[theScribe]

Hi guys, I was just chatting with my favorite electrical engineer friend (if you read him from an earlier post) and again he is skeptical that a power tube will change the sound signature.

I notice a change myself, but he said that a power tube is only suppose to amplify the sound and not chance the sonics itself. I recently installed a RCA 6AS7G to replace a sino tube.

Is anyone familiar with tube technology? How and why does the power tube change the sound signature? I am curious to know the physics of it.

-JC

 

[moonboy403]

I can't answer your question, but what makes him think that all power tubes sound the same?

Does he have any experience in tubes?

 

[olblueyez]

He is full of it.

 

[Toby M]

I have an engineer friend who similarly assures me op-amps make no difference to sound. Lets hope he and your friend stick to designing bridges and remote control toys.

 

[joewatch]

I don't get it. Every electrical engineer knows that op-amps and tubes introduce distortion, and frequency response is never completely flat. Also, tubes and op-amps have difference in their design and production that affects their characteristics.

 

[Uncle Erik]

Here's some tube curves for a 6SN7.

As you can see, tubes aren't perfectly linear. They vary by model, brand and even from tube to tube. Further, the curves change slightly over time. If you have the proper equipment, you can measure these curves yourself.

The curves lend a particular signature to any tube. Also, you'll notice that the curves change depending on how the amp is designed to run. Or that the same tube will sound different in different amps.

Nothing is perfectly linear, ever. Your EE friend should know that. There's always a wide gap between the theoretical and what happens in the real world, when you have to consider manufacturing, variations, etc. etc.

 

[pabbi1]

You can always 'tell' an EE, you just can't tell 'em much.

 

[Shahrose]

Quote:

Originally Posted by Toby M /img/forum/go_quote.gif I have an engineer friend who similarly assures me op-amps make no difference to sound. Lets hope he and your friend stick to designing bridges and remote control toys.

Agreed. They just don't have enough experience/knowledge.

 

[theScribe]

to me, it seems like they been "schooled" in how godly and superior transistors is. But you guys are right, he doesn't have experience in this "outdated" technology.

All he showed me was the diagram for an opamp and how that tiny, tiny chip can do all the things that my big tube audiotailor jade can. He owns a tube guitar amplifier himself and he knows that the 12AX7 in his guitar amp can introduce lots of distortion, but NOT when it comes to the power tube. I don't understand, what are these schools teaching these kids?

Why do they rever SS so much and not leave an open mind? I'm just curious of everything naturally.

-JC

 

[Uncle Erik]

Probably because solid state is 99% of the market and employers aren't looking to hire anyone who understands tubes.

Also, fundamental research into vacuum tubes stopped in the 1960s. You have no idea where they'd be today if R&D had continued or a company like General Electric threw millions, talented engineers and computer modeling at tubes. Maybe it'll happen some day, but the industry seems content to reproduce decades-old designs. Further, while tubes are extremely popular here, keep in mind that they are only a small part of the audio market and don't really lend themselves to mass production, at least how it is understood today in terms of Apple ordering four million new iPhones.

Still, tubes are going to persist. There's enough of a market in audio to keep them alive -they really are wonderful for listening to music. Tubes are also ideal for guitar amps. They'll distort in a way that no chip ever will. Maybe some DSP will replace them, but it'll never quite be the same. Tubes are also great for high power RF amplification applications. You might be surprised at how many radio stations still use them to transmit.

 

[-=Germania=-]

Yeah, there are definately some custom High voltage tubes being used since they seem to be one of the few things stable at multiple thousands of volts. We had a interesting discussion today involving power stations and transmission. Another fun one volving parasitic inductance, skin effects, and relative capacitance along with the effects of shielding. That one is being left to finish at another time.

 

[Joelby]

You have to understand that when a person becomes an engineer their farts start smelling sweet and refreshing. Hence, why all engineers have their heads up their asses!

 

[-=Germania=-]

^ I resent that!

 

[Joelby]

^ I'm actually a stationary engineer, lol

I just like to make fun of the other types of engineers!

 

[finoyvoy]

Quote:

Originally Posted by Toby M /img/forum/go_quote.gif I have an engineer friend who similarly assures me op-amps make no difference to sound. Lets hope he and your friend stick to designing bridges and remote control toys.

Yeah, theory has no place anymore, only experience matters. Let's replace all those silly engineers with people who have experience. Hey, audiophiles have plenty of experience! We should let them design your grandfather's pacemaker.