February 7, 200917 yr Cool. Does that include making up one or two prototype boards, which we can stuff and test, and then any revisions leading to the final production run? No, that's just for a production run.
February 7, 200917 yr Also, here is an Eagle library archive including the dual package devices: 2SJ109, 2SK389 transistor-toshiba.lbr 2SA1349, 2SC3381 transitor-pnp.lbr, transistor-npn.lbr respectivelyEagle_toshiba_trans.zip
February 7, 200917 yr Should we do prototype boards? It would be a good idea, I would think. Not sure who would do them though.
February 7, 200917 yr It would be a good idea, I would think. Not sure who would do them though. Jacob, How's the board design going? Any thoughts on prototype boards? As a flight tester I always favor prototyping.
February 7, 200917 yr I'm in favor of prototyping as well. It'd be a pisser to order 100 fubar'd PCBs.
February 8, 200917 yr It is. They make it different versions for different metals. No idea if it's better than other lubricants but it worked good for me. Plus it has a nice cinnamon smell. Yeah, but the cinnamon smell fades pretty fast and if there's any leftover on the metal or your fingers it starts smelling real bad.
February 8, 200917 yr luvdunhill - 8 - 4Naamanf - 6 - 4looser101 - 4 - 2n_maher - 4 - 0Digipete - 8 - 4Pars - 6 - 2Fing - 4 - 4Asr - 0 - 4Stretch - 0 - 4PFKMan23 - 0 - 4Icarium - 4 - 4Dreadhead - 0 - 4laxx - 0 - 4Torpedo - 0 - 4PICaudio - 8 - 4vvs_75 - 8 - 4I am in too. Also since Dreadhead and I leave few minutes to drive from each other, I think I make sense me to build his amp. I can do also extra amp or S22 board if we need it.
February 8, 200917 yr Author Yes. 2 boards and I guess a sigma22 PSU. 80VA 2x30V trafo (or 30-0-30 or 60Vct). If you are going to do it in a single box, then trafo should be shielded if toroid; split bobbin or r-core should be fine as well. Additional sundry items such as case, volume pot, jacks, wiring, etc. For balanced I'd recommend 160VA 2x30 VAC. I'm planning on using Plitron 057017201. I don't understand all the consternation about a single box build. Look at the number of power amplifiers out there that don't use shielding and using much larger transformers... not all that many two box power amplifiers out there. Anyways, if we need to agree to disagree on this one, I'm fine with that. The group just needs to come up with a recommendation, preferably a single model. I think the SumR toroids are a "good value". I have a custom unit sitting right here in front of me and have another large 2x18VAC unit as well. I'm still waiting to hear back on some more of the semiconductors. Interestingly enough, I have a friend within Renesas that I had no idea he worked there. Small world. Lead time is pretty long (~8 weeks), and that's what I'm trying to work around now. Chris, thanks for your help with the board quotes. I say we just call it $15 per board and use the extra money as a deposit on shipping and packing supplies as well as funding for the prototype boards. I'd rather estimate high. That leaves the rest of the work for me in firming up estimates on semiconductors and heat sinks so we can take deposits for those. I'm waiting to hear back from 2 more bids before balancing cost versus lead time At this time, we can target firm quotes for the end of this next week.
February 8, 200917 yr I have one question for the knowledgeable. I have a Gilmore Reference Balanced, which if I understood well is a balanced Dynalo aka Dynamid, with external power supply. The Dynafet is more or less based in the Dynahi/Dynamight so it would have higher power requirements than the Dynalo, however, would my PS be enough to drive the Dynafet? For me it would be great since would allow me to use the same PS for both amps just by swapping the PS umbilical.
February 8, 200917 yr I have one question for the knowledgeable. I have a Gilmore Reference Balanced, which if I understood well is a balanced Dynalo aka Dynamid, with external power supply. The Dynafet is more or less based in the Dynahi/Dynamight so it would have higher power requirements than the Dynalo, however, would my PS be enough to drive the Dynafet? For me it would be great since would allow me to use the same PS for both amps just by swapping the PS umbilical. No. The original Gilmore dynamic (i.e., dynalo) used a +/- 16.4V PSU, which is probably what your Gilmore Reference uses. The Dynahi, etc. use +/- 30V PSUs. One other thing regarding the boards. The offset adjustment pots present on the Dynahi were not in the DynaFET schematic, nor on the board layouts that I have seen (though I could hav missed them). The pots were present on the google spreadsheet BOM however. The (2) 500 ohm resistors should be replaced with 620 ohm with a 10K pot in parallel with each.
February 8, 200917 yr Thanks for the reply Pars. It's a pity I can't give a double use to that nice PS
February 8, 200917 yr Thanks for the reply Pars. It's a pity I can't give a double use to that nice PS Yeah, I hear you. Marc: Your analogy to power amps should probably be change to preamp as a closer fit in terms of noise performance. But yes, I would think with a shielded trafo (or perhaps use of a split bobbin instead of a toroid) that single box should be fine. My dynalo (V2 headamp board) has an unshielded Amveco in there that was supposed to be mounted on the board (not a PCB trafo though). Mine is just off the board and I don't hear noise thru it. Granted, I dont have any IEMs to check it with.
February 8, 200917 yr BTW, Charles Hansen has been noting some interesting observations on MOSFETs: DIYHiFi.org • View topic - push and pull me back into the limelight
February 8, 200917 yr I'd find that set of posts very interesting if I knew what the hell they was talking about Ok, can I get put down for 2 boards if someone can build them. I'll power them from a Beta 22 psu with a switch.
February 8, 200917 yr One other thing regarding the boards. The offset adjustment pots present on the Dynahi were not in the DynaFET schematic, nor on the board layouts that I have seen (though I could hav missed them). The pots were present on the google spreadsheet BOM however. The (2) 500 ohm resistors should be replaced with 620 ohm with a 10K pot in parallel with each. Chis, Good catch!! When Jacob presents us with the next rev. of the PCB, we builders should all read the headwize thread, and then go through the pcb with a fine tooth comb - and identify any errors, or functionality that we think ought to be incorporated. Hopefully with a good scrub of this next iteration, Jacob can go back revise again, and we should have a prototype design ready to be built and tested.
February 8, 200917 yr I'd find that set of posts very interesting if I knew what the hell they was talking about Ok, can I get put down for 2 boards if someone can build them. I'll power them from a Beta 22 psu with a switch. Smeggy, I can take care of building your boards for you. Pete
February 8, 200917 yr Other gottchas from the Dynamite build - need matched led's with a verified correct voltage drop. The NPN and PNP output devices did not match very well (the mean values were offset from each other making it impossible to get close matches) so you end up correcting that with the DC offset pots. Is there any merit to designing an onboard voltage source (ala Dynahi) so a cheaper opamp can be used? When builing my Dynamite I over ordered resistors as well, and did closer matching. Do we have a preference for this project? I prefer screw on rca jacks but like the idea of a pcb for all the I/O wires and the pot to connect/solder into. All I can think of now.
February 8, 200917 yr j4cbo, Are you following any of the these pcb related discussions? Any opinions? Cheers, Pete
February 8, 200917 yr Smeggy, I can take care of building your boards for you. Pete Thanks Pete, I very much appreciate it
February 8, 200917 yr Author j4cbo, Are you following any of the these pcb related discussions? Any opinions? Cheers, Pete Pete: We all appreciate your enthusiasm, but you do realize that the lead time for the parts (then resulting matching) will be the long pole in tent here? We will have plenty of time for the boards, trust me
February 8, 200917 yr Pete: We all appreciate your enthusiasm, but you do realize that the lead time for the parts (then resulting matching) will be the long pole in tent here? We will have plenty of time for the boards, trust me O yeah, I am in no rush. I know this will take many months. Sorry, i'll be quiet in a corner somewhere
February 8, 200917 yr In the process of switching to 0.2" + 0805 resistors, I wound up redoing a fair amount of the layout; it's a lot less cramped now. The offset trimmer pots are in, and there's room now to add 7815/7915 regulators for the servo. I'll post an updated version tonight.
February 9, 200917 yr luvdunhill, can you let me know the dimensions of those heatsinks? Take a look at post #7, I think this may be what you are looking for.
Please sign in to comment
You will be able to leave a comment after signing in
Sign In Now