Hey everyone,
I found a review online for my old Crate CR 112 that suggested upgrading the power amp transistors from TIP110/TIP115 to nte2343/nte2344 and the preamp opamps to OPA 2134. No other instructions beyond that. It looks like the nte2343/nte2344 combo is just a little more robust overall, and 80 watts vs 50 with the TIP's. Would these NTE's work as a drop in replacement in this circuit and if so what/ if any improvement would they really offer? I'm assuming it wouldn't really be much louder? (The watts vs db's ratio)
The main problem I'm having is what I believe is harmonic distortion coming from the boosting circuit in the feedback loop of the 2nd half of the 4558 opamp. Ear stabbing sound pressure harshness unless the mids and bright switch are off.
It actually sounds like piercing, whistling overtones. What I dont know is if the harshness is coming from the boosting within the opamp itself, or if the boosting from the op amp is hitting the transistors too hard downstream in the power amp causing harmonic distortion there. Hence maybe beefier transistors would help? Anyone have any ideas?
I've already had some good suggestions for mods to the first op amp loop in this circuit from forum members in the past, and after tinkering alot with the preamp circuit in a simulator, and learning to use a simulator in general, I have some plans for that section. Many thanks for the help in the past. I'm using this amp circuit to learn about electronics. Thinking about this amp gives my mind something to do other than be anxious. Of course, a hemp cone speaker might be all I really need, but then what would I learn? Schematic is in the manual attached.
I found a review online for my old Crate CR 112 that suggested upgrading the power amp transistors from TIP110/TIP115 to nte2343/nte2344 and the preamp opamps to OPA 2134. No other instructions beyond that. It looks like the nte2343/nte2344 combo is just a little more robust overall, and 80 watts vs 50 with the TIP's. Would these NTE's work as a drop in replacement in this circuit and if so what/ if any improvement would they really offer? I'm assuming it wouldn't really be much louder? (The watts vs db's ratio)
The main problem I'm having is what I believe is harmonic distortion coming from the boosting circuit in the feedback loop of the 2nd half of the 4558 opamp. Ear stabbing sound pressure harshness unless the mids and bright switch are off.
It actually sounds like piercing, whistling overtones. What I dont know is if the harshness is coming from the boosting within the opamp itself, or if the boosting from the op amp is hitting the transistors too hard downstream in the power amp causing harmonic distortion there. Hence maybe beefier transistors would help? Anyone have any ideas?
I've already had some good suggestions for mods to the first op amp loop in this circuit from forum members in the past, and after tinkering alot with the preamp circuit in a simulator, and learning to use a simulator in general, I have some plans for that section. Many thanks for the help in the past. I'm using this amp circuit to learn about electronics. Thinking about this amp gives my mind something to do other than be anxious. Of course, a hemp cone speaker might be all I really need, but then what would I learn? Schematic is in the manual attached.