What is it?

Here is a cheaper version of my other kit. The boards are standard green and a bit thinner, and it includes a JRC2068M which cost about 22 cents each when you buy 50 of them from LCSC, but are still far better than the HA1458W. My initial prototyping was actually done with a 2068.

Consider it a free opamp. Use any modern opamp you like that is considered to be stable and well-behaved. Keep in mind that you may have to modify the circuit *around the new part for the best possible performance. The original manufacturer of your device may have used some ugly hacks to make the 1458w behave.

The 2068 is very respectable. It's been used in a whole lot of professional recording gear.

The capacitors are optional but the SMT cap across the power rails is probably a good idea. The 22pf caps are just used to shunt RF noise to unity gain, if you have noise or oscillation issues.

It's awkward that the pins are so long on the male-to-male pin strips, but this style is the only style i have been able to find.

Why did you make it?

I have a Hitachi HMA6500 power amplifier that i really like, and it came with an HCA6500 preamp based in the 1452w that is pretty but sounds very dry and noisy. The 1458w seems to be an externally compensated dual opamp with pretty poor performance, even for the era. The HCA6500 isn't too common because nobody liked it when it was new, either.

The capacitors are optional but the SMT cap across the power rails is probably a good idea. The 22pf caps are just used to shunt RF noise to unity gain, if you have noise or oscillation issues.

What makes it special?

While I am sure that technicians before me have come up with ways to replace the 1458w, I believe my kit is the only one of its kind.