kevin gilmore Posted December 28, 2014 Author Report Share Posted December 28, 2014 Birgir will be building the T2's. I am just going to watch. smaller version of my attenuator board, definitely want to see this. if you make it surface mount only, then you can shrink it a fair amount. The one knob control is definitely one of the better ideas. Quote Link to comment Share on other sites More sharing options...
Kerry Posted December 28, 2014 Report Share Posted December 28, 2014 It must nice to have a Birgir for that I've used these relays, G6KU-2F-Y-DC4.5, controlled by the MAX4821EUP in another project. Very simple circuit and works perfectly. The relays are much smaller than the original ones. Going to all SMD parts would help a bit as well. Quote Link to comment Share on other sites More sharing options...
kevin gilmore Posted December 28, 2014 Author Report Share Posted December 28, 2014 how do you drive bipolar single coil relay with single switch to ground? Quote Link to comment Share on other sites More sharing options...
spritzer Posted December 28, 2014 Report Share Posted December 28, 2014 We will do a competely SMD attenuator as Í'm not going to assemble them... I'm also in charge of parts procurement. If everything I've bought turns out to be real then I'll have parts for at least 50 T2's... or even 100. Quote Link to comment Share on other sites More sharing options...
Kerry Posted December 28, 2014 Report Share Posted December 28, 2014 I used two pins per coil. Here's the tech note I followed: http://www.maximintegrated.com/en/app-notes/index.mvp/id/3288 That's a lot of T2's in the wild Quote Link to comment Share on other sites More sharing options...
kevin gilmore Posted December 28, 2014 Author Report Share Posted December 28, 2014 the amb method. trouble is they dont switch as fast that way. should be ok though. Quote Link to comment Share on other sites More sharing options...
Kerry Posted December 28, 2014 Report Share Posted December 28, 2014 (edited) The nice thing with the maxim driver is that I can set all of the pins low/high with one set instruction. It is programmable via a 3 bit address. I'm using an expander to control the address and set/reset. I've designed it so I can control two drivers with one expander, so two expanders and 4 drivers per channel. I've been setting one relay at a time, which is the same as I was doing with the original boards. I think I can get each channel to about 4" x 1.5". I'd like to see them mount one to the other. If we offset the relays this should work fine. Total dimension for balanced would be about 4" x 1.5" x 1". Edited December 28, 2014 by Kerry Quote Link to comment Share on other sites More sharing options...
Kerry Posted December 31, 2014 Report Share Posted December 31, 2014 (edited) I finally got the HV caps and the PS up and running. The voltages look good including bias and pre-reg voltages. I mounted the transformer and board to a temporary wood cutout that I milled. Fit looks good. The wiring is nice and neat... Here you can see the transformer in the steel case mounted to top plate (wood for now)... So far so good Edited December 31, 2014 by Kerry 1 Quote Link to comment Share on other sites More sharing options...
guzziguy Posted December 31, 2014 Report Share Posted December 31, 2014 I'd say really good! Quote Link to comment Share on other sites More sharing options...
headinclouds Posted December 31, 2014 Report Share Posted December 31, 2014 Yes, great work Kerry. Very satisfying for you I trust. Hope it sounds great too. Quote Link to comment Share on other sites More sharing options...
n_maher Posted December 31, 2014 Report Share Posted December 31, 2014 Nice work, Kerry! Quote Link to comment Share on other sites More sharing options...
Laowei Posted December 31, 2014 Report Share Posted December 31, 2014 Beautiful work Kerry. Immense envy here. Quote Link to comment Share on other sites More sharing options...
kevin gilmore Posted December 31, 2014 Author Report Share Posted December 31, 2014 I actually think I can get a balanced step attenuator with those relays in the same size as the original, all 16 relays. But a human is unlikely to ever be able to assemble it. Quote Link to comment Share on other sites More sharing options...
Kerry Posted December 31, 2014 Report Share Posted December 31, 2014 Thanks - and yes it does sound great. Kevin - Are you thinking of doing two columns and continuing to use both sides? Could be interesting. It would be nice if it could be soldered by hand too. Maybe trim down the control area a bit too. Quote Link to comment Share on other sites More sharing options...
kevin gilmore Posted December 31, 2014 Author Report Share Posted December 31, 2014 yep 2 colums and both sides. you might as well put it all on one board because of the size of the drivers determines the minimum width if you solder all the resistors first, then possibly the inside row of pins on the relays could be hard to get at. Quote Link to comment Share on other sites More sharing options...
Kerry Posted January 1, 2015 Report Share Posted January 1, 2015 (edited) I've done the test fit for the amp section as well. Here's a better approximation of what it will look like. From underneath (Excuse the mess of wires. I'll fix those up once I'm happy with the fit)... Here's a shot from the top of the amp... I've just been listening for the past hour. Sounds great EDIT: PS. Happy New Year! Edited January 1, 2015 by Kerry 1 Quote Link to comment Share on other sites More sharing options...
kevin gilmore Posted January 1, 2015 Author Report Share Posted January 1, 2015 (edited) but but... its upside down. anyway http://gilmore.chem.northwestern.edu/atten2stereobal.jpg 2.05 x 3 inches but only 2 layers and still have to add or change the drivers Edited January 1, 2015 by kevin gilmore Quote Link to comment Share on other sites More sharing options...
Kerry Posted January 1, 2015 Report Share Posted January 1, 2015 I think it sounds better upside down I see you did a lot of work on the board since last night. I love it I noticed the serial interface for the drivers. That really simplifies the board. This will fit perfectly in my build. Quote Link to comment Share on other sites More sharing options...
kevin gilmore Posted January 1, 2015 Author Report Share Posted January 1, 2015 (edited) 3 hours total 6 shots of various vodka's (new kickass Russian/French restaurant with 50 different vodka's) http://dekarestaurant.com/ and after generating the netlist, its still correct. scary The nice thing is this way you can drive all 32 relays at the same exact time. but unless you can calculate relay position, a lookup table is necessary board file posted, needs checking Edited January 1, 2015 by kevin gilmore Quote Link to comment Share on other sites More sharing options...
luvdunhill Posted January 2, 2015 Report Share Posted January 2, 2015 Kerry, would it be possible to get ahold of your 9-pin pattern? Or hole diameters and outer circle radius and angles? Quote Link to comment Share on other sites More sharing options...
chinsettawong Posted January 2, 2015 Report Share Posted January 2, 2015 Really nice work Kerry. You really amaze me everytime I see your build. Happy New Year! Wachara C. Quote Link to comment Share on other sites More sharing options...
headinclouds Posted January 3, 2015 Report Share Posted January 3, 2015 I have been running in my build and it sounds better than the first - really very pleased. I put a heat-sink across the middle and bolted the current sources to that so it runs cooler. 5 Quote Link to comment Share on other sites More sharing options...
cetoole Posted January 3, 2015 Report Share Posted January 3, 2015 Very nice! Details on the case? Quote Link to comment Share on other sites More sharing options...
Laowei Posted January 3, 2015 Report Share Posted January 3, 2015 Very beautiful build Geoff. Eye catching aesthetics. Polished and modern look. I know it sounds great, asI have your boards. That heat sink is giving me ideas... Thanks for making your PCBs available to all. The KGST is spoiling me. Quote Link to comment Share on other sites More sharing options...
headinclouds Posted January 3, 2015 Report Share Posted January 3, 2015 (edited) My own design; 3mm anodised aluminium alloy panels, thick machined FP. Knob turned by me, Ring illuminated mains switch by me. My original design was a little more ordinary, the style was the input of www.incredibledesign.co.uk Edited January 15, 2015 by headinclouds Quote Link to comment Share on other sites More sharing options...
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