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Last Update: 29-Mai-2016

Portrait of a tube

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The Upgraded family 5693 - 5814 - 6189

Author: Jac van de Walle

These tube are higher quality Versions if ECC82 / 12AT7. So they can replace the ECC82, but with some special extras, that we'll describe here.

As you notice, these part numbers are military numbers. Don't panic.... these tubes will not sound aggressive because of that. Whatever the reason, military tubes are definitely NOT preferred by some collectors. .Those guys want "originals" and original is a nice fat tube from Philips or Telefunken, but they ignore the special tubes that were made to deal with some of the problems commercial ECC82's had- So try to jump over your shadow, and look at it from the point of view of those people who made those tubes. Perhaps those engineers were more knowledgeable as you expect. But.... we can't ask them anymore, and now we can only study the remains of their work, in the form of NOS tubes and old books.

What puzzles me most, is what makes people want to have impossible-to-get commercial versions of this tube, while so many "upgrade" versions are available at reasonable prices. Honestly I don't know! I think from the collector's point of view there is no point in collecting Gizmo's that are no Gizmo's at all. Real Gizmo's are hard to get and expensive. When you finally have one of those, after being cheated on Ebay a few tines, you can say: "Hey, guys.. I have this and that tube"... and everybody says : Wow!, and you feel good about it. I think that what makes a Gizmo.

5693. The "stand by" ECC82

5693 This is a nice one. Perhaps you have seen amplifiers with a standby switch. Imagine the musicians walk on the stage to play with electric guitars, and first need to warm up the amplifiers. These guys want the amplifier to be "dead" when on stand-by and it must work immediately when switched on. This sounds logical to me.

I noticed some HiFi users have this requirement also. So they are in sitiations where they need to use the amplifier instantaneously or unexpectedly. So you have no time for a normal warm up cycle. You can't use that, because for you every second counts. So the amplifier designer added a Stand by switch for you. Now, the moment you flip the switch -bang- the amplifier is working. As we all know, stand by is very bad for any tube, but you accept that because for what counts for you it to have the desired function. You need this for the special way you use the amplifier, and for that you are prepared to exchange tubes more often.

Even those tubes that are made for it, don't get any better from stand by. The total lifetime reduces when it is used on stand by often. The tube wears out much faster, and even worse the cathode can poison from this, meaning the tubes loose emission much faster then expected. So a stand by switch fulfills for you this important requirement of instantaneous operation, but this is done on the cost of much faster tube wear out. Here is where the 5693 comes in the picture. This tube has some of the functions of the famous Telefunken ECC802S.

  1. The 5993 cathodes will not poison during longer and repeated periods of use without plate current flow. This was first seen with tubes like ECC802S
  2. The two triodes have a defined maximum difference to each other. (max 0.8mA). The definition is in a particular Radio application, where this is important for circuit designers. For us HiFi users this number cannot be easily translated to the DC (idle) state. At least it is better than no specifictaion at all, like with commercial ECC82. Measurements have given that NOS 5993 is not more than2.5 mA off at 10mA. So if one triode is 10mA the other is not above 12.5. This is much better than commercial ECC82, where it can happen that you have 7mA and 14mA in one bulb, and you have to call it a "good" tube! They sold a tube like that. Note that American tube companies HATED this requirement, so with thge 5693 they really did something. Is it coincidence that 5692 (not 5693!) is a simular tube? Perhaps not!

6189. The "long life" ECC82

5814 . The "low leakage" ECC82

Telefunken ECC802S has all of the above, and more!

  • Stand-by allowed
  • Low leakage
  • Long Life
  • Lower hum
  • Balanced
  • Gold pins

Standard ECC82 has nothing of the above!

  • NO Stand-by allowed
  • NO Low leakage
  • NO Long Life
  • NO Lower hum
  • NOT Balanced