Hello everyone! What replacement would you recommend for the 4559 in this scheme? This is the Sherwood EQ-7080C equalizer.
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I listened to several amplifiers from what was in this circuit. So: 1. KIA4559S is excellent control over the entire range, but the stereo panorama is small. 2. NJM4580L - the sound is bright, a lot of sibilants, you get tired quickly. 3. NJM2068LD is a beautiful middle, a good stereo panorama, but the bass is sluggish. 4. NJM2114L is an excellent stereo panorama, analytical tops, but very poor bass control. What would you recommend with a good stereo panorama and the same control as the 4559?
From the 4559 datasheet and the circuit it looks like the good old NE5532 would work fine here. Still cheap and widely available. That's if for some reason the 4559 is broken and you need to replace it, but if you're looking for an upgrade that will give you "better sound", I doubt you'll hear a difference even with a much higher performance opamp, a line level eq is just not a very demanding application and the 4559 looks perfectly adequate for the task.
Cheers,
Cabirio
Cheers,
Cabirio
Try a TL072.
Trust your ears and trust what you hear, make up your own mind rather than being swayed by what you read. If that diagram is accurate and the first opamp really does have no other connections to the inverting input other than R3 and C3 then you should link out (short out) R3. Try the TL072 and see what you think.
Trust your ears and trust what you hear, make up your own mind rather than being swayed by what you read. If that diagram is accurate and the first opamp really does have no other connections to the inverting input other than R3 and C3 then you should link out (short out) R3. Try the TL072 and see what you think.
No obvious reason why not based on what you show but please try a TL072 as well. Fit a socket and then you can experiment.
If there are a lot of opamps in a unit you should always look at the power supply to make sure it will be OK as current requirements add up. Also if they are resistively fed from higher voltage rails using Zener's for regulation then a high current consuming opamp can pull the rail voltage down if the resistors are to high in value.
So 95% sure a single LM4562 would be OK. The TL0 series consume less current. The Texas Instruments LM833 is another one (but get the Texas version such as LM833DR which is an updated version with a Quasi Complementary output stage and not the LM833N which has the older and slower output stage)
If there are a lot of opamps in a unit you should always look at the power supply to make sure it will be OK as current requirements add up. Also if they are resistively fed from higher voltage rails using Zener's for regulation then a high current consuming opamp can pull the rail voltage down if the resistors are to high in value.
So 95% sure a single LM4562 would be OK. The TL0 series consume less current. The Texas Instruments LM833 is another one (but get the Texas version such as LM833DR which is an updated version with a Quasi Complementary output stage and not the LM833N which has the older and slower output stage)
Thanks, but there is enough power supply there. This scheme is from a younger model, but is almost identical to mine. The only difference is in the power supply of +/- 15 volts for my model.
And which one should I choose? They have a different letter index: IP, CP, ACP, BCP. How are they different?
Those are all imaginary differences, specially those referred to "stereo panorama".
So use whichever you like or find and attribute it desired qualities.
Nobody "outside" can help with what's in your mind only.
All I would say is that when you change the opamp be sure to listen for an extended period and certainly over a few days.
R3 balances the impedance of the inverting and non-inverting inputs (R3=R1) and in many cases lowers distortion. Though more pronounced with FET input op amps there's also a benefit with bipolar op amps. https://www.proaudiodesignforum.com/forum/php/viewtopic.php?t=1290
Jung has also written about impedance balancing to reduce CM distortion.
There are many twists and turns to design 🙂 One unknown is what the impedance feeding the first stage might be.
This is a reference worth saving: https://www.electronicdesign.com/te...protection-for-low-distortion-op-amp-circuits
Didn't realize until now Merlin Blencowe is "merlinb" on this forum. 👍
Didn't realize until now Merlin Blencowe is "merlinb" on this forum. 👍