If "Tube Sound" Is a Myth, Why Tubes?

[dfuller]

Depends a lot on the circuit. Maybe principally on the circuit.

Have you measured the interelectrode capacitances? I don't have a Tesla E83CC on hand, but I've compared long plate Telefunken ECC83 with some of the very short plate Eastern Europe 12AX7/ECC83 and they weren't very far apart. Cgp is the most critical for common-cathode topologies.

I've not (I don't have an LCR meter that is accurate to the pF range). Like I said, this is all conjecture on my part.

Anyway... I'd agree with you that the circuit matters more than anything else and tube rolling is something of a fool's errand when you're not after the different clipping characteristics.

 

[solderdude]

I'd hazard a guess that barring tolerance for mu, gm etc (i.e. if you have two bogie spec tubes from different manufacturers in the same circuit), most of the differenc in the linear region is the inter-electrode capacitances of the tube , as well as how microphonic the tubes are (and make no mistake, all tubes are microphonic to some degree - part of the advantage of transistors is that they essentially don't have any microphony).

I was just audiophool-joking to get the thread back on track.
I have a whole bunch of tubes lying around (mostly ECC88 type pulls, for to me obvious reasons) and found none of them really had well matching tube halves.
But as SIY already said, whether or not this leads to problems is application dependent. Yes, gains all differ.

 

[PRL]

I have just joined the forum and probably wading in here half-cocked but....

You would think that with decent levels of negative feedback in a valve circuit tube rolling would not make much of a difference but I wonder if the content of the noise generated by the valves has an audible and therefore an emotive affect? High levels of hiss from the tweeters is annoying but when the noise is just perceptible and primarily lower frequency in content it can give that sense of "being there" as its the noise that is often associated with being in an auditorium or recording studio. More of a stimulus from a cue than the actual playback itself. The pictures below are just to give a general idea of the variations in noise generated by valves from sample to sample.

 

[solderdude]

As soon as hearing comes into play things differ.

In the end it's the circuit/implementation that defines the device performance, not just the tube. Many different tubes exist for many different purposes and reasons. Most of them are not simply inerchangeable. Just like there are substantial tolerances between all individual tubes and tube halves.

 

[JazzGene]

A lot of intelligent folks here. As a pro guitarist all my adult life, I have yet come across solid state guitar amps that sound like a tube guitar amp. I wish someone would make one as tube amps are HEAVY!

 

[Wombat]

A lot of intelligent folks here. As a pro guitarist all my adult life, I have yet come across solid state guitar amps that sound like a tube guitar amp. I wish someone would make one as tube amps are HEAVY!

Emulation is getting there. By the way, the audience can't tell the difference.

My take on a Soldano Atomic 16:

Standard basic circuit. High gain. Attention to wiring layout, especially input stage.

Full custom tube effects loop.

This build is as quiet as a mouse on idle.

A good recording Rock amp, maybe. Definitely not HiFi.

'Noise' is usually a design/cost compromise.

 

[JazzGene]

Emulation is getting there. By the way, the audience can't tell the difference.

Lol. My wife tells me all my guitars sound the same.

 

[solderdude]

A lot of intelligent folks here. As a pro guitarist all my adult life, I have yet come across solid state guitar amps that sound like a tube guitar amp. I wish someone would make one as tube amps are HEAVY!

I assume you have tried to use a guitar amp as an hifi-amp at one point in your life.
When you did you will know guitar amps are not suited for HiFi. Horses for coarses
Guitar amps and hifi amps have completely different purposes and are used in completely different ways.
You don't see guitarists using hifi tube amps when playing guitar either.

 

[Wombat]

A lot of intelligent folks here. As a pro guitarist all my adult life, I have yet come across solid state guitar amps that sound like a tube guitar amp. I wish someone would make one as tube amps are HEAVY!

The transformers are heavy.

 

[mhardy6647]

A lot of intelligent folks here. As a pro guitarist all my adult life, I have yet come across solid state guitar amps that sound like a tube guitar amp. I wish someone would make one as tube amps are HEAVY!

Creation of music has a different set of "deliverables" than does reproduction of someone's created music.

 

[JazzGene]

I assume you have tried to use a guitar amp as an hifi-amp at one point in your life.
When you did you will know guitar amps are not suited for HiFi. Horses for coarses
Guitar amps and hifi amps have completely different purposes and are used in completely different ways.
You don't see guitarists using hifi tube amps when playing guitar either.

Actually, some jazz guitarist have used tube monoblocks for guitar. Yes, I realize they have different purposes. My question is if there should be no difference between tube or solid state, I wish someone would make a solid state amp that sounds great for electric guitar.

 

[JazzGene]

The transformers are heavy.

lol, I used to carry a 100 lbs Fender Twin Reverb up 5 flight of stairs up and down every gig in Boston years back. Never again.

 

[solderdude]

Actually, some jazz guitarist have used tube monoblocks for guitar. Yes, I realize they have different purposes. My question is if there should be no difference between tube or solid state, I wish someone would make a solid state amp that sounds great for electric guitar.

These guitarists probably play their amps really loud near the softclipping point.

Guitar amps are purpose made for instruments and are designed to 'colour' the sound and to add richness (the amp sound).
Hifi amps have a totally different goal.
Some SET tube amps also have a different goal to change sound.

This thread isn't about guitar/instrument amps.

As mentioned so many times... tube amps can sound different from SS. Certainly near/at clipping points. It is no myth and certain designs do sound different (on purpose).
A well designed hi-fi tube amp that is driven below its limits probably can not be distinguished in a blind, level matched comparison with a SS amp that also is used below clipping point.

So 'tube sound' depends on the circuit used more so than magic properties tubes are supposed to have.
You can design as good as equal performing amps with SS and tube technology.
One can also design an amp that sounds different on purpose.
Musical instrument amps are not designed with 'hifi rules' as they are designed to differ and add 'house sound'.
Often this house sound is not so tube dependent but more determined by the circuits/components around it.

 

[Wes]

Thermionic Noise Rocks!

Get with the Glow, people!

 

[mhardy6647]

Thermionic Noise Rocks!

Get with the Glow, people!

Dude, I am so there...

DSC_0335 by Mark Hardy, on Flickr

SE84B zoomin by Mark Hardy, on Flickr

 

[DonH56]

By Mark Hardy, on Flickr -- how appropriate.

 

[SIY]

I've not (I don't have an LCR meter that is accurate to the pF range).

Trivia: the best way to measure the capacitance is using a large series resistor to the grid, feeding it a square wave, then measuring rise time using the tube to amplify it. You can then calculate the capacitance from the rise time equation, accounting for the Miller effect. If you're just looking at comparative rather than absolute, you don't even need to do the Miller calculation, just see if the rise times are equal.

 

[PRL]

These guitarists probably play their amps really loud near the softclipping point.

Guitar amps are purpose made for instruments and are designed to 'colour' the sound and to add richness (the amp sound).
Hifi amps have a totally different goal.
Some SET tube amps also have a different goal to change sound.

This thread isn't about guitar/instrument amps.

As mentioned so many times... tube amps can sound different from SS. Certainly near/at clipping points. It is no myth and certain designs do sound different (on purpose).
A well designed hi-fi tube amp that is driven below its limits probably can not be distinguished in a blind, level matched comparison with a SS amp that also is used below clipping point.

So 'tube sound' depends on the circuit used more so than magic properties tubes are supposed to have.
You can design as good as equal performing amps with SS and tube technology.
One can also design an amp that sounds different on purpose.
Musical instrument amps are not designed with 'hifi rules' as they are designed to differ and add 'house sound'.
Often this house sound is not so tube dependent but more determined by the circuits/components around it.

Myself, I’ve struggled to reliably hear differences between well designed amplifiers. I used to have a KT88 PP amplifier a when I compared it to a DIY SS class A/B amp I couldn’t tell the difference. I sold the KT88 amplifier on as I didn’t see the point of the extra expense in usage.

However, I thought that there was a difference to be heard and that was the point of the old Bob Carver TFM chestnut. If there was no difference at all he could have just not bothered altering the transfer function, assuming that the valve amp used for the comparison had an obvious character.

 

[solderdude]

It is a question of design, audibility thresholds, blind & level matched testing to do truthfinding. Most are not interested in truth finding but are more comfortable with their own truth. The one that suits their convictions.
The way of testing is paramount as is training in listening for specific changes.

Of course some designs are purpose made to sound different. Others are not and aim for top notch fidelitly (the least possible modification of the to be amplified signal)

Was it ever disclosed what Bob Carver exactly changed and the reasoning behind it ?

As long as the measured differences reach audible levels (differs from person to person but not hugely) one can hear differences. Much more likely to happen with speaker amps. The fact that all amps in the world all measure differently (even not well cloned designs) doesn't mean they all sound different nor that some amps measure the same but secretly still sound different.

Tubes glow mysteriously and have a great (magic) appeal. It is ensured to create a certain mindset.

 

[d'Brit]

Sometime in the early eighty's I attended a Stereophile hosted Audio show in Los Angeles. The first and only show I've ever attended. After 3-4 hours of going from room to room and finding myself less than impressed with what I was hearing, I walked into the Conrad Johnson room and the effect on me was profound. I immediately felt a great deal of tension leave me, (tension I hadn't even been consciously aware of) and a feeling of relaxation came over me as the tension was released. It was an "AH" moment. It just sounded 'right'. Finances kept me from buying a tube amp until a few years ago. Circumstances interfered with my connecting up my new tube integrated until recently. In fact, it's burning in as I write with about 50-60 hours on it and I'm also simultaneously breaking in some full range alnico drivers in an open baffle "Decware/Caintuck 'Betsy' Baffles". Those full range drivers cover about 80Hz-12kHz but damn does that rig sound good. It compares favorably with a Drop THX AAA 789 - Ether CX headphone rig. Not in transparency but in what to my ears is a clear organic / palpability aspect. It too just sounds 'more right'.