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Old 5th December 2011, 04:52 PM   #3291
MiiB is offline MiiB  Denmark
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So f....king shi...t that there is not many sj74's left on the planet...!!!
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Old 5th December 2011, 07:35 PM   #3292
sampler is offline sampler  Lithuania
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True... true.... I think mods wouldn't be mad if you didn't left spaces between some words as it is such a big issue. Prices ramps up almost every day for what is left and marked is full of fakes. I just have my fingers crossed for linear releasing complementary for lsk170. Shame on toshiba for loosing interest in what was really not a niche market.
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Old 5th December 2011, 08:45 PM   #3293
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A friend of mine is vice president of Toshiba Germany. I asked him why they do not produce discrete semiconductors any more. He told me that Siemens or Beko buy transistors in the millions and then the price got down to less then a cent per unit. They simply could not make a profit any more and already 25% of the employes had to go in early retirement, so this was a really hard and unpopular decission, also inside Toshiba. He personally was very sorry because he is also a High End freak.
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Old 5th December 2011, 09:35 PM   #3294
sampler is offline sampler  Lithuania
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Sad story... well it's just the way this big old world turns 'round these days I guess. Here's spectrum with complementary pair. Averaging set to 100 with peak hold. I know it says nothing on how it sounds, but at least noise is were it should be. There is some hiss left with 26dB amp and 89dB speakers on max volume, but I could put my head in a speaker box on normal listening level and there would be nothing. 50Hz and harmonics gets picked by my bench supply leads, with batteries there is none.
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Old 5th December 2011, 09:46 PM   #3295
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Wow, this is mighty fine for a circuit as simple like that. I would say, mission accomplished.
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Old 5th December 2011, 09:50 PM   #3296
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Yes, i have that too. Sometimes one channel is a bit less noisy then the other. I have build a simple pre-pre where i can put in transistors in pin holes for noise screening with a headphone, but honest i do not use it often.
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Old 5th December 2011, 10:49 PM   #3297
RCruz is offline RCruz  Switzerland
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"transistors in pin holes for noise screening "

would you care to explain ?
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Old 5th December 2011, 11:01 PM   #3298
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Now, that we have such fine phono amp designers helping me i have more time for fundamental research. If you have followed my thread you know my obsession with buffers. I use them almost everywhere, behind the RIAA, behind my CD player, etc.
I found surprising gains in sound even after already good analog stages. I recently had a real enlightenment when i put my latest buffer behind my Forsell CD player that has quite an elaborate analog stage build in already. What struck me with the Forsell over the years is a sound that is totally free of fatigue but also is rather warm sounding. This is the total opposite what you normally experience from CD. Clean and dynamic, yes, full bodied, liquid and musical, no. Usually i switch off after less then an hour. The new buffer behind the Forsell injects excitement and air but still retains the low fatigue effect. Strange, it sounds more open, free and much more transparent but also big, bold and extremely spacious with incredible focus. The soundstage expands now from close before my ears to 5 meters up, 20 meters deep and as wide as the program allows. It is simply so much there there. The buffer is based on the diamond principle that has some advantages. It can be DC coupled without servo, it has low early effect and the miller capacitance is not amplified by voltage gain, so it is as high speed what the transistor specs allow. But it also has problems. Namely modulation of Ube and that modulates Gm because there is a straight relationship between the Ube and collector current. If you hold Ube still by modulating the base you end up with a very linear amplifier. This is more or less the translinear concept. I will show now the evolution of my buffer but the final version is not done yet so this is a work in progress. First i put in a driven, cross coupled cascode over the input trannis. They supply the input transistors with a copy of the signal that drives the output transistors. That gave an amasing improvement in sound all by itself. The second idea is to drive the output transitors from the current mirror, effectively dynamically cascoding them. The third idea is to drive the driven cascodes also from the mirror, this time the right side so that currents balance in the mirror again. This has not being tried out so this is rather hypothetical. The ultimate in entanglement is then to drive the mirror with a copy of the input signal. See Per Anders Super Buffer.
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File Type: pdf Entanglement Buffer 2.TSC - TINA.pdf (8.3 KB, 89 views)
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Old 5th December 2011, 11:14 PM   #3299
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Ricardo, this is the noise test jig for BJTs. It is more or less a Rosi. The trannis can be inserted into the DIL sockets ( aka pin holes ). How is the weather in Portugal ? We have the first snow and frost.
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Old 5th December 2011, 11:21 PM   #3300
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Here is Per Anders idea. It is shot through the head into the eye but nevertheless a stroke of genius.
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