I've never been completely happy with the passive cross over, either before or after the re-cap. I hear distortion around the mid to tweeter x-over point. I've heard it on other examples of the NS-1000M, I had it on my Celestion 66's and hear it to some degree on almost every passive three way I have come across. It's mostly noticeable on voices, especially Female. I decided to try a simple analogue active filter circuit in an attempt to get rid of this problem,  I'm using the ready made modules by KMTech. The passive is a simple circuit without any notch filters or zobel networks so a simple analogue filter using Op-Amps might work without the need for any frequency equalisation etc. The PDF file linked on slide 14 shows the layout I drew up, it has a power supply, also by KMTech, you just need to add a Transformer. The 30VA I used is overkill and one of 15 to 20VA would have done the job if I could have found one. I've tried to keep the AC path well away from everything else and avoid the DC tracks crossing the signals which I have kept as short as is practical. I am building high quality volume pots into the outputs to allow channel matching for amplifiers of different power ratings and sensitivity. The standard PCB mounted RCA sockets will be removed from the boards, I just used library pictures of the products for the layout.


It all fits into a 17" x 1U case which is 250mm deep, this is only marginally bigger than my Croft pre amplifier so it will sit under this on the shelf. I bought a ready made case and started work fitting the power supply.