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    Radial Engineering Space Heater Analog Summing Mixer & Tube Drive

    2 In Stock

    The Radial Space Heater is an analog summing mixer and studio grade 12AX7 tube overdrive can be run clean or dirty! The Space Heater is a versatile piece of kit, with features and routing capabilities that allow it to be used in a number of ways. For example, the Heat setting (plate voltage for the tube) as well as the position of the Drive and Level controls will all have an impact on the overall sonic outcome. Get ‘spaced out’ with the Radial Space Heater!

      • Radial Space Heater PRODUCT FEATURES:

        • 8-channel 12AX7 tube overdrive with summing mixer
        • 35, 70 and 140 volt Heat switch
        • Channel outputs allow for use on single tracks
        • Transformer coupled outputs for vintage tone

        The Radial Space Heater is a single space 8-channel tube overdrive that can be used as a stereo summing mixer or as multi-channel studio distortion. Connect it to your digital interface to sum tracks in the analog domain, or use it as a hardware insert to add character to individual channels. With complete control over each tube circuit, the Space Heater can provide everything from subtle transformer warmth to full on harmonic distortion.

        The design begins with eight +4dBu balanced line level inputs that feed four 12AX7 tubes wired in stereo. A heat switch on each channel lets you apply between 35, 70 or 140 volts to the tube to modify the performance. When set to a lower voltage; it starves the tube, increasing distortion producing filthy layers of grit. When the voltage is set to maximum; the signal cleans up resulting in natural tube warmth with wonderful harmonic overtones. Separate DRIVE and LEVEL controls let you fine-tune the settings on each channel to increase or decrease distortion to suit. Each of the eight outputs is equipped with an oversized output transformer for beefy character while providing galvanic isolation to eliminate noise. You can also bypass the tube circuit and drive the transformer on its own to produce a vintage feel that is reminiscent of the finest audio designs from yesteryears.

        Connections to and from the Space Heater include ¼" TRS and 25-pin D-Sub balanced inputs, balanced ¼" TRS send and receive insert points, and an 8-channel balanced D-Sub output. The send jacks or the D-subs can be used to process individual instruments, enhance a sterile vocal track, add 'grind' to a bass track or 'sparkle' to an acoustic guitar. Used as four stereo pairs, the Space Heater can be used to fatten stereo stems or with in-ear monitor systems to add natural tube compression to create a more enjoyable on-stage experience. All eight channels can be sent to the master left-right XLR outputs for stereo summing with odd channels routed left and even channels routed right. This set up is often used to add crunch to drum kits or for traditional analog (out-of-the-box) summing and can be expanded using the link connectors for 16, 24 or 32 x2 summing requirements. This is supplemented with high-pass filters on each channel that help clean up tracks by removing excessive low frequency resonance.

        The Space Heater… a character box with an attitude you will love!
      • Radial Space Heater TECHNICAL SPECIFICATIONS:


        Circuit type:

        Class A tube gain stage with IC buffers

        Frequency response:

        20Hz – 20Khz, +0/-3dB

        Total harmonic distortion:


        Dynamic range:


        Input impedance – bypassed:

        50kΩ in parallel with your load device

        Input impedance – active:


        Maximum input:



        +33dB@140V, +29db@70V, +27dB@35V

        Gain - mix bus:

        6dB above individual channel output


        Full bypass

        Clip level - output:


        Output impedance - balanced outputs:


        Output impedance - headphone out:


        Output impedance - mix bus out:


        Common mode rejection:

        -70dBu @ 55Hz

        Equivalent input noise:


        Noise floor - maximum gain:

        -64dBu@140V, -66dBu@70V, -70dBu@35V

        Noise floor - controls at 50%:

        -70dBu@140Hz, -72dBu@70V, -76dBu@35V

        Intermodulation distortion:


        Unity gain control setting:

        Drive and Gain at "11 o'clock"


        Number of channels:

        Eight channels

        Input connectors:

        ¼" TRS, DB-25

        Output connectors:


        Insert Connectors:

        8 x ¼" TRS Send, 8 x ¼" Receive

        Mix bus output:


        Low pass filter:

        -5dB @ 40Hz, 6dB/Octave slope

        XLR configuration:

        Pin 2 +, Pin 3 -, Pin 1 GND


        Power supply (included):

        External switching type 100V – 240V AC, 1600mA output with 5 pin XLR


        14 gauge steel chassis and outer shell


        Durable powder coat

        Size: (L x W x D)

        17.5" x 6" x 1.75" (44.5 x15.25 x 1.75cm)


        8.5 lbs (3.8kg)

        Shipping size: (L x W x D):

        22" x 11" x 5" (55.9 x 27.9 x 12.7cm)

        Shipping weight:

        9.5 lbs (4.3kg)


        For use in dry locations only between 5°C and 40°C


        Radial 3-year, transferable

        Specifications are subject to change without notice.

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