Tube amp bass vs. SS amp bass? Anyone experience Tube Amp bass to be better?

[morricab]

You might be thinking global feedback. It's a bit more complicated, but without feedback basically you either get 0 gain or the open loop gain will go wild and not be possible to use with music.

Well... but... in classD it's possible to have none.

The gain of tubes is not too high to be feedback free...

 

[lscangus]

The gain of tubes is not too high to be feedback free...

A tube amp with feedback does sound more like a typical SS amp. One point which hasn't been mentioned is the output transformer of the tube amplifier, transformer tends not to work so well in lower frequency.

 

[morricab]

A tube amp with feedback does sound more like a typical SS amp. One point which hasn't been mentioned is the output transformer of the tube amplifier, transformer tends not to work so well in lower frequency.

Depends on the size of the transformer core, its core geometry and winding design....They can work very well at low frequencies when done correctly...most companies skimp on the transformer because of it's cost.

 

[Blackmorec]

My friend had an all-tube Balanced Audio Technology set-up with VK75 amp, playing into some big Tannoys.
I had a similar Balanced Audio set-up but instead of the VK-75 I had VK-1000 SS monoblocs playing into a pair of Sonus Faber Extremas.

I don’t remember either set-up lacking anything in the bass. What the VK-75 lacked in absolute drive it made up for in speaker efficiency. Bass extension was never an issue. We had certain recording; Flight of the Cosmic Hippo or Michel Jonasz’s Le Fabuleuse Histoire de Mr. Swing that would give you that trouser flapping (not the Extremas quite), chest thumping bass and in my opinion, neither amplifier was found lacking in this regard.

Of course with any comment about amplifiers, there has to be a qualifier....’with properly matching speakers”. It really is only sensible to consider the pairing when looking at any amplifier characteristics, because as we all know, there are no amps that match all speakers, but there are some pairings that are absolutely made in heaven.

 

[morricab]

My friend had an all-tube Balanced Audio Technology set-up with VK75 amp, playing into some big Tannoys.
I had a similar Balanced Audio set-up but instead of the VK-75 I had VK-1000 SS monoblocs playing into a pair of Sonus Faber Extremas.

I don’t remember either set-up lacking anything in the bass. What the VK-75 lacked in absolute drive it made up for in speaker efficiency. Bass extension was never an issue. We had certain recording; Flight of the Cosmic Hippo or Michel Jonasz’s Le Fabuleuse Histoire de Mr. Swing that would give you that trouser flapping (not the Extremas quite), chest thumping bass and in my opinion, neither amplifier was found lacking in this regard.

Of course with any comment about amplifiers, there has to be a qualifier....’with properly matching speakers”. It really is only sensible to consider the pairing when looking at any amplifier characteristics, because as we all know, there are no amps that match all speakers, but there are some pairings that are absolutely made in heaven.

Well, the BAT VK 60 was not very linear in the bass as can be easily seen in Stereophile's measurements of the amplifier. The THD vs. frequency measurement shows clearly the output transformer is saturating. My guess is that the VK75 is similiar to this becuase the comments from the reviewer noted that they are quite similar sounding. There are better examples of tube amps with regard to bass than the BAT VK series...

 

[Blackmorec]

Well, the BAT VK 60 was not very linear in the bass as can be easily seen in Stereophile's measurements of the amplifier. The THD vs. frequency measurement shows clearly the output transformer is saturating. My guess is that the VK75 is similiar to this becuase the comments from the reviewer noted that they are quite similar sounding. There are better examples of tube amps with regard to bass than the BAT VK series...

I take your point; however I’m betting that ninety nine point several nines percent of the population would be utterly thrilled by the bass it produced. I’m also guessing that room and speaker non-linearities would be a lot, lot more detremental. There may well be better examples of tube amps with regard to bass, however it did a pretty nice job of reproducing the entire audio spectrum, with a surprising amount of bass slam for what is only a 60W amplifier. Personally I don’t actually remember reading a negative review of the amp but then my memory used to be better when not so much time had passed.

 

[morricab]

I take your point; however I’m betting that ninety nine point several nines percent of the population would be utterly thrilled by the bass it produced. I’m also guessing that room and speaker non-linearities would be a lot, lot more detremental. There may well be better examples of tube amps with regard to bass, however it did a pretty nice job of reproducing the entire audio spectrum, with a surprising amount of bass slam for what is only a 60W amplifier. Personally I don’t actually remember reading a negative review of the amp but then my memory used to be better when not so much time had passed.

The VK60 is a good amp...just not ideal to demonstrate bass capabilities of tube amps, IMO. The 6C33C is a good output tube to make music with, I have owned a few amps with this output tube...but either SET or OTL...the VK60 is neither.

 

[Blackmorec]

The VK60 is a good amp...just not ideal to demonstrate bass capabilities of tube amps, IMO. The 6C33C is a good output tube to make music with, I have owned a few amps with this output tube...but either SET or OTL...the VK60 is neither.

I was curious about the Stereophile test so I had a look and now I remember. They raised a few measurement anomalies as you mentioned, but then they wrote, “The bass from the VK-60 was actually quite impressive, deep and well controlled, with just a bit of added warmth. A far cry from the warm-and-woolly bass that characterises so many tube amps”
Anyway, be that as it may, the point I was making was that my friend had a relatively puny 60w tube amp and I had 500W of solid state brawn and neither of us were unhappy with our bass performance nor had any cause to be....mainly because speaker matching was optimum for both amps.

 

[Atmasphere]

You might be thinking global feedback. It's a bit more complicated, but without feedback basically you either get 0 gain or the open loop gain will go wild and not be possible to use with music.

Well... but... in classD it's possible to have none.

We run zero feedback in our preamps and some of our amps. The preamps have a fair bit of gain- they have to, working with a low output moving coil cartridge. When feedback is applied, gain is reduced. If there is no feedback that's when you have the most gain.

In an opamp, if there is no feedback then the circuit won't be linear.

 

[Folsom]

Uhuh. I'll believe truly 0 when I see the schematic. I haven't seen one yet. There's lots of designs with as little as possible, but absolutely zero I've only seen when the gain is done by transformers or classD.

 

[Atmasphere]

Uhuh. I'll believe truly 0 when I see the schematic. I haven't seen one yet. There's lots of designs with as little as possible, but absolutely zero I've only seen when the gain is done by transformers or classD.

Our circuits are fully differential, so there's no cathode resistor to create degenerative feedback. So if there is no degenerative feedback and no loop feedback, is there no feedback?

 

[lscangus]

Depends on the size of the transformer core, its core geometry and winding design....They can work very well at low frequencies when done correctly...most companies skimp on the transformer because of it's cost.

I am no expert in output transformer design, but I would think it is no easy task to design a wide band output transformer which is as efficient at 20hz and 20khz.

 

[Folsom]

Our circuits are fully differential, so there's no cathode resistor to create degenerative feedback. So if there is no degenerative feedback and no loop feedback, is there no feedback?

I'm not making a call without seeing a schematic.

 

[morricab]

I am no expert in output transformer design, but I would think it is no easy task to design a wide band output transformer which is as efficient at 20hz and 20khz.

True and it's expensive.

 

[Atmasphere]

I'm not making a call without seeing a schematic.

That seems wise. But just for the record, the preamps and amps I just described are in fact zero feedback. Our two smaller amps employ a small amount of loop feedback but our larger amps do not.

 

[assessor43]

I have an MC275 amplifier. My speakers are 8 ohm speakers yet my speakers sound better and amplifier sounds in many ways better through my amps 4 ohm taps than the 8 ohm. Why?

 

[Empirical Audio]

I sold my highly modified 1000W/side JC-1 monoblocks when I purchased and modded my Arte-Forma 805A/T SET monoblocks. No comparison in the bass or anything else. Tighter bass with 35W SET than the 1000W modded SS monoblocks. I still offer the JC-1 mods BTW.

I have heard the D'Agostino monoblocks at shows and they are one of my favorite SS amps, but I think with my speakers, the SET amps will kick their butt.

Steve N.

 

[Empirical Audio]

I have an MC275 amplifier. My speakers are 8 ohm speakers yet my speakers sound better and amplifier sounds in many ways better through my amps 4 ohm taps than the 8 ohm. Why?

That is an expected result. The 4 ohm taps are lower impedance, so the amp is able to drive the speakers with a flatter frequency response. The lower the amp output impedance is, the response of the whole system is improved.

Nothing is free however. There are other aspects of the sound quality that may suffer as you drive the output transistors or tubes harder. You be the judge by listening to which is best, 8 ohms or 4 ohms.

If you look at any Stereophile review of a power amplifier, JA's measurements will show the frequency response plot into a simulated speaker load. The lower the amps output impedance is, the flatter this plot becomes.

Steve N.

 

[Atmasphere]

I have an MC275 amplifier. My speakers are 8 ohm speakers yet my speakers sound better and amplifier sounds in many ways better through my amps 4 ohm taps than the 8 ohm. Why?

Many speakers are listed as '8 ohm compatible' when what is happening is that the woofer array is really more like 4 ohms with only the mids and highs being 8 ohms or so. If your speaker has dual woofers this is pretty likely. So then the 4 ohm tap would be correct.