Will
Been here a while!
Ribena abuser!
Member since 2008
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Post by Will on Sept 6, 2012 18:55:33 GMT
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Post by Deleted on Sept 6, 2012 22:25:56 GMT
Did you notice the mention of I2S at the bottom of the top linked page above, anybody? Dave.
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Post by Deleted on Sept 6, 2012 22:49:39 GMT
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Post by gommer on Sept 7, 2012 5:45:56 GMT
Very nice part indeed, but it comes in only one SMD package and not any SMD package, its QFN with a thermal pad I'm comfortable with soldering smal SMD parts, but not QFN, they are a PITA. Who can handle this package?
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Post by Deleted on Sept 7, 2012 6:35:02 GMT
PCB assemply lines with very expensive wave soldering machines. A heatgun (aimed at the bottom of the board) and pre-soldered pads with low melting point solder should also work though. It should be mounted before all other parts go on the PCB otherwise other parts would be 'swimming' on the PCB as well. LT1763 (0.5A low noise in SMD-SO-8) or LT1963 (1.5A TO-220 but twice the noise level of 1763) but granted they are not as good, certainly not above 4kHz (20kHz for LT1763). If you use those behind a normal regulator you would still have a very quiet PS for analog circuitery. For digital you would have to decouple the proper way and condition the powerlines feeding those circuits.
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Post by Deleted on Sept 7, 2012 7:38:26 GMT
It would be interesting to try an evaluation board or 3. A few of our members should be able to obtain these due to industry connections. Alex
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Post by Deleted on Sept 7, 2012 10:10:06 GMT
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Post by gommer on Sept 7, 2012 10:33:11 GMT
Yep, indeed, discourage.
I'd need yet another tool. I already have 1 very good soldering station (Pace), a mediocre hot air rework station (Aoyue), but no preheater. I must say, it's difficult to get a good feel for handling a hot air nozzle.
Allthough, it's a good guide. I never thought of hot air soldering as mimicking the recommended reflow temperature curve.
I should have a go and practice with a thermocouple (all available at work, luckily).
Cheers, Marc
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Post by Deleted on Sept 10, 2012 23:03:02 GMT
Did any of you guys with suitable industry credentials follow up by ordering an evaluation board ? IIRC, the price was only around $20 and it could still be used in some of the recent projects, even if you found the idea of using the I.C. in other projects a little daunting. Alex
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Post by gommer on Sept 11, 2012 6:28:27 GMT
I didn't, with good reason. Any freebie you order these days, is followed-up by sales guys that persist in meeting, in order to find 'mutual opportunities'. They are a real PITA. On top of that, if you do meet, then every false word will be used against you as in: if they can link a component to a project, then they'll claim the lead and fix your price on that component worldwide, from any distributor.
I bet the world wasn't as harsh 20 years ago.
Cheers, Marc
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Post by Deleted on Sept 11, 2012 6:31:06 GMT
I didn't, with good reason. Any freebee you order these days, is followed-up by sales guys that persist in meeting, in order to find 'mutual opportunities'. They are a real PITA. On top of that, if you do meet, then every false word will be used against you as in: if they can link a component to a project, then they'll claim the lead and fix your price on that component worldwide, from any distributor. I bet the world wasn't as harsh 20 years ago. Cheers, Marc Heaven help Friedrich if he orders any more freebies for his spare parts draws !
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Post by gommer on Sept 11, 2012 8:48:00 GMT
Alex, i don't know what your trying to say this time, but i do wonder sometimes how some guys get away with it, while i never seem to.
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Post by Deleted on Sept 29, 2012 7:17:27 GMT
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Post by Deleted on Sept 29, 2012 7:33:32 GMT
too bad nobody tested the (in RG widely used) JLH add-on.
Burson sucks !
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Post by Deleted on Sept 29, 2012 7:35:41 GMT
Hi Javier I don't think it is good practice to connect another power supply across the output of a voltage regulator, whether or not it has input power to it. However, there may be no problems with this particular regulator if you do. If you have a spare regulator you could try it. Regards Alex
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Post by Deleted on Sept 29, 2012 8:16:53 GMT
too bad nobody tested the (in RG widely used) JLH add-on. Burson sucks ! There was a paper comparing distortion on different opamps from different brands and Burson's came last they had terrible figures. House signature?
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Post by Deleted on Sept 29, 2012 8:40:46 GMT
It was tested in another forum after a DIYAudio G.B. a while back. There have now been >800 made available worldwide, and all proceeds have been, and will be, going to charity.The demand is still there which suggests that people believe they give a worthwhile improvement. Aussies have been lucky in that they have received 1 or 2 of the Greg Erskine designed dual JLH PCBs free of all charges including postage, when requested. Lark has also been a recipient and I understand that he is using one in his SC (Jaycar) H.A. Attachments:
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Post by Deleted on Sept 29, 2012 8:49:48 GMT
The fact that people actually like the sound of them tells ME a lot about the audibility of things.(minimum requirement specs). Fun part is it tells others specs don't mean anything and bad measuring amps can sound heavenly. Two ways of looking at it, both feel they are correct. The technical measurements don't lie as they are performed by the same person under equal circumstances (it appears that way). Noisy or badly regulting power supplies are just that. You wouldn't believe how many of the bad and poorly designed devices have really crappy power supplies. Whether a regulator can have a (technical) effect on a circuit mostly depends on the immunity of the circuit (PSSR or PSRR), the levels and 'modes' involved (be them digital or analog). a regulator can be noisy by itself but if a simple inductor and proper decoupling is performed afterwards noise figures could be 30 to 50dB improved with just 2 or 3 added parts. Also PCB layout and wire routing can work wonders on PSSR. For instance a SUPER power supply used in a digital circuit with wires of just 1 or 2cm and improper decoupling at a digital circuit, power supply line routing, ground plane scheme can cause this as well, can deteriorate a PS line (if it runs further away from that super PS) can reduce the HF noise levels 80 to 100dB even. Thereby effectively killing all effort and improvements made in th PS section would be pointless. I'll say it again, for digital even more important than analog, decoupling with the proper caps, signal and power routing/layout can be MORE imprtant than specs of individual parts. It looks so easy... just install a good reg and the result is always better. In practice it actually might not work that way. a NOT properly installed/designed circuit with a superregulator may still perform worse (electrically) than if another one or other surrounding parts were used. Use the power supply noise sniffer to find out about noise in the analog domain. In the digital domain one can only use extremely expensive testequipment and even that has to be connected the right way. Connect the 'PS sniffer' to a soundcard and 'record' the noise spectrum and evaluate using audio software (Audacity for instance, which is freeware). have fun tinkering with power supplies and know a few parts and a (high spec) soundcard that can record to 50kHz are enough to actually measure. NOTE how changing even wiring or entry points to PCB's can have a measurable effect already. I hope this might help you (Javier) improve things technically and objectively for your current project. Don't forget to use the same PS circuits but use different types of caps on various positions. See what it does.
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