Tube Amp soundstage

tablejockey1,815 posts12-20-2020 8:16am"Sweet EL34s, plump KT88, and the all time best 6L6 (I think)"

oldhvymec-That’s what I hear. Not the modern 6L6, but the lower power RCA 6L6G.

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TJ I know the old RCAs will take a heck of a beating, the military metal cover is another tough valve.

Something about a good 6L6, my buddy in Sheldon, great musician, great person. He use to be a BIG time bass player. ALL his bass amps were 6L6. He plays just about anything well, so he starts working on his 6-12 string stuff, again, back to the 6L6. He doesn’t like the British sound, EL34. KT88 are to fat on the bottom, he is tinkering though.. After 55 years of rockin’ he’s not gonna change to much..

I’ll say this though, DON’T buy the cheepos’ (6L6) that are being advertised on EBay from, the Eastern block.. BAD, design and sound. They come out of the box at 10-25% of a new Sylvania, RCA or GE. Just JUNK.. They won’t hold a bias, and take a while to sound OK.. I lost over 10% due to out of the box failure and another 5% with a 24 hour break-in. BAD.

Merry Christmas Everyone.. / Have a Good Holiday..

Regards

MC says "Designers never came up in my post at all. Now you’re pretending it did. Crazy."

Look...the inconvenient truth is that when talking about tubes vs SS You CANNOT separate the equipment from the design if you want to discuss the harmonics that are produced. Period!

Any device, tube or transistor, will display the same basic character with respect to odd or even harmonic distortions depending on how it is used. In a single ended design there is one amplifying device covering the entire musical signal while in a push pull or complimentary design there are two: one for one half of the signal and the other the remaining half. The simple fact that second order harmonics are louder than third order harmonics in most any device dominates the single ended approach while push pull and complimentary designs cancel these distortions by the very nature of their operation. What this means is that any device, tube or transistor, will display the same basic character with respect to odd or even harmonic distortions depending on how it is used.

MC makes these erroneous claims about even harmonics being attributable to the tubes themselves...and SS gear (w/o any design considerations) produces more odd harmonics. This is just plain wrong regardless of how MC chooses to spin it. It’s not about a tube vs a transistor - it’s all about implementation...yes, the friggin’ design!

From a practical standpoint most SS designs are not single-ended and lend themselves to producing odd harmonics so MC falls into the trap of believing it must be due to the gear using SS components instead of valves. Wrong. So very wrong. This isn’t word play MC, this isn’t a game, this isn’t dastardly use of a Cusinart...this is just you not understanding something.

The Sylvania 6L6 is very nice indeed.

Ralph post is a Phd,

of course SS with a tube front end SS output , liquid cooling, no emiter resistors, etc and a few other tricks can sound incredible, see Vandersteen M5, M7
of course soundstage depends on preserving those subtle time and phase related cues as well as not burying them in whatever flavor of distortion you may prefer.... lots of feedback kills image depth, easy test with an SPL meter, genius ( mindful designer ) Roger Modjeski designed RM-9 with variable feedback :-) ears are required

@dtapo
You may have already answered your own question, comparing first hand. Trust your ears. Maybe there is some magic in the distortion and 2nd and 3rd order harmonics.   

Gotta ask oneself why many of the high-end class A solid state designers and amp builders continue to try and build circuits and test various output transistor types to try and make their amps sound like valve tube amps. Getting closer, not fully 3D or as layered yet.   

Ralph’s post is perfect to demonstrate how the design and implementation are applied to get the desired outcome from an amp. Designers of both tubes and transistors make choices and tradeoffs to achieve their goals. Tubes have a relatively high output impedance and are not easily capable of driving a loudspeaker directly – where the opposite is true for transistors. This is why most tube power amplifiers have large output transformers and transistor amplifiers do not. The transformer addresses the tube output issue but certainly has sonic drawbacks. This is why a number of Ralph’s designs "fix" this problem by creating output transformerless amplifiers. It’s all about the implementation.