It seems a lot of this forum is talking about trying to source or substitute transistors that are no longer made (funny, just like tubes!)
What inspired this post was reading about the Semisouth SJEP120R (or the Sony VFET stuff), and seeing the prices those command (but by no means limited to just those parts).
I work with a lot of manufacturers (but not semiconductors/raw parts like this), and am familiar with MOQ (minimum order quantities) + the fixed costs to do stuff. I am also familiar with some processes that can be done in small quantities (order sizes of under 1,000), and some things that only make sense to do in huge quantities (usually because there is a huge fixed cost to setup a line and run it - even if you wanted 1,000 of them, you might have to pay 5x per part of ordering 10,000). I would be willing to bet almost all the cost of a transistor is in the fixed cost of the line, not the cost of the part itself.
Curious what the economics would be for small runs of highly-desirable parts like this. I think the wild card is the margins are normally razor thin on these products when new (before they became desirable), so they need to make 10,000 or 100,000 to even make it a consideration. I'll be VERY charitable and say they make $1 in profit per unit (likely much less than that, offset by HUGE volumes, might be more like $0.10/unit in profit).
What if the business case is they make $20...or $50 in profit per unit? Could they justify doing a production run of <1,000 units? If people are willing to pay $100 for a NOS part, and they could sell a new one (that might even be better) for half that, maybe it would be a low-volume but highly profitable venture. It would need to be contingent on having buyers lined up before production began, so very much a chicken or egg situation. Only a fool would build a $50 transistor and then hope someone would buy them.
I don't think this would ever make sense for just our little DIY community, but curious if it was something that could be used in a commercial product, and the parts were made available externally as well. Same way some speaker brands sell their raw drivers in addition to finish loudspeakers.
What inspired this post was reading about the Semisouth SJEP120R (or the Sony VFET stuff), and seeing the prices those command (but by no means limited to just those parts).
I work with a lot of manufacturers (but not semiconductors/raw parts like this), and am familiar with MOQ (minimum order quantities) + the fixed costs to do stuff. I am also familiar with some processes that can be done in small quantities (order sizes of under 1,000), and some things that only make sense to do in huge quantities (usually because there is a huge fixed cost to setup a line and run it - even if you wanted 1,000 of them, you might have to pay 5x per part of ordering 10,000). I would be willing to bet almost all the cost of a transistor is in the fixed cost of the line, not the cost of the part itself.
Curious what the economics would be for small runs of highly-desirable parts like this. I think the wild card is the margins are normally razor thin on these products when new (before they became desirable), so they need to make 10,000 or 100,000 to even make it a consideration. I'll be VERY charitable and say they make $1 in profit per unit (likely much less than that, offset by HUGE volumes, might be more like $0.10/unit in profit).
What if the business case is they make $20...or $50 in profit per unit? Could they justify doing a production run of <1,000 units? If people are willing to pay $100 for a NOS part, and they could sell a new one (that might even be better) for half that, maybe it would be a low-volume but highly profitable venture. It would need to be contingent on having buyers lined up before production began, so very much a chicken or egg situation. Only a fool would build a $50 transistor and then hope someone would buy them.
I don't think this would ever make sense for just our little DIY community, but curious if it was something that could be used in a commercial product, and the parts were made available externally as well. Same way some speaker brands sell their raw drivers in addition to finish loudspeakers.
What if the masks and/or processes no longer exist though? It becomes a reverse engineering job. Its not unknown for a device to go out of production because the masks were lost/accidentally destroyed, or because the process used was made obsolete.
Some parts have surface-mount equivalents (and its often not straightforward to work out what these are and if they exist).
And there may be production parts that are superior that obsoleted the old ones, and these may be SMT only...
There are examples of substitutes for historical devices made specifically for the spares market - Exicon lateral MOSFETs for example, although even they've stopped TO3 footprint production (my guess is the production line for TO3 was closed as it was uneconomic, probably outside Exicon's control too).
There's definitely a market for low volume niche device production, many exotic RF and opto-electronic devices are like this, but use highly specialized processes with other semiconductors than just silicon, and are current devices for new designs, not legacy.
The truth is most commercial (i.e. high volume) audio electronics is digital and class-D, and this will not change.
Some parts have surface-mount equivalents (and its often not straightforward to work out what these are and if they exist).
And there may be production parts that are superior that obsoleted the old ones, and these may be SMT only...
There are examples of substitutes for historical devices made specifically for the spares market - Exicon lateral MOSFETs for example, although even they've stopped TO3 footprint production (my guess is the production line for TO3 was closed as it was uneconomic, probably outside Exicon's control too).
There's definitely a market for low volume niche device production, many exotic RF and opto-electronic devices are like this, but use highly specialized processes with other semiconductors than just silicon, and are current devices for new designs, not legacy.
The truth is most commercial (i.e. high volume) audio electronics is digital and class-D, and this will not change.
People want them
But not that many to get rich.
The actual industrial use, has been replaced with updated devices.
Prices may look amazing and high for old stock.
Lucky for the people that own stock.
Who knows how long they sit on them.
They get over priced, nobody buys.
Some more recent obsoleted devices now show no stock or obsolete.
Minimum order is usually 1000 and lead time can be 6 to 24 months.
Actual devices that can be made. Typical High voltage PNP
E waste recyclers, pull real devices from trashed items.
Not done here, other countries.
Requires a full recycle center. To many permits and over regulated here
But not that many to get rich.
The actual industrial use, has been replaced with updated devices.
Prices may look amazing and high for old stock.
Lucky for the people that own stock.
Who knows how long they sit on them.
They get over priced, nobody buys.
Some more recent obsoleted devices now show no stock or obsolete.
Minimum order is usually 1000 and lead time can be 6 to 24 months.
Actual devices that can be made. Typical High voltage PNP
E waste recyclers, pull real devices from trashed items.
Not done here, other countries.
Requires a full recycle center. To many permits and over regulated here
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Thanks, interesting info. Of course the other issue is it would likely be impossible to gain consensus on what part to try and rebuild vs. there being just 'The One' that a large group wanted and was willing to pay for.
Or the other wildcard, a from-scratch new design that could cover a wide range of uses in high-end audio applications.
Or the other wildcard, a from-scratch new design that could cover a wide range of uses in high-end audio applications.
You can use IRF240 and irf9240 with a 5.6v zener bias. With little difference in performance.
That Jfet is for very high voltage high speed applications. It would work well in a class d amplifier.
That Jfet is for very high voltage high speed applications. It would work well in a class d amplifier.
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