Thursday, June 20, 2013

So where are all the panels?

Was going through the two large boxes that constitute the rather large number of boards that have been etched, stuffed and variously debugged and qualified to some extent then abandoned... This is YuSynth's ARP VCF that actually works really well! I plan to put in an order for more of the polycarbonate panels and the Cliff sockets and the chicken head knobs and make them a bit more useable rather than twisting the odd wire together... When I look at the gloat thread of muffs and the 2013 build pix on e-m i am amazed at the finished panel quality -- particularly the very black one that someone did recently -- so it really is time to get it looking good!
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Monday, June 17, 2013

According to Jung

Typical! After berating AbeBooks on a public forum it turned up... whoops... So that Karma is dished out the damn book doesn't have a description of the circuit that I bought it for!! It must be in one of his other books and since this book ended up costing me about $100 when you include the money shelled out for the first one that failed to show last year I don't really feel that inclined to go after the other ones. Having said that this book does have quite a lot of interesting articles -- particularly a section about Norton Amplifiers. Kind of wish that they would just put them on Lulu for $15-$20 bucks. I am now thinking that I might ask Bernie Hitchens as he mentions that they did an investigation into the Jung trick with modulating the power lines of the CA3080 in Electronotes En#63 -- had a bit of a look inside a LM13700 and seems like it should also work for that, but obviously effect both OTA's at the same time (which for Ian Fritz's Wood Wind waveshaper would be fine!)

Thursday, June 13, 2013

Stay on Target....

Well more work on the Bergfotron VCO but during lunch while day dreaming did experiment with a phase modulation option for a sawtooth oscillator... seems quite simple so not really sure why people haven't provided this before... probably sounds a sub-optimal?

Tuesday, June 11, 2013

Bergo Waves

Well the waveshapers are starting to work! Sawtooth, Sine, Square & Triangle all look good. The Double Frequency Sawtooth is a bit munted but I may have a wrong component in there... Have to check tomorrow. Was a bit surprised that all the waveforms are +ve rather than around ground when i realized that the voltage controlled wave selection won't work with a -ve signal... Got to drill a couple of missed holes with the dremel and with some luck should be able to try out the wood wind shaper tomorrow!
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Thursday, June 6, 2013

The Bergo Awakens!

I have been building the Bergfotron Advanced VCO for a very long time. I am pretty sure that I started this at least four years ago and it has lain dormant and unloved in the large box of Forbin possible modules. Recently I decided that it was a badge of honor to actually get this beast to life. Any self respecting Synth DIYer would rise to the challenge that Jörgen had thrown down. Well here we are -- we have the VCO core actually doing something. There has been a fair carnage in the component count that have visited this board and a lot of head scratching. There are a few wires that seem to be missing from the overlay drawing (the -1V to the CMOS switch) and a track missing (the -ve supply stops after the ferrite bead) but for sheer mid boggling options stuffed onto one board this is pretty much the pinnacle of design and you would have to take your hat of to Jörgen to have achieved that on a single sided board! Anyway I will keep trundling along as I want to get the wood-wind waveshapers to go! I have no idea how I am going to get all this onto a Forbin front panel but wait and see... hopefully not too long!