Can you remember...
On grandma's old tube radio with the "magic shining green thing" in the front panel which showed the quality of the signal reception?
If you're looking on the well known selling platforms for "Magic Eye" than you'll find not only a lot of tubes but also offers of VU meter kits. But here as against the most available offers you need not to supply all the voltages (normally 6 V and 250 V), you do not need to build a case, solder adapter wires for the tube's connections, have only an one-tube display, etc...
Mr. Nixie has taken all these kits, put them in a pot, added a hefty dose of the legendary Mr. Nixie Magic, and finally the EM800 Magilyzer was created.
Absolute unique on the (DIY) world market
The EM800 Magilyzer is an analog audio spectrum analyzer, based around the BA3830F analog analyzer chip. It offers the display of six selective audio bands: 63 Hz, 150 Hz, 330 Hz, 1 kHz, 3.3 kHz and 10 kHz.
As an extra feature, you can mix the signal of a build in microphone to the display, to use the Magilyzer as a stand-alone device when no audio source is connected (as done in the video, standing in front of Amazon's Echo).
The EM800 Magilyzer operates with six EM800 Magic Eye tubes and has two RCA stereo in- and outputs (for easy daisy chaining the device within an existing audio path) and also two 1/8" TRS jacks for simple connecting your MP3 player, mobile phone plus headphone for listening etc.
Both signals (RCA and 1/8" TRS are only internal mixed and do not affect each other.
The EM800 Magilyzer uses no digital processor or FFT (Fast Fourier Transformation); so the display is stepless and fully in realtime.
EM800 Magilyzer Alexa Live Demo
What is an audio spectrum analyzer?
The EM800 Magilyzer now separates this audio signal into six selective bands and show their special audio level within this frequency band:
• 63 Hz = Low Bass (e.g. Bassdrum)
• 150 Hz= Mid Bass (e.g. Bassguitar)
• 330 Hz = Low Mid (near concert pitch of the most musican instruments)
•1 kHz = Mid of voice frequency (e.g. the "beep" sound for indecent words in interviews)
• 3.3 kHz = Presence (e.g. "sch" in the word Schedule or the imitated sound of a steam locomotive)
• 10 kHz = Heights (e.g. "sssss")
You'll get a fully complete DIY kit and complete means complete:•PCBs with pre-assembled SMD parts
•All necessary through hole components
•All necessary mounting hardware
•Complete enclosure with anodized aluminium and acylic frames
•15 VDC wall mart power supply with EU mains and (if necessary) adaptor for US/AU included
•6 x EM800 tubes on request (you can order a 2nd set for spare)
- 15 V 2 A power supply.
- Inrush current suppression.
- Stereo RCA in- and outputs for easy daisy chaining in an existing audio path.
- 2 x Stereo 1/8" TRS jacks for easy connecting your MP3 player, mobile phone or headphone.
- Selectable audio channel (right / both / left) for display.
- Build-in microphone signal can be mixed.
- 63 Hz, 150 Hz, 330 Hz, 1 kHz, 3.3 kHz, 10 kHz spectrum level are displayed.
- Positive grid bias for the tubes adjustable for a kind of "screen saver" when no signal is applied.
- Audio compandor for a wider display range.
- Engraved frequencies on top cover are red illuminated.
- Solid anodized Aluminium side profiles.
- Anthracite mirrored acrylic top cover with engraving.
What you'll need:
- 3 hour of your evening time with no hurry
- A clear, well-lit area in which to work
- Soldering station and fine electronic solder
- Multimeter to check the generated voltages
- Electronic tools
- A loupe may be helpful
- TX10 (Torx) and mini slotted screwdriver
- Download of the manual
- Enjoyment of your work of course
- 6 x Magic Eye tubes (offered separately)
- A line audio source or simply use the build in microphone
The EM800 story
However, the time was just too late for preamplifier tubes as in the end of the 60's transistors came up to be used in the tuner stages of the TV sets and tubes become extinct (except for the picture tube for sure and their high voltage supply).
This very first production batch of the TELEFUNKEN EM800 tubes were comercial never used in many devices. Radiomuseum.org for example reports only from three GRUNDIG colour TV sets from 1967 and two DYNACHORD power amplifiers which has used this tube.
So the EM800 have never left Germany or Europe, are very unknown in the rest of the world and has spend their last 50 years unused in German warehouses.
On the other hand, these tubes has been a big improvement of the well known EM84 / EM87 (6FG6 / 6HU6) or their clones 6E2 (China) and 6E3-P (Russia) as the illuminated screen started here from bottom (like a real VU meter) and not from the middle.
The EM800 are still available in thousands of pcs. for a resonable price.
You have the choice...