I am still doubting the design of my new (DIY) pre-amp.
At the begin of the spectrum is a simple opamp design like this:
amplifier stage - volume pot - buffer stage
Use a dual opamp per channel, some resistors and done for very little money.
At the other end of the spectrum are the fully discete designs like for example the Salas DCG3.
Another "in between" option is to use the op-amp schematics but use a discrete op-amps like the ones from Burson or Sparkos labs.
Can the best discrete op-amps compete with a fully discrete "classic" design for Single-Ended in-out ?
At the begin of the spectrum is a simple opamp design like this:
amplifier stage - volume pot - buffer stage
Use a dual opamp per channel, some resistors and done for very little money.
At the other end of the spectrum are the fully discete designs like for example the Salas DCG3.
Another "in between" option is to use the op-amp schematics but use a discrete op-amps like the ones from Burson or Sparkos labs.
Can the best discrete op-amps compete with a fully discrete "classic" design for Single-Ended in-out ?
Integrated opamps al cheap and space saver, but limited in their parameters.
Discrete are all diameter opposite.
In any case I would try the first of them, because it is easier to design, and if the performance is not as good as expected, is easy to change the opamp, while discrete solution may require a complete re-design with its time consumpting cons.
Discrete are all diameter opposite.
In any case I would try the first of them, because it is easier to design, and if the performance is not as good as expected, is easy to change the opamp, while discrete solution may require a complete re-design with its time consumpting cons.
My intention was to build an op-amp based design with discrete built op-amps like Sparkos / Burson.
Going this way "op-amp rolling" remains possible when new designs emerge.
Going for a fully discrete pre-amp I must replace the complete board when I ever want to try something else.
Finally the result of the pre-amp in my audio system will be dependant on component matching and op-amp rolling gives me this flexibility.
Although if the final consensus is that a fully discrete designed pre-amp like the Salas DCG3 always beats any discrete op-amp design then I might reconsider.
Going this way "op-amp rolling" remains possible when new designs emerge.
Going for a fully discrete pre-amp I must replace the complete board when I ever want to try something else.
Finally the result of the pre-amp in my audio system will be dependant on component matching and op-amp rolling gives me this flexibility.
Although if the final consensus is that a fully discrete designed pre-amp like the Salas DCG3 always beats any discrete op-amp design then I might reconsider.
When I have time/ motivation i will post my preamp design. Using only some transistors, class A without feedback.
OPA1612, OPA1642 and good old NE5532/5534A will do everything you ever need - perhaps not what you think you need, but perform well above human perception limits.
I am not searching for a pre-amp schematics in general but want to decide if op-amp style in discrete execution can compete with traditional designs.
I think I have collected quite some designs already but any addition is welcome ;-)
I think I have collected quite some designs already but any addition is welcome ;-)
Everything has its own sound signature.
I am not convinced the NE55xx is already the ultimate in high-end sound but not a big waist of money to buy a set of these too for rolling.
You're welcome ... 😀
For one, your link does not work.
For two, you are opening a can of worms, as said above.
For three, any design is implementation specific. You can make a NE5534 sound good or bad, although it is harder to make it sound bad vs good. I used one for a pre-amp design back in the 70's and it was very detailed, good enough imo.
I was looking at Wayne's linestage amp, if you want discrete, I would consider that one but they do take up way more space. If i was to use that design, I'd go smt all the way as much as possible, since the jfets are in a sot-23 to begin with.
Wayne's BA 2018 linestage
For two, you are opening a can of worms, as said above.
For three, any design is implementation specific. You can make a NE5534 sound good or bad, although it is harder to make it sound bad vs good. I used one for a pre-amp design back in the 70's and it was very detailed, good enough imo.
I was looking at Wayne's linestage amp, if you want discrete, I would consider that one but they do take up way more space. If i was to use that design, I'd go smt all the way as much as possible, since the jfets are in a sot-23 to begin with.
Wayne's BA 2018 linestage
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For one ... which link ??
I know this linestage too ... is also intersting, I had looked at it and can probably make a more compact PCB.
Size constraints is indeed an issue for my plans.
I know this linestage too ... is also intersting, I had looked at it and can probably make a more compact PCB.
Size constraints is indeed an issue for my plans.
And there the lid falls off the can.
I'll just say, I'm not after 'high end sound' I'm after neutrality. These may not be the same thing 🙂
At the begin of the spectrum is a simple opamp design like this:
amplifier stage - volume pot - buffer stage
i thought that you would show a link to your schematics since with out them there is not much to discuss
amplifier stage - volume pot - buffer stage
i thought that you would show a link to your schematics since with out them there is not much to discuss
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Seeing lot's of new pre-amp designs like Wayne's BA 2018, Salas DCG3 and more I wonder why they keep developping new idea's if op-amp is already that good ?
Is it because they can (with no real audible benefit ?) or are these design really supperior to any op-amp based design ?
And how does the discrete op-amps like Burson and Sparkos fit in ?
Is it because they can (with no real audible benefit ?) or are these design really supperior to any op-amp based design ?
And how does the discrete op-amps like Burson and Sparkos fit in ?
Ask John Curl 🙂 he says it is because an opamp can not drive a load as well as a discrete design. ? is do you need that capability?
It does make sense from a noise perspective, since your feedback network can be lower Z.
Still to this day, they have not made a jfet opamp with as low noise as the discretes, 2sk209, lsk170 etc. It is splitting hairs here since is such a low noise level necessary for the levels involved in the application.
Discrete is more fun than opamps.
It does make sense from a noise perspective, since your feedback network can be lower Z.
Still to this day, they have not made a jfet opamp with as low noise as the discretes, 2sk209, lsk170 etc. It is splitting hairs here since is such a low noise level necessary for the levels involved in the application.
Discrete is more fun than opamps.
Somewhere between marketing($) and reality imo. Not for me.
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I'd say because it's fun to perpetually reinvent the wheel.
More seriously, discrete opamps have their place in some cases, when you really want a strong output stage, higher supply voltages or really want a particular sound signature (in cases where neutrality isn't the goal as in music production).
From a quick look on their specs, the Burson doesn't really offer any of that. No real advantages over IC and worse specs all around. The Sparko at least seem to have a stronger class a output stage.
More seriously, discrete opamps have their place in some cases, when you really want a strong output stage, higher supply voltages or really want a particular sound signature (in cases where neutrality isn't the goal as in music production).
From a quick look on their specs, the Burson doesn't really offer any of that. No real advantages over IC and worse specs all around. The Sparko at least seem to have a stronger class a output stage.
I just had an idea, implement Bob Cordell's double cross OPS in a discrete opamp. I'll see what he has to say about that idea, crazy or not.
Most pre-amps alone can not drive headphones, so having a good drive can address this issue. I was looking at OS's line stage, blowtorch I think it was, lots of possiblities, depends on the feature set's, which should be your starting point, not discrete vs chip.
Most pre-amps alone can not drive headphones, so having a good drive can address this issue. I was looking at OS's line stage, blowtorch I think it was, lots of possiblities, depends on the feature set's, which should be your starting point, not discrete vs chip.
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I have to feed my power-amp (22k or 47k input impedance .. not sure) so no high loads involved.
I want to build an all-in-one source with volume device containing:
- Beaglebone Black computer for streaming --> LAN in - I2S out
- Soekris dam1121 R2R dac
- Source selector
- Pre-amp / volume / buffer
Volume and source will be something like Relaixed Passive (latest version from 2017)
With an extensive power supply with seperate windings and regulators for most (some with Salas UltraBib 1.3)
This leaves probably little space for the pre-amp / buffer in a standard sized chassis.
My power amp is an upgraded Odyssey Khartago with Boenicke W5 speakers (to keep the wife happy 😀 )
The pre-amp performance must match the rest of the input / output equipment / components so a simple e-bay pre-amp board will not be my cup of tea 🙄
I want to build an all-in-one source with volume device containing:
- Beaglebone Black computer for streaming --> LAN in - I2S out
- Soekris dam1121 R2R dac
- Source selector
- Pre-amp / volume / buffer
Volume and source will be something like Relaixed Passive (latest version from 2017)
With an extensive power supply with seperate windings and regulators for most (some with Salas UltraBib 1.3)
This leaves probably little space for the pre-amp / buffer in a standard sized chassis.
My power amp is an upgraded Odyssey Khartago with Boenicke W5 speakers (to keep the wife happy 😀 )
The pre-amp performance must match the rest of the input / output equipment / components so a simple e-bay pre-amp board will not be my cup of tea 🙄
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Anyone interested in ultimate objective performance, which also just so happens to be relatively simple to implement, should check out Sam Groner's unique composite super op-amp. It consists of two IC op-amps and 7 passive parts, so, 9 parts in total.
The performance is simply astounding. It can drive a 10kHz signal at over 7VRMS in to a 600 Ohm load, with all harmonics up to at least 100kHz laying somewhere below -180dB. With noise of around 1.1nV/rootHz. Yes, you read all those figures correctly. This is all such performance overkill that strict objectivists can likely end the search for the best single-ended line level amplification stage as far as measurements are concerned. While, subjectivists can unquestionably discover whether it's actually some particular character of distortion they are searching for in a gain stage, should this stage subsequently sound lacking to them in some respect.
Samuel Groner's super opamp
The performance is simply astounding. It can drive a 10kHz signal at over 7VRMS in to a 600 Ohm load, with all harmonics up to at least 100kHz laying somewhere below -180dB. With noise of around 1.1nV/rootHz. Yes, you read all those figures correctly. This is all such performance overkill that strict objectivists can likely end the search for the best single-ended line level amplification stage as far as measurements are concerned. While, subjectivists can unquestionably discover whether it's actually some particular character of distortion they are searching for in a gain stage, should this stage subsequently sound lacking to them in some respect.
Samuel Groner's super opamp
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