pair of HIFIMAN 400i's and all sound cleaner, punchier, and generally better.I am slightly concerned about the longevity of this amp based on a review I read, but as long as this amp holds up I'll be a happy listener.

Yup...Heard many good things about this amp, and they are all true sonically. but alias it was eclipsed by Toppings A70 Pro. Both sound great, both can drive about any headphone out there. but the functionality of the A 70 Pro made it a better choice for me.

Lots of people are having issues with their A90d with them either 'blowing up' or developing static in one or both channels.I'd stay away from topping with so many other great options out there.