OK so I've been a bit slack getting to the second instalment. I actually finished the last coil about three weeks ago and have made the crossovers.

Tip number 1. Wear Gloves!! After the first coil my fingers were killing me. I'd pulled back the skin on my fingertips so hard that it was coming away from under the fingernails. Ouch!!! The gloves I subsequently wore were just normal rubber dish washing gloves. These worked quite well because they allowed me to put tension on the wire (holding the spool) and I no longer got sore fingers

Tip number 2. If you can make the same value with different size formers, choose the one with the lesser turns per layer. My pancake coils were much easier to make than the taller ones.

I think that the reason for tip 2 is that the more turns per layer, the more chance that small kinks in the winding wire will add up to enough to make it hard to get the last turn on for any particular layer. The coils...

Wind my own coils, yeah why not, how hard could it be? Well if you are as much a perfectionist as I can sometimes be, pretty damn hard!!!

I suspect it would actually have been a whole lot easier if I'd not obsessed about getting a low DCR for my coils, and gone with a smaller gauge wire. As it turns out I was (obsessive), and decided to use 1.6mm (~14 AWG) wire.

I originally had thoughts of measuring off the length I needed, clamping one end in a vice and slowly turning the former (in my hands) until I wound it all on, luckily that Idea didn't last very long and I started to think about making a winding jig.

I hit google and saw some pretty fancy jigs, motorised with clutches, speed control, turn counters, that all looked too hard, so I thought about what I actually needed. Georges Transformer winding jig was in the back of my mind too, which gave some inspiration as well

The pictures below are what I came up with. I had...

So I have almost all of the parts (yeah I know) for my YARPS power supply. As part of the order I got myself a prototyping breadboard.

I've knocked up one half of the yarps power supply, ie the positive side, and hooked it up to my old model railroad transformer which has a 15V output.

Parts still to be ordered are the dual secondary 15V transformer and some 50K trim pots. However I had enough to make one side of the dual rail supply.

It didn't smoke, and the CRCRC part of the PS works very nicely Pics attached at the end.

I need to do a further test with BC560c's with different HFE's to see whether this affects the output voltage (my suspicion is that it will). I put a 36K resistor (which I had at hand) in place of the 50K pot and only got 8.6V even though spice said I should get 9.13V with that value resistor so something isn't working as per the sim, the use of a pot certainly seems to be required to get the desired voltage...

Well I said no more excuses, and I for the most part started to make some progress. But good old Murphy stepped in and threw a spanner in the works.

The Boot Drive on my main computer decided to die on me, I've got backups of all the important stuff so no big deal other than the inconvenience. I could always use my work laptop... step in Murphy again, it too decided to die... once again have backups but all of a sudden nothing to run LT spice on, bring up my Plans, test data or anything.. I've got a loan one but I'm not going to set it up for a couple of weeks only.

So since my main computer was nearly 8 years old (single core Athlon 2000 which is really only 1667Mhz) I decided an upgrade was in order... This would probably have been a relatively modest machine if it weren't for my recent discovery of LTSpice and the knowledge that it takes a lot of cpu grunt, and that it benefits from multiple cores!!

So What have I been doing? Not working...

I think I must be afraid of failure. I still haven't built the YARPS power-supply I've mostly worked out the layout on verro-board, and I still have a number of components (not least of which is a transformer) to purchase. You would think that the three months I've been waiting for the silmics I could have got the rest organised... sigh...

The Synergy active crossover, I haven't even started on the layout for the YARPS is a prerequisite for powering it up, but once again, nothing stopping me from doing other stuff.

Today finally received the 14, 1000 uF elna silmic II's today that I ordered months ago. I need two for the PS output and the other 12 are destined for the Synergy (yeah I know WTF?) the current schematic doesn't show them but in a case of gross overkill they will be used for separating different sections of the circuit if I can fit them Basically they will be decoupling the various sections from the supply (and each other). 1 cap per...

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),...

Well for me anyway I think I must be borderline obsessive compulsive! It happens every time I start a project (or even before I start it). I spend hours and hours and hours deliberating on whether this would be better or that would be better. Honestly in some ways I wish I'd never become "aware" of alternatives to the kits that were available from the local electronics shops Dick Smith and Jaycar

I got the jfets for my B1 a few weeks ago. I finally started matching them earlier this week, I hadn't started because I was obsessing over the fact I needed a 100 ohm precision resistor and a transistor socket. I hadn't got those because I wanted to order all the other bits as well and only pay for one lot of shipping. But do you think I could make a decision on what parts to get?

First off I obsessed over the resistors (yeah I know).. wanted vishay RN60D's but local sources are 5 - 10 times the price of mouser, problem with mouser is unless...

Its been really cold the last two days.. I was thinking whilst walking to the train this morning that I should have worn my winter coat! (Cold by Sydney standards anyway, The Northern Hemisphere people would laugh at my notion of cold)

The weather has unfortunately had a damping effect on the progress of my speakers too. First problem is that my workspace is the balcony, and it has been very windy and stormy, so I haven't risked doing any more veneering.... Second thing that worried me was that with the wet weather I might have troubles with splitting.

So Last weekend I placed an order for 100 2SK170BL's from Spencer. He sent them on Monday so hopefully will have them in about a week. The plan is to build a B1 buffer (ultimately I suspect there will be more than one), to finally do away with the abomination that passes for a preamp in my Integrated Series 200 amp.

The B1 will I think be the easy bit... I will probably build it on perfboard...

I woke up this morning, and immediately had a slightly uneasy feeling. There was a strange orange glow seeping through the gaps in the blinds! I tentatively pulled aside one of the vertical pannels and saw what appeared to be red fog. Thoughts of armorgedden, and the cover of Midnight Oil's "red sales in the sunset" came to mind. I was about to grab the camera when Mya decided it was time to wake up and have some milk. Best not to delay the milk supply for a 21 month old with a nasty cold, or armageddon might seem like a palletable alternative, so I made the milk and appeased the small one.

By the time I got the camera, the sky was more orange than red, took a snap and started to get ready for work.

It would have been sensible to take the good camera with me but I was not thinking along those lines as I hurried off to work. Driving to the train station was weird in itself, the headlights of oncoming cars had a strange blue tinge, and so did the...

I've never had a blog before. I've always regarded them as a bit like a non-private (in the extreme) diary that any one with an internet connection can read. What possible attraction could that have!!! (I guess if your a complete extrovert/exhibitionist then there could be some attraction).

I've never really been keen on diarys, I used to keep one for work to keep track of what I was doing, but at some point just got plain lazy and haven't used one for probably more than 10 years. I've never kept a personal one, though now that I'm getting older I do sometimes regret that. When I was 25 I could remember just about everything I'd done in my life (from about the age of 12)... Now that I'm over 40 It's a bit more of a challenge

Anyway I guess I'm going to treat this blog as a kind of diary of what I've been doing with my DIY Stuff. I always think that blogs are supposed to be witty and interesting and lots of people are supposed to like to subscribe to them...