Cwlondon, a few years ago I rebuilt a pair of Tympany IVA xovers for a friend with no technical skill and who was willing to sell me a set of tube mono's at a fantastic price in exchange for the work. I had previously rebuilt the xovers for my MGIIIA's as well as his.
First of all, understand that not all xover components are in the external box; the mid to tweeter xover components are in the midrange panel behind the sock and metal plate that holds the connectors for the cables to the external xover box. The components in the panel need (should) be replaced as well; in fact, IMO, the parts in the panel will have the biggest impact after upgrade. What I did was to house ALL the xover parts in an external stained wood box with an acrylic lid. Stock components were replaced with Solen air core inductors, MIT Multicap capacitors (per my friend's request). Inductor coils were oriented at right angles to each other to minimize interference and all caps were placed on dampening pads.
You should know that as significant an improvement as upgrading xover parts was, IMO just as significant was hardwiring the new xover parts directly to the panel using the same Siltech cable that he uses for speaker wire; thus taking all those steel connectors out of the signal path including the fuses which were bypassed. The six foot length of wire going to the top of the ribbon tweeter was replaced with a single conductor of the same Siltech.
The results are stunning. He drives them with Jadis mono's, and to this day one of the very best sounding systems I have ever heard, with an expansive stage, beautiful tonality, and the best (natural) bass that I have ever heard. Highly recommended.
First of all, understand that not all xover components are in the external box; the mid to tweeter xover components are in the midrange panel behind the sock and metal plate that holds the connectors for the cables to the external xover box. The components in the panel need (should) be replaced as well; in fact, IMO, the parts in the panel will have the biggest impact after upgrade. What I did was to house ALL the xover parts in an external stained wood box with an acrylic lid. Stock components were replaced with Solen air core inductors, MIT Multicap capacitors (per my friend's request). Inductor coils were oriented at right angles to each other to minimize interference and all caps were placed on dampening pads.
You should know that as significant an improvement as upgrading xover parts was, IMO just as significant was hardwiring the new xover parts directly to the panel using the same Siltech cable that he uses for speaker wire; thus taking all those steel connectors out of the signal path including the fuses which were bypassed. The six foot length of wire going to the top of the ribbon tweeter was replaced with a single conductor of the same Siltech.
The results are stunning. He drives them with Jadis mono's, and to this day one of the very best sounding systems I have ever heard, with an expansive stage, beautiful tonality, and the best (natural) bass that I have ever heard. Highly recommended.