I just bought this amplifier 4 days ago upon discovering a bad resistor decided to OPEN this amp with the first soldering mod.
A am really force to modding this at a very early stage. Ideally I would have like a few more days or maybe week reading and understanding the circuit before any modification. I like to procrastinate and dream about every mod.
The following mod is what I would like to have done at this stage
1) Change the to Output bypass capacitor to MKP, But I do not have the required parts at home.
2) Change 2 of the resistors to Vishay-dale connecting Pin 2 and pin 6 of the LR Amplifier to ground.
The 2 feedback resistors are already using Vishay-Dale and I would like the input resistor to match that as well.
3) Change the 2 Input coupling capacitor to something else. This would be hard to source as I could only place the cap on this side of the board and I only have about 3 or 4mm thickness to play with.
I end up only being able to have sufficient parts at home for the following mods
A) This 2 capacitors is to help the frequency response of the input DC coupling capacitors. I have wima at home but it just could not fit here.
B and D ) Power supply decoupling. This help reduce the RF interference and is quite effective especially for blocking mobile phone signal.
C) what I could make do at home with the Output DC blocking capacitor
E) This is to match the other resistors so that we could have a balance output when Gain is set to High.
So far the main benefits I hear from the above mods are better RF interference – this is very obvious
Better clarity at the high end. I would not hear the whistle of Jennifer Warnes’s Lights of Louisianne which is not present before the mod. The mid is more mellow as well.
I am still using the original Op-Amp and have yet to roll, I have gather enough information for Op amp selection.