Solid state/class d vs tube amps

[DavesnothereCA]

I believe he meant to say "lower" the Q with resistive loss as Q = WL/R. The power amp would the deal with the loss. Again very subjective since I never knew an Acoustic owner who did not approve of the EQ shelving.
A core, initially saturates as a function of the hysteresis properties of the core material hence it's "soft" I believe agedhorse may be referring to the nonlinear saturation that happens beyond.
Again, it does not say anything concrete about Tube Watts vs. SS Watts.

~
Yes, I realize that my remarks about the EQ mods were a digression [ and that NEVER happens around here ], but since Andy cherry-picked my post, I responded accordingly.

Mind you, by not disputing anything else from that post, it may also mean that he agreed with the rest of what I stated.

Let me emphasize that both the scope and my ears confirmed that I achieved the desired result by my performing my stated mods (performed about 20 years pre-Internet), and that just because nobody else had commented about how the filters of those amps behaved does not negate that they behaved that way.
~

 

[agedhorse]

Yes, you can decrease the Q by adding series resistance, but that won't help the bands that are too wide.

 

[agedhorse]

True saturation of an output transformer sounds pretty bad (depending a bit on how the global feedback attempts to correct), but the saturation of the output stage itself is typically what's preferred in a power amp.

 

[DavesnothereCA]

Yes, you can decrease the Q by adding series resistance, but that won't help the bands that are too wide.

~
I have been thinking some more about that, but it was some 40 years ago now, eh ?

If I could scare up a skizmatic for an Acoustic 370 or 450/470 series top, I might speculate that THEY had already put a resistor in series or parallel with some of the other bands' inductors (not sure without the diagram though), and if they HAD done this, then I would (both then and now) be able to change the value of that resistor, or remove it entirely to just leave the coil, and could get a narrower Q as a result.

But that is only a theoretical guess ATM.
~

 

[Chucky Stiletti]

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I have been thinking some more about that, but it was some 40 years ago now, eh ?

If I could scare up a skizmatic for an Acoustic 370 or 450/470 series top, I might speculate that THEY had already put a resistor in series or parallel with some of the other bands' inductors (not sure without the diagram though), and if they HAD done this, then I would (both then and now) be able to change the value of that resistor, or remove it entirely to just leave the coil, and could get a narrower Q as a result.

But that is only a theoretical guess ATM.
~

Sure

 

[DavesnothereCA]

True saturation of an output transformer sounds pretty bad (depending a bit on how the global feedback attempts to correct), but the saturation of the output stage itself is typically what's preferred in a power amp.

~
So maybe the push-pull power tubes rather than the O/P transformer ?

That's believable.
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[agedhorse]

~
So maybe the push-pull power tubes rather than the O/P transformer ?

That's believable.
~

This has been much more of a consistent factor than the OT.

 

[Drgonzonm]

~
I have been thinking some more about that, but it was some 40 years ago now, eh ?

If I could scare up a skizmatic for an Acoustic 370 or 450/470 series top, I might speculate that THEY had already put a resistor in series or parallel with some of the other bands' inductors (not sure without the diagram though), and if they HAD done this, then I would (both then and now) be able to change the value of that resistor, or remove it entirely to just leave the coil, and could get a narrower Q as a result.

But that is only a theoretical guess ATM.
~

a schematic for the 470 series is available on line. Look for the service manual

 

[DavesnothereCA]

a schematic for the [Acoustic] 470 series is available on line. Look for the service manual

~
I found one for my 150 top earlier this year, when I needed to perform a repair to it, and it is about the same age, give or take, so prob'y docs for all of those old models should be out there.

Thanks for the nudge.
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[ThisBass]

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Even when solid state instrument amps were first introduced (pre-Internet), the impression which I kept hearing was that at least for LEAD guitar, that the sound of an output transformer saturating was what gave them the sound and sustain which those players preferred, and to which they had become accustomed.

IIRC, this characteristic was mainly due to even-numbered harmonics being re-enforced when such saturation occurred.

The re-inforcement of even order harmonics would give us kinda a harmonizer effect to the sound.

For a distinct gain of the signal at a preamp tube stage it can happen that the 2nd harmonic distortion number is dominant above all of higher order harmonics but, that's only possible if cathode self biasing of the tube stage is odd. This can be caused by distinct schematic sound design goals (especially with electric 6-string preamps) or just even by a wrong type of tube that is out of specs.

 

[Chucky Stiletti]

The re-inforcement of even order harmonics would give us kinda a harmonizer effect to the sound.

For a distinct gain of the signal at a preamp tube stage it can happen that the 2nd harmonic distortion number is dominant above all of higher order harmonics but, that's only possible if cathode self biasing of the tube stage is odd. This can be caused by distinct schematic sound design goals (especially with electric 6-string preamps) or just even by a wrong type of tube that is out of specs.

Y'all mean odd order right?

 

[DavesnothereCA]

Y'all mean odd order, right?

~
Well, the first even-order harmonic is the 2nd harmonic, which is also the octave, and that would qualify as a musical harmony in pretty much all instances.

And the first ODD-order harmonic is the 3rd harmonic, which is also a perfect fifth above that octave, and might qualify as a musical harmony too, at least in passages of single notes.

However, where the odd-order harmonics might begin to sound harsh (musically dissonant) could be when multiple notes are being played (such as in chords or blends), as they may make prominent a 'phantom' note which does not fit the chord.

Since bassists are less likely to be playing chords than other musicians, one might suggest that distortion might not matter as much to us.

But that said, I still prefer my sound to be clean, regardless of whether I play single notes or not, and would rather avoid BOTH orders of harmonic distortion.

And that requires a certain size and grade of amp, whether it be tube OR solid state.
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[BadExample]

However, where the odd-order harmonics might begin to sound harsh (musically dissonant) could be when multiple notes are being played (such as in chords or blends), as they may make prominent a 'phantom' note which does not fit the chord.

Note to self: don't learn cords.

 

[Chucky Stiletti]

~
Well, the first even-order harmonic is the 2nd harmonic, which is also the octave, and that would qualify as a musical harmony in pretty much all instances.

And the first ODD-order harmonic is the 3rd harmonic, which is also a perfect fifth above that octave, and might qualify as a musical harmony too, at least in passages of single notes.

However, where the odd-order harmonics might begin to sound harsh (musically dissonant) could be when multiple notes are being played (such as in chords or blends), as they may make prominent a 'phantom' note which does not fit the chord.

Since bassists are less likely to be playing chords than other musicians, one might suggest that distortion might not matter as much to us.

But that said, I still prefer my sound to be clean, regardless of whether I play single notes or not, and would rather avoid BOTH orders of harmonic distortion.

And that requires a certain size and grade of amp, whether it be tube OR solid state.
~

Thanks for the informative post. I could be wrong but I believe you may have taken this out of context.
When I meant odd order harmonics, I was referring (and I think ThisBass may have been as well) to the make up of a single note and it's harmonic content as analyzed by a Fourier series. The more "square" a signal becomes due to saturation of active devices as they near B+, Vdd or Vcc the more augmented it's odd order harmonic content becomes.

 

[Drgonzonm]

I love the name of this thread. As I research class d amplifiers, I found a post where tubes are being used in class d amplifiers. While I don't see anyone producing, an all tube class D amp, I can see the hype "ALL TUBE CLASS D bass amp", get those tube sounds. I honestly believe this thread is class d vs. ab tube amps

 

[agedhorse]

I love the name of this thread. As I research class d amplifiers, I found a post where tubes are being used in class d amplifiers. While I don't see anyone producing, an all tube class D amp, I can see the hype "ALL TUBE CLASS D bass amp", get those tube sounds. I honestly believe this thread is class d vs. ab tube amps

Much of the initial work with class D (conceptually) was done using tubes.

 

[Drgonzonm]

Much of the initial work with class D (conceptually) was done using tubes.

From what I have found, class d amplification from tubes is the easy part, Keeping the FCC and the ASACP off your back. If my memory serves me correctly, walkie-talkies, with 5 watt output had about a 1/4 mile range. building a quiet 10 watt class D, and not have the FCC knocking on your door every other day, sounds like a challenge.
The more I read, the more I realize, you don't build a class d on a bread board,
Wow, I can only imagine the challenges of meeting the class a and class b radio interference standards
Yeah, I see where some of those engineering challenges make one life difficult. First you build a working amplifier, then the real work begins, making sure, a 100 different standards are met.
I just glad I am a dinosaur.
I thought about going to the local university and study electrical engineering, at $10/class. I can see the senior project, a working class d champ amplifier.
@agedhorse, I got a new appreciation for the work you are doing.

 

[dukeorock]

Just read this entire thread (what is wrong with me?!) then re read the original post. Boy, was that a lot of twists and turns in 24 pages!

The OP said he was pleasantly taken aback after trying an all tube amp. “Should I get an all tube amp?” Yes, you should. Everyone should. At least once. It’s a thing. If ain’t your thing, at least now you know!

“I’m put off by the size and weight.” I guess the sound is either worth it or it ain’t. I don’t always use em either. Upright gigs, for example.

There’s a ton of variety with SS or Tube. Not sure how you could do a ‘vs’ thing in the first place. I try lots of stuff because it’s a blast. No need to get all precious about it!

 

[J-Bassomatic]

Just read this entire thread (what is wrong with me?!) then re read the original post. Boy, was that a lot of twists and turns in 24 pages!

The OP said he was pleasantly taken aback after trying an all tube amp. “Should I get an all tube amp?” Yes, you should. Everyone should. At least once. It’s a thing. If ain’t your thing, at least now you know!

“I’m put off by the size and weight.” I guess the sound is either worth it or it ain’t. I don’t always use em either. Upright gigs, for example.

There’s a ton of variety with SS or Tube. Not sure how you could do a ‘vs’ thing in the first place. I try lots of stuff because it’s a blast. No need to get all precious about it!

This is hitting the nail on the head, thanks DukeORock, get out there and MAKE YOUR NOISE people and whatever it is you end up with is the SOLUTION. You gotta look, you gotta hunt you gotta go for it. Luckily for me the Rumble 500 and 2 210s speak the truth. May your search end up so perfect. (I'd really like an SVT with the 8 10s or the 2 Acoustic 215s that I used to have but there is no sense in pining for the 'OLD DAYS') Because that J Bass and rig is long gone and even though there are 'miracles' posted here every day I do not think I will be in possession of that treasured relic ever again
Now let's move on to more relevant topics, like is there too much garlic in Kim Chee?

 

[Sunset Shalom]

This is hitting the nail on the head, thanks DukeORock, get out there and MAKE YOUR NOISE people and whatever it is you end up with is the SOLUTION. You gotta look, you gotta hunt you gotta go for it. Luckily for me the Rumble 500 and 2 210s speak the truth. May your search end up so perfect. (I'd really like an SVT with the 8 10s or the 2 Acoustic 215s that I used to have but there is no sense in pining for the 'OLD DAYS') Because that J Bass and rig is long gone and even though there are 'miracles' posted here every day I do not think I will be in possession of that treasured relic ever again
Now let's move on to more relevant topics, like is there too much garlic in Kim Chee?

There's such a thing as too much garlic?