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Old 18th May 2005, 08:59 AM   #1
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Default what does everyone think of this amp?

here

http://img.photobucket.com/albums/06...hemy_OM150.jpg
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Old 18th May 2005, 09:44 AM   #2
MikeB is offline MikeB  Germany
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Hmm, i think it's not functional at all ?
The biasing in the outputstage is not defined at any point,
collectors from predrivers connected to base of drivers
without any resistor defining a voltage ?
Also, i can't see how the vbemultiplier should work ?
Is the schematic incomplete ?

Mike
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Old 18th May 2005, 10:09 AM   #3
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hi Mike I think its complete, q208 is output biasing/vbe.

q216 is the pre driver, the collectors are obviously the voltage amplifiers
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Old 18th May 2005, 10:26 AM   #4
MikeB is offline MikeB  Germany
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But how should q208 set anything through the diodes which are closed ?
These collectors can't make any voltageamplification, they can only
supply full voltage (minus vce-sat) , then they enter reversebias.
So you supply near full railvoltage to the base of the drivers, blowing them up ?

Mike
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Old 18th May 2005, 10:27 AM   #5
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Quote:
Originally posted by lt cdr data
hi Mike I think its complete, q208 is output biasing/vbe.

q216 is the pre driver, the collectors are obviously the voltage amplifiers

There is no collector resistor defining the pre-drivers as voltage amplifiers and nor is the VBE multiplier is adequately implemented.

The schematic lacks major key factors to act as an amplifier, is it really complete or you might forget something to draw.
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Old 18th May 2005, 10:46 AM   #6
sajti is offline sajti  Hungary
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Quote:
Originally posted by MikeB
Hmm, i think it's not functional at all ?
The biasing in the outputstage is not defined at any point,
collectors from predrivers connected to base of drivers
without any resistor defining a voltage ?
Also, i can't see how the vbemultiplier should work ?
Is the schematic incomplete ?

Mike

I agree. This schematic doesn't work. There are some missing connection, and/or missing parts.

I think that the anode of the CR202 should be connected to the collector of Q210 and 212, and the cathode of the CR203 should be connected to the collector of the CR211 and 213.
With this modification the bias will works, and I think the amp too.

sajti
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Old 18th May 2005, 07:20 PM   #7
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Default Remove diodes, and bias will work!

The circuit is interesting.... and will work...some small changes only.

Carlos
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Old 18th May 2005, 07:44 PM   #8
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Default Hi Carlos

Hi Carlos,

I have been away for a while. Good to see you are still here.

mike
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Old 18th May 2005, 11:21 PM   #9
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Default I am still happy to see you here.

Good old guys...always good to see them here...i miss a lot of them..... halojoy too.

regards,

Carlos
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Old 19th May 2005, 08:39 AM   #10
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At last, he is back.

Help me, Carlos, because you were gone they have been picking on the words in my posts.
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