Agreed - which is why I said I don't have much insight into your business. I always did direct customer sales, distribuors and end users.
You do solutions, I do end user products. Similar in some things, very different in others.
Bingo .... ! 20% in development 80% in marketing , flip that = failure !!!
That's so disappointing! I recall around age 8, during TV coverage of the Gemini program, seeing no less than Walter Cronkite telling of some of the spinoffs of the NASA space program, including Teflon no-stick cooking pans.
How could Walter Cronkite be wrong?
I don't know what Nasa used, but in Russian shuttles ceramic tiles were used. I consulted one avionic corporation in Samara that had a common fence with enterprise that used to build Soviet space shuttles. They told an anecdote, when Michael Gorbachov had to visit facility, they prepared for him a nose of space shuttle in one building, to show their production. Nose fit into the building, the rest would not. But they were very disappointed, because President even did not enter that building.
Darn these FETs are fast. I am still trying to make the DH-120 completely stable. With the Exicon outputs, and 330, 220 gate resistors, it now has a full power bandwidth of about 80K, up from about 50K. It keeps trying to oscillate at about 300 meg. I moved the gate resistors to the sockets, added 47uF power supply bypass at the sockets with dedicated run to ground, reduced C8 to 68p and maybe that will be it. I thought I had it a couple of times, but when all buttoned up, it comes back. I may need to up the gate resistors again to slow it down. It took a while to find my mystery distortion. R15 must have been damaged as it was 14 Ohms, not 10. Feedback was clipping trying to fix it. In spite of what the simulator says, the dominant pole is not loading down the VAS as the 10Khz square wave looks just fine. The sim is no help on the parastatic oscillation either.
Back to the sound of amps, I identified another "simple" amp that was built under the less is more idea, somewhat like the Rotels. That is the little Adcom 535 designed by Mr. Pass. I know nothing about how they sound, but remember many years past not being in love with the bigger 555 everyone wanted to sell you. Of course, I had not honed in on the wife hearing test yet. The small Nak PA5 and small Threshold of the same era have been recommended as examples of his work that are practical to live with. A 20% efficient 10W amp or one that costs three times my new car are both not in the running.
Back to the sound of amps, I identified another "simple" amp that was built under the less is more idea, somewhat like the Rotels. That is the little Adcom 535 designed by Mr. Pass. I know nothing about how they sound, but remember many years past not being in love with the bigger 555 everyone wanted to sell you. Of course, I had not honed in on the wife hearing test yet. The small Nak PA5 and small Threshold of the same era have been recommended as examples of his work that are practical to live with. A 20% efficient 10W amp or one that costs three times my new car are both not in the running.
Hi,
Unless you have double-die Mosfets (the 16A ones) your gate resistors are too low, try 470/680...
Ciao T
Unless you have double-die Mosfets (the 16A ones) your gate resistors are too low, try 470/680...
Ciao T
Hi,
Nasa also used tiles.
Sad as the ignominious end of the Buran Program was, I think to it's credit, it never crashed...
Ciao T
Nasa also used tiles.
Sad as the ignominious end of the Buran Program was, I think to it's credit, it never crashed...
Ciao T
T,
The small ones, 16N10 in TO-3 packages. 680/470 is way slower than the tech sheet but probably way safer too.
Any recommendations for an "ugly" passive load for full power testing? I just have a resistor plate. As stability is the test in question, and I am not doing steady state 60W tests with a speaker on it, I would like a generic typically ugly load to test. 6 Ohms with some additional network. Is there a standard? What is in that load cube thigie?
The small ones, 16N10 in TO-3 packages. 680/470 is way slower than the tech sheet but probably way safer too.
Any recommendations for an "ugly" passive load for full power testing? I just have a resistor plate. As stability is the test in question, and I am not doing steady state 60W tests with a speaker on it, I would like a generic typically ugly load to test. 6 Ohms with some additional network. Is there a standard? What is in that load cube thigie?
Hi,
680 (N-Ch) & 470 (P-Ch) are canonical across many amplifiers using lateral Fet Followers. You may also want a small value LOW INDUCTANCE (short leads) cap from Drain to Heatsibk/Earth/Ground. In this day and age I'd probably use a Siemens/Epcos naked "stacked film"for that.
Any speaker with highly reactive bass loading (large phase angle low impedance).
But with a single single die output Mosfet using that would be completely hopeless...
Ciao T
680 (N-Ch) & 470 (P-Ch) are canonical across many amplifiers using lateral Fet Followers. You may also want a small value LOW INDUCTANCE (short leads) cap from Drain to Heatsibk/Earth/Ground. In this day and age I'd probably use a Siemens/Epcos naked "stacked film"for that.
Any speaker with highly reactive bass loading (large phase angle low impedance).
But with a single single die output Mosfet using that would be completely hopeless...
Ciao T
Have the cap in place already. Even Hafler did that. Have the larger resistors. I was looking for a network, not a speaker to test with.
Fortunately, the eventual use is for a 6 inch two way in a small room.
I made a thingy from external hard drive enclosure, adding one more fan for cooling of wirewound resistors. It has inside resistors, and binding posts outside. I can connect it as 2,4,8,16 Ohm load. For observing behavior of amp designed for 8 Ohm it is enough to test it on 4 Ohm, for 4 Ohm amp enough to load on 2 Ohm. No need for reactive loads that look more like real load, but make observation of behavior inconvenient.
This reputation boils down to comparison between Soviet electronics for military vs Soviet electronics for civil consumers. Night and day difference. As the result, even good products for civil usage were regarded as garbage.
I heard a rumor, when Shokin stepped on the post of Minister of Electronic Industry he visited some flagman institutes and plants. Above the entrance to some floor on some plant he spotted huge red banner, "Praise Soviet Transistors - the Biggest Transistors in the World!". He whispered into the ear of his assistant, "Remove it immediately!"
Yes, maybe there is something going on.
This paper has some interesting spectral graphs. (I didn't post any cuz they're distinctly marked copy write):
There's life above 20 kilohertz! A survey of musical instrument spectra to 102.4 kHz
Boyk is interested in the harmonic spectra above 20 kHz but looking at below that range is interesting.
I think there's plenty going on under 20 kHz to give a system some grief. Given the energy maybe even under 1kHz.
And if the guys doing a recording got things messed up there could be some nasty artifacts waiting for just the right amp/speaker to express them.
Harmonica spectrum is even scarier.
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