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The Foundation 4K UHD Surround Sound Processor couples award winning Krell preamplifier circuitry to the latest in HDMI technology to create the centerpiece of a high performance home theater system. The Foundation 4K UHD adds HDMI 2.0 and HDCP 2.2 technology to the award winning Foundation processor.


Designed to be upgradeable, existing Foundation processors can be upgraded to the Foundation 4K UHD platform at the Krell facility. The Foundation 4K UHD updates 4 of the 10 HDMI 1.4a inputs to HDMI 2.0/HDCP 2.2 capability. New on screen display functionality adds status messages including volume, active source, video resolution and audio format. System setup is accomplished from the front panel or a network tablet/computer.

Additional functionality has been added to the second HDMI output. The two HDMI video outputs are now independent and can be configured to send different video signals to two individual displays. Both outputs support 4K signals being simultaneously displayed.

Both HMDI outputs feature Audio Return Channel (ARC). With ARC, a display device is able to send audio back down the HDMI cable to the Foundation 4K UHD. Televisions with built-in web streaming capability like Netflix or Pandora, can send the audio signal back to the Foundation 4K UHD use the full home theater system instead of just the TV’s speakers.


Featuring the latest digital connectivity, the Foundation 4K UHD maintains Krell’s exacting standards for analog audio reproduction.

From decoding the latest lossless audio formats, extensive digital switching, 3DTV pass-through, and more, the Foundation 4K UHD is fully compliant with the digital age. The 7.1-channel processor also features balanced audio outputs, automatic setup and room EQ, and Krell’s legendary robust hardware. A slim form factor exudes the Krell aesthetic, while allowing placement in smaller equipment racks.


The Foundation 4K UHD features Krell’s Automatic Room Equalization System (ARES), to ensure the best possible performance from every theater. ARES analyzes all the speakers in the system, their location, phase, and distance from each other, to determine the best crossover frequency, delay, and more. In addition, ARES incorporates the acoustics of the room to determine unique EQ curves for each of the 7.1 output channels. Unlike other room EQs, ARES can be programmed to only adjust the troublesome low frequencies, leaving high frequencies unaltered.


The Foundation 4K UHD includes a new Krell development—Intelligent HDMI switching. Intelligent HDMI switching is a combination of circuitry and innovative software that optimizes HDMI operation. Various parameters including the monitor’s electronic ID and source video resolution are stored in non-volatile memory. All 10 source inputs are always active so source, channel, video resolution, and audio format changes are instantaneous. The Intelligent HDMI design provides the fastest signal recognition possible.

The Foundation 4K UHD passes video signals directly without any video processing, ensuring bit-for-bit accuracy of the signal, up to 3840×2160. However, to simplify cabling, setup, and use, there is full transcoding of the 2 composite and 3 component analog video inputs to the HDMI outputs.


Krell designed the Foundation 4K UHD with flexibility and ease-of-use in mind, with extensive routing capability of the audio inputs to the various outputs. During setup, the specific paths will be chosen based on how the user intends to use each source, displays, and audio output channels.

The Foundation 4K UHD supports stereo and multichannel DSD decoding via any of the 10 HDMI inputs. Playback options include DSD 2-ch Direct, DSD Stereo, and DSD Multi modes. DSD 2-ch Direct converts a stereo DSD signal to analog and directly passes it to the left and right analog outputs. DSD Stereo first applies any left and right channel crossover configured in the Foundation 4K UHD menu, converts the signal to analog, and then sends it to the left and right outputs. DSD Multi supports multichannel DSD recordings and utilizes all crossovers configured in the Foundation 4K UHD menu. There is no configuration required as the Foundation 4K UHD automatically recognizes a DSD signal and defaults to the last used DSD mode for playback. Pressing the mode button on the remote control or web server interface will cycle through all three DSD modes.

The Foundation 4K UHD will allow owners to take full advantage of the best audio soundtracks available, with decoding of Dolby Digital, Digital Plus, Dolby TrueHD, DTS, DTS-ES Discrete, Matrix, and DTS-HD Master Audio. In addition, a full suite of post-processing modes are included, including Dolby Pro Logic IIx and DTS Neo 6. Krell’s proprietary surround modes, Party, General Admission, Front Row, and On Stage, offer a different way to listen to favorite tracks.

The Foundation 4K UHD also offers features that make it perfect for custom installation, such as 3.5mm jacks for IR input and 12-volt trigger input and output, as well as RC-5 and optional rack-mount ears. Additionally, the unit can be controlled with home automation systems via RS-232 or the Krell web server through its Ethernet connection.


Signal to Noise Ratio

“A” Weighted 106 dB

Total Harmonic Distortion

(THD) Unweighted 20 Hz-20 kHz, +0, – 0.003 dB


(1) Pair Balanced via XLR connectors
(4) Pairs Single-ended via RCA connectors
(10) HDMI 2.0 (4 w/HDCP 2.2) via HDMI connectors (9 on rear, 1 on front)
(3) EIAJ optical via Toslink connectors
(3) Coaxial via RCA connectors
(3) Component Video via RCA connectors
(2) Composite Video via RCA connectors


(9) Balanced via XLR Connectors
R, L, C, SR, SL, SBR, SBL, S1, S2
(9) Single-ended via RCA Connectors
R, L, C, SR, SL, SBR, SBL, S1, S2
(1) Zone 2 Output
(2) Single-ended via RCA connectors
(2) HDMI via HDMI connector
Both Include Audio Return Channel

Control / Update

(1) IR Receiver for Remote Control
(1) RS-232 via DB9 Female Connector Straight Wired
(1) RC-5 via 1/8″ stereo “trs” Receptacle
(1) Ethernet via RJ-45 Connector
(1) Mini USB used for firmware updates
(1) 12vdc Remote Trigger Input via 1/8″ Mono receptacle
(1) 12vdc Remote Trigger Outputs via 1/8 Mono receptacles

Digital Decoding Modes

Dolby True HD
Dolby Digital Plus
Dolby Digital 5.1
Dolby Digital EX
Dolby Pro Logic IIX
DTS-HD Master Audio
DTS-HD High Resolution Audio
DTS 5.1
DTS ES Discrete 6.1
DTS ES Matrix 6.1
DTS Neo:6
PCM 5.1
PCM 7.1

Surround Enhancement Modes

General Admission
Front Row
On Stage
Enhanced Stereo
Full Range + Sub

RS-232 DB9 pin out

1. Data Carrier Detect
2. Received Data
3. Transmitted Data
4. Data Terminal Ready
5. Signal Ground
6. Data Set Ready
7. Request To Send
8. Clear To Send
9. Ring Indicator

RC-5 pin out

Tip = RC-5 data, Ring = +5 V, Sleeve = GND

XLR pin out

Pin 1 (ground) Pin 2 (non-inverting “Hot”) Pin 3 (Inverting)

Maximum Input

Balanced 6.3 Vrms
Single Ended 3.15 Vrms

Maximum Output

Balanced 16.7 Vrms
Single Ended 8.35 Vrms

Audio Input Impedance

Balanced 58K Ω
Single Ended 58K Ω

Audio Output Impedance

Balanced 100 Ω
Single Ended 100 Ω

Power Consumption

Stand-by 2w
Operation 59w


Inches (L) 16.83 x (W) 17.06 x (H) 3.47
Centimeters (L) 42.76 x (W) 43.33 x (H) 88.1


18lbs Unit only
8.16kg Unit only
24lbs Shipping Weight
10.89kg Shipping weight



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