Yes—a vacuum fluorescent display (VFD) tube can be used as an active component in an audio circuit. In a build reported by Hackaday on December 8, 2022, hobbyist JGJMatt used a DM160 VFD indicator tube in an audio preamp, rather than using it only to display information. It is a preamp, not a complete power amplifier, and the report does not publish measured audio performance.
How the DM160 VFD is used in the preamp
The DM160 is normally encountered as an indicator tube. In this project, the builder put it to work as an active circuit element. The idea was inspired by Korg Nutube, a low-voltage triode product derived from VFD technology. Hackaday reported that the builder chose the DM160 as an alternative after finding Nutube components expensive at the time; that is the builder’s reported motivation, not a current price comparison.
Reported circuit layout
Hackaday describes the DM160 between a 2N3904 input stage and a 2N2007 MOSFET output stage. The build also uses a USB boost converter. Its custom-etched printed circuit board combines surface-mount and through-hole parts, with a separate riser card for displaying the tubes and a 3D-printed enclosure.
This is a high-level description, not a complete schematic or verified bill of materials. The report does not establish the DM160’s operating points or provide enough detail to reproduce the circuit reliably from the article alone.
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What the report does—and does not—show
The project is described as an audio preamp. It should not be mistaken for a power amplifier that directly drives speakers. Hackaday does not publish measured gain, distortion, frequency response, or listening-test results for this build, so there is no basis for claims about its sound quality or performance relative to other preamps.
The reported component names—the DM160, 2N3904, 2N2007, and USB boost converter—identify parts used in the project, but they do not make up a complete parts list. The account also does not establish present-day availability, tube condition, a suitable pinout, or compatibility for any particular DM160 listing.
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How the DM160 approach compares with Korg Nutube
Nutube provides a documented, purpose-designed comparison, but its specifications should not be transferred to the DM160 build. Korg describes Nutube as having an anode-grid-filament structure and operating as a triode vacuum tube. That is the manufacturer’s description, not an independent test of the DM160 project.
| Comparison point | DM160 DIY preamp | Korg Nutube |
|---|---|---|
| What it is | A DM160 VFD indicator tube adapted as an active device in a reported preamp; Hackaday, December 8, 2022. | A VFD-derived, directly heated twin triode; Korg’s official product information and application notes. |
| Electrical details | Operating points and supply requirements are not stated in the Hackaday report. | Korg’s application notes describe operation from 5 V, a 5–80 V supply range, and recommended anode load resistances of 100–330 kΩ. These are Nutube details, not DM160 circuit specifications. |
| Audio output figure | Measured gain and other audio performance results are not stated in the Hackaday report. | Korg’s application notes state 12 mW per channel. This figure describes Nutube, not the DM160 preamp. |
| Documentation | The report gives a high-level construction account, not a full schematic or detailed parts list. | Korg publishes an evaluation-board page with manuals, circuit diagrams, and a parts list. |
| Vibration sensitivity | Not stated in the Hackaday report. | Korg warns that Nutube’s direct heating can make it susceptible to microphonic noise caused by vibration. |
| Other manufacturer claims | Not stated for this build. | Korg/Noritake claim a continuous life expectancy of 30,000 hours and power consumption below 2% of that required by a conventional vacuum tube. These are manufacturer claims for Nutube, not measured results for the DM160 project. |
Which approach makes sense for a builder?
- Choose the DM160 route if the goal is experimentation. The project shows an unusual way to use an indicator tube, but the published account does not supply the detailed circuit information needed to treat it as a ready-to-build design.
- Look at Nutube if documentation matters more. Korg’s evaluation-board materials include circuit diagrams, manuals, and a parts list, which provide a clearer starting point for examining a VFD-derived audio device.
- Do not choose between them on sound quality from this report. It contains no controlled audio comparison, and no measured results are given for the DM160 preamp.
For a DM160, verify the exact tube listing, condition, pinout, and circuit compatibility before buying or adapting one. The Hackaday report identifies the tube used, but does not establish a current source or approve a particular seller.
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Quick Recap
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- Compact phono stage
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- Tube MM Phono Preamplifier: This Fosi Audio phono preamplifier removes low-frequency noise and ensures clear sound quality by converting phono signals to line-level signals using high-quality components and low-noise integrated circuits. It is designed to safeguard your turntable thanks to its grounding post
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- Applicable Vacuum Tube Model: The compatible vacuum tube models are 6K4, 6J1, 6J4, GE5654, 6AK5, 66, etc. To make changes to your stereo system yourself, simply swap out the vacuum tubes. Consider that distinct tubes produce various sounds
- Package Content: You will get 1 x Box X2 phono preamp, 2 x vacuum tubes, 1 x RCA cable, 1 x power adaptor, and 1 x user manual
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