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Michael Samra

From the beginning of hifi audio tubes, whether it be triodes,Pentodes,or tetrodes,there has been a lot of brand relabeling from manufacturers. Take the KT88 GEC/Genelex products you see in the picture.I put one out of each type that are supposedly different from each other.The one on the left is a GEC CV series made for the military,the next one is a GEC made for consumer electronics,the next is a US Genelex labeled Monarch,supposedly more durable and made for industry,the next is the US Genelex labeled put in a lot of 1960s tube amps.The next is a blue label Genelex,maybe an aftermarket replacement? The last one is a single flasher Genelex.
If you look at these tubes close,the internal structure is virtually identical.The only difference is the last one with three ring halos all being at the top for single getter flashing.
You might ask,why do you they do this? It is called marketing.Back in the day when everything with an amplifier used tubes, whether it be in industry,home use,or military applications,these companies had to fight like hell to beat out their competitors and a lot of that marketing came into labeling.
Even tho these tubes have identical construction,they did test different and therefore sounded different in some ways.They could have tested for transconductance,innerelectrode capacitance,vacuum purity,and then labeled their tubes accordingly.I have 8 or 9 of the sealed in the bag Genelex with a data sheet that were given to me by a Ford production engineer.I didn't open them because I have an opened quad of ones I got years ago with Data sheets and I never liked the sound of them.I posted them on here before.They were industrial application tubes no doubt.
The GEC and Genelex labeled ones that had no data sheet,sounded much better so that tells me that industries like Ford Motor company were not looking for audio purity,but durability in this case.
This goes back to my original title theme.Today,we still have the same issues confronting us but to a different extent.Many dealers that sell tubes, sell them as factory matched quads but I can tell you that factory matching is not what most people think it is.Keep in mind that the tube manufacturers lean heavily toward the guitar market and much of their testing and matching is set up for that market which is centered on early distortion in many cases. Being audiophiles,we look for the opposite of this. We want max power,lowest distortion,and flattest response and sellers like Jim McShane test for these very things.Sure,you can buy a factory matched quad on Ebay and maybe get lucky but more times than not,these tubes don't suit our needs even tho they sound ok.I have some friends that will drop five grand on new cables,but they will buy their tubes at a place they can save 10 or 15 dollars on a quad.I just go over and plunk my tubes in their amp and make their head's spin.This is why properly matched tubes tested for hifi applications will yield bigger improvements than spending a month's salary on new cables many times.I still have my original KT66 and KT88 reissue Genelexs I got from Jim McShane back in 2007 or 2008 and they still have all their flashing other than a slight rainbow ring around the flashing edge and these are the tubes I use 90% of the time.They still bias perfectly and there is no unbalanced glow in one tube vs the other that you often get with factory matched tubes.The way Jim McShane tests and matches his tubes is one of the big reasons for the long life and superb sound I have been getting from the reissue Genelexs. Rest assured that McIntosh,Audio Research,and Conrad Johnson reject a lot of new tubes just as automobile manufacturers reject tons of tires.

"For every complex problem there is an answer that is clear, simple, and wrong" H. L. Mencken

Edits: 04/22/17

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