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Everything In Music Since 1958
Everything In Music Since 1958

4ms Listen IO Modular Signal Converter

by 4ms
Out of Stock
Original price $125.00 - Original price $125.00
Original price $125.00
$125.00
$125.00 - $125.00
Current price $125.00
About Inventory Status


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In stock: It is in stock and available to ship or pickup. Apparel must be shipped from another location and is not available for in-store pickup. We can usually ship or have these items available for pickup by the next business day if they don't require inspection, special handling, or setup. Our pickup location is 11151 Veirs Mill Rd. Silver Spring, MD 20902.

📆 Preorder: It is on the way to our warehouse. We can't predict when preorder items will arrive due to current supply chain issues. If you place an order for one of these items someone will contact you to estimate the delivery date.

Out of stock: We don't currently have it available but you're not out of luck yet. We still may be able to get it. If you order one of these items we will contact you with an estimated fulfillment date. You have the option to cancel the order if you change your mind.

Special order: The item is so special that it needs to be custom ordered for you. Some of these items are works of art and have to be made individually. Orders for special order items must be prepaid and we cannot accept cancellations or refunds.

█ Sold out: We don't think we can get this item because it was either discontinued by the manufacturer or was limited in quantity. If you want or need this item call or text us. Sometimes we can help you track down the item through other sources or help you find something similar.

About Item Conditions


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Call or text us at 301-946-8808.

New: The item is brand new as received from the manufacturer with a full manufacturer warranty. Instruments such as guitars, snare drums, drum kits, brass and woodwind instruments may be opened for photography and quality control inspection and may not be in a factory sealed box.

Mint or Open Box: The item may have been opened and tested but has been repackaged. The original packaging may have superficial issues but the item itself and any originally included accessories are in perfect, like new condition.

Display Model: These items are so cool that we put them on display in our legendary shop. The condition is brand new as received from the manufacturer with manufacturer warranty. Rest assured, these items undergo a very careful inspection before shipping.

Demo: These items have been on our sales floor for demo purposes and will likely show signs of use. The original packaging may no longer be included, but you can be assured that you are receiving an awesome item and an awesome price.

Used: The item is used. These item may have varying degrees of wear. Please read the description for information about the condition of the item. Used items do not carry a warranty.

B or C Stock: Factory refurbished. These items were purchased from the manufacturer in a refurbished condition. They will show some cosmetic issues, but nothing that would impact performance. Being that these are sealed from the manufacturer, we generally do not open these to photograph the cosmetic issues. They are guaranteed to work and may have a limited warranty or you may purchase an extended warranty in some cases. Please see the listing description for item specific information.

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Convert Signal To And From Your Modular Setup For Infinite Integration Possibilities With The 4ms Listen IO Modular Signal Converter

The Listen IO is a simple module which gets signals in and out of a Eurorack system by converting to and from normal modular levels. The top section converts any external signal to modular levels by providing up to 30x gain (+30dB), allowing you to use table-top synthesizers, keyboards, phones/tablets, computers, toys, microphones, etc. in your patches. The bottom section does the opposite: modular signals are converted to normal line level signals. The bottom two jacks can be used as line outs or as headphone jacks, so you and a friend can listen in stereo at the same time. 

Each section has two inputs and outputs for use with a stereo signal or two mono signals. An LED bar graph for each output shows the signal level and clipping.



  • Line to modular conversion, and modular to line/headphone conversion
  • Works with guitars, table-top synths, effect pedals, keyboards, groove boxes, and many microphones
  • Dual mono or stereo conversion
  • LEDs show signal level and clipping
  • Gain knob allows for wide range of boost or cut
  • Headers in back for connecting to Listen Up or DIY adaptor module (1/4", banana, etc.)
  • Two headphone outputs and stereo inputs for use as a compact headphones module


  • 6HP Eurorack format module
  • 0.95" (24mm) maximum depth (includes power cable)
  • 10-pin Eurorack power header
  • POWER CONSUMPTION
  • Maximum values - All output jacks shorted to ground, 22Vpp signal on all input jacks, knobs at 100%
  • +12V: 62mA
  • -12V: 55mA

LINE TO MOD SECTION (TOP)

  • Output: 1k impedance
  • Input: 100k impedance
  • Frequency Response: +/-0.1dB max deviation, 20Hz – 20kHz
  • Maximum output level: 22V peak-to-peak
  • Maximum gain: +30dB
  • Channel cross-talk Test conditions: Test signal input into left Line In jack. Sine wave at frequencies from 20Hz to 20kHz tested. Gain adjusted to maximum value without clipping. Result given as a ratio of the appearance of test frequency measured on right Mod Out jack to left Mod Out jack. Test repeated with left and right jacks swapped. Worst-case results for any channel and frequency reported. Note: cross-talk is much higher when clipping occurs.
  • @1kHz: <-110dB
  • @10kHz: -78dB
  • @20kHz: -74dB

MOD TO LINE SECTION (BOTTOM)

  • Output: 68 impedance
  • Input: 100k impedance
  • Frequency Response: +/-0.1dB max deviation, 20Hz – 20kHz
  • Maximum output level: 22V peak-to-peak
  • Maximum gain: 0dB (unity)
  • Channel cross-talk Test conditions: Test signal input into left Mod In jack. Sine wave at frequencies from 20Hz to 20kHz tested. Result given as a ratio of the appearance of test frequency measured on right Line Out jack to left Line Out jack. Test repeated with left and right jacks swapped. Worst-case results for any channel and frequency reported.
  • 20Hz – 20kHz: <-110dB

Manufacturer: 4ms
Model: LIO
SKU: I581246-N-0-WHXX


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