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Old 17th January 2017, 06:21 PM   #11
6L6 is offline 6L6  United States
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Fixed. Thanks!
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Old 17th January 2017, 06:31 PM   #12
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Great job Jim!
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Old 17th January 2017, 06:51 PM   #13
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I see the boards available, is it possible to get in a line somewhere, or are the output transistors all gone?

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Old 17th January 2017, 06:57 PM   #14
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Originally Posted by Russellc View Post
I see the boards available, is it possible to get in a line somewhere, or are the output transistors all gone?

Russellc

Hi Russellc,

Sign up while you still can. Please see this post:

Sony VFET Amplifier Part 2

Dennis
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Old 17th January 2017, 07:03 PM   #15
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damn

6L6 again faster than Mighty Moi

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Old 17th January 2017, 07:18 PM   #16
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Fantastic. Thanks for this.
Your work is much appreciated
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Old 17th January 2017, 07:49 PM   #17
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Anyone know the price for the kits? Search turns up nothing.
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Old 17th January 2017, 09:01 PM   #18
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A little bit over two hundred bucks depending on postage
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Old 18th January 2017, 03:12 AM   #19
delecoy is offline delecoy  United States
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Default Measuring v-fets Vgs for starting bias point

Thank you Jim! The case for my vfet amp arrived today so I will be following closely

I do have one question: I know the article presupposes that one bought the full vfet kit ( which I did ) - but I also bought vfets long before the kits were released. How would I go about measuring them ( safely obtaining an accurate Vgs ) to set the right bias point if that was all I had? Guessing there will be others in that boat with vfets they cant afford to mistakenly burn.

Not looking a gift horse in the mouth. I will be forever grateful for your help on my BA3FE and F4

Thank you much!

NP from he Sony Vfet Part 2 article:
"I matched the VFETs for a Vgs within 0.1 volts at 0.5 amp current at 20 volts, and 0.2V Vgs is good enough. Some of you won't have good matches or only enough VFETs for 1 pair per channel, but you can build the amplifier and it will work fine, with somewhat less power and higher distortion. I tested that with 1 amp bias current, and it did just under 20 watts into 8 ohms."
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Old 18th January 2017, 07:30 AM   #20
WalterW is offline WalterW  Netherlands
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Quote:
Originally Posted by delecoy View Post
Thank you Jim! The case for my vfet amp arrived today so I will be following closely

I do have one question: I know the article presupposes that one bought the full vfet kit ( which I did ) - but I also bought vfets long before the kits were released. How would I go about measuring them ( safely obtaining an accurate Vgs ) to set the right bias point if that was all I had? Guessing there will be others in that boat with vfets they cant afford to mistakenly burn.

Not looking a gift horse in the mouth. I will be forever grateful for your help on my BA3FE and F4

Thank you much!

NP from he Sony Vfet Part 2 article:
"I matched the VFETs for a Vgs within 0.1 volts at 0.5 amp current at 20 volts, and 0.2V Vgs is good enough. Some of you won't have good matches or only enough VFETs for 1 pair per channel, but you can build the amplifier and it will work fine, with somewhat less power and higher distortion. I tested that with 1 amp bias current, and it did just under 20 watts into 8 ohms."
This is what Nelson presented how to measure the VFETs
Attached Images
File Type: gif VFET%20TEST.gif (51.9 KB, 660 views)
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