I have built several DIY projects including STK 4192II power amp, STK 6238A equalizer and several other power supply projects. I am still in the early stage of the learning curve of designing the circuits but I am determined to learn it.
For STK amp I have built the preamp-tone control module based on a circuit published in a magazine using LM 349 Quad-op-amps! After visiting this wonderful forum I learnt that for buffer stages the better op-amp options are NE5532, TL072 and some OPA/BB modules. As TL074 is pin compatible with LM349, I am wondering whether I can replace the LM349 in my Preamp module with them. I am planning to build better regulated, discrete PSU for the preamp too.
Can one of the experts here advice me whether I can replace the LM349 with TL074 in the following circuit without any change in the passive components? If passive component are to be changed, what should I change?
Thanks in advance
For STK amp I have built the preamp-tone control module based on a circuit published in a magazine using LM 349 Quad-op-amps! After visiting this wonderful forum I learnt that for buffer stages the better op-amp options are NE5532, TL072 and some OPA/BB modules. As TL074 is pin compatible with LM349, I am wondering whether I can replace the LM349 in my Preamp module with them. I am planning to build better regulated, discrete PSU for the preamp too.
Can one of the experts here advice me whether I can replace the LM349 with TL074 in the following circuit without any change in the passive components? If passive component are to be changed, what should I change?
Thanks in advance
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TL074 is a yucky op-amp IMO. OPA4134 and OPA3142 should work out quite well. Also, replacing the coupling caps with high quality polypropylene or polyester caps (if they are poor parts like electrolytic) will also help. Might as well make sure all the caps aren't electrolytic, since they aren't very large sizes.
OPA packages are not available in quad configuration! OPA 4134 is available only in SOIC package. The local distributor for the Farnell only gives me few options.
As NE5532 seems to be a good cost effective option can somebody help me to find whether quad configuration available with NE series an in TL074 [TL072 series]
I really think tone controls is a must though recent audiophile thinking is otherwise.
http://zero-distortion.com/views/tonecontroles_1/tonecontroles.htm
Can I implement active volume control after the circuit given above shown in the following link?
http://sound.westhost.com/project01.htm
As NE5532 seems to be a good cost effective option can somebody help me to find whether quad configuration available with NE series an in TL074 [TL072 series]
I really think tone controls is a must though recent audiophile thinking is otherwise.
http://zero-distortion.com/views/tonecontroles_1/tonecontroles.htm
Can I implement active volume control after the circuit given above shown in the following link?
http://sound.westhost.com/project01.htm
if u getting opa4134,use it.its a wonderful ic.far better than 074,ne etc.
even if its a surface mount,modify it as something given here
http://www.soundodyssey.com/AudioParts/OpAmps.html
the sonic benifits of opa far outweigh the little extra effort.
even if its a surface mount,modify it as something given here
http://www.soundodyssey.com/AudioParts/OpAmps.html
the sonic benifits of opa far outweigh the little extra effort.
some alternates suggestions that are pin to pin compatible with TL074 are
OPA4134,LM324(crappy though), LM348, TL084, LM349
BTW OPA4134 is available in PDIP package with retailers u have to find the right one
BUt do remeber my experince suggests usage of single OP AMP as dual or quad amps do have some cross talk between channels.
OPA4134,LM324(crappy though), LM348, TL084, LM349
BTW OPA4134 is available in PDIP package with retailers u have to find the right one
BUt do remeber my experince suggests usage of single OP AMP as dual or quad amps do have some cross talk between channels.
Thanks for all the infomation. I have built with separate opamps for each channel for better seapration. I am going to add following circuit from ESP projects after the above preamp circuit. Will it give some problems?
I would love to have links regarding proper earth(ground) techniques and proper routing techniques for building circuits.
I would love to have links regarding proper earth(ground) techniques and proper routing techniques for building circuits.
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TL07xx is the 'low noise' version of the TL08xx version. Though 18nv is not low noise by any means.
The OPA4132/4227 should be a good bet for you if you want to absolutely stick with DIP, though they are more expensive than the 4134.
NE5532/4 only has a single and a dual, no quad. Your options for high performance opamps become very limited when it comes to quads, as the quad design is optimised for cost. It is possible to hack a couple of duals into a circuit which had a quad, but likely the performance of the original itself did not merit anything better than the cheapest quad.
The LM349 is the worst possible choice for the application, it's not even a proper audio opamp. TL074 was pretty common in solid state pro gear but was one of the products that gave SS its terrible reputation (which it's still trying to shake off!). I have few in my junk box, and that's where they'll stay. If you look at Samuel Groner's article on opamp distortion, that 'wave bender' looks an absolute disaster for anything but the lowest resolution systems.
For tone controls, search for Baxandall tone control circuits on Google, even Rod Elliot has a pretty long page about them, tell you everything you need to know. I don't use them at all, except in my guitar amp. Most of the time, speaker tonality issues are caused by poor design or placement issues (mostly the latter), which tone controls cannot reliably fix.
Anyway, it's a pretty standard kind of circuit now. The Douglas Self tone control looks very interesting and different, but terribly complex to build. I would rather not try it, but if you want, it's in his book 'Self on Audio', Available on Google Reader.
The OPA4132/4227 should be a good bet for you if you want to absolutely stick with DIP, though they are more expensive than the 4134.
NE5532/4 only has a single and a dual, no quad. Your options for high performance opamps become very limited when it comes to quads, as the quad design is optimised for cost. It is possible to hack a couple of duals into a circuit which had a quad, but likely the performance of the original itself did not merit anything better than the cheapest quad.
The LM349 is the worst possible choice for the application, it's not even a proper audio opamp. TL074 was pretty common in solid state pro gear but was one of the products that gave SS its terrible reputation (which it's still trying to shake off!). I have few in my junk box, and that's where they'll stay. If you look at Samuel Groner's article on opamp distortion, that 'wave bender' looks an absolute disaster for anything but the lowest resolution systems.
For tone controls, search for Baxandall tone control circuits on Google, even Rod Elliot has a pretty long page about them, tell you everything you need to know. I don't use them at all, except in my guitar amp. Most of the time, speaker tonality issues are caused by poor design or placement issues (mostly the latter), which tone controls cannot reliably fix.
Anyway, it's a pretty standard kind of circuit now. The Douglas Self tone control looks very interesting and different, but terribly complex to build. I would rather not try it, but if you want, it's in his book 'Self on Audio', Available on Google Reader.
Hi Kaushama,
As you may already know, there are basically 3 major types of opamps
1.Linear bi-polar
2.JFET
3.CMOS
We'll deal only with the first two types for your needs.
I've tried or used TL06xx/TL072xx/TL82xx/ LF353/LM324/ NE5532
in most of my projects.
The best & opamps for my money are the NE5532 & TL072
These are "unreasonably" cheap and are excellent devices!
You'd be very suprised with regard to OPA devices in the articles mentioned below.
You should first consider certain parameters of these devices before choosing what's right for the job.
1.Open loop gain
2.Closed loop gain
3.Slew rate (SR)In
4.CMRR...
5.Gain Bandwidth Gain (GBW)
6.Input equivalen Noise- En (V)
7.Input equiv,Current-In ..I can go on..
Please read the following excellent articles before you select the best type/s for your needs.
http://www.sound.westhost.com
http://www.dself.dsl.pipex.com
As you may already know, there are basically 3 major types of opamps
1.Linear bi-polar
2.JFET
3.CMOS
We'll deal only with the first two types for your needs.
I've tried or used TL06xx/TL072xx/TL82xx/ LF353/LM324/ NE5532
in most of my projects.
The best & opamps for my money are the NE5532 & TL072
These are "unreasonably" cheap and are excellent devices!
You'd be very suprised with regard to OPA devices in the articles mentioned below.
You should first consider certain parameters of these devices before choosing what's right for the job.
1.Open loop gain
2.Closed loop gain
3.Slew rate (SR)In
4.CMRR...
5.Gain Bandwidth Gain (GBW)
6.Input equivalen Noise- En (V)
7.Input equiv,Current-In ..I can go on..
Please read the following excellent articles before you select the best type/s for your needs.
http://www.sound.westhost.com
http://www.dself.dsl.pipex.com
you need high impedance after every filter.
This virtually demands a FET input stage after the filter elements.
Don't use a 5534 as the opamp in an active filter.
The tl07x is noisy and very intolerant of capacitive load on it's output.
Use a better behaved FET opamp for the filters.
The 5534 can still be used as the input and output buffers. Although again some more modern devices can do the job a little better at much higher cost.
This virtually demands a FET input stage after the filter elements.
Don't use a 5534 as the opamp in an active filter.
The tl07x is noisy and very intolerant of capacitive load on it's output.
Use a better behaved FET opamp for the filters.
The 5534 can still be used as the input and output buffers. Although again some more modern devices can do the job a little better at much higher cost.
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