Basically, change the material will change the sound quality. It is very difficult to explain but if the design is good enough, then change some better brand resistor on the signal path normally will improve the sound quality like details sound stage etc. Resistor in the signal path means any resistor that pass through by signal from input to output. In your case, it should be R6 & R7 ( sorry, it is still very diffuclt to read). two resistors that after the signal caps. It is a common sense that Holco & RMG will yeild better details with sweet sound , dale are more neutral and AB resistor are more musical. Normal carbon firm resistor will sound a little bit dull. Some wire-resistor ( white in color) will sound terrible.
Using different resistor like using salt and suger in cooking.
Normally change the caps and signal path resistors will change the sound quality as signal pass through these materials. If you want to improve the bass, then it will be another story
To get good bass, you really need to look at the power supply ,the frequency response of the transformer, and finally the design of the circuit. Since the transformers and the circuit are fixed, you can only modify the E-Caps on the power supply to provide a bigger supply of power or change the feedback resistor to a different value. Changing the feedback will change the characteristic of the amp. For the E-caps, change to different brand of E-caps will yield different quality of bass. Someitmes, you can increase the value of the E-caps but it really need to be an experience mod. Premium brand like blackgate or Jensen should be able to do the job. Changing the value feedback resistor requires some calculation. It can also be done by trial and error but just make sure that you do blow the speaker by the oscillation if the feedback is too large. As i say before " Good Bass is difficult to get" A lot tube amps is lack of bass as it is limited by the output transformer and the design itself. I had built a 300B amp 10 years ago and try to improve the bass without success. Finally, I find out that there is some limitation on the design of driver stage so it does not provide enough power to drive the 300B. |