Question for Fender guys

[Enzo]

perhaps. I would think that if the bottle size changes, then it won't come off the same machine, or at least a different setup for that machine. it seems unlikely to me that they would fill a case of tubes half with output from one line, then go over to another line to fill the rest. Unless it was THE last dozen tubes from the older line. There would be no reason to mix the output of different lines over many cases.


Imagine they were bottles of beer. Budweiser cranks them out by the thousands. They would not likely fill cases with half of one size 12oz. bottle and the other half with a different shape 12oz bottle. Not unless the last 8 bottles of the old style went into a box and they grabbed enough newer ones to complete the case. But that would be just ONE case.

[g1]

Imagine they were bottles of beer.

That reminds me, we were sitting around one day speculating how many guys got busted teeth when they changed over from the stubby to the long-neck bottles.

[J M Fahey]

Thinking as an amp maker (which I am, although in WAY smaller scale) , one clear reason which would practically force me to do that would be that one type, no matter which, short or tall, was marginal quality and barely met specs or even fell somewhat short.

Now an amp with 4 weak ones would be noticeably weaker than others.

Junking the weak ones and calling it a day?
Not in your wildest dreams !!!!!!!!!!!!! ..... am I wearing a T Shirt printed "Crazy"?

So 2+2 gives you a usable and sellable amp.
Of course evenly spread on both sides.

Only problem is that emission or gm are invisible to the naked eye, bottle size is not.

By the way, maybe somebody even **patents** that and calls it "Simulclass"

I eat and breath SS so I don't have those problems, but a couple times some speaker voice coil holding fixture slipped and a voice coil got somewhat too high or too low ..... not properly centered in the gap so wasting some magnetism.

Speaker still works, specially at lower frequencies, but loses some bite.

Alone it's unusable but at the bottom in a 4 x 12" , mixed with 3 strong ones ... nobody notices, not even me knowing it beforehand.

After all the highs it's not producing would end up annoying crawling babies or being absorbed by socks, so in practice, no big deal.

Wasting stuff? Why?

[Enzo]

That means you tested the tubes to find out you had weak ones. I am sure fender just installed tubes from the box. then during the quick GC test, they would find out if any had non working tubes, and replace any duds.

[loudthud]

Fender had an internal part number for the 6L6GC and probably had an actual spec sheet, but it might not have gone into too much technical detail. Specifically it probably did not call out any certain envelope height or maybe just a maximum. So if the part complied with what was called out on the spec sheet, it was acceptable.

[J M Fahey]

That means you tested the tubes to find out you had weak ones. I am sure fender just installed tubes from the box. then during the quick GC test, they would find out if any had non working tubes, and replace any duds.

Oh, I look at it from the simplest way possible.
Don't think Fender tested tube by tube, no way, but rather that, say, they had a bad batch, noticed it because many or all amps so fitted were weaker than expected, might have also bought a dubious but cheap lot from an alternate supplier , and ordered new guaranteed good ones.
Now they got stuck with the old ones and of course they wouldn't "eat " them, no Sir.
One way to get rid of the bad batch is as I said earlier: mixed with the good ones.
All this pure speculation, only way I see to explain tall and short tubes mixed and used in *many* amps.

As others said, if only difference were bottle height, unless those were the very last 4 in existence (which was not the case), they could have been matched amp by amp.

Even if they were carried from the parts storage room inside individual white boxes (which would hide size) in a wheelbarrow, and only found out when actually opening the individual box, they could still be matched, just open boxes to get 4 same size ( a maximum of 7 boxes) and leave the remaining 3 on the assembly table until the next amp, then open 3 new boxes and so on.
So if they were not, there must have been "some other" reason for the odd pairing.

Just idle thinking while my tongue burning coffee cools down a little.

[Justin Thomas]

Not to drag this up again and be contentious, but I just noticed in the initial post, the pic of the back of the head... the rightmost 6L6GCs has a GT logo painted on it. Given that the Bassman 100 was discontinued in the mid 70s and replaced by the BM135, I highly doubt that tube came from the Fender factory. Was it and/or its pair replaced at some point? I think so... at the time it was replaced, the 6L6GC USA tubes were probably still plentiful.

Justin

[52 Bill]

... the rightmost 6L6GCs has a GT logo painted on it.

So does the second tube from the left, which is a tall one.

According to the original poster, the photos are of two different heads.

[Justin Thomas]

I'm inclined to think that both amps were retubed randomly at points in the long ago in the past, when 6L6GCs were still common from a variety of sources, and when "matching" and "balanced distortion" and other such things were not in vogue. As in, "it sounds good and doesn't self-immolate, so send it out the door."

Justin