Ibanez DE7 delay is noisy, distorting signal

[nbabmf]

Pretty self explanatory... there's a considerable amount of noise when this pedal is in line, and the clean signal comes out noticeably distorted in both bypass and when the effect is engaged.  It sounds like a cheap practice amp with delay.  There were some previous issues with the pedal that I believe came as a result of using an incorrect power supply.  When it turned out to be more than just the protection diode, the owner just gave me the pedal rather than have me fix it for him.  As it turned out, the JRC720UL3383A voltage regulator was putting out far less than the 3.3V that the delay components wanted to see and that was the cause of the glitchiness.  It turned out to be an obsolete component, so I replaced it with 78L33 which has a much higher input voltage tolerance.

Anyways... after straightening out the power issues, the pedal worked fine in the delay mode, but in the echo mode, the repeats were almost inaudible.  I checked the voltages on the 4580 dual op amp that the echo mode used, and half of it was dead.  I took that out and put a socket in to audition other dual op amps that I had on hand (with the same pinout - 4558, 1458, etc).  That's when the noise started.  I thought I was so close to having a functional delay pedal!

Here's the schematic...
http://www.ibanez.com/parts/2004_PARTS/electronics/tonelok/circuit%20diagram/DE7-01.pdf

The only thing I can think of it that somehow the 062D JFET op amp which handles the input and output buffers is faulty.  Are they particularly sensitive?  I haven't really dealt with them.  I have a few TL072 on hand, as well as other non-JFET op amps.  Is there a special reason why this particular part would be used?