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Old 27th August 2003, 06:49 AM   #21
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Default parallel output stage

Wich parallel output is better? A or B?

I think in B R1 will genarate too much heat!

circuit is still underway!
Comments and Ideas Corrections are Still Welcome!
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Old 27th August 2003, 07:13 AM   #22
sajti is offline sajti  Hungary
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The "B" version is the only good solution.

Sajti
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Old 27th August 2003, 07:16 AM   #23
sajti is offline sajti  Hungary
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And You can reduce the R1 to 0.1ohm. Due the local feedback inside the CFB the value of this resistor is not really critical.
I found that some small resistors (say 1-2ohms) series with the base of the output trannies help to avoid oscillation.

Sajti
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Old 27th August 2003, 10:56 AM   #24
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R3 en R12 must be the same value! (the whole schematic)

Quote:
hugobross how did you calculate the output power?
it's quite easy:

Uv = supply (rail) voltage
Zl = load impedance (4 ohm, 8 ohm, ...)
Prms = continuous power

Prms = (Uv x Uv) / (Zl x 2)

actually Prms will be a little smaller, because there will always be a Uce across the transistors

best regards,

HB.
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Old 27th August 2003, 04:47 PM   #25
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Quote:
R3 en R12 must be the same value! (the whole schematic)
hugobross So you mean they must be both 22K
or must they be both 27K
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Old 27th August 2003, 04:57 PM   #26
sss is offline sss  Israel
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try also triple putput stage , its the best one but hard to stabilize
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Old 27th August 2003, 04:59 PM   #27
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with 27k the gain is 27x and with 22K it's 22x, but the most important thing is that both resistors have the same value (otherwise the LTP is not balanced well). gain = R3/R2
You can also place resistors of 47ohm (more or less) in series with the emitters of Q1 and Q2 to reduce small differences between both transistors.


best regards,


HB
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