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Old 22nd July 2012, 05:48 AM   #581
lhquam is offline lhquam  United States
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Default Roots of the F5 Turbo

I just ran across this. Perhaps it has been mentioned before in this thread, but I have not seen it.

Bob Cordell Interview: BJT vs. MOSFET

Nelson says:
BTW, there is a pair of diodes - I also used a trick that I got from
Barney Oliver of using power diodes to shunt across emitter
resistance so as to limit the maximum voltage at high current.
It made the job easier for my (admittedly crude) bias circuit.
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Old 22nd July 2012, 07:00 PM   #582
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Similar trick. Actually I didn't get it from Barney Oliver, but later discovered
that he had done it before me.

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Old 23rd July 2012, 05:46 AM   #583
lhquam is offline lhquam  United States
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Quote:
Originally Posted by Nelson Pass View Post
Similar trick. Actually I didn't get it from Barney Oliver, but later discovered
that he had done it before me.

In the F5 Turbo, would you say that the goal of the diodes was to increase transconductance by decreasing the effective source resistance, or to increase the output voltage swing at high currents, or something else?
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Old 24th August 2012, 02:50 AM   #584
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Quote:
Originally Posted by lhquam View Post
In the F5 Turbo, would you say that the goal of the diodes was to increase transconductance by decreasing the effective source resistance, or to increase the output voltage swing at high currents, or something else?
In user point of view, may I consider this diode trick as a kind of power saving solution for class A schematic
We don't need to set highly idling current (Id) but we still can get large, intact output power out signal (without clipping at negative half cycle)

Not too hoot, not bad at all. Sorry, if may I wrong!
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Old 24th August 2012, 09:18 AM   #585
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no. not at all.
the bias is just as high.
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Old 1st March 2013, 12:43 AM   #586
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24v secondarys for f5 turbo right
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Old 1st March 2013, 01:31 AM   #587
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Depends. 50W yes. 100W, you need 32V secondary.
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Old 1st March 2013, 01:37 AM   #588
labjr is offline labjr  United States
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Would 800 VA be enough for 100 watts?
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Old 1st March 2013, 02:11 AM   #589
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For 100W V3, you are gonna be dissipating about 250W per channel. I would think 800 per channel or monoblock is more ideal.
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Old 1st March 2013, 02:19 AM   #590
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when are there going to be boards available? I need v3 and f5c
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