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Review and Measurements of L20.5 Loudspeaker Amp

YMY

New Member
Joined
May 11, 2019
Messages
1
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Location
SHANGHAI CHINA
#1
New to the forum. budget stereo speaker amp Measurements
To be honest,it comes to my mind for a long time that i want to introduce this array of products,but it was put on hold for a variety of reasons,it's my honor to have a brief introduction.
introduce the L20.5 amplifier & which was designed for the monitor speaker
This array of power amplifier prototypes started being created in 2003(maybe more earlier) in Sichuan province of China.
The designer paid more attention on scientific data of AP(audio precision),however,it still has some shortcomings--that will be mentioned later.
SO..the mother board must be MODification,finally can be use,Warning!!Must remember don't use switching power supply at any time&Please don't use pre-amplifier
“science datasheel”
8Ω 200 W 4Ω 400 W CLASS-AB
frequency response 20-25 Khz -0.15 DB 20 Khz-0.05 DB 10 Hz -0.7 DB
AP TEST (8Ω)1-50 W
THD+N 50 HZ 10 W(9 Vrms) <0.0007
THD+N 1 Khz 10 W(9 Vrms) <0.001
THD+N 10 Khz&20 Khz 10 W(9 Vrms) <0.0008
THD+N 50 W(20 V rms) 1 Khz <0.0015

IMD+N 50 W <0.0015
output impedance L 20.5=0.02Ω(theory)=damping factor:8Ω 400 4Ω 200
L 20=0.004Ω
SR:35
Unfortunately,the seller himself demostrated a very wrong way to use AP..which led to the master design error and insisted on the wrong AP test method,we have different views,so we could not communicate with each other,fortunately,my friend is an experienced university professir who is very interested in this product and makes a simple MODification (feedback) I'll show you how to MOD the motherboard later.
最后:price
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MODification


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simple mod complete

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Special thank Dr. Yi &Chloe


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