Denon and Marantz issue hardware fix for AVR 4K/120 and 8K issue

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by Andy Bassett
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Denon and Marantz issue hardware fix for AVR 4K/120 and 8K issue
SRP: £2,299.00

Owners of Denon and Marantz AVRs affected by an HDMI 2.1 incompatibility issue that prevents correct pass-through of 4K/120 and 8K signals will be offered the SPK618 HDMI adapter -  a free of charge hardware solution.

Many AV enthusiasts who were looking forward to using their Denon and Marantz AVRs with the latest generation of 8K ready gaming consoles only to come up against a compatibility issue will be relieved to hear that a hardware solution has been devised. The SPK618 HDMI adapter solution will start shipping from the end of May 2021 in Europe at no additional cost to owners of affected Denon and Marantz AV devices.

What is the HDMI 2.1 problem?

Specifically, when users attempted to output a 4K/120 or 8K signal via the new 8K source devices, the 4K/120 or 8K video could not be passed through the AVR. This issue occurred even with the AVR’s menu/GUI option “8K Enhanced” enabled. 

To be fair, the problem affected other manufacturers too, including Onkyo, Pioneer and Yamaha, and lay in a chipset designed to process the HDMI 2.1 signal which had been sourced from a single supplier that was used by these AV companies.

Once identified, Denon and Marantz parent company Sound United acknowledged the issue and resolved to issue a solution in 2021. 

Which Denon and Marantz AVR models are affected?

The full list of affected audio visual hardware is below:

AVC-A110 AV7706
AVC-X6700H SR8015
AVC-X4700H SR7015
AVC-X3700H SR6015
AVR-X2700H  SR5015

The current recommended workarounds include:

  1. Connecting the gaming console directly to the display, and then sending audio back to the AVR using ARC or eARC.
  2. Outputting the 8K source at 4K/60 resolution. At that video resolution, the AVR could pass the image with no issue. 

What does the SPK618 Adapter do?

The SPK618 adapter takes an HDMI input signal from the gaming source and delivers the corrected HDMI data to the AVR’s HDMI 2.1 port, thus remedying the error and allowing a 4K/120Hz or 8K signal to pass. The SPK618 adapter will be available for the customers who own an affected AVR and are observing the aforementioned pass-through issue. Current Denon & Marantz AVR users will be asked to update their firmware to ensure the adapter compatibility if they do not have their products set to Auto Update

Denon AVC-X6700H

How do I get hold of the SPK618 Adapter?

Customers who have an affected receiver will not need to ship anything or retrofit their products at home. The low-profile adapter will be provided to customers with the listed AVR models at no cost during the warranty period. Those interested in receiving SPK618 will need to:

1. Go to or

2. Fill out the form with the required information.

3. Once received, users will need to update their AVR’s firmware to complete the process.

The adapter will ship starting from the end of May 2021 in Europe.

This process is valid for owners living in the UK, Germany, The Netherlands and France. Customers in other countries can contact the retailer where they bought their eligible product.

For more information, visit or  

How many AVForums members have been affected by this? If you register for the SPK618 HDMI Adapter solution, be sure to let others know how you get on in the comments thread. 

Source:  Denon/Marantz Press Release
Image Source: Denon

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