Do tubes produce less bass?

[gagelle]

This might sound like kind of a stupid question but the reason I ask is that a well respected member has something like, "for clarity, tubes, for bass solid state" at the bottom of his posts. I'm just paraphrasing, so I apologize in advance if I didn't get the quote right. I'm still toying with the idea of tubes.

[Danzo]

Woofers are quite harder to drive than tweeters or midrange and require substantially more power. Their impendance can dip quite low.

To get best of both, some biamp with tubes running highs/mids and solid state - lows. Higher power (150w-200w or so) tube gear tends to be rather expensive.

[pzannucci]

One of the key things with bass is high dampening factor. Most tube amps don't have it.

As far as tubes being clean, many believe that they are not as clean as solid state though our ears like the distortions of the tubes. Most amps like SETs measure poorly.

[T.H.E. Droid]

The problem is the question. Do you really want to ask if a tube amplifier with a certain power rating has the same bass as a solid state amp of the same power rating? The answer should be yes, of course. The misconception about tubes probably comes from the fact the tube amplifiers generally have lower output ratings than solid state. It's not unusual to find SS amps with output ratings in the 200w/chan range, but that would be an unusual tube amplifier. And often, many of the best tube amps are class A designs, which generally put out under 10 watts. Even then, a 10 watt class A tube design should have about the same bass capabilities as a 10 watt solid state amp.

As for damping factor, that has more effect on the quality of the bass than the volume of the bass. SS amps typically have much higher damping factor than tube designs and can thus have more bass accuracy. And since bass content often includes some very high energy transients, having a higher power amplifier can make the difference in accuracy. My vintage Scott LK48 integrated amp has been relegated to a secondary system with small bookshelf speakers because it doesn't have the power for my main system, and yes, the symptom of not having enough power is degraded bass response at higher volumes. It simply "wimps out" in a way that I can easily hear.

Bottom line is that you need enough power to handle your normal listening levels and the speakers you are driving. Someone with Khorns can get by with a lot less power than someone with much less efficient loudspeakers. If you're considering spending some money on tube equipment, I urge you to get something that you can return if you don't like the way it sounds with your equipment. Given that so many tube designs are hand built, they can get quite expensive on a per-watt basis, so you want to make sure you will get what you expect.

[Guest " "]

A tube amp can be and have been designed to reproduce bass just as well as an SS amp. Some considerations. Most tube gear in circulation of a vintage flavor are console or console related technology which were used to drive speakers in consoles that were pegboard backed for the most part. Music had very little low end and these systems were very musical. Modern tube amps have higher current power supplies and can drive bass drivers pretty well. These amps have large high inductance transformers, large power caps, and multi paralleled output tubes. While these elaborate tube amps can reproduce bass pretty well, the tube ambience is less present in low end bass which allows for the use of SS amps to drive low end drivers for both adequately of sound as well as conservation of power tubes. Reproducing bass puts higher wear and tear on power tubes. The attached pic is of a 250W 10 tube power amp. Caps are the size of coke cans. I have 5 of these units. 3 came out of electric lady studios in NYC and were used in studio A, B, and C to play back tracks before pressing to vinyl for a lot of major recording artist.

[MikeFord]

Certainly less bass per dollar with tubes.

At this point in technology I don't think I would even consider anything but a solid state class D switching type amp for bass. They are cheap, efficient, and do a fine job with bass.

[Colin]

The only stupid question is “does this make me look fat?” If you have to ask…

Woofers impedance IS hard to drive. Plus, bass notes require a lot of energy. Tubes do have power though. In fact, they produce about five times more voltage than their rated wattage compared to solid-state amplifiers.

Therefore, a 30-watt tube amp can compete a 150-watt solid-state amp…in mid and upper range sound QUALITY. Especially on Big Ole Horns. But not the low bass. Even on Big Ole Horns.

One of the very best tube amps for bass that I heard driving Big Ole Horns was NOSvalves’ VRDs. I remember Quads being good. And the $6K Deltas (http://www.enjoythemusic.com/magazine/equipment/0306/delta_studio_6s33s.htm) were warm and a bit boomy, but nice in a lush way.

Much of the measured Total Harmonic Distortion (THD) of tube amplifiers is actually good – it is natural distortion our super-computer brains likes to hear from musical instruments.

The reason THD is so important for a solid-state amplifier is because much of it’s THD is NOT the type of distortion we like to hear. Tube amplifiers, including Single Ended Triodes (SETS), only measure poorly when using solid-state style measurements, such as THD and square-waves.

The problem is indeed the question. Does a tube amplifier of ANY wattage rating have the same measured bass response as ANY solid-state amplifier? The answer is no.

For the dozen or so amplifiers that I auditioned for EnjoyTheMusic.com with my Big Ole Horns even little, inexpensive class T chip amplifiers can do a good job with bass control compared with most modest price tube amplifiers. I am no electrical engineer, but in my experience, a 10-watt class A tube amplifier does NOT have the same bass capabilities as a 10-watt solid-state amplifier.

I don’t think it is wattage rating, because you can hear the difference between the two amplifiers at moderate SPL in typical size rooms. I think it is the damping factor. What actually shapes the bass frequency response (FR)? Is it the amplifier or is it the woofer impedance? Studies show that with a tube amplifier, the deep bass FR looks more like a combination of the woofer impedance and the signal, meaning the tube amplifier allows the woofer impedance to effect the bass FR.

Refurbished, vintage integrated tube amplifiers may be the best bargain in purist audio, second only to Big Ole Horns. I have heard a few on Big Ole Horns. Just about the best compliment anybody can say about any audio component is their sound is wonderfully musical. Tubes are. Wonderfully musical. Big Ole Horns too. Perhaps as honky, sharp and edgy as hell, but I love the combination. Sounds like music.

My 2A3 Bottlehead Paramours’ maximum output is a mere 6-watts (before distortion goes through the roof.) They drive my Khorns as loud as the ear can stand the pain – I know I measured. Yet even big Khorn bass bins can benefit by the deep and powerful push of class D amplifiers in powerful sub-woofers to provide the deepest bass for both movies and music.

I have not yet heard a tube amplifier “designed to reproduce bass just as well as an SS amp.” In that case, I would like to see tube amplifier wattage double as speaker impedance rating goes down, for example, 6-watts into 8-ohms, 12 into 4, even 24-watts into 2-ohms. When I see that kind of rating in a solid-state amplifier, I hear great woofer control.

I have never heard that “reproducing bass puts higher wear and tear on power tubes.” I don’t doubt it. If the amplifier is working harder, because bass notes require so much more energy than the rest of the frequency spectrum, it should be true. (The notes below 100-Hz require something like 40% of an amplifier’s energy.)

Yet I have never heard it before.

Huge caps make a difference in tube amplifiers. I only heard Manley Stingray (on cones) once. Trying to line up review now. It was startlingly musical.

[seti]

This is one of my favorite topics that Experience Music tackles.

http://hifiheroin.blogspot.com/2011/03/optimal-source-impedance.html

Optimal Source Impedance....

For
years now I have tried to explain (preach? scream?) that tube
amplifiers do not have "slow" or "flabby" bass. This common
misconception originated when solid state amplifiers came onto the
market and the speakers boxes began to be tuned to the lower output
impedance of the new amplifiers. If a box is optimally tuned for a
solid state amplifier's one ohm source impedance, then it will be
severely under-damped (woolly, slow, flabby, etc) with a zero feedback
tube amp of a few ohms output impedance.

But what happens in
the upper regions? Do compression drivers need to be driven from an
optimum source impedance or is lower always better? After all, lower
output impedance means a higher damping factor. We have all been told
that damping factor must be as high as possible. Well, I am saying that
just is not true... please prove me wrong! I was measuring anyway, so I
took these plots:

Impedance plot of a JBL 2435 on LC600 horn:



I
know that the mighty Bell Labs actually specified a driving impedance
for their Fletcher system. It basically was the root mean square of the
peak and valley of the impedance plot. They published that this
driving impedance was required to meet their frequency response
specification. We do not quite meet that formula here, but look at the
difference in the region from 1kc to 2kc when the driver is driven
directly, through a four ohm resistor, and through a twenty ohm
resistor.... and this region from 1kc to 2kc is precisely where the
speaker impedance peaks, dips, peaks... driving impedance will change
frequency response.. that we already knew...

Frequency response
plot of JBL 2435 on LC600 horn - ignore everything above 10kHz, new
computer and mic calibration has not been corrected.. sorry...



This
is a tight zoom on an impulse response of the JBL2435 driven directly
from a solid state amp, through a four ohm resistor, and through a 20
ohm resistor... I did not move the speaker for any of these tests...
just clipped in a resistor on the amplifier end...



oh... I know... I should run a square wave through there... I wonder if my measurement gear is up to it... stay tuned!

Peace,
Me

Posted by
Jeffrey W. Jackson

Excerpt from this post http://hifiheroin.blogspot.com/2010/03/whoever-heard-of-304th.html

When I swapped out the 304tl for the 304th, I upped the output impedance
of the amplifier. The amplifier and speaker form a system. There is
an optimal value of output impedance for critical damping. A higher
output impedance than required for critical results in overly full,
slow, sloppy bass - underdamped. A lower output impedance than required
for critical results in overdamped speakers - fast, controlled, but
thin and unnatural. ...and here is my issue - speakers designed for tube
amps should be used with tube amps. However, when solid state came
along, output impedance dropped dramatically. Speaker designers had no
choice but to accommodate the new amplifiers as they were 99% of the
market. When you use a tube amplifier with a high output impedance on a
speaker designed for low output impedance transistors, of course it has
"flabby" bass... this is no reflection on the amplifier(or speakers), but a
reflection on the mating!

[seti]

This is one of my favorite topics tackled by Experience Music. Here are a couple excerpts from their site.

http://hifiheroin.blogspot.com/2011/03/optimal-source-impedance.html

Optimal Source Impedance....

For
years now I have tried to explain (preach? scream?) that tube
amplifiers do not have "slow" or "flabby" bass. This common
misconception originated when solid state amplifiers came onto the
market and the speakers boxes began to be tuned to the lower output
impedance of the new amplifiers. If a box is optimally tuned for a
solid state amplifier's one ohm source impedance, then it will be
severely under-damped (woolly, slow, flabby, etc) with a zero feedback
tube amp of a few ohms output impedance.

But what happens in
the upper regions? Do compression drivers need to be driven from an
optimum source impedance or is lower always better? After all, lower
output impedance means a higher damping factor. We have all been told
that damping factor must be as high as possible. Well, I am saying that
just is not true... please prove me wrong! I was measuring anyway, so I
took these plots

http://hifiheroin.blogspot.com/2010/03/whoever-heard-of-304th.html

When I swapped out the 304tl for the 304th, I upped the output impedance
of the amplifier. The amplifier and speaker form a system. There is
an optimal value of output impedance for critical damping. A higher
output impedance than required for critical results in overly full,
slow, sloppy bass - underdamped. A lower output impedance than required
for critical results in overdamped speakers - fast, controlled, but
thin and unnatural. ...and here is my issue - speakers designed for tube
amps should be used with tube amps. However, when solid state came
along, output impedance dropped dramatically. Speaker designers had no
choice but to accommodate the new amplifiers as they were 99% of the
market. When you use a tube amplifier with a high output impedance on a
speaker designed for low output impedance transistors, of course it has
"flabby" bass... this is no reflection on the amplifier, but a
reflection on the mating!

[gagelle]

Thanks to everyone for your feedback. I know what you're talking about. I have an old Sansui 881 that needs to be refirbushed. The unit has bass that is overbearing, sloppy and unnatural. I have the same receiver that has been restored and the sound is much more natural. There's bass, but it's clear and defind and doesn't overwhelm the highs. I like the natural sound. My son likes the boomy bass. I took the first 881 out because I was afraid that the old caps would cause a catastrophic failure and blow my expensive Klipsch speakers.

There is a record store in town and the owner uses an old Sansui 9090DB with failing bulbs on big KLH speakers. He refuses to restore the receiver. The bass is so powerful that the room shakes. I guess he thinks it helps him sell records but to my hearing, it sounds terrible. I want accurate reproduction.

[JJkizak]

In 1985 when I switched from a tubed Fisher to a solid state Denon of the same power rating (55 watts) the Denon bass was far superior in every aspect. At very high volumes the Fisher would get very mushy while the Denon would still be tight. No contest. In 2004 when I added a Denon 7.1 the bass was reduced in volume even though the new 7.1 was rated at 110 watts per channel. I had to slave the old Denon to the new Denon to get the power back in the bass. The first old Denon was wasted by lightning.

JJK

[T.H.E. Droid]

Woofers impedance IS hard to drive. Plus, bass notes require a lot of energy. Tubes do have power though. In fact, they produce about five times more voltage than their rated wattage compared to solid-state amplifiers.

Since Watts = volts X amps, then they must produce 1/5th the current in the case you mention. Unfortunately, most loudspeaker drivers are current machines (coils) so drive current is much more important than drive voltage. Couple that with low damping factors, tube equipment is a recipe for inaccurate, underdamped bass.

[seti]

Since Watts = volts X amps, then they must produce 1/5th the current in the case you mention. Unfortunately, most loudspeaker drivers are current machines (coils) so drive current is much more important than drive voltage. Couple that with low damping factors, tube equipment is a recipe for inaccurate, underdamped bass.

That is a generalization and is not the case with all tube amps. It is all in the design criteria of the builder.

[IB Slammin]

The only stupid question is “does this make me look fat?” If you have to ask…

Woofers impedance IS hard to drive. Plus, bass notes require a lot of energy. Tubes do have power though. In fact, they produce about five times more voltage than their rated wattage compared to solid-state amplifiers.

Therefore, a 30-watt tube amp can compete a 150-watt solid-state amp…in mid and upper range sound QUALITY. Especially on Big Ole Horns. But not the low bass. Even on Big Ole Horns. One of the very best tube amps for bass that I heard driving Big Ole Horns was NOSvalves’ VRDs. I remember Quads being good. And the $6K Deltas (http://www.enjoythemusic.com/magazine/equipment/0306/delta_studio_6s33s.htm) were warm and a bit boomy, but nice in a lush way. Much of the measured Total Harmonic Distortion (THD) of tube amplifiers is actually good – it is natural distortion our super-computer brains likes to hear from musical instruments.

The reason THD is so important for a solid-state amplifier is because much of it’s THD is NOT the type of distortion we like to hear. Tube amplifiers, including Single Ended Triodes (SETS), only measure poorly when using solid-state style measurements, such as THD and square-waves. The problem is indeed the question. Does a tube amplifier of ANY wattage rating have the same measured bass response as ANY solid-state amplifier? The answer is no. For the dozen or so amplifiers that I auditioned for EnjoyTheMusic.com with my Big Ole Horns even little, inexpensive class T chip amplifiers can do a good job with bass control compared with most modest price tube amplifiers. I am no electrical engineer, but in my experience, a 10-watt class A tube amplifier does NOT have the same bass capabilities as a 10-watt solid-state amplifier. I don’t think it is wattage rating, because you can hear the difference between the two amplifiers at moderate SPL in typical size rooms. I think it is the damping factor. What actually shapes the bass frequency response (FR)? Is it the amplifier or is it the woofer impedance? Studies show that with a tube amplifier, the deep bass FR looks more like a combination of the woofer impedance and the signal, meaning the tube amplifier allows the woofer impedance to effect the bass FR.

Refurbished, vintage integrated tube amplifiers may be the best bargain in purist audio, second only to Big Ole Horns. I have heard a few on Big Ole Horns. Just about the best compliment anybody can say about any audio component is their sound is wonderfully musical. Tubes are. Wonderfully musical. Big Ole Horns too. Perhaps as honky, sharp and edgy as hell, but I love the combination. Sounds like music. My 2A3 Bottlehead Paramours’ maximum output is a mere 6-watts (before distortion goes through the roof.) They drive my Khorns as loud as the ear can stand the pain – I know I measured. Yet even big Khorn bass bins can benefit by the deep and powerful push of class D amplifiers in powerful sub-woofers to provide the deepest bass for both movies and music. I have not yet heard a tube amplifier “designed to reproduce bass just as well as an SS amp.” In that case, I would like to see tube amplifier wattage double as speaker impedance rating goes down, for example, 6-watts into 8-ohms, 12 into 4, even 24-watts into 2-ohms. When I see that kind of rating in a solid-state amplifier, I hear great woofer control. I have never heard that “reproducing bass puts higher wear and tear on power tubes.” I don’t doubt it. If the amplifier is working harder, because bass notes require so much more energy than the rest of the frequency spectrum, it should be true. (The notes below 100-Hz require something like 40% of an amplifier’s energy.)

Yet I have never heard it before. Huge caps make a difference in tube amplifiers. I only heard Manley Stingray (on cones) once. Trying to line up review now. It was startlingly musical.

Colin you have a PM.

tc

[MikeFord]

Since Watts = volts X amps, then they must produce 1/5th the current in the case you mention. Unfortunately, most loudspeaker drivers are current machines (coils) so drive current is much more important than drive voltage. Couple that with low damping factors, tube equipment is a recipe for inaccurate, underdamped bass.

That is a generalization and is not the case with all tube amps. It is all in the design criteria of the builder.

Seems like you have been mislead, or misinterpreted some sales literature, in all cases watts = volts x current.

Tubes vary, but the workhorse power tube used in many many designs is the 6L6GC, which has an operating voltage of 450 volts and current max of 0.045 amps. Not very practical for a 8 ohm speaker, so typically a transformer is used to "step down" the voltage by about a factor of 30:1 so the speaker sees 15 volts and 1.3 amps. (Actual numbers are much less due to various losses).

Some people like the sound of clipping with tubes, where peaks in the signal are chopped off, but not flat making square waves like a solid state amp with lots of even order harmonic distortion, tubes chop the peaks off in I think more a saw tooth shape with odd order harmonics that are more acceptable to the ear. A 100 watt amp is still a 100 watt amp, but with music that has an average level of 7 watts and peak level at 100 watts, some may be happy setting the gain higher so average level is 14 watts and peak signals have the top half chopped off (still limited to 100 watts, but may seem louder from the distortion, Hey I just invented Bose Acoustimax or whatever).

[Marvel]

The attached pic is of a 250W 10 tube power amp. Caps are the size of coke cans. I have 5 of these units. 3 came out of electric lady studios in NYC and were used in studio A, B, and C to play back tracks before pressing to vinyl for a lot of major recording artist.

Nice amps. Manley makes some really nice gear... expensive, but nice.

Bruce

[T.H.E. Droid]

That is a generalization and is not the case with all tube amps. It is all in the design criteria of the builder.

I will agree with you that the latter part of my argument is somewhat general, but no tube amplifier designer can violate the laws of physics and get away with it. That happens in the marketing department.

[Arash]

I have a 50wpc Raysonic tube gear and the bass is so tight and kicking even using LS... needless to say about CWs

[mike stehr]

I have a 50wpc Raysonic tube gear and the bass is so tight and kicking even using LS... needless to say about CWs

With LaScala's in a small room, I recall having reasonable bass reproduction using 800 milliwatts per side from a 71A triode. The driver circuit for the 71A was a 6SL7 in SRPP, using James output transformers. 5 volt DC heating for the filaments...

The sound was not much unlike a 45 SET...But at 800 milliwatts, there just wasn't much of it. It made one appreciate the higher wattage of a 2A3.

But I would easily guess that 500 pounds of breadboarding gear using Eimac transmitting triodes, will net a strong powerful bass response compared to a solid state amp of moderate high wattage...It all boils down to a preference thing...

[gagelle]

I never thought my question would produce a debate like this. Someone on the forum has a unique amp. It's hand made in the US, completely class A, with expensive high voltage transistors and it supposedly sounds very much like a tube amp. I lost the link, but there's a waiting list for their gear. I can't afford those amps but they look very nice. I may be able to dig up the link.