spritzer Posted February 5, 2014 Report Posted February 5, 2014 One can never have too many transformers... For the parts hoarding crowd that likes to pretend they will build stuff eventually, is there a spec for this transformer on file with the company and available for order? Especially since 48x 4686A just arrived and the sumr keep having issues? Nope, it's a company that only does bulk orders so anything below 800$ FOB carries a hefty penalty.
nopants Posted February 6, 2014 Report Posted February 6, 2014 inefficient designs? electrostatic circlotron??
Pororo Posted February 13, 2014 Report Posted February 13, 2014 I have 2 offboard amp PCBs that LilKnight sent me. The problem is that one is Rev 0.4 and the other is 0.6. I'm guessing it would be a bad idea to build one channel with 0.4 and the other with 0.6? Does anyone have a spare single PCB either 0.4 or 0.6? Thanks.
GeorgeP Posted February 14, 2014 Report Posted February 14, 2014 Shouldn't make a difference except that you should ensure the feedback on 0.6 is set correctly. I believe 0.4 may have had an error or two that is/are easily corrected while building - but corrected in 0.5 - this should be set out somewhere in this thread.
Pororo Posted February 14, 2014 Report Posted February 14, 2014 If I'm not mistaken, on Rev 0.4 a pair of 50k resistors have to be "crossed" with one mounted on the underside. There's also at least one additional resistor between 0.4 and 0.6.
Pororo Posted February 14, 2014 Report Posted February 14, 2014 I'll certainly give it a go if Kevin Gilmore gives his stamp of approval.
kevin gilmore Posted February 14, 2014 Author Report Posted February 14, 2014 the crossed resistors for sure. not sure what the other resistor is. Otherwise the circuit is identical.
Pororo Posted February 15, 2014 Report Posted February 15, 2014 Thanks Kevin... can't get more definitive than the word of the designer.
Pororo Posted February 15, 2014 Report Posted February 15, 2014 Thanks for the tips/pics guys. I'll start stuffing the boards on Monday. Yes, I have the offboard amps.
spritzer Posted February 15, 2014 Report Posted February 15, 2014 (edited) Speaking of offboards... As some of you might have spotted, I quite like to push the envelope in making smaller and smaller amps. Going with what Kerry did but in an off the shelf chassis and no SMD parts it is a challenge to shrink something this complicated. PSU isn't ready yet but it is version of the BH design so +/-400V max. That does mean more current though... The chassis is about 10mm wider than a SRM-727, similar height but much shorter. Ohh and far more power... Also, one should never do the chassis artwork 1 hour after they should have gone to bed... Edited February 15, 2014 by spritzer
chinsettawong Posted February 16, 2014 Report Posted February 16, 2014 Really nice! Sent from my iPhone using Tapatalk
Kerry Posted February 17, 2014 Report Posted February 17, 2014 I'm loving the way that build is turning out Are you still sending the artwork out to have it etched? I'm looking for a DIY way to label my projects and was wondering if you've mastered that.
spritzer Posted February 17, 2014 Report Posted February 17, 2014 They are still being etched for me but it's close to my work and not terribly expensive. The black panels are just showing the natural aluminum underneath the anodizing but the silver panels are covered in some film and then exposed to the laser. This leaves the color residue on the panel and a nice textured feel. I can have this in pretty much any color so I might do a pink one... This shows just how tight a fit this is, roughly 180*100mm that's completely unobstructed. The PSU will have the fets connected to the bottom of the chassis for heatsinking but even so it's 108mm by 80mm. The area with the caps is a bit smaller so they should meet the 100mm limit. I've started to shop around for a transformer so we'll see if anybody is feeling brave and can make a shielded one for me. I can also fit one of my power boards to the back panel so easy AC wiring.
justin Posted February 17, 2014 Report Posted February 17, 2014 just do a real DIY and stick the transformer leads into the wall outlet
kevin gilmore Posted February 17, 2014 Author Report Posted February 17, 2014 nah, 220 volt version of firestarter (power cord on clip leads)
spritzer Posted February 18, 2014 Report Posted February 18, 2014 Just think about how much space I would have saved by simply sticking the boards on with some doubler sided tape. That's NorthWestern engineering style... A fully shielded transformer does fit in that space and I'm working on getting a slightly taller one that is less obstructive to internal airflow.
nnotis Posted February 19, 2014 Report Posted February 19, 2014 Spritzer, maybe working on amps after bedtime isn't such a bad idea. It looks brilliant to my amp engineering ign'ant eyes.
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