The cite does offer an insight into just how successful you and your colleagues were.
But I'd rather not think about what still may come.
Most of the advances IMO are in the next gen HE required and smaller trigger devices. But, the underground tests data characterized and predicted weapon design so well in developing computer models, that a 'ban' on testing could be done. Now it is all designed in computer models/SIM design. Further modelling is done thru plasma research studies (fusion experiments, etc). Lots of new nuclear toys now... ones with enhanced radiation. Different types of radiation. Ones without radiation. Etc. If we wish, we can kill every living thing in a city without destroying the buildings and infrastructure... with short-lived radiation. What fun the next Big One will be.
We live in interesting times.
-RNM
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transitioning from WMD to Weapons of Living Destruction.
What a capitalist dream. Save the capital and get rid of the bothersome organic bits.
What a capitalist dream. Save the capital and get rid of the bothersome organic bits.
Most of the advances IMO are in the next gen HE required and smaller trigger devices. But, the underground tests data characterized and predicted weapon design so well in developing computer models, that a 'ban' on testing could be done. Now it is all designed in computer models/SIM design. Further modelling is done thru plasma research studies (fusion experiments, etc). Lots of new nuclear toys now... ones with enhanced radiation. Different types of radiation. Ones without radiation. Etc. If we wish, we can kill every living thing in a city without destroying the buildings and infrastructure... with short-lived radiation. What fun the next Big One will be.
We live in interesting times.
-RNM
It is not the big guys I worry about. It is the small single stage device with only partial yields.
If we wish, we can
(Mr. Marsh, if you're attempting to stimulate my G-spot, it's working)
Nuclear weapons , is definitely stupidest human invention of all times,![]()
My father was Corps of Engineers stationed on Okinawa Japan preparing for the invasion of Japan. Casualty rate on the European Omaha Beach landings was 41% for the Corps. It was expected to be much higher in Japan.
Radiation implosion
Now that’s some slew rate to manage!
Hundreds of terajoules emitted, the impulse created being of a trapezoid form with 1us rise and fall times
And we can’t handle clicks and pops
George
Now that’s some slew rate to manage!
Hundreds of terajoules emitted, the impulse created being of a trapezoid form with 1us rise and fall times
And we can’t handle clicks and pops
George
The BF471/472 models are seriously compromised from my experience - I just got very bad sim results. I went through them carefully, but could not find the problems - I ditched them and went with the Fairchild 1381/3503.
The 471/2 family were discontinued many years ago - I think they are only available as NOS.
I used them on my Ovation 250 Amp for the VAS - nice specs.
Just be careful of the models though.
The simulation models show a very low Vaf for all but the BFSR19A and the BF821. Almost all of the rest of the transistors have a Vaf of ~20. Since Phillips didn't bother putting charts in the datasheets those of us who haven't used them are left to speculate that they really are that bad.
It is not the big guys I worry about. It is the small single stage device with only partial yields.
That would be a very 'dirty' device for sure.
-RNM
The simulation models show a very low Vaf for all but the BFSR19A and the BF821. Almost all of the rest of the transistors have a Vaf of ~20. Since Phillips didn't bother putting charts in the datasheets those of us who haven't used them are left to speculate that they really are that bad.
which are the remaining transistors that are good compl pairs with low C and high voltage and low Vaf?
THx-RNMarsh
which are the remaining transistors that are good compl pairs with low C and high voltage and low Vaf?
THx-RNMarsh
I suppose you mean high Vaf.
Damir
John - what's the difference between the Perseus and Orion phono stages?
The marketing seems to indicate the same circuit was used. I don't expect the schematics until several adult beverages later, ( I suspect that wouldn't help, given the need to match a number of NOS jfets anyway) but some general comments on what differentiates the 2 products would be of interest.
Better device selection?
More parallel input devices?
Better passive components? Tighter component selection?
Teflon versus Polypropelene RIAA caps?
More local power supply regulation?
Bigger raw supply caps and transformer?
The lowest noise selected input devices saved for the Orion?
Better jfets ? (2SK147 / 2SJ72 or?)
More cascoding of devices?
Better chassis shielding and mechanical isolation?
Fewer user adjustments?
Fewer inputs?
The simulation models show a very low Vaf for all but the BFSR19A and the BF821. Almost all of the rest of the transistors have a Vaf of ~20. Since Phillips didn't bother putting charts in the datasheets those of us who haven't used them are left to speculate that they really are that bad.
These are very, very old devices that targeted TV applications and not audio.
I think Philips Semiconductors, now NXP, never got to be one of the biggest suppliers into the auto and banking industries (your credit card is NXP powered) with shitty data sheets.
Cheap shot in my view.
For audio, a Vaf of 20 isn't very good, I wasn't meaning to imply anything else. It wasn't a judgement on NXP as a whole. Those devices would work well in other applications for sure.
which are the remaining transistors that are good compl pairs with low C and high voltage and low Vaf?
THx-RNMarsh
I don't see any good NXP transistors we don't already know about, and it's still possible the models are wrong and the BFR's have high Vaf. It would be nice if someone could confirm this.
Hi, where is everybody? I do want to warn you that the schematic put up for the Orion-Perseus phono stage probably won't work correctly as shown. This is an early schematic, and we changed a lot of things over the years.
My goodness - a lot of JFET's in there.
Did you consider going parallel single ended:-
-potentially less noise - BF862 is the lowest noise JFET available at <1nV/rt Hz with very low 1/f corner. Parallel 8 of 'em and you are in <0.3nV/rt Hz territory. They cost pennies at Mouser
-second harmonic dominates the distortion spectra - not odds - pleasing sonic signature
- certainly easier to source parts
- marry to a good quality 'Scottie' (aka AD797) and all active feedback RIAA EQ for >35dB OLM
- = best of all worlds
See Syn08's website for inspiration and Dennis Colin's LP797 for a good primer.
more l8r 😉
Did you consider going parallel single ended:-
-potentially less noise - BF862 is the lowest noise JFET available at <1nV/rt Hz with very low 1/f corner. Parallel 8 of 'em and you are in <0.3nV/rt Hz territory. They cost pennies at Mouser
-second harmonic dominates the distortion spectra - not odds - pleasing sonic signature
- certainly easier to source parts
- marry to a good quality 'Scottie' (aka AD797) and all active feedback RIAA EQ for >35dB OLM
- = best of all worlds
See Syn08's website for inspiration and Dennis Colin's LP797 for a good primer.
more l8r 😉
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