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Old 1st October 2010, 01:46 AM   #341
opc is offline opc  Canada
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ichiban,

SMD parts really are the best parts for job in this case, which is why I chose to use them. It helps minimize signal path length and makes for a better layout. The decoupling caps on the top layer that return to the ground plan are the shiznit when it comes to performance.

They're actually much quicker and easier to solder than PTH parts, but just the same, I can solder up all the SMD parts on your board before I send them out to you. Several of the parts might be arranged as a group buy anyhow, so I'll probably have most of them here anyhow.

I'll send along a spare section of an old PCB and some 0805 resistors you can practice on. Once you get the hang of it, it's about 3 times quicker than doing PTH.

Cheers,
Owen
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Old 1st October 2010, 02:01 AM   #342
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Can anyone suggest some "Audiophile" grade linear regs that could be used in place of the LM317/337?

I'm just making the BOM now, and if people feel like spending more on these, then I'd like to give them the option. I need a Vin of 60V Vout of up to 50V and at least 250mA of current capability.

I have heard great things about the Salas regs, but they're fully discrete and it would mean that I would have to design them in, order parts, test the circuit, and then redo the layout for them. All of that takes time, and I like to get these board out the door.

qusp:

You seem like the type of guy who like regs... what are you planning to use in place of the LM317/337?

Cheers,
Owen
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Old 1st October 2010, 02:15 AM   #343
ichiban is offline ichiban  United States
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Owen,
I have some old scrap pcbs with smds. I'll try and melt some off .
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Old 1st October 2010, 02:16 AM   #344
qusp is offline qusp  Australia
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yeah I was going to suggest the ohmite thin film power R's, COG/NPO caps and thin film R's (if any) for a GB. sure mate I can suggest some regs, in fact I can suggest some that might mean I can use them as they are SMD too. linear tech are IMO world leaders at the moment in the IC reg area. give me a minute i'll dig up some datasheets
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Old 1st October 2010, 02:22 AM   #345
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Quote:
Originally Posted by opc View Post
Can anyone suggest some "Audiophile" grade linear regs that could be used in place of the LM317/337?

I'm just making the BOM now, and if people feel like spending more on these, then I'd like to give them the option. I need a Vin of 60V Vout of up to 50V and at least 250mA of current capability.

I have heard great things about the Salas regs, but they're fully discrete and it would mean that I would have to design them in, order parts, test the circuit, and then redo the layout for them. All of that takes time, and I like to get these board out the door.

qusp:

You seem like the type of guy who like regs... what are you planning to use in place of the LM317/337?

Cheers,
Owen
The most obvious option is the LT317/337 which are supposed to be drop in replacements. See also this thread Where the LT1085 and LT1033 are briefly discussed.
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Old 1st October 2010, 02:29 AM   #346
opc is offline opc  Canada
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Ichiban:

Start with a pair of clean pads, and then melt a little solder on one of the two ("tin it" if you will) get some decent tweezers, and hold the part with them and position it in front of the tinned pad.

Melt the solder and push the component into the molten solder while making sure it's flat on the board and centered on the pads. Let that side cool, then solder the other side without over-heating the component, and it'll stay right where it is. I usually go back after that, and clean up the first solder joint with a little more solder. That will give you two nice joints, and going back helps to ensure you don't have any cold joints.


qusp:

I'm using one Caddock and one Ohmite thin film right now, since the Ohmites aren't available in the 200R value. I like the specs on the Ohmite, but the absurd leads and lack of a mounting hole are getting on my nerves. I've honestly tried to bend the leads with all of my strength and they won't budge. I have no idea what they're made out of, but it's not copper.

I agree with your other suggestions though... I should have a BOM ready pretty soon.

Owen
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Old 1st October 2010, 02:35 AM   #347
qusp is offline qusp  Australia
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but in answer to your question, i'm using the coffin minigold dual, which is a HV capable bipolar jung type super reg. but just having a look for something for you now. only limiting factor is the voltage, I know of plenty of excellent replacements for them at up to 35v, but above that it becomes a bit scarce.
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Old 1st October 2010, 02:43 AM   #348
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AFAIK LT1083/33 arent capable of that input/output V Jacques. I know the linear tech catalogue pretty well as i've been spending quite a bit of time there lately, but these specs are limiting, i'll find something though. yeah owen I had seen you were using one of each and had noticed the lack of a 200R which is a bit odd. dont they also come in SMD though? and then could use the SMD for the lower wattage part and the caddock for the higher wattage.

depending on the BOM values, the vishay Zfoil SMD might be suitable for the smaller (not power) ones haha. but thats just silly.

not having much luck at linear; all of the higher V parts are soic16 with ground pad underneath, or DFN type packages. 30-35v is about where the rest start topping out

Last edited by qusp; 1st October 2010 at 02:51 AM.
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Old 1st October 2010, 02:54 AM   #349
opc is offline opc  Canada
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Is that 35V Vin to Vout, or just 35V max input? The Vin to Vout shouldn't be any higher than 15 volts, which is fine with floating regs like the 317/337.
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Old 1st October 2010, 03:03 AM   #350
qusp is offline qusp  Australia
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right, yep, Jacques yopu were on the money. not the LT317/337, go with the LT1085 and LT1033. both of these can be used in a similar floating manner, so the Vin/Vout doesnt matter so much. so you could go with the LT1083 in this instance as we dont need that much current and the 1033 is the complimentary. I have used these before with very good results for their type. the max Vin is only like 35 or something, but there is no ground pin

the rest are either too hard to solder for the average hobbiest, or have a ground pin that is used for adjustment or sense. also the size of the transformer could be smaller with these, because they are LDO regs

Last edited by qusp; 1st October 2010 at 03:08 AM.
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