Frequently Asked Questions
Q: Why would I want one of these?
A: Maybe you don't. These amplifiers are all out of the mainstream, reflecting quality in simplicity and intrinsic linearity, often with little regard for the usual performance specifications. I presume a subset of audiophiles will appreciate them.
Q: What about all the other amplifiers that measure better?
A: The ear is not a microphone, the brain is not a tape recorder, and measurements are limited in describing subjective quality. I like to have low distortion and so on, but these things take a back seat to what I experience when I listen. There are plenty of products which have great specs – I will not be offended if you buy those.
Q: Why such simple circuits?
A: It is my experience that simple linear circuits tend to sound better. I think they are more interesting and subtle than complicated circuits, and I find that measurements and subjective sound quality correlate better with simple gain paths. Exploring their potential for high performance is what I like to do.
Q: Why do they run hot?
A: They are Class A amplifiers. They are very linear, but they run hot. Can I make them sound good without Class A? No. Because they run hot, it is important that they get good ventilation. Do not place them in a closed cabinet or on top of another hot amplifier.
Q: Isn't Class A bad for the environment?
A: Everything is bad for the environment, in case you haven't noticed. When I look at the cost of enjoying my 25 watt/ch class A amplifier as compared to watching a big screen television or running a porch light all night, I see that I get as much or more value for the same sort of consumption. If I drive down the hill to shop at Fry's, I consume about as much power as running one of my amplifiers for 2 hours a day for a year. So I go to Fry's less often, and I turn the amp off when I'm done.
Q: What's so bad about feedback?
A: Feedback isn't so bad. Sometimes I use it, sometimes I don't. It all depends on what makes a particular design sound better. In the ideal case, we wouldn't need feedback to improve the performance, but our parts are not ideal.
Q: What's so special about Jfets?
A: They have intrinsically lower distortion in the circuits that I like to work with. When even better parts come along (and they will), I'll be using those instead.
Q: Why don't you just build First Watt amplifiers as part of Pass Labs?
A: I could, but it's easier not to burden the PL staff with this stuff. When I discover a particularly good technique or part, Pass Labs is the happy beneficiary.
Q: Do you really build them yourself?
A: Yes, until this last year, when my son Colin and nephew Sean began helping with assembly.
Q: Why do they all look the same?
A: Years ago I bought a lot of chassis parts in order to get volume pricing, and they are not used up yet. You can look forward to seeing this chassis for quite a while.
Q: What is the warranty?
A: 3 years parts and labor. We have not experienced a warranty case yet, but I imagine the service is good...
Q: Is there really a 0 percent failure rate on these amps?
A: Pretty much. One customer reported a case of bad solder connection, but the amplifier was apparently still running when it was discovered. He soldered it himself. Other than that, just the odd case of shipping damage.
Q: I have 230 volts AC, but my amp is rated for 240 volts?
Don't worry, it will run fine.
Q: What about warm-up and break-in time?
A: Unless there's a big rush I burn them in for several days prior to final tweaking, so when you get a new one it already has some time on it. Customers often report that the amplifiers improve over a period of weeks. As to warm-up, one hour of operation is adequate prior to critical listening.
Q: Will a power conditioner help the performance?
A: I don't think it will help a lot, but assuming that it has adequate capacity (500+ watts) then I don't think it will hurt. The design and evaluation work is done without power conditioners. Try one and see what happens.
Q: How about an after-market power cord?
A: Some customers have reported good effect. I still like the ones I provide, and again, these are the ones I evaluate with.
Q: What do these amplifiers have for protection circuitry?
A: Generally, they have a fuse and a thermal switch. For 120V models, the fuse is 2.5 amps slow blow, and for 240V it is 1.25A slow blow. In addition there are internal fuses on both AC input connections which are not user accessible. The thermostat is designed to interrupt the power when the internal temperature exceeds 75 deg C. The F5 has actual limiters at 10 amps, which will kick in with 1 ohm loads.
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