Hello I have (with quite difficulty) copied this circuit diagram. Basically its in a preamp and the sound is very clear but thin. How can I beef it up?
Its a Ne5534 circuit. The easiest thing for me to remove is the 1pf cap which I tried changing values to higher but the sound is just more muffled with higher capacitance!
I just need a little more bass. Any help? Please 🙂
Its a Ne5534 circuit. The easiest thing for me to remove is the 1pf cap which I tried changing values to higher but the sound is just more muffled with higher capacitance!
I just need a little more bass. Any help? Please 🙂
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Try increasing the 30k to 100k, or else eliminate the 2.2uF input capacitor altogether.
I doubt that this circuit is the source of your bass problem, though.
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Thank you kind sir. At first it was very subtle but surely enough more bass!
Doesn't make any sense to me, can you possibly explain? Has the sound been compromised in any way?
Thank you!
Doesn't make any sense to me, can you possibly explain? Has the sound been compromised in any way?
Thank you!
Did you increase the 30k? If so, the bass roll off point was lowered from
2.4Hz to just under 1Hz. Maybe then you actually heard less bass phase shift.
If you removed the 2.2uF input coupling capacitor, that would make a bigger difference.
Then there would be no bass roll off or bass phase shift at all in this circuit.
The sound can only improve with either option.
You've got around 16dB of gain with a -3dB point of around 2.2Hz.
Is the chip getting hot ? If so, it's oscillating and thats why the sound is "thin".
edit: No, dont remove the input coupling capacitor. You'll simply get more DC offset if you do that.
Is the chip getting hot ? If so, it's oscillating and thats why the sound is "thin".
edit: No, dont remove the input coupling capacitor. You'll simply get more DC offset if you do that.
It's possible, since this is a bipolar input op amp. He can check for DC output offset with a DVM.
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Thanks for input guys!
I updated the resistor to 100k and the lower/mid sound was more forceful. I can only really test quality of it tomorrow.
I cant believe I'm actually doing this stuff! And its actually working lol!!
Can I ask this gain is it just lower frequency gain or is it cut off point has been lowered?
I updated the resistor to 100k and the lower/mid sound was more forceful. I can only really test quality of it tomorrow.
I cant believe I'm actually doing this stuff! And its actually working lol!!
Can I ask this gain is it just lower frequency gain or is it cut off point has been lowered?
Same circuit can the high frequency be lowered?
Just wondering since low frequency can be increased was wondering if high frequency can be decreased?
Just wondering since low frequency can be increased was wondering if high frequency can be decreased?
What if I put a 200k resistor? What is the normal safe point resistor in this position generally? Thanks
Sure, increase the feedback capacitor. For a 50kHz bandwidth, use about 75pF.
For just the audio band, use 150pF.
You may need to adjust the value of the external compensation capacitor for stability
at unity gain, but the 22pF already there should be ok.
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The resistances that the two inputs see should be about equal for best results.
Also, the lower the values, the better. You may be at about the highest values
of resistances that will work well for this op amp.
Two things limit the HF cutoff... the 220pF capacitor on IN+ (it forms a highpass filter with the 4K7 resistor), and the small capacitor across the feedback resistor (the 1p across the 220K resistor).
The capacitor across the feedback resistor also controls the stability of the circuit.
The capacitor across the feedback resistor also controls the stability of the circuit.
Is that 1pf capacitor? Its the only feedback that makes sense to me!
I already tried to increase that and it just sounded muffled!
I think rather than just suggest random values, the best question to ask here is - what is this for ? What sort of gain do you need ?
Currently the high resistances in the feedback network are going to be sacrificing a good deal of performance the NE5534 is capable of due to Johnson noise. I'd be looking to cut them down to something more sensible such as 10K and 2K2 if you need ~15dB of gain
Currently the high resistances in the feedback network are going to be sacrificing a good deal of performance the NE5534 is capable of due to Johnson noise. I'd be looking to cut them down to something more sensible such as 10K and 2K2 if you need ~15dB of gain
So for sweeter treble / less harsh treble I should increase 220pf? I dont wanna mess with the 1pf as it sounds muffled with even the slightest increase!
The amp has a pre and power sections with a connector at the back for pre and main in.
I has another pre that I tested the power amp section of the amp and found the bass good so its the pre that needs tweaking.
The treble is ever so slightly bright and the bass is good but just a but shy. At the moment it sounds cold and I like warm amps!
Yes. As is, the HF rolloff is 723kHz (without the input filter).
You should be able to use as much as 22pF before it's too much.
How much capacitance did you try?