Hi 
I have a home made class A amplifier (based on JLH 1969 amp) which gives me awesome sound. It gets the signal from a htpc with W7 ultimate 64bit and a Audiotrac PRODIGY HD2 ADVANCE DE sound card. So far so good.
The reason why i have this homemade class A is because of good friends. I don't know anything about soldering or electronics myself. I just love to listen to good music with good sound quality.
Please take that into consideration when you write the answer to this post.
Recently i found out that the Audiotrac sound card has sockets for op amps. What i can understand about op amps is that it kinda gives the sound different properties (more bass punch, better treble and so on). Seems interesting
But where can I buy opamps? I see that eBay sell opamps that costs 2-3 usd, but I doubt they are any good Or are they?
Therefore I ask you guys;
can you tell me about op amps - why I need them, where I should buy them and how much do they cost?
I appreciate your help And if you have any question or maybe helpful comments regarding my setup, please feel free to comment.
I have a home made class A amplifier (based on JLH 1969 amp) which gives me awesome sound. It gets the signal from a htpc with W7 ultimate 64bit and a Audiotrac PRODIGY HD2 ADVANCE DE sound card. So far so good.
The reason why i have this homemade class A is because of good friends. I don't know anything about soldering or electronics myself.
I just love to listen to good music with good sound quality. Please take that into consideration when you write the answer to this post.
Recently i found out that the Audiotrac sound card has sockets for op amps. What i can understand about op amps is that it kinda gives the sound different properties (more bass punch, better treble and so on). Seems interesting
But where can I buy opamps? I see that eBay sell opamps that costs 2-3 usd, but I doubt they are any good
Or are they? Therefore I ask you guys;
can you tell me about op amps - why I need them, where I should buy them and how much do they cost?
I appreciate your help
And if you have any question or maybe helpful comments regarding my setup, please feel free to comment.
The differences between op amps are subtle.
Sound can be modified by resistor-capacitor networks, as in a graphic equalizer, or flanger pedal. Sound can be modified by digital devices as bit bucket CCD's or DSP's. These modifications can be quite overwhelming.
In these modification circuits, op amps are sometimes used to maintain the voltage level, or provide more current out.
Early op amp were sometimes slow, weak, or hissy. Later ones can be better, although many are designed for instruments instead of audio, and don't provide any benefit to listeners.
E-bay is a source of mostly counterfeit IC's. As somebody takes a $.33 IC, erases the marking and paints a new one on, and sells it for $3. IC quality can be assured by buying from a distributor authorized for resale by the factory, such as farnell, RS, mouser, digikey, depending on your country which is best.
The Analog Devices (old IC company) tutorial is most often used by people to start out with op amps. The book can be bought, or sometimes downloaded.
If you want to modify sound with op amps, study circuits of graphic equalizers or other devices. Reading articles here on analog line level forum can provide sample circuits. Commercial schematic diagrams are on eserviceinfor.com or other services.
I took a hissy, hummy $15 disco mixer, and turned it into a useful hub of my sound system for interfacing record player, CD player, and FM radio, to my power amp. I changed the op amps from generic 4558 to excellent 33078 then modified the circuit to cope with the oscillations caused by the newer faster op amps. Both parts cost about $.38. I also did a lot of work to the power supply to eliminate hum. I have some $4 op amps but don't see the need to take the covers off and rework the device, because the $.38 devices are the least of my problems right now. Electrolytic capacitors, those are a constant plague, causing major problems now in my 1970 ish FM radio and my television.
Much of op amp swapping talked about on the internet IMHO comes under the realm of psychoacoustics. As, in, anything I did must sound better than what the clowns at the factory did. In the case of the disco mixer above, 4558 when used at 50x gain is quite audibly hissy. 33078 is pretty quiet. Nothing subtle about it. Factories use 4558 because it is fine at 2x gain, but other op amps need three $.30 capacitors to not oscillate, and people would rather not pay the extra $1 for those when 4558 would do.
A course in 2nd year physics, with kirchoff's laws and vector algebra analysis of RLC circuits, can be quite useful for understanding sound modification. Happy learning.
Sound can be modified by resistor-capacitor networks, as in a graphic equalizer, or flanger pedal. Sound can be modified by digital devices as bit bucket CCD's or DSP's. These modifications can be quite overwhelming.
In these modification circuits, op amps are sometimes used to maintain the voltage level, or provide more current out.
Early op amp were sometimes slow, weak, or hissy. Later ones can be better, although many are designed for instruments instead of audio, and don't provide any benefit to listeners.
E-bay is a source of mostly counterfeit IC's. As somebody takes a $.33 IC, erases the marking and paints a new one on, and sells it for $3. IC quality can be assured by buying from a distributor authorized for resale by the factory, such as farnell, RS, mouser, digikey, depending on your country which is best.
The Analog Devices (old IC company) tutorial is most often used by people to start out with op amps. The book can be bought, or sometimes downloaded.
If you want to modify sound with op amps, study circuits of graphic equalizers or other devices. Reading articles here on analog line level forum can provide sample circuits. Commercial schematic diagrams are on eserviceinfor.com or other services.
I took a hissy, hummy $15 disco mixer, and turned it into a useful hub of my sound system for interfacing record player, CD player, and FM radio, to my power amp. I changed the op amps from generic 4558 to excellent 33078 then modified the circuit to cope with the oscillations caused by the newer faster op amps. Both parts cost about $.38. I also did a lot of work to the power supply to eliminate hum. I have some $4 op amps but don't see the need to take the covers off and rework the device, because the $.38 devices are the least of my problems right now. Electrolytic capacitors, those are a constant plague, causing major problems now in my 1970 ish FM radio and my television.
Much of op amp swapping talked about on the internet IMHO comes under the realm of psychoacoustics. As, in, anything I did must sound better than what the clowns at the factory did. In the case of the disco mixer above, 4558 when used at 50x gain is quite audibly hissy. 33078 is pretty quiet. Nothing subtle about it. Factories use 4558 because it is fine at 2x gain, but other op amps need three $.30 capacitors to not oscillate, and people would rather not pay the extra $1 for those when 4558 would do.
A course in 2nd year physics, with kirchoff's laws and vector algebra analysis of RLC circuits, can be quite useful for understanding sound modification. Happy learning.
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Are you referring to Walt's book?
I agree---the 33078 is about the best bargain to be had for an opamp, along with the old standard NE5532.
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