Tubes and Tone

[golfnutt67]

I am curious to that others think with regard to tubes and the tone in given amp can produce. I have always thought that both the power and pre-amp tubes played a huge role in an amps sound characteristics, but was recently told by a tech that it was all about the pre-amp tubes and the power's had no influence on the tone.

I am not being critical of his statement I was just surprised because of what I had experienced with my late model Traynors after trying different power and pre tubes.

I would love to hear others opinions on this.

[candid_x]

Originally Posted by golfnutt67

I would love to hear others opinions on this.

Hold onto your golf hat, cuz you'll probably get lots of opinions. It's a topic of cult proportions.

[TweeDLX]

Originally Posted by candid_x

Hold onto your golf hat, cuz you'll probably get lots of opinions. It's a topic of cult proportions.

...of the impending flood you'll probably get. They both make a diff, but pre tubes have the biggest impact on tone.

Mike

[mike shaw]

It really depends on the amp, how loud you crank etc.
In a MV amp at relatively low volumes - preamp tubes.
Non-MV at high volumes - output tubes.
Both tubes will influence the sound, but as to how much depends on how you use the amp.

[candid_x]

Gosh, Mike, but that's so sensible.

I can't aspire to the level of tube geekdom to answer from a strong knowledge base, only my modest personal experience.

The V1 spot is typically responsible for shaping much of an amp's preamp tone. As Mike said, if you drive the power section to any significant degree, the power tubes also have a significant effect on an amp's tone. At low volumes, not nearly as much.

[WaltC]

... and... if power tubes didn't matter to the sound, why would we use either 6V6s or EL-84s, why 6L6s and not EL-34s, or... why 5881s or short bottle 6L6s and not tall 6L6s or KT-66s? Why 6ca7s instead of EL-34s? <BG>

at bedroom volumes it doesn't matter as much, which I suppose (asbestos shield in place) is why so many "bedroom" amps are solid state and/or modeling amps.

But at Fillmore East stage volumes w/ your les paul and a 50 watt Marshall giving it all up, they *all* matter!

[pgissi]

I am not being critical of his statement I was just surprised because of what I had experienced with my late model Traynors after trying different power and pre tubes.

I would love to hear others opinions on this.

You have the answer and its not as simple as power tubes are not a factor. Power tube swaps are a valid way to change your tone but with a caveat, at higher levels, when the amp is driven harder is when they are more likely to be heard. At louder levels their influence becomes more apparent. At lower bedroom levels, your not driving the power stage, OT or speakers all that hard but can push the preamp (if its a master volume amp) which means the preamp tubes are most dominant. If its a non master this still applies though and with any amp where this occurs is dependent on its rated output with low watt amps getting there sooner, before your ears bleed that is.

The more powerful any amp the louder it needs to be to bloom to where the power tubes are becoming more influential tonally with other factors coming in to play. But the preamp tubes get to shape the tone first, that never changes, its just at higher levels the resulting tone is the aggregate of all the tubes more so than at lower levels. Its a generalization and where that distinction falls varys from amp to amp and dial in as well as other elements in the signal chain.


Take a low watt combo or head and turn it up till it begs, it should be easier to hear the power tubes and maybe some supply sag voicing on top of the preamps tonal character. But at lower levels this is typically less apparent if at all. Thats the easiet way to get familiar with power tube tonal character since turning up 5, 15 or 20 watts is not as loud, its a little more comfortable to where you can really listen without running for cover. It feels different too and of course power supply sag is the primary reason there and there there is the Output Tran, speakers etc.

When you get to that place the power tubes are not the only factor, a huge tonal influence is the OT and the speaker/load imp/cab/wiring styles of course. Its all relevant.

IMO the best way to sum it up is that the preamp tubes remain dominant regardless, they shape the signal first.

But saying the power tubes have no influence is just not accurate.

I have been a member of the power tube cult for some time and needless to say, my ears are ringing more than ever.

[strat a various]

I play at medium volumes with mostly 50 to 100 watt amps. I hear a major difference with various power tubes. Just changed from Groove Tubes to Winged "C" in a Musicman, warmed up the tone considerably, the mids are much more full ... Switched to 5881s in a TR (from old RCAs), amp gets grittier and sounds less glassy. Installed Groove Tubes in 68 Bassman, replacing old Phillips tubes ... cleaned up the mud on the Bass channel and made the Normal channel more sparkly.
These results are at medium volumes. I believe the power tubes all have different characters that may be subtle, but certainly noticeable.

[pgissi]

I play at medium volumes with mostly 50 to 100 watt amps. I hear a major difference with various power tubes.

yep and medium volume is where you hair starts standing up. its hard to get inspired by anything 40 or 50 watts and beyond at anything less, its all preamp buzzsaw on a master volume amp. That may be tamed with different speakers but its hit or miss. If I am playing my jmp or slx, its turned up pretty loud.

On my alchemist the 20 watt setting gets some output section in there before your on stun. I like the 5881 in this amp for improved high gain grit over the glassy 6l6, low or full power. It was immediately there. Converted the jmp from the stock 6550's to el34's, immediate difference. The el34 slx got retubed with some unused 90's groove tubes I had forgotten, yanked out the newer sovteks I used to replace the stock factory teslas with, hello tone, where have you been. 30 watt rivera, different output tube different tone.

With each of these amps, 20/40, 30, 50 and 100 watts, they were turned up to more easily hear the differences and although the difference is subtle, its there.

Of course what comes before in the preamp is going to alter your results so trying combinations of different preamp tubes in different positions (depending on what that stage does) and balanced against output tube swaps/rebias is where you can further experiment and tweak your results.

So your tone is more the sum total of its parts rather than saying its just preamp or output tube types and especially saying output tubes have no influence on tone.

[golfnutt67]

Well thanks so much for the replies a lot of what is being said makes sense to me