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Skooby

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Everything posted by Skooby

  1. I've copied BH zener regulated PS to use for a DTH 45 (ignore the B+ delay/FDA217, I got an unpleasant thump).
  2. Are these valid DIY T2 tranny specs? 30-0-30/500mA, 2x6.3V/1.5A, 2x6.3V/4.5A Two of 485V/150mA, 285V/60mA, 75V/60mA Thanks!
  3. Try: https://drive.google.com/drive/folders/0B_iJFfZStuVhSE5nOHBVdTByR1k?usp=sharing https://drive.google.com/drive/folders/0B7egryukiT7_TFlEQlBRejdVdDQ Kevin retired.
  4. I took a stab at Mouser BOMs for the diamond_buffer and unbal_2_bal SMD boards. Can someone kindly enough to check and correct the BOMs? Many thanks! **** Edit **** The below lists hadd these changes (thanks to mypasswordis!): LED from 2V to 1.9V 300-Ohm LED resistors from 250-Ohm 0.1uf C2/C3/C7/C8 caps to 0603 package 10uF C1/C4 to X7R Other note: OP27G U1/U2 can be changed to other op-amp ************** Unbal_2_bal SMD Mouser # Description Order Qty. 757-2SC3324BLTE85LF Bipolar Transistors - BJT Audio Freq Low Audio Freq Low 7 757-2SA1312BLTE85LF Bipolar Transistors - BJT PNP Trans -0.1A LN -120V VCEO 7 284-APC1206B1K00N Thin Film Resistors - SMD 1KOhm 0.1% 1206 25 PPM 4 667-ERA-8AEB103V Thin Film Resistors - SMD 1206 10Kohm 0.1% 25ppm 12 667-ERA-8AEB132V Thin Film Resistors - SMD 1206 1.3Kohm 0.1% 25ppm 2 647-UWX1E101MCL1 Aluminum Electrolytic Capacitors - SMD 25volts 100uF 8x5.4 20% 2 584-OP27GSZ-R Precision Amplifiers LOW-NOISE PREC IC 2.8V/uS 2 581-06033C104K4T4A Multilayer Ceramic Capacitors MLCC - SMD/SMT 25V .1uF X7R 4 710-885012209028 Multilayer Ceramic Capacitors MLCC - SMD/SMT 2 710-150120SS75000 Standard LEDs - SMD WL-SMCW SMDMono TpVw Waterclr 1206 4 603-RT1206BRD07300RL Thin Film Resistors - SMD 1/4W 300 ohm .1% 25ppm 6 Diamond_buffer SMD Mouser # Description Order Qty. 649-68016-404HLF Headers & Wire Housings 4POS R/A HDR SnPb 1 279-CPF1206B10RE1 Thin Film Resistors - SMD CPF 1206 10R 0.1% 25PPM 1K RL 4 279-CPF1206B24R9E1 Thin Film Resistors - SMD CPF 1206 24R9 0.1% 25PPM 1K RL 2 756-PCF1206R-20KBT1 Thin Film Resistors - SMD .125W 20K ohm 0.1% 25ppm 1 757-2SC3324BLTE85LF Bipolar Transistors - BJT Audio Freq Low Audio Freq Low 4 757-2SA1312BLTE85LF Bipolar Transistors - BJT PNP Trans -0.1A LN -120V VCEO 4 710-150120SS75000 Standard LEDs - SMD WL-SMCW SMDMono TpVw Waterclr 1206 2 603-RT1206BRD07300RL Thin Film Resistors - SMD 1/4W 300 ohm .1% 25ppm 6
  5. Another vote for FX-888. Got all functions I ever need in a solder. Did some smd with the standard tip, tough but not impossible. Still going strong, 6 yrs 'n counting...
  6. I'm up for some 2SC33810-BL, Justin! Hook me up, pleaseee...
  7. It would be nice to also have 5.0VAC tap-offs from the 6.3VAC filaments on LV trafo for future 20B usage...
  8. That's one fine soldering work on the QNF chip, sir! Ruined two boards, getting 3rd and 4th boards for another attempts. Damnit, this ain't rocket science! (*** if you can't get the QFN on. No sweat, just get the AMB Lab off-board/pre-soldered regulators! ***) My problem is getting just the "right amount" of solder on pins and pad.
  9. I refer a mechanical mean to keep the heatsinks on, easier for serviceability. I modified mine a bit with an extra heatsink to provide a conductive mean to transfer the heat to the chassis. The extra heatsink contacts the top plate once it's screwed on. The BJTs get real hot (John said of 74C sounds right). Radiative/convective heat transfer via the heatsinks in the small chassis space may not be enough. Try someway to get the heat to the chassis...
  10. I have had tube amps with the 60Hz buzz due to AC heater and OPT interference. This is more of gain hiss, pretty sure it's not AC hum. I will have to move the 32VAC wires to the GRLV boards away from the signal wires. Right now, the heatsinks are at 42-47C after 30-min on (nominal from what I've read?). Thanks Dr. KG and Steve for setting up the GB!
  11. Got 0.75V bias with strapped 500R parallel to 1K to get a new floor of 200R; 5-min job... Two chassis was my initial plan; however, a simple single chassis with small footprint/stack would be nice. I did try the amp out with the trafos off the chassis (a foot or so away). No noticeable improvement on the noise floor with trafos on-board. Yes, the AC/signal wiring is sloppy (so excited to get the thing humming into life). Will have to clean-up the wiring...
  12. Good point...didn't think about safety issue; being a cheapass, I was just thought to save some resistors for other projects The 500R is nestled pretty tight in against the pot and 5K, so 1K is easier to replace/mod with. Will work out what needs to get lower floor (~200R or so?). I'll run it at 0.75V bias; the heat was ok, just warm, not hot. Though, my heat sink is smaller than yours, so may be keep it low (will test it out and decide). Yours is so beautiful, mine is so bland and ugly! So jelly...
  13. Alright, thanks guys for clarifying the high noise floor. That dual Dynalo/hi combo is a great solution for that problem, nicely thought out! LCD-3 definitely sounds better on the Dynahi. So took on this idea last night, I strapped 750R parallel to R1/500R (300R equiv.) and adjusted RV1, I was able to get the bias up to 0.75V. The resultant resistance across R1 was about 250R. Look back at the schematic, the 1K/R50 and R51 are there to keep the resistance from getting below 333R. So, thinking of shorting R50/51 out; just have to remember to set RV1/2 to max before power up. No problem right?
  14. Super build! I am having the same problem of biasing my Dynahi (ver1.5). I can only manage to get one set (inboard or outboard) of transistors to 0.75V but zero for the other; around 0.402V for both sets. Would like to know a solution to this problem too. Also, on low impedance/high sensitive cans (D7K notably), I hear quite a bit of floor noise (running at 0.4V bias). But no noise for high impedance cans, LCD3/HD800. The way it is? MiniDynalo were dead quiet though...
  15. I usually search on eBay for MIL-16878 for silver plated wires (same stuffs navships sells). Some sellers sell bulk rolls (500ft-1000ft) at steep discount prices. There are spec sheets for MIL-16878 wires somewhere on the web. There are listed voltage ratings which handy as a reference for HV hookups. I use this stripper for teflon, works fine even for 16 awg: https://www.amazon.com/gp/product/B000IBOP70/
  16. Fascinated neutrino facts! Just wonder, due to their abundance, would their mass's enough to account for the universe "missing" mass without the need of "dark matter"? Sorry for hijacking the thread...we need a general thread on physics.
  17. Just finished my Dynalo Mini today. Sounds fantastic (GS-X in a palm)! Many thanks to KG and Kerry for the design/gerber files and Steve for setting up the group buy!
  18. Finally gave up on getting the QFN regulators on the board (even with Amtech flux). Getting shorts probably due too much solder. Ordered these instead: http://www.ebay.com/itm/TPS7A4700-Ultralow-noise-4-VRMS-low-dropout-linear-regulators-3-5PIN-1-4V-20-5V-/252348749037 Any chance that we can have gerber files for these boards (positive and negative regulators) for the group buy? I would like to practice some more but not on the dynalo mini board and ruin more.
  19. 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!
  20. 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.
  21. Thanks many, I'm in the process of populating the board...will jump the 0-ohm!
  22. 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!
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