It seems I have been doomed to not do any of my DIY projects since my main computers hard drive crashed followed shortly after by my laptops (the laptop has had another crash after that, and the drive is now on the way out again!!)

After having to pull the cables out of my chipamp last week and plug the TV into it (because the MythTV box refused to play a DVD and I can't plug the DV18 DVD player direct to the chipamp because it has no volume control) I decided I had better get off my backside and finish my pre/active crossover. I had to do it again tonight as well (plug the tv into the chipamp), sigh...

This is all because my playmaster had something in the pre die again and is only working on one channel and I just haven't been bothered fixing it. I thought that being inconvenienced might make me more likely to finish the other projects but it has been broken for about 6 months

So on Monday I decided that I should re-install Holm-Impulse...

Following on from YARPS I thought I would post the design I have been working on for my active crossover (which is in fact is what the YARPS power supply was designed to drive).

So here I present the Synergy "Active" Crossover. Please note I have only simmed it at this stage (and when I started I knew nothing about active filter design) so there is no guarantee it will work.

Why have I put "Active" in quotes? Because whilst this filter uses active components, for all intents and purposes it behaves like a passive filter. It basically emulates either an LC or a CL passive 2nd order filter.

Why the name Synergy? Well I though it was the best word to describe the differing technologies working together to give the end result

The design goal is to have an active crossover that for all intents and purposes is transparent. That is it does nothing other than split the frequencies at the desired crossover point....

10 Feb 2011. AndrewT pointed out something really dumb I had done (in a most polite way) in the original circuit. The caps in the filter section are in series and effectively halved in value. The circuit will behave much better simply by deleting half the caps. I've uploaded the latest version of the file. Sorry to the 125 people who have already downloaded, and I hope I didn't cause too much head scratching as to why I had done that, I'm not even sure myself, and I'm surprised I never realised. I'm going to revamp this blog entry as there are some things I have realised since I first posted, but that will be over the next couple of weeks. Hopefully I will finally build it soon.

I have been spending an inordinate amount of time using LTSpice lately. The more I use it the more I like it! For someone like me who is somewhat challenged mathematically, and who's electronics theory knowledge level is well below where it should be (to be doing this sort of design anyway),...