Not really even with no computer.
May-be the reason can be found, searching for "Fletcher & Munson" ?
I know about this.
Most conventional bass and treble controls boost plenty of midrange too. They boost frequencies that the ear is quite sensitive to. "On paper" it looks right. In the field it sounds terrible.
The "loudness" control is supposed to compensate for the Fletcher-Munson curve. Most of those don't work very well, either.
Hi and thanks again. No no ... i understand that is a more tricky solution
I need something very basic. Given that also AC coupled could just fine no more questions about this.
Just a last question ... you mentioned the fact that simpler topologies have usually a higher distortion. Do you think that is possible to achieve remarkable distortion figures even with very basic topologies maybe taking care of device selections, supply voltage and so on ?
That would be interesting ... i am a little uncomfortable with line stage with 20 active devices per channel ... on principle.
The old good KISS principle i mean
Thanks again and kind regards, gino
Richard Marsh's advice is to use a big electrolytic and parallel it with a decent film cap.
I quote Nelson Pass "So you're worried about the coupling caps? Get over it."
Hi and thanks for the valuable advice
Actually i was thinking of a parallel of a decent PP with a very good 0.1/0.22 uF PP higher quality (still reasonably priced)
But now i am set on just a decent plastic cap and stop.
This is a less dramatic issue than circuit topology and lay out from what i have understood.
First things first.
Kind regards, gino
Yes but the distortion profile is much lower order. A single stage amplifier can have relatively high distortion and still "sound clean" because the distortion is first harmonic only. It is still possible to get the distortion of a single stage amplifier below 1%.
A two stage amplifier can employ global feedback and so can provide lower distortion levels, but the distortion profile is going to be more complex. And a class B output stage provides a very complex and nasty distortion profile. Increasing loop gain is going to drive distortion down, but the distortion profile is almost always going to be more complex.
Anyway, you might check out some of the circuits on the Elliot Sound Products webpage. Simple and basic low distortion circuits for you might be either an op amp gain stage (like a 2134 or even a 5532), or a simple two stage, 3 transistor gain stage; coupled with the volume control / attenuator of your choice.
Circuit layout is very important for lowest distortion. There are hidden sources of distortion lurking in bad layouts. You need to read the link on grounding to maybe understand this.
I thank you sincerely because i think you have answered completely to my questions and solved my remaining doubts.
I am in a middle of a job crisis because my boss insisted to work and now i have to repair his mistakes
But i promise that i will be back soon with an example of a insanely simple circuit that one guy has simulated for me with unbelievably low distortion figures
By the way it is just one stage of the above mentioned vintage Radford ZD22 preamp
With a 0-48V supply the distortion spectra appear almost completely clean of harmonics
Of course a nice and low ripple 48V is also important.
I am planning to build it ... to confirm the simulation results.
The layout considerations are what really concern me. I just imaged that, but you have confirmed my bad feelings.
Thanks a lot and kind regards, gino
Have you read the grounding link that I provided? That should help you come up with a decent layout.
Hi do you mean this one
Grounding Principles - The Signal - Archives - TI E2E Community
well it is difficult ... i need to study it more.
If understand well a bad executed grounding can be very detrimental for performance. This is going to be tricky and worries me most.
And actually i would not be able to understand if in a kit the grounding is good or not
But as in the article the writer says i understand is science and not art
If the evaluation boards were not so expensive and so surface mounted i would try one of those.
I am pretty sure that at TI, Analog Device and similar they know about how to execute proper grounding.
I feel i will pass on the idea. It is difficult.
Thanks a lot again and kind regards, gino
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.