Help with Modified Audible Illusions Modulus 3

Those are good sounding caps and may well sound better then the originals. But they are not originals.

If the caps that were replaced are shorted or the wrong value it could cause the preamp to be unstable. I am always careful to use the same value parts in any preamp I update. That preamp also has solid state regulators in it and that could also be a problem. Do the tubes light up?

Clearly, someone has added some green cylinder-type devices and circled them with yellow wire. They have also added some silver and yellow ones and done the same. There appears to already be enough wire, so why add more I have no idea. Very, very odd mod if you ask me.

First instinct is to say, WTF; as AI interiors are a thing of beauty. This one sure ain't! However, on a second look it seems as if they by-passed some circuitry. Do all the switches work?

I work on a lot of gear and own a stock Modulus and I'm going to come down on the other side of the ball here.

First, it is not a modification, the circuit appears to be completely stock. It is an upgrade, where simple parts have been substituted with other similar parts.

As mentioned the silver capacitors are Russian K40Y paper in oil types that will be richer and rounder than the Wonder Caps or other film types that were originally there. Likewise the green caps - Either Russian K42 or K72 types, in all likelihood - at the top of the photo, are simply replacements of the original caps that were in these interstage and output coupling positions. These are in the signal path.

At the bottom of the photo, you will see the original blue Mallory power supply electrolytic caps, and the upgrade has added more Kommie Kaps to bypass those electrolytics. Bypassing Electrolytics with faster film, or oil, caps has been common practice in audio for the last twenty to thirty years and is a conservative practice. Some do not like the resulting sound, but when the bypass caps are of high enough value, most find this a sonic enhancement.

In that context, the work looks clean and orderly to me. Some of the other posters have mistaken the circles that you have drawn around the caps for wire, so you can ignore those comments.

Overall, it is an orderly, conservative, change that does not stray from the original circuit and probably will retain much of the original sound, while sounding richer, or slower than the original, depending on your perspective, and will not affect reliability. Though it will adversely affect value.