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Old 15th November 2012, 08:43 PM   #41
tbece is offline tbece  Australia
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Glyn > Mitsubishi Electric RF Devices

http://www.mitsubishielectric.com/se...4/rd16hhf1.pdf
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Old 16th November 2012, 12:50 AM   #42
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Quote:
Originally Posted by Jon Lord View Post
Take the MRFE6VP5600HR5, you get it from Mouser and DigiKey in single quantities.

No SiC-switching-transistor will ever reach this performance !
Well the prices are comparable but SiC has ten times higher voltage rating - why would one compare oranges with apples.
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Old 16th November 2012, 01:30 AM   #43
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hmm interesting thanks !
Will try and buy a couple of RD100HHF1 to try out in the F6 and see what blows up (rf transistors, inductors and capacitors in close prximity - )
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Old 16th November 2012, 01:03 PM   #44
flg is offline flg  United States
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Originally Posted by Jon Lord View Post
:The commercial SIT is dead: long live the V-FET !!!
First of all, this must be humourus. Absolutely no one in this bisness has the ability to know what will be happening even in the near term. It's a little like the Stock Market

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This 1000W-Transistor eats SiC-FETs and V-FETs for breakfast in Audio.
You have some proof of this? Some examples maybe? If this actually were the case, there are plenty willing to do whatever is necessary to build the best equipment with the best components. Where are all these products? Just calling them 1000W transistors is incorrect when refering to DC characteristics like typical parameters of typical audio devices.
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Old 17th November 2012, 05:30 AM   #45
tbece is offline tbece  Australia
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Originally Posted by flg View Post
...snip...
You have some proof of this? Some examples maybe?
...snip...
RF devices are good because the nonlinear capacitances are much smaller, so their contribution to distortion at 20kHz is much less. For example, here is a test setup with 2x RD16HHF1, Zen Classic, 30V/2A, 1W/8ohm, measured at 1kHz and 20kHz. While at 1kHz the RD16HHF1 measures very similar to the original, the distortion at 20kHz is essentially unchanged - big improvement.
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Old 26th November 2012, 06:59 PM   #46
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http://www.infineon.com/dgdl/Infineo...376f50964a3e6b


Seems infinon have also integrated a diode
There are some coss ciss crss curves in there
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Old 26th November 2012, 10:12 PM   #47
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Default V-FET (SIT) was great, but RF LDMOS is promising to be better in simplistic Class A

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Originally Posted by flg View Post
First of all, this must be humourus. Absolutely no one in this bisness has the ability to know what will be happening even in the near term. It's a little like the Stock Market
This was related to DIYaudio and yes: At the moment the commercially available SIT seems to be dead, except Nelson Pass starts selling his SET-1 without an amplifier around it for less than 100 USD ...


Quote:
Originally Posted by flg View Post

You have some proof of this? Some examples maybe? If this actually were the case, there are plenty willing to do whatever is necessary to build the best equipment with the best components. Where are all these products? Just calling them 1000W transistors is incorrect when refering to DC characteristics like typical parameters of typical audio devices.
A transistor, which is able to dissipate 1000W DC and source currents of 20A+ is ahead of anything conventional regarding SOA, and there are enough 55V RF linear transistors around, which meet this spec or come at least close.

As tbece mentioned (bravo !!), regarding AC performance, in Class A these must be better than any Audio transistor and 600V+ (SiC, SIT or whatsoever) switching transistor, because Crss and its nonlinear portions are a few degrees of magnitude smaller at voltages around 20V and that's the region where audio is taking place, not at 200V or 500V, where SiC switches get somehow better but not very good.

And: If a big gray crowd is not able to get a certain point for decades or even centuries, a single visionary or a few of them can nevertheless be totally right. The history of science teaches this lesson. There are many examples.

And No: I don't have a proof of an actual circuit for you, but I have an open mind and probably many other members here have also one, instead of running behind a guru or second order marketing blah from Hifi mags, saying that SiC is superior to Silicon for Audio whatsoever ...

Btw.: I promoted the classic V-FET amplifier and the transistors for more than eight years (At times, when they weren't en vogue) on another forum, but only a few people believed me. Some also asked for a proof. My proof is that I listened to all commercially available classic V-FET amps and I drew my own independent conclusions ... I could even pretend that I listened to more different SIT amplifier designs than anybody else on this planet. Unfortunately this doesn't help to convince people, who didn't actually listen to any of these amplifiers.

Probably we need to wait until NP starts to promote LDMOS RF transistors in let's say five years (When perhaps the die attach solder of his SIT-1 transistors starts to get non RoHS compliant or the like), then the crowd of LDMOS believers will certainly grow but the number of people, who are looking into the future will still stay very small.
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Last edited by Jon Lord; 26th November 2012 at 10:15 PM.
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Old 26th November 2012, 10:25 PM   #48
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Quote:
Originally Posted by tbece View Post
RF devices are good because the nonlinear capacitances are much smaller, so their contribution to distortion at 20kHz is much less. For example, here is a test setup with 2x RD16HHF1, Zen Classic, 30V/2A, 1W/8ohm, measured at 1kHz and 20kHz. While at 1kHz the RD16HHF1 measures very similar to the original, the distortion at 20kHz is essentially unchanged - big improvement.
This is really great, the Zen design is probably the most pathologic case for Crss induced distortion, because Crss lies there parallel to the feedback resistor.

Using an ordinary VMOS or a Power-J-FET provokes Phase Intermodulation Distortion in the range of a microsecond or so.
Nobody would ever like to listen to digital Audio with a Jitter of 1us at 20kHz.
PIM and Jitter have the same mechanisms behind of them and sound very similar ...

Let me guess, the RD16HHF1-Version sounds more open, less blurry, much wider and deeper in sound stage etc., even when the 1 kHz THD is not (much) better ...
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Old 26th November 2012, 11:19 PM   #49
flg is offline flg  United States
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The data sheet seems to show some qualities such as linearity and low C that are quite worth the experimentation excerise. The device seems to have miniscule amounts of gain? And, it seems a little power limited for Class A use. But, I see you are running it at 30V - 2A in your Zen? That's more than the Absolute Max Rating even if you could keep it cool with that Rth j-c?
How does it sound would be the real point of the matter.
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Old 27th November 2012, 12:13 AM   #50
vizion is offline vizion  United States
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Health care costs are going up especially for corporations.

Back to mosfets then...
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