How we put this guide together
On October 24, 2026 we went through the Apos online store (apos.audio): the product pages and US dollar prices of six items, the store's shipping, return and terms pages, its about page, and its public reviews on Trustpilot. Nobody on our team has used these products yet, so this is a buyer's guide, not a hands-on review, and we do not give a star rating.
What Apos sells
Apos is an Oakland, California audio retailer. It says it is an authorized retailer that partners directly with the brands it carries, and it sells headphones, headphone amplifiers, DACs, cables and vacuum tubes from brands such as TOPPING, FiiO and HIFIMAN, plus its own lines: Apos Flow cables, Ray Tubes and community-designed gear like the Gremlin amp. On its about page the store lists free shipping, a lowest price guarantee, a one-year transferable Apos warranty and a 45-day return policy. We did not test the price guarantee or the warranty process.
The six products below are the ones we were asked to cover: two amplifiers, a DAC/amp, two cables and a vacuum tube.
The 6 products
1. TOPPING A90 Discrete Headphone Amp
Photo: Apos
The store calls the A90 its best-selling amplifier. The A90 Discrete (A90D) is a redesign of the original A90 with four discrete NFCA modules of 39 transistors each, in a fully balanced layout. Apos says it has the output to drive planar magnetic and high-impedance headphones and low enough noise for sensitive in-ear monitors, and that it can also act as a preamp. Price on October 24, 2026: $599 for the amp alone, in black or silver. Apos also sells it as a stack with the D90 III Sabre DAC and an XLR cable for $1,509.99 (listed down from $1,584.21), or $1,699.99 with a rack. It suits someone who already owns a good DAC and demanding headphones. Drawback: it is an amplifier only, so you still need a DAC, and $599 is a lot for a first desktop setup.
2. Apos x Community Gremlin Tube Amp
Photo: Apos
A small hybrid headphone amp: vacuum tubes in the preamp stage and transistors in the output stage, Class A and fully balanced, with 1250mW of output according to the store. The base price includes a matched pair of Ray Tubes 12AU7 CORE tubes. Price on October 24, 2026: $120 for the amp with tubes (listed down from $204.99), with bundles up to $592 that add better tubes, a cable, a stacker and a DAC. It suits a listener who wants to try tube sound without spending hundreds. Drawback: the store itself describes it as "ugly, naked, and small", and in the photos it sits in an open acrylic frame rather than a closed case; tubes run hot, so place it where it can breathe and cannot be knocked.
3. Apos Flow Balanced XLR Cable (Pair)
Photo: Apos
Short balanced interconnects for linking a DAC and amp. Each cable has four cores laid out in a cross pattern to reject interference, five layers of protection and Neutrik connectors. Price on October 24, 2026: $84.99 for a 20cm pair or $119.99 for a 50cm pair, in red or black. It suits someone stacking a balanced DAC and amp like the A90D. Drawback: only two short lengths, and you can buy basic XLR cables for far less; the extra money buys build quality, not proven better sound.
4. Apos Flow Headphone Cable for HIFIMAN
Photo: Apos
A replacement cable for HIFIMAN headphones with 3.5mm sockets, listed for the Sundara, Edition XS, Ananda, Arya, Susvara, HE1000SE, HE400i, HE400s and HE1000 V2. It uses single-crystal copper that the store rates at 99.99997% purity. Price on October 24, 2026: $109.99 for 1.5m or $139.99 for 3.0m, with a 4-pin XLR, 4.4mm, 2.5mm or 6.35mm plug. It suits a HIFIMAN owner whose stock cable is stiff, short or has the wrong plug for a balanced amp. Drawback: the store's claims about richer bass and airier treble are subjective; the sure gain is a balanced plug and a better-made cable.
5. Ray Tubes 12AU7 SELECT Vacuum Tube
Photo: Apos
A premium 12AU7 tube from Apos's Ray Tubes line. The store says SELECT tubes come from the same batches as its CORE tubes but are individually picked by its audio engineers for better clarity and detail. Price on October 24, 2026: $99 for a single tube, $224 for a matched pair and $479 for a matched quad. The single tube was marked out of stock until October 31. It suits someone who owns a 12AU7 amp, such as the Gremlin, and wants to try tube rolling. Drawback: a matched pair costs almost twice the Gremlin itself, and how much a selected tube changes the sound is hard to judge before you hear it.
6. TOPPING DX3 Pro+ Bluetooth DAC/Amp
Photo: Apos
An all-in-one desktop DAC and headphone amp with USB and Bluetooth 5.0 with LDAC. It uses an ESS ES9038Q2M DAC chip, and the store says it has 60% lower distortion on the DAC side, 85% lower on the amp side and more than twice the power of the older DX3 Pro. Price on October 24, 2026: $199 in black or silver. It plugs into a PC or Mac without drivers; Windows ASIO apps need one. It suits a first desktop setup that also streams from a phone. Drawback: Google search interest in it has dropped over the past year, which suggests buyers are moving to newer models, so compare before you buy.
What it costs
Prices on apos.audio in US dollars, checked October 24, 2026:
| Product | Price | Notes |
|---|---|---|
| TOPPING A90 Discrete | $599 (amp only) | stacks from $1,509.99 |
| Gremlin Tube Amp | $120 | listed down from $204.99, tubes included |
| Apos Flow XLR Cable (pair) | $84.99 – $119.99 | 20cm or 50cm |
| Apos Flow HIFIMAN Cable | $109.99 – $139.99 | 1.5m or 3.0m |
| Ray Tubes 12AU7 SELECT | $99 – $479 | single backordered to Oct 31 |
| TOPPING DX3 Pro+ | $199 | black or silver |
What buyers say
- On Trustpilot (checked October 24, 2026) Apos has a TrustScore of 4.0 from 30 reviews, but the split is sharp: 47% five-star and 44% one-star.
- Recent five-star reviews (April to September 2026) praise fast, knowledgeable support.
- Recent one-star reviews (January to March 2026) describe a wrong item with no reply to email, an order that never arrived and needed a card chargeback, and headphone pads and a cable that failed.
- With only 30 reviews, these numbers can swing quickly, so read the latest ones before a big order.
How it compares
- Amazon and big-box stores: easier returns for many US buyers, but a narrower range of enthusiast brands and fewer bundles.
- Specialist audio stores (Headphones.com, Linsoul, HiFiGo and others): overlapping brands. Compare the exact model and the return terms, which differ a lot.
- Buying direct from Apos suits you if you want its own Flow cables, Ray Tubes or the Gremlin, which are Apos products, or a ready-made TOPPING stack.
Shipping & returns
The store advertises free shipping. Its shipping policy gives two speeds: standard in 5 to 15 business days and express in 2 to 5 business days, both plus processing time.
Returns: you can request a return within 45 days of delivery if the product and all original packaging are in like-new condition. Requests made between 8 and 45 days after delivery carry a 20% processing fee. Each customer can make at most 3 return requests in 12 months, accidentally damaged items cannot be returned, and the parcel must reach the courier within 5 days of approval. If you return part of a bundle, the items you keep are charged at full retail price.
Who it suits / who should skip
Apos suits buyers who already know which amp, DAC or headphone they want, like its own cables and tubes, and plan to keep what they order. Skip it, or buy elsewhere, if you expect to try several items and send most back: the 20% fee after day 7 and the 3-returns-a-year limit make that costly.
Using the code
We do not have a tested Apos coupon code. If a code appears on this page later, check that it applies in your cart before paying.