Semiconductor Shortage? Never Mind That, There’s A Vacuum Shortage!

As those of us who work in electronics are grappling with a semiconductor shortage making common devices unobtainable and less common ones very expensive, it’s worth noting that there’s another supply crunch playing out elsewhere in the electronics industry. It’s not one that should trouble most readers but it’s a vexing problem in the guitar amp business, as reports. At its root is the Chinese Shuguang factory, which it is reported has been forced to close down and move its operations. There’s nothing about this on the Shuguang website, so we hope that the plant has been relocated successfully and production will resume.

The specialist audio market that forms the lion’s share of tube customers in 2021 is a relatively tiny corner of the electronics business, but it’s interesting to note that the three major plants which supply it, in Slovakia, Russia, and China, are still not enough to prevent it being vulnerable when one of them fails. The likelihood of a fourth tube plant emerging somewhere else in the 2020s to take up the slack is not high, but it’s evident that the demand remains healthy enough.

If you’d like to know more about the supply of new vacuum tubes, we went into the subject in greater detail last year.

28 thoughts on “Semiconductor Shortage? Never Mind That, There’s A Vacuum Shortage!

  1. One of those back-burner, I’ll-do-it-one-day projects in my mind has often been to wonder how feasable it would be to produce FET-based tube replacements. I’m thinking a tube base with a vertical tube-sized circuit board to be a plug in replacement (my interest is tube-based radios). The hardest part might be to reproduce the “tube sound” but the cynic in me thinks maybe just a low pass filter would do it. *ducks*.

    1. This was a thing. Solid state was smaller, but also lower power, and less heat. People had this tube equipment which was still viable, but not solid state. So people converted it.

      Some tried modules that were direct plugins for tubes. There were even a couple of companies making them. But only a few specific tube types, the ones so common that there’d be an impact. Heathkit even sold a mod kit, a couole of “tubes” to replace the real ones in a VTVM.

      More “commonly”, people would adapt stage by stage, fit something for that stage, and maybe change some existing resistors. Some kept the existing voltage, others dropoed it to 12v orso.

      Another group would just treat the equipment as a chassis, a whole new design making use of the chassis and IF transformers, but not trying to keep close to the original.

      But it was a brief time, soon the tube equipment replaced, and anyone interested in tubes wanting intact tube equipment.

      I doubt we will ever run out of vacuum.

      1. Teledyne made “ersatz” tubes in the 1970s, but these things weren’t generic replacements – the solid state 6AK5 was offered in three variants for different applications.

        1. I don’t remember the variants. I remember a letter from someone tryi g them, and if I recall properly he said the 6AK5 was good for limiters in 2 way radios, but less good for linear use.

    2. I still remember a late 70’s radio i once tried to repair that had a tube socket for the power amplifying circuit, but instead of a tube, there was a circuit board adapter that adapted the tube socket to some 15cm long wires which went to a single sided pcb about 8×8 cm with resistors, capacitors, diodes, inductors and mosfets.
      So it wasn’t a quick and dirty adapter, but clearly something with effort put into it.
      But the particular radio model was a popular upper class model that sold well, so they probably wanted to keep selling them despite dwindling availability of the power amp tube.

    3. I can see a FET design standing in for some triodes. But a triode is just one small segment of the vacuum tube family.

      And then the “tube sound” involves more than just the vacuum tube. It involves final output transformer and surrounding circuitry.

  2. there are some folks doing tubes also.
    elrog is one doing modern versions of classic audio tubes (211, 300b, etc).
    korg makes a very modern triode (nutube)

    making classic tube styles/shapes still seems to be heavy on manual labor
    except the korg which seems like it was designed for as much automation as possible

    1. These are toys for people with too much money. Elrog makes simple but extremely overpriced audio power triodes and rectifiers. The Korg Nutube is a modified VFD made by Noritake Itron, probably the weakest electron tube ever made. You cannot do much with 32µA plate current and 1.7mW plate dissipation, but at least it doubles as indicator lights.

  3. Not being ‘into’ vacuum-tube design since college days, (got a VERY thorough grounding from several VERY thorough tube-design experts, however; still have my ’63 RCA tube manual), I have to wonder:

    if all the pack-rats like me quit hoarding (I have at least 7 or 8) ALL the 5- (and 6-, 7-, and more) tube AC / DC superhets (and some not-so-AC/DC; some multi-band), and released them to the open market–how much of a dent would this make in the vacuum-tube vacuum [there you go, sjm4306].

    1) Could the 5-tube AC/DC-type tubes even be used by the still-active tube-design business / industry?

    2) I was literally floored when I checked on the price, about five years ago, on the cost of a PACK OF FIVE tubes for a “standard” 5-tube ‘all-American five’ (sorry, rest-of-world; that’s what it was called by us/we colonials). If I remember correctly, back then, the price of a 5-tube ‘standard’ pack was ≈ $50. This, when I remember being able to by the complete set of five tubes in a pack for 99¢ (I told you I still have my 1963 tube manual). What’s unsaid here is that it is, in retrospect, almost unconscionable how many good tubes were thrown away simply to replace one bad one–all because of the 99¢ price.

    You can bet that whenever I fire up any of these antique ‘oldies-but goodies’, it’s done by bringing the line voltage up verrrry slowly with a Variac between the line and the radio.

    Nostalgia ain’t what it used to be.

  4. I don’t want to sound alarmist but the Germanium lovers must also deal with a crazy supply crunch. New-Old Stocks have depleted faster than the arrival of newcomers who want to play with them, turning the damn lazy OC70 into expensive unobtainium (adding price to low performance).
    The prices have more than tripled for some references, reserves have molten…
    There might be one factory that still manufactures these parts to the spec but that’s only a rumor.
    One OC139 is now about 4USD which is fine when you need to repair one pedal.
    but if you want to play seriously, like making digital circuits, this becomes obnoxiously expensive.

    That’s the price of obsolescence…

    1. In the early seventies, the local parts store Etco, was selling small bags of germanium PADT transistors, good for RF. I know I bought a few bags, they were cheap, and circuits using germanium were still almost current.

      I have a vague memory of clearing them out as I got access to silicon, and better, transistors.

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