DISCLAIMER: Vacuum tube circuits work with dangerously high voltages. Do not attempt to build circuits presented on this site if you do not have the required experience and skills to work with such voltages. I assume no responsibility whatsoever for any damage caused by the usage of my circuits.

All rights of photos and text reserved. Usage of photos or text from my blog on other websites or for any other purpose only with prior permission. If you want to use any material from my blog please contact me by email.

Thursday, April 19, 2012

Tube of the Month: The 183/483


This months tube is a quite uncommon directly heated triode, the 183/483.

This tube exisits junder two designations 183 and 483. The photo above shows a pair 483s branded Marvin. apparently this tube was only manufactured over a short peroid. While the RCA RC13 receiving tube databook does not list it yet, the RC14 lists it as 'replacement type' which means it is not recommended to design new equipment for it. RC15 lists it as discontinued type. So probably only a few radio sets used this tube.

The 183/483 is very similar to the 45. It has the same UX4 base. It has an amplification factor of 3 while the mu of the 45 is 3.5. The plate resistance is 1750 Ohm at a 250V plate voltage and 30mA current. This is very close to the values of the 45: 1600 Ohms at 34 mA. So it would work in a circuit designed for the 45. Only the filament voltage differs. It is 5V, double the value of the 45. Filament current is 1.25A, slight.ly lower than the 1.5A of the 45, but at double the filament voltage this is a significantly higher filament power requirement. Both can provide a power output of about 2sw in single ended. I have not found any databook which shows plate curves of this tube, so I measured it on a curve tracer:

Very linear as one would expect from a directly heated triode designed for audio purposes.
Construction is quite similar to that of the 45. Only the size of the bottle is bigger. The 183/483 comes in the same bottle as a 2A3. below a photo which shows a 2A3, 483 and 45 in comparison.

The filament follows the same 'M' shape as that of the 45, with two filament support on the top:

A very interesting tube, but since not many seem to be available not really recommended for DIY use. If you have some in your stash. It might make sense to adapt the filament voltage in a 45 amp to allow to use these. I do not have many 183/483 myself, so I'll probably never use them in an amp. Since little can be read about this type, I found it worthwhile to give it a place in the tube of the month series. Maybe somebody with some more information about this tube can provide details about it's history and background.

Best regards



  1. I discovered these some time ago as cheap alternative to the 45 (few people seem to know about them). I really like these, I found them to be nicer sounding than the 45 to my ears, perhaps it's the greater filament power?

  2. Marvin Master-Built? I have NEVER heard of this manufacturer - I wonder if they survived past WWII?

    I like the sculptor/pedestal illustration - I wonder where I could get a hires scan of that side of the tube box, hmm?


  3. Hi J,

    I will email a scan of the box to you :-)


  4. Hi
    I'm looking for some 183/483

    1. Hi!
      Try Radio Electric supply at vacuumtubes.net They list some on their site but I don't know if they actually have them


  5. They were used by Sparton mainly in 1929 to 1930 consoles. I'm going to try and used for a hopped up replacement for a 71A audio output tube in a Zenith 11E radio from 1927, which was Zenith's very first AC powered radio. The filament voltage is the same. Amperage is more. Set uses an external speaker so I can mate an output audio transformer to a speaker and should sound amazing. Will be same as getting console radio sound in a compact table top. Simple tweaks to old radios can show their full potential. Most radios could use upgraded tubes, audio output transformers and or speakers. Companies were limited by technology of the time, budvet, etc.
    Too bad more people did not try to hot rad these beasts that can be converted back yo OEM easily.
    Maybe more would be saved as tube amplifiers for phonos , media instead of being scrapped.

  6. Used in sparton radios 192o to 1930. Will upgrade zenith 11E radio to this should sound amazing. Console radio sound in table top.
    Too bad more people didnt upgrade old console radio to use as audio amps besides radio. Upgrading the speakers, audio output transformers and or speakers majes these old beasts shine. More could if been saved by scrap heaps. Now all of the hifi tubes are showing up. Want a nice amp-upgrade an old radio for cheap. Can be gone back to OEM if wanted