Rob Flindall (flinly)
Further to my other posts I got the bug again to mess around with the ICs in my RD112 100 (June 1981 build date) after visiting an electronic supply shop that opened up near me. (Sayal electronics).
I replaced the TL072's with new Texas Instruments TL072ACP and replaced the LM1458's with new Motorola LM1458's. While doing this I found what I deduced to be IC-2 had a TL072 in the circuit not a LM1458 as indicated on the schematic. IC-2 appears to be in the low voltage front panel insert jack circuit (which I have never used,,,,) so I put a LM1458 in its place. Has anyone seen this? There was no discernible negative effect, so it appears to be OK.
Also, I purchased a few KF353 op-amps thinking to try them in place of the TL072 as indicated on the schematic, or as replacements for the LM 1458 as suggested to reduce RF interference. I could not determine the manufacturer of the KF353. The schematic says LF353 (National) but not being sure if KF353 is equivalent to LF 353, I decided against it.
Any thoughts on the KF353?
|Rob Flindall (flinly)|
I replaced all of the TL072 with a variant of JRC4558 chip. This seems to be a good sounding replacement option. The amp sounds a bit quieter,less hiss at lower gain settings and low volume. The bass notes seem to last longer and sound better.
Tue, 03/25/2014 - 09:55#1