Uh Oh, Tubes Don't Sound Different. Scientific, Controlled Variable Test.

HotBluePlates

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I agree! I think Johan's test is more-valid under more circumstances.

Note quoting anyone, lest they think my comment is directed at them. The plus in Johan's test is no feedback loop around the tubes being swapped, giving a better chance at tube-differences to actually be heard.
 
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Imagine my disappointment expecting a “scientific test” and opening the thread to see that dude’s face
Spiner.jpg
 
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While I respect the effort and the methodology here, I think there may be a false presumption:
Modern tubes all sound very much the same > Therefore, tubes don't make any difference in amps.

AFAIK, all modern vacuum tubes come from just two factories, and their production is highly automated.
It isn't surprising to me that these would be virtually identical regardless of brand name.
My understanding is that today's Mullards, JJs, and Mesas are all made on the same machines.
Of course they'd test the same.

I would be very surprised if the results were still the same testing classic vintage 12AX7s made in different factories - a real Blackburn Mullard, a French Mazda, a Dutch Amperex/BugleBoy, and a long plate RCA.

Or even some less scarce & pricey 1960s/70s tubes, like American Sylvanias vs British RFTs.
IME tubes from the vacuum-tube heyday can and do exhibit audible differences in tone character.

Those who've spent enough time with one amp to be highly familiar with it can verify this by swapping a couple of different NOS tubes into their V1 slot.
This is absolutely not true and I find it odd this myth still lingers on.

You have one plant in Russia, one in Slovakia (using some Tesla machinery but still doesn't sound like Tesla) and I believe 4 plants/ sources in China.

Then each of these spec their products differently when sold as different brands or STRs.
 

HotBluePlates

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I will say that yesterday I tried a quick hot-swap of 12AX7s in V1 of a 1962 Deluxe. Had a Tungsram, long-plate Ken Rad, long-plate RCA, I61 Mullard, an RFT, and a ribbed-plate Telefunken.

In a "quick strum, install the next tube, strum" I heard a lot less change than I expected from the tube swaps. The RFT was indeed a touch darker than the others, the Mullard might have had a bit more bass & mids. What actually surprised me was noticing the slight upper-mid/treble bump in the Telefunken that I never noticed before.

Regardless, all of them sounded like "1962 Deluxe with a 12K5-3 speaker". It would have been interesting to have a null test, but I'm not gonna be set up for that for months.
 

Steviecaster

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804
I can tell the difference between preamp tubes in my 1959. However, I can change from 6L6 to EL34, and I can't hear a lick of difference clean. Not at all.
 

AintNoEddie

Member
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823
I will say that yesterday I tried a quick hot-swap of 12AX7s in V1 of a 1962 Deluxe. Had a Tungsram, long-plate Ken Rad, long-plate RCA, I61 Mullard, an RFT, and a ribbed-plate Telefunken.

In a "quick strum, install the next tube, strum" I heard a lot less change than I expected from the tube swaps. The RFT was indeed a touch darker than the others, the Mullard might have had a bit more bass & mids. What actually surprised me was noticing the slight upper-mid/treble bump in the Telefunken that I never noticed before.

Regardless, all of them sounded like "1962 Deluxe with a 12K5-3 speaker". It would have been interesting to have a null test, but I'm not gonna be set up for that for months.
If you have a looper (pedal) and the possibility to mike your amp, you can really easily capture nice samples with different tubes. Does not take long & it would be fun to challenge your "memory" results against the recording!
 

Mystix

Gold Supporting Member
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Well, what I know is if you plug in 3 JJ ecc83 into my amps and play them they are dull. Pull those out and put in 3 old Mullard I61 and the amp is vibrant, chimy, and sounds correct. Power tubes:
Same story, they all have different sounds. I’m not going to claim favorites because each amp responds differently. I swap around until I find the mate for the amp.

Same thing ive experienced...especially once tubes get hot...
 

aynirar27

Double
Platinum Supporting Member
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33,155
Buy new production! That just leaves more nos for me!

I have a few NOS lying around for when vintage amps come through, but for the most part I stick to new production. I treat tubes are like tires, have fun doing burnouts then put on new ones
 

Muffdriver

Silver Supporting Member
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791
Put 4 different brands of pre amp tubes in your amp and then just swap positions and tell me there's no difference.
I did that for an amp I bought that I didn't like... I still didn't like it but it makes a noticeable difference.
 

Muffdriver

Silver Supporting Member
Messages
791
Also, if you've ever owned a thd bivalve you'd know the effect it can have.
I will say that the knob that switched from 6l6 to el34 in the Egnater Renegade was pretty pointless imo.
 

Shiny_Beast

Gold Supporting Member
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11,272
If I was going to record an album and my rig and tone was all part of that, and the main dude at some studio told me not to bother bringing my amp in because he had the same one there already I would want to bring my amp anyways. If he pressed me on it I'd probably want to look for another studio. I think I get his point and where he's coming from, just saying...
 

HotBluePlates

Member
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13,582
I can tell the difference between preamp tubes in my 1959. However, I can change from 6L6 to EL34, and I can't hear a lick of difference clean. Not at all.

The output tubes & phase inverter of your 1959 are in a feedback loop, which enables the functioning of the Presence control. The other preamp tubes are not inside any feedback loop.

Check out my previous "unsolicited comments" for how that impacts whether a tube-change is audible.
 

Steviecaster

Member
Messages
804
The output tubes & phase inverter of your 1959 are in a feedback loop, which enables the functioning of the Presence control. The other preamp tubes are not inside any feedback loop.

Check out my previous "unsolicited comments" for how that impacts whether a tube-change is audible.
Haha. Unsolicited comments. Im kinda confused on that one. You are probably the most knowledgeable poster here. I've learned a lot from you.
But yes. That makes sense. Does that loop make my power section stiff, too? Lawd, that is one stiff amp! I like it.
My drummer also modded it. For one, so I can put any kind of octal tube in it. And two, for more clean headroom. I don't know what all he did for headroom. I know he raised the voltage on the preamp. Both transformers and the choke have been replaced.
 




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