SS equivalents are very wide BW.... I think you missed the point.... Has nothing to do with transformers. If you filter at input to reduce BW, you can avoid a lot of RFI issues.
However, if you already have a minimal BW for audio and still have RFI issues, you would have to find the ingress else-where and reduce it... often thru shielding and grounding methods.
-RNM
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This is really depressing with so many great Discrete transistors disappearing. I guess it had to happen. Maybe the mfr of replacements like Linear Systems will add more to their list of legacy transistors ---- like they now make the ...170/74's.
Yet, the 2N2905A, 2N2219A, 2N2222A etc have been around forever and are still available. Maybe we need to think about high performance audio circuits using those? We have more tools to work with since those were invented and processes are even better now. And there are some long living fets around also.
Time to stretch this discrete design way of life a little further using more readily available parts and still get great audio performance.
THx-RNMarsh
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These were made on 4" (yes 4") wafers in Nijmegen along with a lot of other esoteric RF stuff. They did not transfer it to 8" because the processes were really, really optimized and ran very well for years (milk the assets - that's how you do it in semiconductors!). They built up a large die bank in 2015 and have been assembling off of this. I guess that must be running down now.
I just ordered 1000 pieces to see me though the next year or so. I will have to find another solution after that.
(Scott, I am no longer with NXP BTW - but after 20 years they looked after me well enough for me to hang my gloves up at 59 and go out and pursue my real passion - audio)
.Thanks, waly, for clarifying. Certainly not as good but not the end of the world audio wise. For instrumentation, a much bigger loss. There was a sanyo jfet/bipolar (cascode) that is/was low noise too that you recommended. What was the part #?
And no problem, Jan, just took a couple more posts to drill down the question at hand.
And no problem, Jan, just took a couple more posts to drill down the question at hand.
You may notice that the thread was moved to The Lounge area (off topic), despite strange mod interventions to enforce non-lounge rules.
Kind of sad that a high effeciency speaker would have way more range on the same power.
So is the RF literally flying off the LED's, or from the cables to them? All of it?
DVV: this is something we are starting to explore over on the analog source forum. Slow progress as none of us have much time, but it's entertaining in that we all accept its a flawed medium and its just a bit of fun to pick apart long cherished beliefs. For example the 2M series may actually not be as good as the older SuperOM series.
But many heresies being committed, such as transconductance MM stages
It's about the same thing, not ideally but near enough. 2MRED is the lowest priced offer, and in my view it's a bit unruly for my taste. The 2MBLUE replaces the elder OM 20, and does so very well indeed, using my Luxman LO-C3 preamp with its RIAA eq amp stage and/or Marantz 3250 B preamp with its RIAA stage. Very slight preference for the Luxman preamp.
Both 2Ms are less susceptible to input parallel capacitance where the OM series were VERY sensititive to any greater mismatches.
Unfortunately for analog switches the N is good for noise by luck and the P is VERY bad.
The LEDs are built into a module containing basically everything but the power supply. The ones I know of have signal in and out to the adjacent module. Whole shebang fed from a fiber.
Just think of the area with a low power emitter every 5mm. Roughly 3600 per square foot at maybe 50mW each.
SuperOM40 is still available new in Germany for around €300. FG70 for the price of the 2Mbronze fine line and a much wider range of options available. For me was no choice. Although looking at the results Scott got with a U-turn orbit and cheap Grado I realise I am possibly deluding myself.
Feh. Many ways around this in DIY land. All discovered 40 odd years ago then forgotten until recently. IMO the problem has always been the phono stage not the MM cartridge. What MC have is the story. Hogged from billet, hand carved wood (by monks/virgins/aliens) etc all makes for good marketing copy and looks bling on the tonearm compared to the poor plastic MM.
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