not on this one. but i do alot of that to other, more worthy gear.
funny that recently, i flattened the jvc ax66 phono response like ruler flat using my ebay 'motronix' iriaa board...i just built my own iriaa board and handmatched precision parts and remeasured the jvc...it's got humps where i compensated the phono stage for defects in the ebay board
when i plotted the ebay board, it LOOKED good but i never compared exact dB with the standard. it's off a bit. not bad. might not be able to hear the difference but i could see it.
i'll get back into that unit before long and post plots and stuff when i readjust it.
i got burnt on repairs and restos. i been doing more mods lately...and playing. tinkering. just having fun.
Late 70's or very early 80s was peak analog
Many / most circuits became cook-book designs
De-rating components for cheaper components is mandatory in engineering school and Eng departments
- I put an end to it on the industrial data com products I was in charge of , it wasted 2-3 months and reduced the quality of the product for pennies. The 1% components used for prototypes are what we shipped.
Increasing the power of a conventional amp requires a lot more engineering and components;
- greater density and thermal management problems, heat kills.
- More components = lower reliability cumulative noise and other distortions and trade-offs.
- aka Starting with a straight piece of wire, every component added decreases reliability and increases noise and risks.
- The argument for low-power and flea-weight amps and uber efficient speakers.
This is why I wonder if hot-roding a name-brand low-power late 70s amp with better discrete components
- yields big jumps in measurable performance .
- The product line sold in good stereo stores, not JC Penny and Sears.
Cook Book circuits with the good components ...........
When Yamaha got back in the quality stereo business a few years ago,
- their amps were / are discrete throwbacks that were and are well received. Sound good.
- using best quality discrete components
- better ones use differential aka tube like circuit topology
Note
The TI amp chips may have changed the formula,
- I think of these chip amps as lots of low quality power for cheap price.
- I have never spent time in a good environment to listen to one and see if the girls sound like girls etc.
- Maybe the TI chip set and two speaker connectors blows everything else away ? Better performance MIL versions are now appearing in stereo gear.
- Surface mount was new when I exited hardware, also everything was moved to Mexico, then Singapore, then China with the outsource manufacturers. I have no idea how you mod surface mount. or if most of it can be repaired. or worth the trouble to repair.