Preamp-power amp interconnectors advice

Prophos: If you're not willing to take the positive suggestions and advice as well as a very different viewpoint here than yours, you're on the wrong site.
Your priorities are indeed your own. But to claim dynamics and bottom-octave bass and any kind of reasonable soundstage attributes with a cassette source is silly at best relative to LP and digital sources. Chasing cables and noting capacitance in this implementation is futile. $100 cables will be so compromised and not any less so than $20 cables.

Hope it all works out for you.

Inna: You are right. He's heard enough criticism. Now he's on his own.

Prophos: You seek advice for a solution to deal with your flawed electronics. And yet you dismiss the idea to change these products.

I can understand the convenience of "control", but compromise the performance of a system in the year 2011 for the sake of a cassette player? Really? As long as convenience is your priority, sound quality will always take a back seat.

Many of us started at the low end with the infamous japanese receiver, budget turntable and/or CD player and equally compromising speakers. But in time we discovered the benefits of the midfi products from Adcom, PS Audio, etc., which took the system performance up a notch. We lost many "features" with this change, but the sonic benefits outweighed these. And then we step into the top tiers of performance .... it can be very impressive. But the result is due to the focus on sound, not "features" or conveniences. We all have our favorite brands or product lines, but willingness to let go and appreciate the benefits of the next tier of components is what allows us to achieve the improvements.

The flaws that you want to resolve are just not going to happen with cable swapping. Trying to mask or correct for tonality flaws in the system with cable changes is a forever-losing battle. No $100-150 cable is going to resolve your problem. You're a lot better off with $20 Monster cable products from Best Buy and put your focus elsewhere.

Tonal coherency should be your focus with the electronics, sources and speakers. Once you improve on this, I think your "soundstage" attributes will take a step up unexpectedly. Praising soundstage performance but dealing with tonal coherency flaws seems a bit goofy anyway.

The soundstage is great and instrument separation is just incredible, IMHO due to dual mono design.

"Dual mono" implementation here is more about marketing than benefit. There are many amps and preamps out there that share a common power supply for the two channels, that mightily outperform your electronics.