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Old 12th February 2014, 01:33 AM   #1
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Default FORTE 44 Line Stage Schematic Reconstructed

Hello Friends.....

Recently I was contacted by a Forte 44 owner who was looking for a copy
of the schematic. I didn't have it, having left Threshold prior to that product,
but he sent me a picture of the circuit board and it did look similar to the
last front end that I designed for Threshold power amplifiers. He did some
additional work connecting the dots and I managed to fill in some of it, so
here we are.

In this drawing, you will note that dots are made for all crossed connections,
transistors with shorted Collector-Base are used as diodes for current mirrors,
transistors shorted Emitter-Base are used as zener diodes.

The MPSA18 are high gain/low noise, as are the 2N4250. The others are
generic parts, and you all know our mostly unavailable friend the 2SK170 -
you might want to consider the LSK170 replacement.

And thanks to Mr. Baine for his efforts.

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Old 12th February 2014, 08:54 AM   #2
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before anyone else chime in with same question - resistor marked as 200+ , ditto on positive rail - means trimpot ?

tnx , as always

(all that spoon feeding can really choke some of us )
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Old 12th February 2014, 05:29 PM   #3
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Value somewhere above 200 ohms, trimmed for DC offset.

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Old 12th February 2014, 06:07 PM   #4
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I'm somewhere above choked

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