Solid state/class d vs tube amps

[bumble yeti]

I'm almost sure our illustrious engineers have other things to do, like, um… design an OD pedal that sounds like me and AlKraft's favorite amp or, uh, engineer that Eagle… something or other… cab we've been pining for for some time.

 

[BadExample]

+1
AE1, if you'd like to continue, please start your own thread instead of piggybacking on the OP's. I'm sure he had no intention of the direction(s) you've taken his original post. If you look back, you'll notice he hasn't replied in a long time.

If OP is following the thread, I expect he is in his basement now, in a fetal position, gun in mouth.

 

[agedhorse]

The principle I was attempting to simply explain is that as speaker impedance naturally rises SS amplifier power naturally falls. Falling amplifier power, resulting in falling "loudness", is a real world issue for bass.

As I said before, exactly the same thing happens with a tube amp. It is not a real world issue for bass, because the sensitivity tends to rise as the impedance rises so much of the effect cancels out.

 

[bumble yeti]

If OP is following the thread, I expect he is in his basement now, in a fetal position, gun in mouth.

Hopefully not. It ain't worth it, man. It just ain't worth it.

 

[AE1]

+1
AE1, if you'd like to continue, please start your own thread instead of piggybacking on the OP's. I'm sure he had no intention of the direction(s) you've taken his original post. If you look back, you'll notice he hasn't replied in a long time.

This thread is "Solid state/class d vs tube amps"

The original poster told us how amazed he was at the sound of a tube amp

As quick as a flash the very first responder countered that by saying: "I've never played through a tube amp. But if you can try a Mesa Subway, it's about as tubey as you're going to get from a small class D amp."

Subsequent early posts were quite pleasant and well balanced in opinion between the modalities, but since then it has become a battle largely dominated by engineers and dealers promoting Class D and a minority of users supporting tubes - both sides holding firmly entrenched opinions.

History suggests tube amps are becoming a niche market and the mainstream world is progressively change to Class D - lower cost, lower weight and ease of portability win hands down for Class D. It's just technological evolution. History also tells us that in time, Class D will be displaced by something even better.

But does the current generation of Class D amps deliver a better bass sound than tubes ? As many posters have said - "to each his own".

I wonder if the original poster has changed his mind after reading 41 pages of discussion presenting overwhelming endorsement of Class D ?

 

[bumble yeti]

This thread is "Solid state/class d vs tube amps"

The original poster told us how amazed he was at the sound of a tube amp

As quick as a flash the very first responder countered that by saying: "I've never played through a tube amp. But if you can try a Mesa Subway, it's about as tubey as you're going to get from a small class D amp."

Subsequent early posts were quite pleasant and well balanced in opinion between the modalities, but since then it has become a battle largely dominated by engineers and dealers promoting Class D and a minority of users supporting tubes - both sides holding firmly entrenched opinions.

History suggests tube amps are becoming a niche market and the mainstream world is progressively change to Class D - lower cost, lower weight and ease of portability win hands down for Class D. It's just technological evolution. History also tells us that in time, Class D will be displaced by something even better.

But does the current generation of Class D amps deliver a better bass sound than tubes ? As many posters have said - "to each his own".

I wonder if the original poster has changed his mind after reading 41 pages of discussion presenting overwhelming endorsement of Class D ?

la la la… la la-la la… la la la… la la-la laaa

 

[Eddie LeBlanc]

LOL
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because of
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and
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LUV IT

 

[Chucky Stiletti]

Guess we should have left it at, "To each his own...."

 

[Drgonzonm]

Back to the topic of this thread, how prone are class D amps to sag, the 5ype typically found in the 5f6a bassman?

 

[Chucky Stiletti]

Back to the topic of this thread, how prone are class D amps to sag, the 5ype typically found in the 5f6a bassman?

Like with the bassman or any other amp, this would depend on the Z of the power supply. Sag = power supply Z/cost

 

[agedhorse]

It depends on the design of the amp. Class D amps and their supporting circuitry can be designed to do so.

 

[JimmyM]

Back to the topic of this thread, how prone are class D amps to sag, the 5ype typically found in the 5f6a bassman?

I've heard at least a little tiny bit of sag in every micro amp I've ever plugged into, and quite frankly, I think it's why I like them. However, if you DI them into the board, you don't get that sag through the PA since it's just the preamp going into the board.

 

[Drgonzonm]

It depends on the design of the amp. Class D amps and their supporting circuitry can be designed to do so.

Thank you,
I know some of the dave zimmerman designed amps, have this circuitry, I do not know of any more common amps with the circuitry.

I guess my question was too general, I guess my question should have been, Are class D amps inherently prone to sag, like the Fender 5F6a?

 

[agedhorse]

I've heard at least a little tiny bit of sag in every micro amp I've ever plugged into, and quite frankly, I think it's why I like them. However, if you DI them into the board, you don't get that sag through the PA since it's just the preamp going into the board.

In pre mode this is generally true, but in post mode some preamps incorporate circuitry that emulates some of this (to the degree that the designer chooses to fit the target user).

An example of this is the Streamliner, where there's some "sag" type feel. Not overwhelming by any degree though.

Generally, for most (not all) players, a little bit of sag goes a long way.

 

[Drgonzonm]

Thank you,
I know some of the dave zimmerman designed amps, have this circuitry, I do not know of any more common amps with the circuitry.

I guess my question was too general, I guess my question should have been, Are class D amps inherently prone to sag, like the Fender 5F6a?

There is another discussion on this forum, regarding sag, that lists a couple of tube amps that have "sag" control.

 

[BadExample]

Hopefully not. It ain't worth it, man. It just ain't worth it.

In pre mode this is generally true, but in post mode some preamps incorporate circuitry that emulates some of this (to the degree that the designer chooses to fit the target user).

An example of this is the Streamliner, where there's some "sag" type feel. Not overwhelming by any degree though.

Generally, for most (not all) players, a little bit of sag goes a long way.

I feel I am rapidly approaching *that* age.

 

[JimmyM]

In pre mode this is generally true, but in post mode some preamps incorporate circuitry that emulates some of this (to the degree that the designer chooses to fit the target user).

An example of this is the Streamliner, where there's some "sag" type feel. Not overwhelming by any degree though.

Generally, for most (not all) players, a little bit of sag goes a long way.

A legit point that I forgot about. In the ones that I've DI'd to the board, the level of sag seems to be related to how much gain you use, but I see exactly what you're talking about. And you're right... A little bit of sag goes a long way, and I'd much rather have plain old Overdrive when the sag gets to that level where it's too much.

Also, I should add that I just went to Sam Ash, and though I know it's slightly before your time as a designer at Mesa, I just got to play through a strategy for the first time. It was hooked up to a Hartke hydrive 210 so I didn't get the full on Mesa experience, but it's a nice amp. Definitely has that Mesa vibe.

 

[ThisBass]

Please explain how obviously non-linear amplifier power output v load specs are linear

May be I suck on a language barrier and totally miss the point but (honestly) I have got no idea about the meaning of a "non-linear amplifier power output".

Please explain how inversely proportional amplifier and speaker impedance characteristics become linear when connected together by a two core cable

Global feedback loop design helps to keep amplifier output impedance (very) small within headroom (power) limits.
SS amplifier are "superior" versus tube amplifiers cause SS output impedance is too small to have noticeable interaction with the impedance curve of a cabinet.
That's totally different with tube amplifiers cause "soundwise" tube amplifiers tend to act as current source which interacts "soundwise" with the impedance curve of a cab. Its not unausal to get a noticeable hump at the lowish side of the response where the cab shows a impedance peak, while you won't get similar sound response "artifacts" with "typical generic" SS amplifiers.

Please post a typical frequency response graph showing what actually happens in the real world of live performance. Professional PA operators, recording studios and live TV shows often use microphones stationed in front of the bass speakers, so perhaps one of you might have a suitable graph available to post

Microphones show different response at the lowish side of the spectrum depending on near field versus far field position of the microphone.
The effect is caused by different phase angle relationship of sound particle velocity versus sound pressure which differs with both distance to the source and wavelength.
In practice its the reason WHY the Sure SM57 shows way better performance in practice than the manufacturer published respone reads on paper.
Many (pro) manufacturer show response graphs for far field and near field microphone positioning.

Please post verifiable details of an affordable commercial portable amplifier/speaker/cabinet set suitable for bass players which does not suffer LF rolloff in the bass instrument range

I'd start to ask the player for his lowest tuning and his music genre and his sound goals.
Its not so bad to design for 2nd Harmonic at the lowish side of the spectrum to make a player feel happy so far.
IMO/IME not every player was satisfied with the lowest roll off possible.
Some players prefer sealed cabs while others prefer coloring of EVM drivers while others feel happy with a lowish roll off etc etc

If a bass player wants solid bass down into the LF range, what specs should he look for when looking for a new amp and speaker set ?

What kind of LF range do you mean? Do you mean the LF range for the 2nd Harmonic or do you mean the LF range for the 1st Harmonic?
Both considerations address totally different sound goals. While its possible to design for flat response of the 2nd Harmonic E1 or B0 there is reasonably no way to design cabinet flat response for 1st Harmonic B0 or F#0.
Similar consideration is for tube amplifiers while at the other hand lots of SS amplifiers can easily amplify down to "flat" 20Hz unless there is no HPF implementation.

Is it possible to select a best fit amp and speaker set by specification or description rather than a listening test ?

No,
If you read all of my words CAREFULLY you may understand that a tube head that powers a ported cab f3 60Hz will be (very likely) perceived (soundwise) as "more of bass" than a SS amp that powers a cab with f3 50Hz.

That's Talking Bass.

That's only me. BTW I don't feel need to prove myself beyond my limits via internet.

 

[AE1]

While I found it a tad confusing to follow that lengthy post where AE1 covered all those basic electrical equations relative to explaining amplifier and speaker relationships and performance, what did jump out at me was how basic equations for electricity don't come close to adequately explaining/reflecting what's actually happening in that dynamic interactive environment. In so many areas (including mechanical and aerodynamic) where you find interactive components and varying operating states creating different driving functions throughout an operational realm, our more basic equations/relationships are simply inadequate.

Right on Al.

You can't make "sound" without the amplifier and speaker both working together in a closed system - as I keep trying to explain to a disbelieving audience

The two components of the system are not independent but interactive - if you remove one or the other from the system there is no sound

If you run an amplifier into a resistive test load the amplifier may deliver a dazzling linear power output across the full frequency range with flat frequency response and extremely low distortion - but no sound.

You can hook a speaker up to a pair of wires connected to an amplifier but if the amplifier is not delivering power to it then there will also be no sound

Hard to believe but it's true

But when you hook up a speaker to an amplifier the load becomes non-linear - because the load impedance changes with frequency - so the power gain of the amplifier becomes non-linear and the system becomes non-linear. The whole ball game changes.

What we hear is not the amplifier or the speaker but product of the system.

Here is an independent paper on the subject of MI amplifier/loudspeaker systems -

Link Removed

There is a reason why modelling and simulation is so valuable and requires so much computing power.

Modelling and simulation only work if the cause/effect relationships and their interactive supporting parameters and elements are well understood

How can the software be written if those are not already known ?

How many software developers have that level of understanding and experience ?

From where do they source their design data ?

Until all is known it remains a "best fit" or "best guess" option for us bass players - it is we who take the risk when buying and matching amplifiers and speakers and use them in good faith.

All we have to work with is manufacturer ratings, user manuals, salesperson advice and anecdotal hearsay evidence

So the more we can learn about their interactive relationships the better and more satisfying our musical experience will be

 

[agedhorse]

That paper is an "old man rant" recalling the good 'old days that were never as good as remembered. I lived and worked those good 'old days and there's no way I would ever go back. The sound quality of today's line arrays (and speakers in general) are so much better than they ever were. To claim otherwise is beyond absurd based on having used both over a 50 year career both as a pro touring user and as a designer.

A properly designed solid state high NFB amp produces a signal with a frequency response that is independent of the amp. The dependency is based almost 100% on the speaker itself. Substituting 1 amp for another doesn't change the frequency response.

Lower FB tube amps do produce more interaction, which is where the modeling is typically focused on. Especially in guitar and bass amps where there is emphasis placed on overdriven operation.