Ed what do you use as a rule of thumb for crest factor? 12dB is pretty wimpy that puts us at a peak power of 2600W, 15 dB and our PA is 5200W.
So you folks like the sound of clipping?
I have two batches of samples but distinctly remember the prelim DS was found by their search feature. BTW all parts I have seen are from one date code.
The j17x family from Fairchild is lousy for noise, if their SST174 was quiet the issue would be somewhat moot.
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10 db is bus station paging, and rock concerts
20 db is almost everything from churches to college level performing spaces
30 db is live symphonies, past that I don't hear a difference.
The caveat is places such as NFL stadiums require 105 db "A" maximum SPL but 10 db headroom for announcements and 15 for music during the game and 20 for pregame. (Subtract 10 for colleges and minor leagues.)
Now those numbers are for live performances from pros. Amateurs may suddenly eat the mic and require operator gain control. Recorded music is 20 db for analog sources and 0 for digital, but digital 0 is often equal to analog -12.
Normal home listening is 75 db with 20 db of headroom. Headbangers may want 95 and 15. Then there is the fellow on this site who wants to hit 140.
The use of digital has really reduced the need for headroom in reproduction systems. It really is hard to duplicate a stylus drop or record warp power requirements.
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Sorry I was mistaken they list the 2SJ74V at $11.85, get them while you can.
Personally, while at home, I doubt that I ever exceed 100W, with my 250W/ch amps. And I worked for the Grateful Dead for years, go figure!
So how come George Massenburg puts FET's in the same class as IC's. You guys just can't agree. Dick Burwen thiks a 100 op-amps each coupled with back to back electrolytics are OK, what are we all to think?
There's a lot of truth to that - RFI immunity, freedom from coupling capacitors, noise matching. Plus, something FETs *can't* help with, the 800 pound gorilla of dirty grounds: pernicious ground loops. Lots to be said in their favor.
Thanks,
Chris
Folks,
Each and every device has it's advantages and drawbacks.
There are good reasons as to why one or the other may prove more appropriate in a given position than another and why sometimes compound circuits are an even better choice, if we have a "only the best, cost no object" application and why we may have to compromise on these choices if we have cost as an object.
For example with cost constrains, I may have the choice between a mediocre Op-Amp plus a mediocre Buffer which will drive 32 Ohm at 7V RMS without rise in THD but sounds mediocre, or using the whole budget on the best sounding op-amp I can get for the money and accept that if anyone wants to use silly loads there will be a worsening of measured (and perhaps audible) performance and simply do a Steve Jobs ("Just don't do that!").
A competent engineer knows the advantages and drawbacks and how they affect a given circuit, as well as the requirements. He should also realise that a specific devices specific drawback may, with concious, deliberate and careful application, be turned to advantage.
There is little use in Dogma's and much to be said for being pragmatic, as in: "It doesn't matter if the cat is black or white as long as it catches the mice".
My GF wanted to get a Dogma ones, one of of those yappy, bugeyed toy dog's Paris Hilton and Brittany Spears have. I just gave her a STRONG NO and told her if get anything we get a real Maneki Neko with odd coloured eyes... She told me: "YES SIR!"...
Ciao T
PS, for those who do not get the bit about the strong no, watch this (warning, watch to very end, before getting offended about the misogynoism in this video)...
The Girlfriend Trainer - YouTube
Each and every device has it's advantages and drawbacks.
There are good reasons as to why one or the other may prove more appropriate in a given position than another and why sometimes compound circuits are an even better choice, if we have a "only the best, cost no object" application and why we may have to compromise on these choices if we have cost as an object.
For example with cost constrains, I may have the choice between a mediocre Op-Amp plus a mediocre Buffer which will drive 32 Ohm at 7V RMS without rise in THD but sounds mediocre, or using the whole budget on the best sounding op-amp I can get for the money and accept that if anyone wants to use silly loads there will be a worsening of measured (and perhaps audible) performance and simply do a Steve Jobs ("Just don't do that!").
A competent engineer knows the advantages and drawbacks and how they affect a given circuit, as well as the requirements. He should also realise that a specific devices specific drawback may, with concious, deliberate and careful application, be turned to advantage.
There is little use in Dogma's and much to be said for being pragmatic, as in: "It doesn't matter if the cat is black or white as long as it catches the mice".
My GF wanted to get a Dogma ones, one of of those yappy, bugeyed toy dog's Paris Hilton and Brittany Spears have. I just gave her a STRONG NO and told her if get anything we get a real Maneki Neko with odd coloured eyes... She told me: "YES SIR!"...
Ciao T
PS, for those who do not get the bit about the strong no, watch this (warning, watch to very end, before getting offended about the misogynoism in this video)...
The Girlfriend Trainer - YouTube
Hi,
I never knew there was anything about it there? I had a standing sample request for them with Paul for years.
I figured the LSJ74 was just like one of them yellow submarines, or it must've been one of them "Unidentified Flying Cupcakes". Or a pigment of me imagination.
But I don't have an imagination.
Good thing we bunkered a few k's worth of K170/J74 and even already sorted them into pairs. Once they have aged a bit (semiconductors are like wine, worth more well aged past obsolescence) I might even start designing a High End product with them, around the time Charles's stash has run I should think...
Ciao T
I never knew there was anything about it there? I had a standing sample request for them with Paul for years.
I figured the LSJ74 was just like one of them yellow submarines, or it must've been one of them "Unidentified Flying Cupcakes". Or a pigment of me imagination.
But I don't have an imagination.
Good thing we bunkered a few k's worth of K170/J74 and even already sorted them into pairs. Once they have aged a bit (semiconductors are like wine, worth more well aged past obsolescence) I might even start designing a High End product with them, around the time Charles's stash has run I should think...
Ciao T
Yes, watch to the very end so instead of getting offended about the misogyny, you can get offended about the misandry. 😀
se
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