Tag Archives: 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.

Trusting your senses

Trust is a funny thing. We’d sooner trust a restaurant recommendation from a stranger or a Yelp review before a friend we suspect has an agenda—even if that person is a food expert.

Often, we have trouble trusting ourselves. “Did I make the right decision?” “Can I trust what I am hearing with this new piece of equipment?” “I thought I was right until I read a bad review”.

I often question the accuracy of what I hear or conclusions that I make and I can’t help feeling I am not alone in that insecurity.

What I have come to recognize over the years is our innate ability for accurately sussing out complex patterns in music with little or no effort or experience at the task. In fact, the harder I try to discern differences, the worse I am at it. Relaxing and trusting my senses makes it easier.

When I first started honing my listening skills I feared I wouldn’t be able to tell two units apart, yet the opposite happened. I often became overwhelmed—like when I first started comparing the sound of tubes and solid-state electronics. They were so far apart from each other that I had more trouble identifying similarities than differences, yet because I hadn’t developed an adequate vocabulary nor trusted my senses, I often just kept my thoughts to myself.

I see this same pattern in newcomers to high-end audio. Each conversation begins with a lack of trust in their hearing. “I am certain I can’t hear any differences, but I’ll give it a go.” Inevitably they turn out to be some of the best listeners.

It’s almost as if the more we do this the less we trust our senses—the same senses that worked so well in the beginning of our high-end journey.

For me, it’s a matter of relaxing: assuring myself I am a better listener through years of experience and earning the trust I know I should have but fear I do not.

 

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.

Solid state vacuum tubes

Most of us like the sound of vacuum tubes on an amplifier’s input: sweet, rich, full-bodied, musical. An equal number aren’t too happy about their downsides: heat, microphonics, size, and the 300-pound gorilla—their ephemeral lifespan. Which is why most customers rejoiced when we began to leverage a solid state equivalent, the FET.

Vacuum tubes are voltage controlled devices while bipolar transistors rely upon current. The two are very different sounding technologies.

FETs, on the other hand, are very much like tubes in the way they require almost no current from the incoming signal. Not surprisingly, FETs—in particular, JFETs (and MOSFETS)—sound much closer to tubes than the more conventional bipolar transistors.

One of my first experiences with JFETs happened more than 30 years ago. In the mid-1980s designer Bob Odell had joined PS Audio’s design team. He had brought with him a new power amplifier design that would become the famous 200C—but not before we made some major changes to its input stage. The original design relied upon a traditional bipolar differential pair at the amp’s input. This worked well but the amp still had a slightly cold and transistory tinge to its musical character, one we wanted to eliminate before releasing it as our premier offering for power amplifiers. We decided to replace the bipolars with JFETs to see if this might help. Of course, rarely is it a drop in replacement (that’d be too easy). The JFETs of those days were limited in voltage requiring us to add a cascode circuit on the top of the new diff pair. It worked.

By replacing the input bipolars with a new type of transistor, the JFET, we were able to help the 200C amplifier get closer to the sound of vacuum tubes and honor the music. Nearly all PS amplifiers following the venerable 200C have enjoyed the benefits of either FETs or vacuum tubes at their input. And now you know why.

Vacuum tubes still outperform FETs on the input circuit of an amplifier, but FETs are a close second and without the PITA characteristics of tubes.