Burning Amp Is November 9 & 10, 2019!!!

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gwolfman

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Joined 2011
Soundhappy said:
OK is H2 update :) My hope is SE Sony Vfet amp or something with big Tokin SIT's.
Any informations ? Surprise DIY project maybe ?
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News of a variable/adjustable crossover. Select your caps as desired, and adjustments can be made after the fact via pots(?) on board. It also has selectable falloff (e.g., 3, 6, 12db).

Soundhappy said:
F8 = Circlotron topology ?
Wishes of the very goood rafle :D
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Won a set of 3.5" drivers. There were some other very hot items and some no one bothered to put a ticket in.
 
chromenuts

chromenuts

Member
Joined 2008
Paid Member
Soundhappy said:
My hope is SE Sony Vfet amp or something with big Tokin SIT's.
Any information?
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There was a question posed to Paul of Linear Systems inquiring about the possibility of them producing power JFETs I believe.

There was no indication by Paul in his response that it was something they were considering.

However, there was an off hand comment by Papa directly afterward regarding a letter he needed to send them regarding SITs. Whether this was jokingly or not I have no idea.

I suppose you could cross your fingers.
 
Wavebourn

Wavebourn

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Joined 2006
wavebourn.com
WBS said:
??? I'm not even on FB but was able to access.

Thanks WB!

I probably should have left the mike with you so you'll have it for next year. I think it helped save Papa's voice! And he was clearly heard.
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Yes, this year thanks to the mike, Papa was finally heard well! :D

Unfortunately, I do not know yet if I will be able to come the next year, we plan to move to Texas.
 
Wavebourn

Wavebourn

Member
Joined 2006
wavebourn.com
chromenuts said:
There was a question posed to Paul of Linear Systems inquiring about the possibility of them producing power JFETs I believe.

There was no indication by Paul in his response that it was something they were considering.

However, there was an off hand comment by Papa directly afterward regarding a letter he needed to send them regarding SITs. Whether this was jokingly or not I have no idea.

I suppose you could cross your fingers.
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By the way, Papa's "thousand JFETs" approach is much better than making one big FET, because there is no single crystal with high concentration of dissipated power on the tiny area of a huge thermo-conductive thermo-capacitance of a heatsink. Dynamic distortions are what tubes do better than FETs. Our hearing is dynamic, it does not care how low THD you measured on your bench, but all small dynamic changes reveals artificial reproduction of sounds.
Remember what Bob said about "optimal bias" of output transistors? Slight change of temperature on a loud passage, and it is way off, until the temperature sensor brings it back, with a phase delay!
Thousand of FETs distribute this dissipation in the volume. You can sense temperature of one transistor to compensate all of them at once!
 
wrenchone

wrenchone

Member
Joined 2004
For those interested in trying them, there are some Russian stud-mount power (a few Watts dissipation) jfets available on E-pray. Some people here on Diyaudio have tinkered with them. If I remember correctly, they will pop up if you use the search term "KP" and do some weeding afterwords. You will net both jfets and mosfets using that search term. You can use the part numbers thus harvested here to winkle out the folks who have used them.
I have a few of them, but haven't had the opportunity yet to put them to work. They're not all that expensive... They were probably originally intended for RF duty.
 
Wavebourn

Wavebourn

Member
Joined 2006
wavebourn.com
wrenchone said:
They were probably originally intended for RF duty.
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Exactly.
KP903 means according to GOST on naming:
K: silicone (G germanium, A Gallium arsenide)
P: fild effect (T bipolar)
9: high power high frequency
(1-low power low frequency, 2-medium, 3-high.
4- medium power low frequency, 5- medium frequency, 6 - high frequency,
7 - high power low frequency, 8 - medium frequency, 9 - high frequency)

Sometimes instead of the 1'St letter you can see a number 1,2,3. The same as letters (G,K,A), but mil spec.

KP903A (2P903A) = CP651, CP664, CP665 Transistor silicon USSR Lot of 2 pcs | eBay
 
M

mordikai

Member
Joined 2005
“Missing Speakers”
I had a great time until I got home and realized my speakers were not in my car. I’m not sure if I left them in the room at the event or on the side walk when loading all the other stuff in my car. They are small 2-ways made of solid walnut with black baffles. Thanks for any info.
I will of course contact Fort Mason in the morning.
 
Tom V

Tom V

Member
Joined 2010
Paid Member
mordikai said:
“Missing Speakers”
I had a great time until I got home and realized my speakers were not in my car. I’m not sure if I left them in the room at the event or on the side walk when loading all the other stuff in my car. They are small 2-ways made of solid walnut with black baffles. Thanks for any info.
I will of course contact Fort Mason in the morning.
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I have them. Left in the Volta room.

-Tom-
 
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