Tag Archives: vacuum tubes

Asheville, Walnut Cove, Biltmore Forrest and Western North Carolina’s Audio and Home Theater specialists present Cane Creek AV and Paul McGowan – PS Audio, Intl.

Advanced judgement

It has been multiple decades—in fact, most of our adult lives—that neither Terri nor I have consumed meat or fish.

To many Americans we encounter we are an anomaly, a curiosity to be poked and prodded to see if we are real. We both giggle when we get that knowing wink of disbelief from a food server who figures we just say such outlandish things to be in vogue.

In their experience, one cannot live without meat. To them, we are either lying, delusional or that rare once-in-a-lifetime curiosity.

But this rant is not about being a healthy vegetarian or how a plant-based diet helps the planet. It’s about preconceived notions.

It’s about being convinced without listening to how digital versus analog sounds. Vacuum tubes versus solid state stereo equipment. Horns versus boxes. Measurements versus subjective. DSD versus PCM.

To some degree, we all fall into the same trap. We enter a new situation with a prediction of the outcome.

It’s just the way we’re wired.

One of the great joys of age is the freedom to let go of some of my preconceptions.

I no longer feel the need to protect and defend many of my long-held beliefs.

Lowering one’s expectations to the point of openness to new input is the quickest means I know of to advance and learn.

As you get older are you leaning towards becoming more set in your ways or less?

Opening up or closing down?

It’s something to consider.

Asheville, Walnut Cove, Biltmore Forrest and Western North Carolina’s Audio and Home Theater specialists present Cane Creek AV and Paul McGowan – PS Audio, Intl

I don’t agree with this as small signal vacuum tubes, like 12AU7’s, 12 AX7’s, etc, unless defective, should last for years. Power tubes, not as long, but a lot longer than 6 months, at least in a good circuit where they aren’t driven to extremes.
On the other hand, the small signal tubes Paul is referring to are fairly inexpensive, at least pre Putin’s war, so not a big deal to most. Russia is probably the largest tube manufacturing country in the world, so who knows what’s instore, that way.
Changing of the guard
There’s been a bit of kerfuffle lately about a video I made where I detailed my experience in changing vacuum tubes.

I do it often. As often as every 6 months on the main stereo system. I do it because once replaced, new life is breathed into the music.

The resistance to my statement seems to have come from those that have the opposite experience.

That for them, changing tubes hasn’t the same new life result and therefore is a waste of money.

They are probably right in their situation.

Unless you have exactly the same everything as me why would a different result not be the natural occurrence?

The right and wrong of something are only valid as they pertain to the situation in its entirety.

In identical circumstances, we’d likely agree.

Asheville, Walnut Cove, Biltmore Forrest and Western North Carolina’s Audio and Home Theater specialists present Cane Creek AV and Paul McGowan – PS Audio, Intl.

PCB vs. point to point

Long ago, when vacuum tubes ruled and Bell Labs dreamt of sending electrons through solid materials instead of a vacuum, few consumer stereo products had circuit boards.

Though today PCBs (printed circuit boards) are common, back in the 50s they were rare, though hardly unknown. Over 100 years ago in 1903, German inventor, Albert Hanson, came up with the idea of incorporating flat foil conductors by gluing multiple layers of thin metal to an insulating board. It worked, but was hardly a practical solution. Even Thomas Edison experimented with the more common approach of plating conductors throughout the early 1900s. Eventually, credit for the PCB goes to Arthur Berry and Max Schoop who together patented the print-and-etch method in the UK and United States respectively.

What this means is simple. Instead of the earliest attempts of adding to a piece of insulating material the thin strips of copper that would carry the electric currents, today’s PCBs are made by removing all the unwanted copper. You start with a fiberglass sheet (the insulator) that has a layer of copper glued onto it. By means of a printing process, the areas of copper we wish to keep are painted with a type of coating that acid won’t bother. The plate is then immersed in an (essentially) acid bath (ferric chloride) and anything not painted is eaten away. What you’re left with is the conductors to make the circuit work.

Before PCB technology was popularized, our audio circuits were hand-wired in a process known as point-to-point wiring. Tube sockets and capacitors had small eyelets where technicians could wrap wire and then solder the connection. Though cumbersome at best, this point-to-point wiring was a definite plus when it came to sound quality.

Today, of course, it is impossible to wire between points as the circuitry and bits and bobs that make it all work are microscopic.

But, back in the day, it was some really cool techniques.

Asheville, Walnut Cove, Biltmore Forrest and Western North Carolina’s Audio and Home Theater specialists present Cane Creek AV and Paul McGowan – PS Audio, Intl.

Secondary truth

Not everything is straightforward.

Take for example brushing your teeth. Despite the minute or two of brushing recommended by dentists, it turns out not more than a few swipes of the brush and paste against your enamel is all it takes to keep them clean. The extra time is about gum health, not teeth.

Just the other day I queried my dentist on this observation. He laughed and said I’d uncovered their secret. “Can’t get people to brush their gums but tell them two minutes with an electric brush will keep your pearls white and we get what we want anyway.”

I think many of these primary tasks are more about their secondary benefits than their primary names. Think about the yearly good practice of reconnecting your HiFi system and dressing up your stereo cables. The real benefit is deoxidation. Same with swapping vacuum tubes. I recommend going through your dozen or so favorite tracks every quarter, not because you need to hear them again, but to recenter yourself and make certain everything’s as you imagined it to be.

There’s often more to routine than meets the eye or the ear.

Asheville, Walnut Cove, Biltmore Forrest and Western North Carolina’s Audio and Home Theater specialists present Cane Creek AV and Paul McGowan – PS Audio, Intl.

Changing tubes

In my many videos and blog posts about changing tired vacuum tubes, I am continually surprised at the variety of answers.

They range from heck yeah to hell no; from whenever the stereo system starts to get a bit lifeless to never more than 10 years; and everything in between.

I suppose I should never be surprised when audiophiles have and express opinions. It’s what makes us family.

One thing to keep in mind is that there are no universal rules. Every design of vacuum tube audio product has a different setup affecting tube life. I remember a few Sonic Frontier amps that benefitted from changing output tubes every few months. Contrast that with the vintage classic from decades ago that still sings with the best of them.

One thing I can tell you for sure is that all vacuum tubes sound slightly different. Take four or five matched set of new tubes and swap them out between listening sessions. The changes may be subtle, but they are there.

What I have found in all the tube preamplifiers I have owned, from Audio Research to PS Audio, changing tubes at least once a year (and maybe twice) brings a remarkable improvement in music’s liveliness.

Before you reject what I am writing, take the time to actually try the experiment.

You might be surprised.

Asheville, Walnut Cove, Biltmore Forrest and Western North Carolina’s Audio and Home Theater specialists present Cane Creek AV and Paul McGowan – PS Audio, Intl.

Our son played trumpet for much of his pre-teen and early teenager years and we had two dogs that used to howl when he played. However, when they would hear recorded versions of the same material, played back on my wife’s cellphone, they would also howl. So, our experience is different than Ed’s.

The dog gets it

When HiFi Family member Ed Spilka sent me the following note I just had to smile. How many times have I heard a similar story? Too many times to count.

And here’s the thing. It’s not just about vinyl. I have heard the same stories about DSD, vacuum tubes, and even good vs. bad cables.

I am sure the measurement folks will have a field day with this one.

“I wanted to share an interesting audio experience that happened the other day.  We were visiting a friend of my wife’s in San Antonio. She was showing us around their new house when we walked into “his” room which held Wilson Alexandria speakers, D’agostino amps, Berkeley DAC’s etc. You get the idea.

When he came home he invited us into his inner sanctum and we began to play. At one point we were A/B’ing between his vinyl collection and streaming on tidal/Qobuz with Sonny Rollin’s Way Out West. On one cut it is just the drummer and Sonny. When Sonny started blowing on the vinyl version, their dog began singing along—howling like crazy. As soon as we switched to the streaming version, the dog was silent, uninterested.

My wife pointed it out to us since we were too engrossed in “listening” to notice the obvious! It happened every time we switched back and forth between vinyl and streaming. Have you experienced that before?”

As I said, this has happened to me with animal reactions more times than I can count.

We might argue like crazy, but the dogs get it.

Asheville, Walnut Cove, Biltmore Forrest and Western North Carolina’s Audio and Home Theater specialists present Cane Creek AV and Paul McGowan – PS Audio, Intl.

Valves

We’re all familiar with the terms amplifiers and valves. We use electronic valves like vacuum tubes and transistors to amplify audio signals. Yet, even writing those words makes me a bit nervous because I can see how they might be misunderstood.

When we talk of amplifying the input signal it sounds like we are taking a small signal and somehow boosting it. Maybe a good analogy can be found in an airport and its moving sidewalk. You’re walking along at your pace and then step onto the moving conveyor belt, boosting your speed. That’s amplifying your walking.

That’s not what’s happening in an amplifier.

In fact, the input signal never reaches the output. It does its work and then is discarded, never to be seen or heard again.

We don’t amplify the input signal in the same way a moving sidewalk amplifies our forward motion. Instead, the input signal turns a virtual valve up or down to release more or less voltage and current from the power supply. What gets passed on to our loudspeakers and headphones is not the input signal, but voltage and current straight from the power supply.

It’s more than semantics.

Our input signals are but instigators.

Once they do their work they are gone forever.

Asheville, Walnut Cove, Biltmore Forrest and Western North Carolina’s Audio and Home Theater specialists present Cane Creek AV and Paul McGowan – PS Audio, Intl.

Walking backwards

The many forms of protection like limiters, fuses, clamps, compressors, and crowbars all have something in common. They don’t make things better. They make sure things don’t get worse.

Very different than a technology that moves the progress bar forward.

Which is why it can be confusing when we read about the amazing improvements wrought by protection devices like a multi-hundred dollar beeswax and honeyed fuse. Confusing because we’re tempted to believe the object is moving the progress bar forward when in reality, it’s just doing less damage.

Semantics?

Perhaps. This line of reasoning is a slippery slope. The difference between sonic improvements achieved through removing obstacles is dangerously close to what we think of as pure forward motion. String together enough removed obstacles and at the end of the chain something new emerges.

The difference I suspect has to do with time. The larger the gap between discovery, solution, innovation, and progress the more it feels like forward motion than tweaks to the stereo system.

Big leaps in progress seem obvious: vacuum tubes vs. transistors, gyrators vs. RCLs, mono vs. stereo, etc. These seem less like examples of removing barriers than pushing forward the envelope of technology.

So where does one draw the line between forward progress and removing layers of cruft?

Hard to say.

It is clear to me protective devices like fuses don’t move us forward any more than the pandemic’s emblematic icon, facial masks do. They protect but don’t improve.

Yet, it’s equally clear to me that we move forward faster when we don’t walk backwards.

Asheville, Walnut Cove, Biltmore Forrest and Western North Carolina’s Audio and Home Theater specialists present Cane Creek AV and Paul McGowan – PS Audio, Intl.

Cross breeding

Purity is appreciated when it comes to purpose, water, and immorality. It’s not so great when it comes to a power amplifier’s architecture, where hybrids rule.

For many years, amplifier manufacturers were determined to keep their designs pure: 100% solid-state, all vacuum tubes, nothing but FETs, class D from input to output. Over time we’ve come to grips with why this commitment to design purity is not such a great idea.

Power amplifiers are misnamed and therein lies the problem.

On the surface, they seem simple enough: little signal in, big and powerful signal out.

What’s missing is the recognition that inside a power amplifier we have two completely distinct systems each with very different amplification duties: voltage and power.

The input voltage gain stage takes a small voltage and amplifies it into a big voltage. From beginning to end there is only voltage and no power. If you were to take the output of a power amplifier’s first stage and attempt to drive a loudspeaker you’d be met with silence.

To produce watts we need the second system, the actual power amplifier (where it got its name).

The fact that each of these two stereo systems has such very different functions should be clue enough to understand why a purebred power amplifier’s a bad idea.

The smart designer recognizes the difference between the two systems and applies the best technologies for the job: vacuum tubes and FETs are much better at delivering voltage while bipolars, power MOSFETS, and Class D stages are best at delivering power.

Purity benefits us most when we apply it to where it matters.

Asheville, Walnut Cove, Biltmore Forrest and Western North Carolina’s Audio and Home Theater specialists present Cane Creek AV and Paul McGowan – PS Audio, Intl.

Audio sensitivities

Even as a kid I never bought the premise behind Hans Christian Anderson’s story, The Princess, and the Pea. Just a bit too far fetched for my young engineering brain to believe that anyone could feel a pea under multiple mattresses.

Fairy tales aside, it is a fact that we are all different when it comes to our audio sensitivities. I might be more sensitive than many to sound staging while someone else really focuses on tonality.

We make choices in equipment and set up based on those differing sensitivities: cables that bring out more details, vacuum tubes that warm and soften, subwoofers that build a solid foundation.

Our systems are all different, just like our tastes and sensitivities.

Few of us could likely tell if there were a pea under the cushion of our listening chair, but if our stereo system’s sound is even slightly amiss we know it instantly.