MOSFET Q???

Am 24.03.2019 um 04:56 schrieb snipped-for-privacy@gmail.com:

I think nothing. Critical by MOSFETs and low frequencies is the input capacity. Choose the MOSFET with lowest capacity (or build a good driver). Using MOSFETS means the problems are displaced to the driver.

regards Leo

Rest of your incomprehensible drivel snipped.

..... Phil

Go look it up, you LAZY Pile of ASD f***ed S*IT.

.... Phil

Tempco in linear operation and DC SOA. Which means biasing may differ (gate voltage offset and tempco).

The audiophiles will say distortion differs; they can't actually hear it.

BTW, ignore Phil, very old and sad troll.

Tim

1. The case is the source connection, not the drain. This permits direct mounting of P and N channel devices on a common heatsink that floats at speaker voltage.

2. Good bias stability is achieved with one resistor in the class A stage as the devices tend to self stabilise at 100mA each, close to the ideal value for class AB operation.

1. The devices do not suddenly fail from over temp, rather they lose transconductance and almost stop working until the temp falls.

2. No source ballast resistors are needed for parallel groups, current sharing is largely self correcting.

1. Predictable current limiting is achieved with a single 400mW zener diode per device or parallel group.

2. With TO3 devices, chip failure causes the bonding wire for the drain to open, removing that device from operation allowing other devices in parallel to continue as before. I kid you not.

1. Many good complimentary pairs exist with lateral mosfets - this is not the case with vertical ( ie switching ) mosfets.

.... Phil

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Thanks, Phil, that's an excellent list, obviously from someone who's had experience and carefully thought about the issues.

.... Phil

Not good advice. Phil Allison really does know a lot about audio electronics. He also has a short fuse, and doesn't suffer fools at all.

He's the very antithesis of a troll.

Not good advice. Phil Allison really does know a lot about audio electronics. He also has a short fuse, and doesn't suffer fools at all.

He's the very antithesis of a troll.

at last I saw that he is a really good expert, but why did he behave like an idiotic troll at first?

No, he likes being a curmudgeon.

So the cost-benefit ratio is meaningless to you, got it.

Tim

The benefits of Phil's advice is obvious to anybody bright enough to unders tand it.

The cost of Phil's intemperate responses to people who don't know enough ab out what they are talking about is a slightly less civil environment, but t hat has to be balanced against the advantage of making less well-informed p osters slightly less voluble.

You may not weigh the costs and benefits in the same way that I do, but tha t doesn't mean that I don't understand the concept. Your claim that I don't is ill-founded, and represents kind of ill-informed post that Phil would b e much ruder about than I'm being.

Two academics supporting me in the same thread !!!

Must be doing something wrong ....

.... Phil

I only spent three fiddy in late feeds at the fahkin' Boston Public Library to learn what I know which isn't a lot but the price was right.

It's an ancient Australian version of foreplay. He's being polite and chatting us up. It's traditional for Australian males to then throw their women through doors and/or plate glass windows to show they're serious about romance. Let's hope it doesn't escalate to that point.

If you get any wronger I'll buy you a coffee.

Bill Sloman, Sydney

Not a tradition that I've ever heard about. Australia includes the usual pr oportion of psychopathic males who beat up their partners from time to time , but this sort of bad behavior isn't confined to Australia, and is frowned on, not to mentioned prosecuted by the legal system, and punished by time in jail.

Kind of difficult to imagine how on a text-only user-group.

.... Phil

My local coffee shop is the Bunker at 399 Liverpool Street. Darlinghurst

If you've got some place you like, tell me in an e-mail to snipped-for-privacy@ieee.org.

Bill Sloman, Darlinghurst. Sydney