2018, Chapter 6:
Amplifying the Future. Maybe.
Yep, I know, I’m monumentally late at getting the coaster amp chapter done. Which is pretty hilarious when we already have the coasters in stock. So yes, I should knuckle down and get the chapter done. But I won’t. Not this week.
...
Maybe #2: let’s talk going low, or Captain Obvious strikes again.
Remember that 25W Class A amp in a Vidar chassis I mentioned in a previous chapter? Yeah, we’re playing with that. Take the Lyr 3’s Continuity™ constant-transconductance output stage, scale it up, bias it wayyyy up, and you might have a pretty neat product, right?
Well, except for one thing. It’d really be more like a 20W Class A amp, or else it gets too hot. How excited would you be about a 20W Class A amp?
Wait. Before you answer, let’s break that down:
- 20W real honest Class A per channel into 8 ohms
- 40W into 4 ohms, falling out* of Class A
- 80W mono into 8 ohms, again falling out* of Class A
*Rather than “falling out of Class A,” a better term may be “transitioning to the Continuity™ constant-transconductance region.” This is, after all, the whole point of the Continuity output stage—it seeks to keep the output stage operating in the gm-doubled region, even when out of Class A. Is it perfect? No, of course not. But it blurs the line between Class A and Class-AB amps, at least in my opinion.**
**Of course, many people think I am crazy. Or incompetent.
Still, that’s a big, hot, heavy 20W amp. Think 50 degrees C heatsink temperatures in a 20 degree C room. And it’s only 20 watts.
On one hand, I really like the idea of going with a low-power amp. It’s the exact opposite of what most people expect us to do—most expect us to go into welding-class amps next, but I’m not convinced that’s the right direction for us…an may be something we simply don’t need to do.
On the other hand,
20 watts.
Jeez, that’s
small.
How do you explain to someone that a 20W amp costs more than your 100W amp? Even though it’s in the same basic packaging, differences in the chassis and feature set would put if about $100 more than a Vidar.
Aside: “feature set” differences are mainly a planned front-mounted button for output stage shutdown, so you can press a button and have the amp go into a low-power standby mode, where it burns very little power (probably less than 10W). But this hasn’t been fully tested. It might work. It might not.
Am I being too sensitive to the low-power issue?
Would we be better off rating it at 25W/50W/100W (8 ohms, 4 ohms, mono), and specifying a lower class A bias (like, 15W into 8 ohms Class A—the total bias has to come down, because the rails get larger.)
Or would we be better off not doing it at all? Is it too much confusion in the line?
What say you?
...