January 6, 20179 yr 2 hours ago, rumina said: Not a Mini Dynalo but a small one. Finished my Dynalo today, thanks to this forum and the members the build was easy and free of trouble, thanks everyone. Was fun to put it in a small case and solve this puzzle. Also a big thanks to Kevin Gilmore for this design and sharing it with us. http://www.diyaudio.com/forums/gallery/showgallery.php/cat/2231 Thanks to sbelyo for the group buy of the pcbs. man..same thoughts here, but I failed squeezing GRLV in it,lol
January 6, 20179 yr @pars thanks for the info, was puzzeld about the 3th rectifier and didn't take much time thinking of it, a bit of wiggling and it's out now. Something new learned about the grlv, used it the first time. That's a part i love about head-case, helpful people and always something new to learn. @ang728 look nice your amp, building this in a small case is like a 3d puzzel, part of the fun for me.
January 17, 20179 yr Hi everyone! I also finished my build of Susy Dynalo! Still doing run-in of the amp but it already sounds really great even driving a HD800! Since the layout from Mr.Gilmore is a little bit too large and cannot fit into a 10cmx10cm pcb, I have to redraw the layout. But good thing is that an extra inductor was added to the power rail of input stage as well as the VAS to prevent distortion from output stage. Also the rails are surrounded by "guard rings", aimed to avoid EMI problems..... Sorry for the crude casing... just carved it out from kinda plastic flowerpot... Some detailed specs: Quiescent Current of Input: 1.2mA Output stage bias: 6.7mA per transistor rail voltage: 18.5V, tried 20V but it's too hot. Gain: Approx 3. Also some interesting results. The THAT340 was then replaced by hand-matched ksc1815/ksa992, beta deviation within 0.1% - Huge improvement in transparency and details! The power supply based on Jung's regulator, but an extra transistor was added after the error amplifier to lower the load seen by the Op-Amp, works well.
January 17, 20179 yr 1 hour ago, kevin gilmore said: no no no, swimming pool, it floats with reference to ground?
January 18, 20179 yr lol, indeed the "casing" was dug up from the basement. A water-resistant version... And the amp sounds a little bit too bright, so the compensation cap was added upto 15pF, much better now
January 30, 20179 yr Noob question to all. On Kerry's 1.4 Dynalo v1.4 SMD board, on the bottom side, there are a couple of masked points with silk marker "AOT" and "0". What are these, jumpers? Thanks for any pointer!
January 30, 20179 yr the 0 is ohms (used as jumper) R27,R45 on BOM LRC-LRZ1206LF-R000 think from schematic that AOT is a voltage adjustment I was hoping someone would ask... cause I'm not sure either Edited January 30, 20179 yr by congo5
January 30, 20179 yr AOT is a resistor (R62) spot in parallel with R54 (10K), feeding the sense line on U3 (TPS7A3301RGWR?) to ground. Maybe used to tune V- to match V+? No value listed in the BOM for it.
January 31, 20179 yr 23 hours ago, Pars said: AOT is a resistor (R62) spot in parallel with R54 (10K), feeding the sense line on U3 (TPS7A3301RGWR?) to ground. Maybe used to tune V- to match V+? No value listed in the BOM for it. Yes. AOT means Adjust On Test. It's not required but can be used to finesse the output voltage on the negative rail.
January 31, 20179 yr Thanks Kerry, for the clarification and providing us the board design. Any advice on the best way to solder the TI 7A4700? That thing's tiny, I ruined one board doing this already. I'm thinking melt some solder first on the pins and then put the chip on. I got a rework air gun, not sure it's the best way though.
January 31, 20179 yr 20 minutes ago, Skooby said: solder the TI 7A4700 watch Louis Rossmann - YouTube I used a candle warmer to preheat the area. clean the pads liquid flux tin the pads clean reflux use hot air station solder with silver content helps with gold plating.
February 5, 20179 yr On 1/31/2017 at 11:30 AM, congo5 said: watch Louis Rossmann - YouTube I used a candle warmer to preheat the area. clean the pads liquid flux tin the pads clean reflux use hot air station solder with silver content helps with gold plating. I watched part of Rossmann's video soldering a chip on a Mac or the like...damn. Soldering free for all. That man doesn't play. LOL HS
February 5, 20179 yr and he definitely does not hold back on opinions...no inside voice...LOL Thanks for posting, congo. HS
February 5, 20179 yr Any idea what brand/type of flux he's using? I bought MG no-clean flux but it's too thin and evaporates too quick (doesn't hold the smd piece still for alignment). Thanks!
February 5, 20179 yr I haven't a clue. He has a video where he describes all the parts he uses as I believe he receives many questions. It's over an hour long... HS
February 5, 20179 yr under video description click "show more" ✖ TOOLS USED: ● Flux: http://bit.ly/2cYIx7t ● Solder paste: http://bit.ly/2epK1JE ● Soldering Iron: http://amzn.to/2cKkMyO ● Preferred tip: http://amzn.to/2d5MgPn ● Micro Soldering Pencil: http://amzn.to/2d5MWUP ● Micro soldering tip: http://amzn.to/2eYrF4a ● Hot Air station: http://amzn.to/2d5M7Lw ● Hot Air EXPENSIVE: http://amzn.to/2cYI6tY ● Tweezers: http://amzn.to/2d5NBpi ● Multimeter: http://amzn.to/2cYJY5T ● Multimeter Probes: http://amzn.to/2cKkvMh ● Fume Extractor: http://amzn.to/2d5MGoD ● Microscope: http://amzn.to/2iLrE16 ● Microscope LED light: http://amzn.to/2d5Mh5T ● Solder: http://amzn.to/2cKkxUp ● Crest CP500HT Ultrasonic cleaner: http://bit.ly/2iv3aci ● Branson EC cleaning fluid: http://amzn.to/2cKlBrp ● Jumper wire THIN: http://amzn.to/2eqF5T7 ● Jumper wire THICK: http://amzn.to/2eAJ5AU ● Nitrile gloves: http://amzn.to/2iUfumS Bench PSU: Agilent 6542 I'm using Kester. turn down the blow. hold with twezers mask off blow zone with aluminum foil?
February 5, 20179 yr Good stuff, congo. I like the look of the Hakko micro handpiece / pencil. Might have to spoil myself with one of those. HS
February 5, 20179 yr 8 minutes ago, HemiSam said: Might have to spoil myself with one of those. Yes, want! don't have small pencil on Flux: its a big deal, what he has is way better, the kester boils off quick and leave's more residue but works I got the positive regulator on the first try, but took three times on the negative Had too much solder under and some side pins would not make contact. flux dries> solder won't stick> start over going slow and careful as I only have one board, that took half a day ;-) Really want the microscope + camera.
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