EL84 Tube Shootout...A/B

[soundcreation]

So I recently decided to buy some new old stock power tubes for my amp to see for my self if the hype is true or not. So I did my research and decided on a set of late 50's Valvo tubes made in Germany. AKA Philips miniwatt, or Mullard or Brimar and probably a bunch of other names depending on factory..etc. Shelled out probably too much money for them but what the hell. You only live once. My amp had a set of Groove Tubes in it which I guess you could say represent a "modern" made tube.

 

I figured I might as well make an A/B vid while I had the chance.

 

Signal chain is my Greco SS500 (SG special) with P90's into my Crate V1512 mic'd by a Shure SM57 into a Focusrite Saffire PRO 14 into Logic X. Final edit was done in Audacity.

 

Settings are all identical. No EQ or compression or whatever....just guitar recorded straight.

 

The lead lines are slightly different just cause I was noodling off the same theme.

 

First part of the vid is blind and second is repeated showing which is which. If you want to think about it after the first listen, hit pause quick when the "which is which" screen comes up at about 1:13 as it doesn't last long.

 

So without further adieu...

 

[YOUTUBE]pV-NLc5Lc0o[/YOUTUBE]

 

 

 

 

[mistersully]

i'm 53 seconds in and A sounds fantastic

 

 

[mistersully]

well there you go

 

apparently i prefer the ******* (edited as an act of anti-spoilerism)

 

and as usual, i LOVE the sound of a good el84 based amp

 

cool vid mate

[jtr654]

A has a bit more presence and articulation.

[thatsbunk]

both sound good & in a band or mix situation i don't think it would make much of a difference, but I agree "A" sounds a bit better...

[Into Nation]

One thing to consider... You already had your chain EQ'd on the amp (im assuming) for the original tubes. It might be interesting to re-do or try to re-do EQ with the NOS tubes for optimal sound, then do another A/B.

 

Might prove nothing, might prove interesting.

[gardo]

One thing to consider... You already had your chain EQ'd on the amp (im assuming) for the original tubes. It might be interesting to re-do or try to re-do EQ with the NOS tubes for optimal sound, then do another A/B.

 

Might prove nothing, might prove interesting.

 

Good Point

[wankdeplank]

Nicely done, kinda wish you had of done something clean as well but so be it. Definitely hear the difference. Now to search for something comparing the Groove tubes with JJs.

[WRGKMC]

Aside from the B track being slightly lower in volume, there's not much difference in quality. The B track is a bit tamer if anything. You didn't mention anything about biasing the tubes, and extremely important item changing power tubes if you want to get the best tone. I have Groove tubes in My Blackface and they used to be sold with different bias ratings. You could buy tamer or hotter tubes depending on what you wanted them for. The ones I have were hotter and actually sound as good as the older RCA tubes I used to use.

 

If the amp has a fixed bias then this may account for the gain drop just swapping them. The big problem doing an A/B comparison like this is tubes often have very small differences and much of it can be a feel factor playing. The amount of compression and some minor differences in response may not be heard. If you were hearing this difference after changing them, It didn't get picked up recording and converting it to a compressed You Tube lossy format. Conversion from a wave file to MP3 would also wipe out any high frequency details that could help identify the differences.

 

Maybe you want to upload the actual wave files to Drop Box and the higher sample rate will reveal more details. The gain pedal you're using also colors the sound so its very difficult to make out any differences. Maybe just running clean and cranking it up would be a better test. That way you can judge the amp.

 

The only way you can really test the difference is to pump test tones into the amp and run a scope and frequency analyzer, then plot the differences between them. The differences in tubes are very subtle. The amplification curves, the level at which they begin to saturate, the frequency responses can vary when you have the volume and tones set the same. Small pot tweaks may get the exact same responses.

 

I'm an old tube tech myself. When I got my degree they still taught you tube applications even though they were becoming obsolete by then. I had allot of experience guitar amps through the 60's and 70's and to be quite honest, I don't buy into the snake oil of NOS tubes. many of the new tubes being built today equal or exceed many of the older mass produced tubes of the past.

 

Factories today are much better and you have engineers redesigning many of the older tube designs on computers using the latest CAD programs and computer testing that far exceeds what they had in the past. Most NOS tubes aren't new either. They amount of hours on the tubes cant be seen or measured. Manufacturers labels and boxes can't be trusted because they can be easily counterfeited. Add to that, so many vintage tubes were not only poor quality, I'd be worried about the getter in the tubes breaking down over such long times.

 

Amp tubes in general have a long shelf life and you shouldn't be too worried about using older ones but you have to realize, some of the elements in newer tubes like Tungsten weren't available in many vintage tubes so the tubes had a much shorter life. A gas called "Getter" is put in the tubes and it collects on the metal elements. The gas is released when the tube is heated and keeps the electrons moving in a straight line from cathode to plate and prevent them from colliding and bounding all over the place. Small amounts of this gas gets lost over time that can affect the tubes quality.

 

Here's part of an engineering article on tubes. Burning in vintage tubes is very important and should not be overlooked.

 

 

"Glass internal anode tubes generally have the gettering material coated on anodes, which must be operated a high temperatures to activate the getter. Glass tubes have a propensity for seal leakage and element out-gassing, both of which lead to a short self life for large tubes. It isn't the glass that leaks gas, but rather a Kovar alloy used to bond the glass to the metal contacts protruding through the envelope. Kovar is also subject to rusting. As odd as it seems, glass tubes should be stored in a dry location. Glass tubes should be operated at full temperature every few months".

 

"Under some conditions a glass tube can be restored to operation by running low anode voltages and positive bias on the grid. This will sometimes allow full operating anode temperatures to be reached, and the tube can be "cooked" for several hours. I've had about a 50% success rate restoring nos tubes that have sat for years without use. Even though they initially arced severely at full voltage, by cooking them at low voltage and positive grid bias to show anode color vacuum was restored".

 

 

[soundcreation]

Aside from the B track being slightly lower in volume, there's not much difference in quality. The B track is a bit tamer if anything. You didn't mention anything about biasing the tubes, and extremely important item changing power tubes if you want to get the best tone. I have Groove tubes in My Blackface and they used to be sold with different bias ratings. You could buy tamer or hotter tubes depending on what you wanted them for. The ones I have were hotter and actually sound as good as the older RCA tubes I used to use.

 

If the amp has a fixed bias then this may account for the gain drop just swapping them. The big problem doing an A/B comparison like this is tubes often have very small differences and much of it can be a feel factor playing. The amount of compression and some minor differences in response may not be heard. If you were hearing this difference after changing them, It didn't get picked up recording and converting it to a compressed You Tube lossy format. Conversion from a wave file to MP3 would also wipe out any high frequency details that could help identify the differences.

 

Maybe you want to upload the actual wave files to Drop Box and the higher sample rate will reveal more details. The gain pedal you're using also colors the sound so its very difficult to make out any differences. Maybe just running clean and cranking it up would be a better test. That way you can judge the amp.

 

The only way you can really test the difference is to pump test tones into the amp and run a scope and frequency analyzer, then plot the differences between them. The differences in tubes are very subtle. The amplification curves, the level at which they begin to saturate, the frequency responses can vary when you have the volume and tones set the same. Small pot tweaks may get the exact same responses.

 

I'm an old tube tech myself. When I got my degree they still taught you tube applications even though they were becoming obsolete by then. I had allot of experience guitar amps through the 60's and 70's and to be quite honest, I don't buy into the snake oil of NOS tubes. many of the new tubes being built today equal or exceed many of the older mass produced tubes of the past.

 

Factories today are much better and you have engineers redesigning many of the older tube designs on computers using the latest CAD programs and computer testing that far exceeds what they had in the past. Most NOS tubes aren't new either. They amount of hours on the tubes cant be seen or measured. Manufacturers labels and boxes can't be trusted because they can be easily counterfeited. Add to that, so many vintage tubes were not only poor quality, I'd be worried about the getter in the tubes breaking down over such long times.

 

Amp tubes in general have a long shelf life and you shouldn't be too worried about using older ones but you have to realize, some of the elements in newer tubes like Tungsten weren't available in many vintage tubes so the tubes had a much shorter life. A gas called "Getter" is put in the tubes and it collects on the metal elements. The gas is released when the tube is heated and keeps the electrons moving in a straight line from cathode to plate and prevent them from colliding and bounding all over the place. Small amounts of this gas gets lost over time that can affect the tubes quality.

 

Here's part of an engineering article on tubes. Burning in vintage tubes is very important and should not be overlooked.

 

 

"Glass internal anode tubes generally have the gettering material coated on anodes, which must be operated a high temperatures to activate the getter. Glass tubes have a propensity for seal leakage and element out-gassing, both of which lead to a short self life for large tubes. It isn't the glass that leaks gas, but rather a Kovar alloy used to bond the glass to the metal contacts protruding through the envelope. Kovar is also subject to rusting. As odd as it seems, glass tubes should be stored in a dry location. Glass tubes should be operated at full temperature every few months".

 

"Under some conditions a glass tube can be restored to operation by running low anode voltages and positive bias on the grid. This will sometimes allow full operating anode temperatures to be reached, and the tube can be "cooked" for several hours. I've had about a 50% success rate restoring nos tubes that have sat for years without use. Even though they initially arced severely at full voltage, by cooking them at low voltage and positive grid bias to show anode color vacuum was restored".

 

 

The amp is cathode biased so no need for biasing.

 

Actually I did have to dial the pre amp gain on the focusrite down a quarter of a turn simply because the Valvo's were so powerful the caused clipping at the same level. I probably should have adjusted the volume up a little bit on them to balance that...but essentially the tone is the tone that was recorded at clipping levels.

 

As for audio file I didn't compress it at all. It's a WAV file straight out of Audacity and loaded into youtube. The youtube might be slightly compressed but comparing it to my original it's barely noticeable. The youtube quality is fine in my opinion.

 

There is no pedal being used. That's all amp and an amazing set of greco P90's.

 

There will obviously be preamp gain in there as well but those tubes were not changed and being cathode biased it's running the power tubes at full all the time anyway. So all that power tube goodness is pretty much there at any volume on my amp.

 

I personally hear a big difference in them both recorded and in person. The valvo's are much much warmer and rounder sounding. The Groove tubes are noticeably sharp on the high end. I find the difference in the lead lines most striking.

 

Thanks for that information about tubes. Don't know if I'll be able to put into practice the burning the tubes in thing though. I've just got my amp. I put them in and that's pretty much it. I guess my amp is pushing them full every time it's on though.

 

It's interesting that most so far have preferred the Groove Tubes. I like the Valvo's much better though. Course that could be my own bias trying to justify the dough I spent! Haha.... But I usually prefer a more "round" tone so I don't think so. I will say it's probably not worth the difference in price though. My amp takes two but I bought a set of 4. I doubt I'll do it again. I'll probably experiment with cheaper new tubes or comparable but cheaper NOS tubes to see what sounds similar.

 

And to others...thanks for the suggestions. I was thinking about doing another one where I mess with the EQ on my amp. Initially to see if I could make the GT's sound like the Valvo's. But maybe I'll see what tweeking the high end does on the Valvo's.

 

I recently got a set of Chinese military NOS 12ax7 tubes that are suppose to be famous for their gain. I've got a set of JJ gold pins in there right now so maybe I'll do another A/B with those preamp tubes. I remember the JJ's being way warmer than the sovtek's that were in the amp when I bought it so it should be interesting.

[knotty]

As somebody stated before. In the real world nobody would discern a difference.

[soundcreation]

As somebody stated before. In the real world nobody would discern a difference.

 

maybe....

 

but I didn't buy them for other people to listen to or for a "band" situation. I simply did the video as a fun thing to show that there IS a difference. I bought them for me while I'm playing in my music room. My guitar plugged into my amp and my ears. For me it doesn't get more "real world" than that.