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Post by Deleted on Sept 4, 2011 22:28:10 GMT
Hi All, is this configuration suitable to power the "Pocket Knife" or do I require more than one traffo? Or what??? Alan
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jonclancy
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Post by jonclancy on Sept 4, 2011 22:50:19 GMT
Nice work Jon! I don't think the internal output stage likes heavy loads tbh but is something we can run tests on a little later once more of us have built the updated version, be interesting to see what its capable of. My previous one is currently on loan at the mo. I do remember it being picky regarding regulation unfortunately , just like its much more expensive brother . I tried those super Teddy regs and found the sound quite boring if I'm honest, it sounded a little lazy, A123 batteries or low output impedance regulation was a lot better to my ears, its certainly one area worth experimenting with. These are capable chips, just needs a little work 9022 is excellent especially for the price but don't be too surprised if it doesn't quite compete with your AYA Jon even after a full fettle, she me getting on but still capable of kicking arse I still listen to AYAII a lot Hi Guys, Ah, so I am giving it a thrashing by using the LS. Hmmm. I haven't actually felt to see how hot the DAC chip gets when it's playing. Something to have a think about. I, too, have some Hypnotise and DCB1 boards here. As the parts count is pretty small, I may well need to revisit this... I'm using some home build Oyaide PA-02 ics, Shaun. I know people talk about cables sounding similar etc, but I reckon I can tell these BLIND every time. They have always sounded "soft" to my ears. I'm using them as I have loaned my Straight Thru ics to a mate while I source him some new leads for the rig I supplied him (Magnums, ES14s). I'm currently stripping my Garrard 401, but will look at the easiest way to get a buffer sorted over the next couple of days. The B1 is pretty simple, from what I remember. Cheers Jon
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Post by Deleted on Sept 4, 2011 23:24:01 GMT
Hi All, is this configuration suitable to power the "Pocket Knife" or do I require more than one traffo? Or what??? Alan Hi Alan At the low voltages here, 5K trimpots are WAY too high in value. It would be a PITA to adjust with the adjustment right at one end of the trimpots. Use 1K or perhaps even 500R. You would also need to use JLHs with current limiters, and adjust the trimpots to compensate for the voltage drop through the JLHs, as without that, the poor little 30VA toroidal would cop a real caning on switch on. Alex
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Post by Deleted on Sept 4, 2011 23:36:05 GMT
Thanks Alex, I see, the regs are adj 1.2v to 15v so 5K is catering for the higher end. Is there anything else you would change or am I good to go with this? Alan
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Post by Deleted on Sept 4, 2011 23:47:14 GMT
Thanks Alex, I see, the regs are adj 1.2v to 15v so 5K is catering for the higher end. Is there anything else you would change or am I good to go with this? Alan Alan Does that toroidal have 2 separate secondary windings ? You don't need 12VAC centre tapped to get the voltages you need. If it does, I would feed analogue and digital areas of the DAC from individual secondary windings. 6V AC will still give your regulators plenty of head room. 10uF Input filter caps are far too low IMO. I would use 1,000uF there. Perhaps Leo or Will need to chime in here re splitting the supplies to different sections of the PCB ? Alex
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Post by Deleted on Sept 5, 2011 6:51:48 GMT
Hi Alex, everything is fluid here, no components purchased yet, in light of your comments I shall re-jig and return later by which time you will probably be in the "land of nod" as I have a pretty full day ahead. Thanks, Alan
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Post by Deleted on Sept 5, 2011 7:33:04 GMT
Thanks Alex, I see, the regs are adj 1.2v to 15v so 5K is catering for the higher end. Is there anything else you would change or am I good to go with this? Alan Alan Does that toroidal have 2 separate secondary windings ? You don't need 12VAC centre tapped to get the voltages you need. If it does, I would feed analogue and digital areas of the DAC from individual secondary windings. 6V AC will still give your regulators plenty of head room. 10uF Input filter caps are far too low IMO. I would use 1,000uF there. Perhaps Leo or Will need to chime in here re splitting the supplies to different sections of the PCB ? Alex Hi drymdrum, I agree with Alex here. The 10uF input cap as shown is used when the regulator is some distance away from the filter cap, but you may want to place a cap across R2 to improve ripple rejection. There also seems to be a connection missing from the bridge rectifiers. regards
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Post by Deleted on Sept 5, 2011 7:47:23 GMT
Hi Greg I think that when Alan redraws it for use with individual secondary windings, that the problem will be corrected, although he should then consider adding a 10uF across R2 for improved ripple rejection. Regards Alex
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Will
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Post by Will on Sept 5, 2011 8:15:29 GMT
On the supplies side of things, I've left it pretty much open to the user.
I put this pcb together initially to see if (initially) I could get a working circuit, and also to leave it as open as possible for experimentation with supplies and either i2s or spdif input.
I've only used it with that supply shown in the first post, but from what people have being saying this dac chip is sensitive to good quality power supplies.
So in this respect, we have lot's to try (Flea's, TeddyRegs, JLH's, Salas shunts, o11, and any other diy reg) including commercial supplies.
However, what I would suggest is to build one 3v3 supply (like one of the rails that Alan has shown) and use that to power all the rails of the dac. Once the build has been proven, then you can try individual regs, traffos etc to your hearts content, mixing and matching to get exactly what you want.
You may find that one supply sounds awful on the dac, but works brilliantly on the XO. Whilst another is perfect for the wm8804, but sounds like tat when used with dac. Lots of variables, but you'll not go to far wrong.
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Post by Deleted on Sept 5, 2011 8:31:34 GMT
Hi Alex, post this and run, revised drawing
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Post by Deleted on Sept 5, 2011 8:34:42 GMT
Hi Will, I'm beginning to get the drift but if I don't get out of here now I'll be in serious trouble. Thanks Alex. Alan
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Post by Deleted on Sept 5, 2011 8:36:56 GMT
Hi Will With Alan's top drawing, the regs will get much hotter than need be due to dropping around 13.5V .The 10uF should be across R2 for improved ripple rejection , and it needs an input filter cap of around 1,000uF. The 2 x 6V AC windings could also be in parallel if desired, if the transformer has a 4 lead secondary. Alex
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Post by Deleted on Sept 5, 2011 8:40:33 GMT
Hi Alex, post this and run, Hi Alan The AC should go into the top and bottom of the bridge rectifiers, not as shown. Input to the LT1086 should come from the junction of D1 and D4. The junction of D2 and D3 should go to the -VE (earth) rail. Also fit a 10uF across R2 Regards Alex
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Will
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Post by Will on Sept 5, 2011 8:48:27 GMT
Hi Will With Alan's top drawing, the regs will get much hotter than need be due to dropping around 13.5V .The 10uF should be across R2 for improved ripple rejection , and it needs an input filter cap of around 1,000uF. The 2 x 6V AC windings could also be in parallel if desired, if the transformer has a 4 lead secondary. Alex Hi Alex, yep, you're right. I meant to add something about once they sorted out.
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Post by Deleted on Sept 5, 2011 11:37:10 GMT
Hi Jon yes some people do say that cables don't sound different. ;D ;D to my ears the differences between my stranded silver on copper efforts and the solid silver ones that I'm using now is OBVIOUS. on the DCB1 your way ahead of me as mine are just at the order stage. some thoughts on using a buffer would be useful and may work out well (or not) but fun to find out magnums and Epos should make a nice combination. stripping the 401 ;D ;D good luck with that. I've owned a few 401 and lastly a 301 with bastin bearing and psu but gave up on it due to the constant TLC it needed. i settled on a Spacedeck with heavy mod and Project PSU. works pretty well (without the deeeep bass of the 301) and needs little work. Hi Alan good work just a few minor adjustments listed by Alex, Greg and it should be good to go. As Will stated with regard to the PSU ''So in this respect, we have lot's to try (Flea's, TeddyRegs, JLH's, Salas shunts, o11, and any other diy reg) including commercial supplies''. He is dead right on that just a quick question with regards to the JLH. with Alan's amended PSU (with minor amendments made) it's hard to believe that the current limiters would be needed on the JLH. the DAC chip is only pulling 27ma and the XO less still. maybe with the duel winding set up the CL is not going to be needed. I'll be trying I2S I'm thinking of using 6-0 6-0 - 2x LM317-2x LV JLH as a starting point to get things up and running. then have a play with some other PSU. it could well be the case that one PSU will be best in one location and one type in another. should be fun finding out. take care
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Post by Deleted on Sept 5, 2011 12:01:07 GMT
Revised Drawing as per Alex's suggestions Alan
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Post by Deleted on Sept 5, 2011 13:31:24 GMT
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Post by Deleted on Sept 5, 2011 14:13:14 GMT
Hi Alan and for the sake of a few more diodes you could do this. which in theory gives you a little protection against O/P short circuit. opinion seems to be divided on how effective adding the IN400X diode is but most of these reg circuits I've seen use one so why not. any opinions most welcome take care
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Post by Deleted on Sept 5, 2011 14:42:15 GMT
...and you could chuck another diode in parallel with the 1086 firing upstream...
ps what programme makes these nice drawings? Eagle?
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Post by Deleted on Sept 5, 2011 15:31:39 GMT
...and you could chuck another diode in parallel with the 1086 firing upstream... ps what programme makes these nice drawings? Eagle? Hi Chris something like this well spotted Alan's drawings used to be nice until i added my scrawl. take care
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Post by Deleted on Sept 5, 2011 16:16:06 GMT
Hi All Wills thoughts on using the Salas simplistic shunt got me thinking. so i had a quick look round and found this. i have a few shunt psu boards on order at the said DIYAUDIO GB so that should be interesting. I've not tried any of the above circuits but thought it may be nice to get some opinions. anyone used a Salas? take care
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Post by Deleted on Sept 5, 2011 18:48:59 GMT
and the teddyreg ;D ;D ;D www.teddypardo.com/articles/TeddyReg.htmlwhich i have used before to power the original B1 buffer. I've since replaced this with a JLH which i thought worked better to my ears in that location. I've also noted Leo's comment re the SQ if this device with the 9022 but for the sake of completeness I've posted it. i built mine up on vero so it's not to hard to build. from memory the limiting factor with this one is it's not so good with low current devices. i may be wrong on that so any comments would be useful take care
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Post by Deleted on Sept 5, 2011 18:57:55 GMT
not forgetting the flea www.acoustica.org.uk/flea_manual.pdfso plenty to chose from not to mention the more exotic options. and I'm going to do my very best to try all of them at some point ;D ;D take care
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Post by Deleted on Sept 5, 2011 19:29:44 GMT
Hi Shaun and Chris, now as can be seen from my initial post I'm in a bit of a quandary when it comes to the theoretical and very prone to senior moments at the practical. However I do like to do my homework.......even though I ran away from school many times before expulsion at 15. Which is why I had already googled...and goggled Linear Tech's data sheet. Protection DiodesIn normal operation the LT1086 family does not need any protection diodes. Older adjustable regulators required protection diodes between the adjustment pin and the output and from the output to the input to prevent overstressing the die. The internal current paths on the LT1086 adjustment pin are limited by internal resistors. Therefore, even with capacitors on the adjustment pin, no protection diode is needed to ensure device safety under short-circuit conditions. Diodes between input and output are usually not needed. The internal diode between the input and the output pins of the LT1086 family can handle microsecond surge currents of 10A to 20A. Even with large output capacitances, it is very difficult to get those values of surge currents in normal operation. Only with high value output capacitors such as 1000µF to 5000µF, and with the input pin instantaneously shorted to ground, can damage occur. A crowbar circuit at the input of the LT1086 can generate those kinds of currents and a diode from output to input is then recommended. Normal power supply cycling or even plugging and unplugging in the system will not generate current large enough to do any damage.
I hope that puts you both in the picture. Chris, Not "Eagle" more like "Budgie" for the drawings which were done in PS a great bit of software once you get a handle on it. Layouts for board cutting done in PS also. Alan
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Post by Deleted on Sept 5, 2011 21:34:57 GMT
Hi Shaun With Alan's later drawing using individual secondary windings and only 2 JLHs , the CLs in the JLH will not be required. Originally, we had 4 JLHs all drawing heavy startup currents. Alex
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