7HZ SEVENHERTZ 71 Portable Headphone Amp Review
A portable headphone amplifier from 7HZ built around AKM's AK4377 chip, which the page describes as battery-free, listed at $29.75. The page names Android 5.1 and above and Apple Lightning devices, and it gives no output power or sample rates, so it suits phone users who want a plug-in amp.

Our verdict
A portable headphone amplifier for someone who wants a named chip (AKM AK4377) and a battery-free design at $29.75, with Android 5.1 and above and Lightning both mentioned. Look elsewhere if you need output power, sample rates or an impedance range, since the listing text gives none. The main caveat is that the page's claims about lossless transmission and a wider sound field are the maker's own and were not checked here.
- Best for
- Someone who wants a plug-in headphone amplifier with a named AKM chip and a battery-free design.
- Skip if
- You need stated output power, sample rates or a list of output sockets before buying.
AKM's AK4377 chip does the digital processing in the 7HZ SEVENHERTZ 71, per the page, which adds a 32-bit digital filter and a 36-pin CSP package. The page calls it a portable headphone amplifier for Android 5.1 and above and Apple Lightning connections, with a battery-free design and a cable built from four 36-core OCC cables. It is listed at $29.75 as a single option.
Options and pricing
The page lists one orderable option at $29.75 and shows no color, plug or bundle choice. It shows $35.00 crossed out beside the price, which is the store's own comparison and not something we checked. The text mentions both Android 5.1 and above and a Lightning connection but does not say whether those are separate versions, so the single option is all the listing offers.
How it compares
The JCALLY JM6PRO II is $28 and its entry mentions the CX31993 chip, against the AK4377 named on this page at $29.75. The HiBy Digital XOE starts at $29, and the Celest CD-3 is $30 with no spec mention in its entry.
Shipping
- Methods and costs. The store's shipping page offers Standard Shipping (4PX, Yanwen or Yun Express), free for most countries, and Express Shipping (DHL Express, FedEx or SF Express) at 15-50 USD depending on the country, free for orders over 270 USD in most countries (checked 2026-11-11).
- Delivery times. It says an in-stock order ships within 3 working days, Standard takes about 2 weeks after shipping out (up to 1-3 months for some countries, and the store makes no refund for that transit time) and Express takes about 3-7 days. Festive seasons and other circumstances can change the timing.
- Taxes and fees. The buyer pays any customs, import or processing fees. The page says Standard via YunExpress is tax-inclusive for some countries, that remote areas can carry extra Express charges, and that a parcel refused or left uncollected over taxes is deducted two-way freight and may be destroyed with no refund.
- Where it ships. The page says the store can generally ship to most countries by Express and many by Standard, and to confirm Standard with the team for your country. It cannot ship to PO boxes or APO/FPO addresses and can only use Express to Hawaii. It does not name the US, Canada, the UK, Australia or New Zealand, so confirm before you pay.
- Lost parcels. If a parcel has been in transit for at least 3 months, the page offers a one-time reshipment or a full refund for orders under $50 and a 50% refund for orders above $50.
Returns and warranty
- Returns. The return page allows returning any non-customized product that is still factory sealed within 30 days of receiving it, with the buyer paying the shipping. Email [email protected] within that period; the store asks for the return to be shipped within 5 working days of the RMA instructions and in most cases processes a refund within 5 business days of inspecting it (checked 2026-11-11).
- Opened items. A product opened within the first 7 days after delivery can be returned for the price minus a restocking fee of 35% of its retail value, including when it still works properly.
- Refund or credit. The buyer can choose a refund to the original payment method (PayPal or card) or store credit; with no answer within 48 hours of confirmation the default is store credit, which can also be prioritized during promotions, final-sale events and for items 40% or more off retail.
- Not returnable. Customized products, including faceplate designs, are non-refundable, and the page says the same applies to carry cases, cables, ear tips and other accessories, "due to hygiene purposes". If one item in a package is defective, incorrect or missing, the refund or replacement covers only that item.
- Warranty. The page gives a 1-year warranty on products, excluding carry cases, ear tips and other accessories, and 3 months on cables and adapters, from the date of purchase. It covers factory defects that affect proper function, not damage from human error, negligence, accidents, dismantling, water, abuse or modification (checked 2026-11-11).
- Not covered or limited. It does not apply to items bought elsewhere (AliExpress, Amazon, local dealers and the like), prize or giveaway items, normal wear or colour change, commercial use, or items that were stolen or went missing. Coverage is limited for products 40% or more off retail, for review units and for items repaired or modified by anyone Linsoul has not authorized.
- Claims. Email [email protected] with the order number, the issue and photos and videos of the fault. The store may ask for the unit back for a replacement. It covers shipping for some defects reported within 7 days of delivery if the fault can be shown on video or photo; after 7 days the buyer ships it back. For wrong or missing items an unboxing video of the whole sealed parcel is required.
Before you buy
Linsoul says it was founded in 2016 by the Crazy HiFi team to bring Chinese HiFi makers closer to listeners worldwide, and that it now sells other makers' products alongside four brands of its own, THIEAUDIO, Kiwi Ears, ZiiGaat and Tripowin (checked 2026-11-11).
We have not read any independent review of this product or of the store. Ratings and owner reviews shown on the store's own pages are the store's and were not verified.
What we liked
- The page names the chip (AKM AK4377) and a 32-bit digital filter
- The page describes a battery-free design, so there is no battery to run down
- Android 5.1 and above and Apple Lightning connections are both named
- The cable is described as four 36-core OCC cables, hand-woven
Worth noting
- The listing text gives no output power, output socket type, sample rates or impedance range
- The page mentions a Lightning connection, but the options list shows only one option
- The listing text gives no weight or dimensions
- Every figure is the page's own claim and none was measured here
Questions before you buy
Which chip does the SEVENHERTZ 71 use?
The page names AKM's AK4377 chip, in a 36-pin CSP package, and says a 32-bit digital filter is integrated into the circuit.
Which devices does it work with?
The page says it suits Android 5.1 and above and can connect to Apple Lightning devices. It mentions mobile phones and music players as typical sources.
Does it need a battery?
The page says it uses a battery-free design and can be driven with low power, so there is no battery to run down.
Can I return it if I change my mind?
The return page allows returning a non-customized product that is still factory sealed within 30 days of receiving it, with the buyer paying shipping. An opened product returned within 7 days carries a 35% restocking fee. Refunds go to the original payment method or to store credit, which is the default if you do not choose.
How long does shipping take?
The shipping page says in-stock orders ship within 3 working days. Standard Shipping takes about 2 weeks after shipping out, up to 1-3 months for some countries, and Express takes about 3-7 days. Standard is free for most countries; Express costs 15-50 USD and is free over 270 USD (over $499.99 for large items such as headphones and desktop DAC/AMPs).
Does Linsoul ship to the US, Canada, the UK, Australia and New Zealand?
The page says Linsoul can generally ship to most countries by Express and many by Standard, and to ask the team about Standard for your country. It names no restriction for the US, Canada, the UK, Australia or New Zealand, but it does not list them either, and it can only use Express to Hawaii.
What warranty does it have?
The page gives a 1-year warranty on products from the purchase date for factory defects, not for human error, accidents or modification. Coverage is limited for items 40% or more off retail and for review units, and it does not apply to items bought from other sellers.
Sources & verification
What this review is based on and the day we last read it. Specs and claims from the maker are the maker’s own; the verdict and the rating are ours.
From the store
- 7HZ SEVENHERTZ 71 product page: specs, options and price (the buy buttons go there)Specs, options and the listed priceRead November 11, 2026
- Linsoul shipping pageStandard and Express shipping, costs and times, import taxes, lost parcels, couriers, trackingRead November 11, 2026
- Linsoul return policy and warranty page30-day returns of sealed items, 35% restocking fee on opened ones, 1-year and 3-month warranties, exclusions, how to claimRead November 11, 2026
- Linsoul support FAQThe same shipping, return and warranty rules in question form, plus order changes and cancellationsRead November 11, 2026
- About LinsoulFounded in 2016 by the Crazy HiFi team; names its own brands; the awards listed there are the store's own accountRead November 11, 2026
What we couldn’t verify
- The page's wording on better sound quality, a wider sound field, lower distortion and lossless signal transmission is the maker's claim and was not checked here.
- The listing text gives no output power, sample rates, impedance range, weight or dimensions, and the page says the chip is easy to drive without giving a figure.
- We have not read an independent review of this product or the store, and the store's own ratings were not verified. We read the store's catalog description only: a specification table or image shown just on the live page was not read.
- The shipping page names no US, Canada, UK, Australia or New Zealand times or fees: its figures are general and we could not confirm them for these countries.
Spotted an error or something out of date? Tell us and we’ll fix it and update the date.


