Message 21895 in TECH.WW
From: G8MNY
Date: Tue, 05 May 26 06:57:00 Z
Newsgroups: TECH.WW
Subject: LM380N/TDA2003 IC Audio Amps
Message-ID: <58920_GB7CIP>
Path: N2MH4|N3HYM|IW2OHX|DK0WUE|HB9ON|IK7NXU|IK6IHL|HB9CSR|IW8PGT|IZ3LSV|ED1ZAC|GB7CIP
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From: G8MNY@GB7CIP.#32.GBR.EURO
To : TECH@WW
From: VE2ACT@VE2TOY.#MTL.QC.CAN.NOA (Updated Mar 06)
(8 Bit ASCII graphics use code page 437 or 850, Terminal Font)
AUDIO PREAMP. avec IC LM 380N
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de VE2ACT..........MONTREAL en packet.....janv04..(D55 audioamp.asc)
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G8MNY Comments: Idealy a large C across the supply to help stability and reduce
battery supply dips on peak 1/2 cycles. For hify use the 200uF LS C should be
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Here is one using a TDA2003
By G8MNY
Sensitivity
HOW IT WORKS
The input Z of the IC is 150k so with the 100k pot this is approx 60k depending
on the slider position. The IC power rail is well decoupled at LF with the
1000uF & @ HF with the u1 cap.
The gain setting NFB is in 2 parts, the basic gain of 100x by the 470R/4R7, and
the HF cut to 20x by 100R/4R7 & 8n2 for stability. Also for stability is the
"Zobal network" of a 1R in series with u1 across the LS, this keeps the output
stage terminated at HF.
This design with its high IC open loop gain with loads of NFB gives very low
distortion, but poor HF stability and possably poor transiant intermod
distortion (TIMD)!
Why Don't U send an interesting bul?
73 de John G8MNY @ GB7CIP
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