Hi,
I want to replace the LM324 on my Fosi Audio BT30D with better opamps since I don't like the sound of the 324, and I believe it produces slight audible distortion. Can anyone suggest which opamp that I can use? The Fosi Audio uses 24v power supply.
Thanks
I want to replace the LM324 on my Fosi Audio BT30D with better opamps since I don't like the sound of the 324, and I believe it produces slight audible distortion. Can anyone suggest which opamp that I can use? The Fosi Audio uses 24v power supply.
Thanks
The LM324 may not actually be in the audio path, it may do something else. You should check before replacing it.
It would be very strange indeed for a manufacturer to use the LM324 for audio.
It would be very strange indeed for a manufacturer to use the LM324 for audio.
If the LM324 is indeed in the audio path, the OPA4134 could be a good replacement. I would point to the LME49740 (the quad version of the LME49710/LME49720) but that has been discontinued by TI. Quad opamps appear to be going away - at least in the audio market.
If the LM324 is not in the audio path just leave it be.
Tom
If the LM324 is not in the audio path just leave it be.
Tom
Thanks for all replies...
The amp uses 2 LM324 and they are placed near the potentiometers, where usually 5532 are placed. Also there is one 5532 inline with the 324. I assume the 324 are used to process the bass and treble while the 5532 is used to process the subwoofer signal. I need to check the traces to make sure, I'll do it later when I got home
The amp uses 2 LM324 and they are placed near the potentiometers, where usually 5532 are placed. Also there is one 5532 inline with the 324. I assume the 324 are used to process the bass and treble while the 5532 is used to process the subwoofer signal. I need to check the traces to make sure, I'll do it later when I got home
I decided to replace the 324 with LF347 since it's one of few suggested opamps that I can find here with reasonable price.
The 324s are indeed in the audio signal path, but replacing them didn't improve the sound quality.
The problem I'm having with this amp is, whenever I set the audio source like youtube or foobar to 100%, the sound becomes clipped/distorted during loud sections. If youtube/foobar is at 50-70% there is no clipping eventhough the volume of the amp is cranked up to match the 100% source
The 347 didn't solve the clipping. I'm sure it's not from the DAC since my previous amp didn't behave like this, and the sound from the headphone amp section of the DAC is clean
At first I assumed that it's caused by the opamps because usually they process the signal before the potentiometer. But now I don't have any idea why it's like that
The 324s are indeed in the audio signal path, but replacing them didn't improve the sound quality.
The problem I'm having with this amp is, whenever I set the audio source like youtube or foobar to 100%, the sound becomes clipped/distorted during loud sections. If youtube/foobar is at 50-70% there is no clipping eventhough the volume of the amp is cranked up to match the 100% source
The 347 didn't solve the clipping. I'm sure it's not from the DAC since my previous amp didn't behave like this, and the sound from the headphone amp section of the DAC is clean
At first I assumed that it's caused by the opamps because usually they process the signal before the potentiometer. But now I don't have any idea why it's like that
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It would seem to be clipping because of overdriving the inputs. Without circuit details we can't really say what is happening. For example what supply voltage are the opamps running on and what gain are they configured for.
I'm amazed the LM342's are in the audio path... it just doesn't make sense at all. Maybe they are biased into Class A with a resistor pull up/down on the output pins to a rail.
Circuit.... we need to see a circuit 🙂
I'm amazed the LM342's are in the audio path... it just doesn't make sense at all. Maybe they are biased into Class A with a resistor pull up/down on the output pins to a rail.
Circuit.... we need to see a circuit 🙂
Replacing mediocre stuff for other mediocre stuff won’t improve anything.
https://www.diyaudio.com/community/threads/quad-dip-op-amp-selection.272076/
TL074 / 084 are quad op amps, IIRC.
TL074 / 084 are quad op amps, IIRC.
I just replaced the LF347s with 4x LM4562. I chose 4562 because I use it on my other amp and I like its sound. That amp originally uses 4558, then I tried 5532, 2134, and 4562. I like 4562 the most. So I thought, it's better to use something that I like than to try this and that without knowing the result. Also, good/original quad opamp is very difficult to find in my place, or they are ridiculously priced. It took good amount of work and time to wire those 4562
The result however, is not as expected. The overall tonality is better, but the clipping is still there.
Maybe putting a resistor just right after the input (rca jack) to reduce the gain?
The result however, is not as expected. The overall tonality is better, but the clipping is still there.
Maybe putting a resistor just right after the input (rca jack) to reduce the gain?
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The flaw in the reasoning is that one never can know results beforehand. Even when one knows the new part in question when used in other devices.
Things may work the other way too. For instance I would never use LM4562 anymore after having a batch that had the meanwhile famous popcorn noise.
One of the more optimal choices is to replace a quad opamp for a better quad opamp. Short or even no excess wiring is simply better.
Attenuating is done with 2 resistors but it maybe is a good idea to draw a schematic and reduce the gain of the opamps. That is more efficient than attenuating followed by too much gain.
However you haven’t even told us what the source or chain exactly is. If that is a tube preamp with 10V rms output we are all busy loosing time on a mediocre device that works as intended. Please check the signal levels of the sources and the input sensitivity of the amplifier before doing anything else.
Things may work the other way too. For instance I would never use LM4562 anymore after having a batch that had the meanwhile famous popcorn noise.
One of the more optimal choices is to replace a quad opamp for a better quad opamp. Short or even no excess wiring is simply better.
Attenuating is done with 2 resistors but it maybe is a good idea to draw a schematic and reduce the gain of the opamps. That is more efficient than attenuating followed by too much gain.
However you haven’t even told us what the source or chain exactly is. If that is a tube preamp with 10V rms output we are all busy loosing time on a mediocre device that works as intended. Please check the signal levels of the sources and the input sensitivity of the amplifier before doing anything else.
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