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Old 25th September 2006, 08:09 PM   #101
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That output stage is not generally a power follower, as its
swing loss is too great at unity gain. For unity gain, I suggest
classic complementary followers.
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Old 28th December 2006, 04:12 PM   #102
routhun is offline routhun  United States
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Dear pass,

I would like to operate the PLH at 28V, as I have 28V,4A regulated power supply. What are the changes needed in the circuit. Also I would like to operate this amp only in push-pull mode. Can I replace P2 with 390ohms + 110 ohms series connected resistors with the bootstrap capacitor connected at their junction?

Thanks
Routhun
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Old 28th December 2006, 06:53 PM   #103
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I would advise finding the exact value you want using P2
and then replacing it with that resistor.
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Old 28th December 2006, 07:00 PM   #104
routhun is offline routhun  United States
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Thanks Mr Pass,

Do you mean that the circuit doesn't need any changes to operate at 28V? I'll try to find the exact value with P2 and later replace it with a fixed resistor.

Thanks,
Routhu
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Old 28th December 2006, 08:32 PM   #105
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I don't recall testing the amp at 28 volts, but probably
you will be able to adjust P1 through P3 to get what you
want. If not, you will need to revise the values of the
resistors in series with those pots. R4 and R6 would go
down in value, and R7 would go up.

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Old 29th December 2006, 12:08 AM   #106
routhun is offline routhun  United States
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Thanks Mr Pass,

I'll give a shot with 28V.

Thanks,
Routhun
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Old 4th January 2007, 08:54 PM   #107
DIGORA is offline DIGORA  Belgium
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Where is the X PLH ?
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Old 12th April 2007, 12:05 PM   #108
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Did anyone build it? Have not seen any on the passdiy site? Is there a direct coupled dual supply version in the works?
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Old 12th April 2007, 06:09 PM   #109
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I don't recall any mention of Xing the PLH. It could be done
if you restore the input transistor - more specifically, creating
a differential pair input.

With a more elaborate effort it could be done without the
diff pair input, setting up the negative output devices differentially
to create the same effect.

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Old 12th April 2007, 06:28 PM   #110
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Quote:
Originally posted by Nelson Pass
I don't recall any mention of Xing the PLH. It could be done
if you restore the input transistor - more specifically, creating
a differential pair input.

With a more elaborate effort it could be done without the
diff pair input, setting up the negative output devices differentially
to create the same effect.

Sorry for the confusion. I was asking about the direct coupled +- supply version of the PHL not an x'ed version.

Thanks!
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