One should not skimp on the power supply for a LM1875. It sounds very good. For some one who gives his music collection higher priority than the hardware ( cost wise) can stop with the LM1875 if the required listening levels are 'normal'.
Lately we tried it with the Behringer 2031B speaker. Sounds pretty good even at the LF end . It isn't a 'small' Krell or a Bryston but it does sound good.
Want to give an audiophile friend a gift ? Give him/her a completed LM1875 !
Lately we tried it with the Behringer 2031B speaker. Sounds pretty good even at the LF end . It isn't a 'small' Krell or a Bryston but it does sound good.
Want to give an audiophile friend a gift ? Give him/her a completed LM1875 !
Not a low-enough impedance PSU for the chip to give its best methinks.... More caps!
No, 2200uF is enough for this 25Watt amplifier. More caps only give small benefit on bass at full power.
One should not skimp on the power supply for a LM1875. It sounds very good. For some one who gives his music collection higher priority than the hardware ( cost wise) can stop with the LM1875 if the required listening levels are 'normal'.
Lately we tried it with the Behringer 2031B speaker. Sounds pretty good even at the LF end . It isn't a 'small' Krell or a Bryston but it does sound good.
Want to give an audiophile friend a gift ? Give him/her a completed LM1875 !
Better give her a small active speaker with LM3886 on woofer and LM1875 on tweeter (bi-amp).
Oddly my own chip amp benefits from lots more caps and the bass improvement is not only apparent at full power. But there are too many differences between our set-ups to speculate as to why there might be such significant variations in SQ. For example you maybe have a linear PSU and I'm using an SMPSU followed by a linear regulator.
More caps or using regulated power supply make less ripple and then the signal voltage before clip improve. Bass improvement is only at full power because of this. More power! Frequency response is already flat although using less caps or unregulated power supply.
The other benefit using good power supply is improving the PSRR. But LM1875's PSRR is already good.
If cost is no object you always can use more caps or regulated power supply. But engineering is all about trade off.
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Yes engineering is all about trade-offs, totally agree there. So then where to spend the money to get the best SQ for the least buck, that's always the question. Capacitors are cheap - my current chipamp (a TDA8566) has 70 * 2,200uF per channel and the cost of all these caps was under $10. Piior to fitting them all up I'd assumed that the PSRR of my amp was sufficient that they'd not make a difference to the SQ, but it turned out that my assumption was in error.
You must a rich man
. $10 is not cheap in my country, considered the minimum salary is $224/month and there are many people that under paid.
Of course I am not under paid or get minimal salary
, but I am sure I am not as rich as you. I build LM1875 amplifier for testing purpose only. Small improvement in bass or SQ is not worth-ed to me than saving $10
. I have another amplifier using BJT (transistor), that I modified from web (I forgot the link). This amplifier is 150 watt/ 8 Ohm, and the SQ much superior than LM1875 at same level.
I am not sure
Maybe discussed somewhere else, as in simulation I see 1V peak to peak ripple on a 10000uF cap with regular bridge rectifier when 1A is consumed(8W at 8Ohm speaker, 4w AT 4Ohm). 2200uF the ripple will be 4V. This is equivalent power of 0.25W at 8Ohm, with superior PSRR it maybe still ok. But you supply will effective drop 4V to provide unclipped sound. I think this is bad. If you consider cross modulation, it is even worse, in theory it will give unlean sound(frequency other than harmonic of original signal).
Maybe discussed somewhere else, as in simulation I see 1V peak to peak ripple on a 10000uF cap with regular bridge rectifier when 1A is consumed(8W at 8Ohm speaker, 4w AT 4Ohm). 2200uF the ripple will be 4V. This is equivalent power of 0.25W at 8Ohm, with superior PSRR it maybe still ok. But you supply will effective drop 4V to provide unclipped sound. I think this is bad. If you consider cross modulation, it is even worse, in theory it will give unlean sound(frequency other than harmonic of original signal).
You can just CALCULATE the minimum required reservoir capacitance, as in the linked post at
http://www.diyaudio.com/forums/soli...n-attempt-number-2-simpler-9.html#post3532280
Note that the needed Vclip value is plotted in the LM1875 datasheet, versus the rail voltage.
http://www.diyaudio.com/forums/soli...n-attempt-number-2-simpler-9.html#post3532280
Note that the needed Vclip value is plotted in the LM1875 datasheet, versus the rail voltage.
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Read through and enjoyed this topic from over 7 years ago which I think is still relevant today.
As I understand both are very good clean amplifier chips, one rated 30 Watts the other 60 Watts.
1. Wondered weather anybody has gained new insights in the past 7 years?
2. Measured with a precise laboratory instrument, what is the rated (or advertised)...
...Total Harmonic Distortion + Noise oof the LM1875 @ 10 Watts output?
...Total Harmonic Distortion + Noise oof the LM3886 @ 10 Watts output?
As I understand both are very good clean amplifier chips, one rated 30 Watts the other 60 Watts.
1. Wondered weather anybody has gained new insights in the past 7 years?
2. Measured with a precise laboratory instrument, what is the rated (or advertised)...
...Total Harmonic Distortion + Noise oof the LM1875 @ 10 Watts output?
...Total Harmonic Distortion + Noise oof the LM3886 @ 10 Watts output?
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