Irony

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ed
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#1 Irony

Post by ed »

The topic is a bit of a pun in itself....but we can rise above it..

It struck me recently that in the beginning it took a long while for mosfets to gain anything like critical mass in the hifi fraternity...there was so much valve snobbery going on that it more or less went unnoticed that solid state had moved on.

One of the prime movers in take up of mosfets was the fact that the most expensive part(the transformers) was removed from the equation when deciding between solid state and valves. IMO a lot of diy investigations occurred simply because it was cheap to find out.

Now move on 20 years and mosfets have a firm hold(IMO they are just as good as valves) and different topologies are surfacing. So back to my musing, since mofo appeared there has been a lot of interest in choke loading in class A circuits and that has brought about a return to big iron.

one of the early arguments for SS was that the removal of the transformers also removed some of the drawbacks associated with them.

So I was tickled when a new thread appeared on diyaudio about a single ended common source circuit using a Tokin SIT with a choke load....a variation on recent avenues of pursuit......BUT the chokes being mentioned were 193V and 195T10......These are monsters...so we've gone full circle and any argument about SS losing the iron and becoming cheaper goes out of the window....
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#2 Re: Irony

Post by steve s »

Big chokes are still cheaper than good outputs Ed..
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#3 Re: Irony

Post by pre65 »

Microwave oven transformers (MOT) can be relatively inexpensive.
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#4 Re: Irony

Post by Nick »

Not sure I understand the time-line, and where bipolar transistors fit into the history.

One could suggest that single ended circuits were first replace by push pull in valve times, then bipolar transistors came along and after a bit push pull transistors replace push pull valves, then mosfets came along and replaced to some extent bipolar. All the mofo is adding is single ended solid state. Same sort of circuits as you may see in a 1965 transistor radio output stage.

Also in term of produced numbers, H bridge is probably the most common audio output stage now.

The advantage of inductive devices is they are power rail efficient, but large and expensive. A current source and a negative rail would give the same sort of result as the mofo.

Its just fashion, if you can't invent something new, mix up something old in such a way that it looks like something new. That applies both to physical things like actual amplifiers, and virtual things like internet posts about amplifiers.
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#5 Re: Irony

Post by Nick »

And of course there were Valve OTL amps in my timeline, and Single ended valve made its comeback in the HiFi world.

The clear and obvious lack of valve transformers available from what used to be the low cost suppliers (other than Hammond), and the fact that most of the old valves have gone, or are being hoarded means that those wanting to play with simple nice sounding low power amps cant look to 6em7 any more, so the solid stage equivalent pops up,
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#6 Re: Irony

Post by ed »

Nick wrote: Mon Jan 18, 2021 1:57 pm Not sure I understand the time-line, and where bipolar transistors fit into the history.
no timeline really and certainly no bipolars.....just irony about the costs

https://www.mouser.co.uk/ProductDetail/ ... 0d%2Fr0%3D


you may be referring to a different discussion....maybe
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#7 Re: Irony

Post by Nick »

Now move on 20 years
Looks like a timeline to me. But yes, I may be replying to what you posted instead of what you thought you posted.
just irony about the costs
Well, yes as I say, its fashion, generally higher cost is better.
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