how good is this amplifier?

davidel94 · 28th August 2012, 12:57 PM

Hi I've made my first MOSFET power amplifier, in the output stage I used the IRFP140 with IRFP 9140. The features are these:
rails +/- 21 V unregulated
output rms power 20W into 4ohm
thd 1 khz into 4 ohm 0.002%
thd 20khz no load 0.002%, 8 ohm 0.03%, 4 ohm 0,064%
signal to noise ratio 97 dB (1W into 4ohm), 108 dB (20W 4ohm)
thd is referred into pure resistive loads.
These are the values found using LTspice, I've built it and it sounds fine but i don't have the instruments to see the real performance.
So how is my amplifier? what do you think about it?

juma · 28th August 2012, 03:54 PM

Quote:

Originally Posted by davidel94

.... So how is my amplifier? what do you think about it?

I must admit that it has at least one very special feature - it's invisible. No schematic, no photos...

moschfet · 28th August 2012, 04:58 PM

Quote:

These are the values found using LTspice..

Sorry, using LTspice to determine THD can give you a good direction for your development. But a realistic simulation of THD is almost impossible, you have to measure it later

davidel94 · 4th September 2012, 06:55 AM

ok but assuming that these values are real how good is this amplifier?

DF96 · 6th March 2013, 05:12 PM

You have made the same post to about 5 different threads. Are you trying for some sort of record?

SY · 6th March 2013, 05:22 PM

Actually, 12 different threads, I've deleted the duplicates. Davide, do not repeat the same post in multiple threads.

28th August 2012, 12:57 PM	#1
davidel94 diyAudio Member Join Date: Jul 2012 Location: Verona	how good is this amplifier? Hi I've made my first MOSFET power amplifier, in the output stage I used the IRFP140 with IRFP 9140. The features are these: rails +/- 21 V unregulated output rms power 20W into 4ohm thd 1 khz into 4 ohm 0.002% thd 20khz no load 0.002%, 8 ohm 0.03%, 4 ohm 0,064% signal to noise ratio 97 dB (1W into 4ohm), 108 dB (20W 4ohm) thd is referred into pure resistive loads. These are the values found using LTspice, I've built it and it sounds fine but i don't have the instruments to see the real performance. So how is my amplifier? what do you think about it?

6th March 2013, 05:22 PM	#6
SY diyAudio Moderator Join Date: Oct 2002 Location: Chicagoland Blog Entries: 1	Actually, 12 different threads, I've deleted the duplicates. Davide, do not repeat the same post in multiple threads. __________________ If there's a sucker born every minute, where do the rest of them come from?

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4th September 2012, 06:55 AM	#4
davidel94 diyAudio Member Join Date: Jul 2012 Location: Verona	ok but assuming that these values are real how good is this amplifier?

6th March 2013, 05:12 PM	#5
DF96 diyAudio Member Join Date: May 2007	You have made the same post to about 5 different threads. Are you trying for some sort of record?