300b lovers

My concern is reliability and unknown, undocumented processes going on in critical components. This is just bad engineering. Imagine an expensive car where the horsepower and handling changed from day to day, and the manufacturer had no idea why. Cars are 100x more complex than an audio product ... the average car has 35,000 parts, 5,000 of which are moving parts, nearly all of which are critical to performance, reliability, and safety. A single-part failure can make the entire car useless.

What’s the capacitor manufacturer’s excuse? "This is how we’ve always done it" isn’t good enough. "We don’t understand what we are making" is even worse. There’s good engineering, making reliable products that people enjoy, and bad engineering, where mysterious things occur and nobody knows why. Regrettably, this is the situation for much of high-end audio.

For all I know, Don, Thom, and I might end up designing a capacitor conditioner for one of the cap companies. Back when I was working with Gary Pimm, he came up with a gizmo that did that ... pushing through 10 kHz square waves at 1/4 of the cap’s rated breakdown voltage. After twenty minutes of that, it either survived or not. Actually, nearly all survived, and they were "broken-in" for sure after that treatment. And it weeded out the parts that were going to fail anyway.

By contrast, using the cap in a normal circuit, with music stimulus, is barely tickling it. No wonder it takes forever.

My concern for the customer experience might sound big-hearted, but actually it’s purely selfish. Neither Don nor I want ’em coming back. I am 100% retired, Don is thinking about it, and we both want the preamp and power amp to be reliable and good-sounding right out of the box. People tell their friends, etc. etc. So every part going in has to earn its keep in terms of reliability and sonics.

 A Cornell Dublier engineer once explained to me that the difference between a 150V rated cap and one rated at 175V was the way the cap was formed up and nothing else. Forming is a process where voltage is applied to the capacitor with a target of the rated voltage; something that is done only once in the factory.

But the cap is almost never used at the forming voltage. Usually for best reliability, they are to be run at about 80% of the rated voltage.

So the cap is not as efficient at the new voltage when new. It takes time for the cap to 'form' to the new voltage. Its important to understand that electrolytic caps have some properties in common with batteries and so are fundamentally different from film caps in this regard. Charging them and polarity are two examples of this similarity. Forming is one way they are unique.

Anyway, when the cap forms up to the new voltage used inside the amp or preamp it will be a more efficient bypass. Its my theory this is what people hear during break-in. I've found it measurable too- the voltage once the caps are formed is every so slightly higher and the supply is less noisy.

@atmasphere 

So the cap is not as efficient at the new voltage when new. It takes time for the cap to 'form' to the new voltage. Its important to understand that electrolytic caps have some properties in common with batteries and so are fundamentally different from film caps in this regard. Charging them and polarity are two examples of this similarity. Forming is one way they are unique.

Anyway, when the cap forms up to the new voltage used inside the amp or preamp it will be a more efficient bypass. Its my theory this is what people hear during break-in. I've found it measurable too- the voltage once the caps are formed is every so slightly higher and the supply is less noisy.

Ralph, this is believable and logical.

I recently had a DAC built and delivered to me from Ukraine. The builder (Abbas Esoteric Audio) told me that it will require roughly 200 hours minimum of burn-in time to sound its best. He specifically cited the Blackgate capacitors utilization as the reason. He explained to me that it takes time for these excellent electrolytic capacitors (His opinion) to form.

Sounds right to me based upon my experience with his DAC.

Charles

Ralph,

Your comments on this this thread, as on any thread, are extremely informative.   I have not had the pleasure of hearing your new affordably-priced Class D monos and maybe they will be playing at the Seattle show later this month so I could hear them then.  

You have had a career as a designer and builder of tube gear.  You now are selling a Class D amp with the new GaN technology.  Don and Lynn of course are solidly tube amplification adherents, make no mistake about that, but you seem to be straddling the line between an affinity for tube gear as well as Class D amplification. 

Are you at the point where you feel your Class D amps are equivalent to your best tube amps?  I have long anticipated that the day will come where the march of technology might render tube gear obsolete, but in the main at the moment, my experience with Class D amplification is somewhat akin to the unwarranted adoption in the 60s of lousy sounding solid state gear (everybody made a variant of it) over tube gear that took a very long time for the industry to recover from.  Tube gear, like vinyl sales, are better than they have been for a long time, but I remain dubious that Class D amps yield the same sonic goodness after extended listen sessions, than the better/best  tube amplifiers.  But then I have not heard your new Class D monos. Comments?