I am agreeing with you. Another way to achieve high power is bridging, which again keeps Vce manageable, at the expense of high currents. These pro amplifiers are usually rated into 4R
Which is why the original macrotech amps were grounded bridge. It's a bridge amp, that's itself bridgeable because the power supplies for each are floating. Bridge operation also squeezes a bit more watts out of a given volt-amp of transformer core.
Matching is no big deal - for the average DIY. Crown, Peavey or whatever transistors are just matched (the term is "binned") by vbe. But just buying a rail or two and separating them into piles will NOT pass the muster for ISO-9001 auditors!!!! They want to see a controlled drawing and a separate SAP number for each and every type, even if four of them are MJ15024s (in 4 different vbe bins). It also makes it easier on the assembly line and service center - they don't need a matching procedure that needs to be followed during assembly or service. And there are service techs that only replace the two that failed and not all five - and having binned parts will get you a decent match even if they aren't all from the same lot... or decade.
Usually the same date code (lot) is enough. They would all fall into one or at most two bins. I buy at least a rail or two at a time, get them within 2 millivolts, and use the oddballs for the drivers.
Matching is no big deal - for the average DIY. Crown, Peavey or whatever transistors are just matched (the term is "binned") by vbe. But just buying a rail or two and separating them into piles will NOT pass the muster for ISO-9001 auditors!!!! They want to see a controlled drawing and a separate SAP number for each and every type, even if four of them are MJ15024s (in 4 different vbe bins). It also makes it easier on the assembly line and service center - they don't need a matching procedure that needs to be followed during assembly or service. And there are service techs that only replace the two that failed and not all five - and having binned parts will get you a decent match even if they aren't all from the same lot... or decade.
Usually the same date code (lot) is enough. They would all fall into one or at most two bins. I buy at least a rail or two at a time, get them within 2 millivolts, and use the oddballs for the drivers.
- Status
- Not open for further replies.