Here's my pedestrian attempt to explain linearity and FR and how a poor operating point for the driver can seem like uneven FR.
Linearity is the uniformity of amplification vis-a-vis the input signal level. If you choose a typical operating point for the supply voltages you should have good linearity of amplification. Your .25v input will be (10x.25v); .5v =(10x.5v); 1v. =(10x1v.) ... for all input signal levels until clipping occurs.
If you have a poor operating point selected you may find that the higher signal levels are not amplified by the same "factor" as the softer, lower, signal levels. In MUSIC this could mean that the stronger instruments in the mid to low frequency range that will almost always be supplying a higher signal level will now be attenuated by the poor linearity produced because of the SUPPLY circuit and the tube operating point. Not a tube characteristic. This COULD sound like the highs are brighter than you would expect. It SHOULD sound like the lows are softer than you expect. How your brain and or hearing interprets that and how the "sound" is reported back to everyone on the boards is what makes posts about different tube sound so frustratingly irrelevant to my amp or your amp or his amp. But this is not a FR problem. If you back the input signal down to where all the input levels are back in the linear range you would find what "sounds" like a flatter FR.
Best find an amp setup with flat FR and then use input EQ to taste and or hearing/speaker problems.
Linearity is the uniformity of amplification vis-a-vis the input signal level. If you choose a typical operating point for the supply voltages you should have good linearity of amplification. Your .25v input will be (10x.25v); .5v =(10x.5v); 1v. =(10x1v.) ... for all input signal levels until clipping occurs.
If you have a poor operating point selected you may find that the higher signal levels are not amplified by the same "factor" as the softer, lower, signal levels. In MUSIC this could mean that the stronger instruments in the mid to low frequency range that will almost always be supplying a higher signal level will now be attenuated by the poor linearity produced because of the SUPPLY circuit and the tube operating point. Not a tube characteristic. This COULD sound like the highs are brighter than you would expect. It SHOULD sound like the lows are softer than you expect. How your brain and or hearing interprets that and how the "sound" is reported back to everyone on the boards is what makes posts about different tube sound so frustratingly irrelevant to my amp or your amp or his amp. But this is not a FR problem. If you back the input signal down to where all the input levels are back in the linear range you would find what "sounds" like a flatter FR.
Best find an amp setup with flat FR and then use input EQ to taste and or hearing/speaker problems.
Would supersonic oscillation be a possible candidate for altered AF frequency response?
Exactly.
Even so, it would be a very poor operting point to create something audible. But when folks plug anything pin compatible into a socket just to see how it sounds...
20
Last edited:
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.