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Posts posted by Arthrimus
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5 hours ago, alcofribas said:
Thanks a lot Arthrimus. Now's my chance to figure out how a voltage doubler works. Unless I'm completely out of it, your circuit is meant for 117V, right?
Pondering over this circuit reminded me that the WEE has a voltage conversion switch... and something clicked in my head. What, do they have a transformer to handle AC in there?
And it looks like it... talk about overdesign. At least this gives some kind of protection, same kind as razors in bathrooms.
This circuit is universal it has a bidirectional 100v Zener Diode on the input that limits the voltage to 100v for the multiplier so it can work worldwide. It's basically Stax's SRD-7 Pro circuit, with a couple of components reorganized to fix their mistake of putting R103 and R104 before C107 and C108 instead of after.
Z101 can be substituted with 2 back to back unidirectional 100v zener diodes if a bidirectional one can't be found. I've used a pair of 1N527 for this. Also you can sub 1N4007 diodes for D101-D106.
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A very very thin coat of contact cement.
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4 hours ago, Torpedo said:
What did you use for the recoat?
I used Endust antistatic gel. It's the same stuff I used to recoat my SR-5s a couple of years ago and it's held up fine.
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While that doesn't fill me with confidence, I might take a crack at it if there are no other options. Can you explain the process you used for success?
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I've got a question for the great Stax minds here on Head-Case. My SR-Lambda Nova Signatures have had minor channel imbalance from the day I got them almost a year ago. Since then the imbalance has not gotten any worse so I believe them to be stable. Obviously recoating the drivers is not realistically possible, but I was wondering if anybody had any ideas for a method of electrically attenuating the louder driver to match the quieter one without having split volume control on the amp. It would be awesome if I had a solution that wouldn't require L/R adjustment on the amp or source. The exact electrical properties of electrostatic headphones elude my understanding so I really don't know.
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Is it too late to join?
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No doubt, but it's the apex of soldering. You can actually pick up retired factory production line Metcal systems for dirt cheap on ebay, that's how I got my soldering station and deslodering gun.
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On 1/31/2017 at 11:05 AM, Skooby said:
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.
I haven't started building my board yet, but the pitch on the regulator appears to be about the same as tsop40 and some qfp packages I'm used to soldering/desoldering. I'd recommend positioning the regulator on the board and holding it in place with tweezers. Flood the area with no clean flux, then with a fine chisel tip try to tack down one corner of the regulator, then move to the opposite corner, adjust the positioning if necessary then tack that corner down. Reflux the chip and load your tip with solder then drag it accross the remaining sides of the chip until you have all contacts soldered. If you have any bridges, then reflux the chip, clean your iron and drag it across any side of the chip that has bridges. Repeat as necessary until you've cleared all shorts, reapplying flux as needed.
I personally only like to use hot air for removing large packages and reworking BGA packages. I really don't think it's any good for soldering projects like these. A reflow oven would be much better for this, but my personal preference is always hand soldering if possible.
EDIT: Now that I look at the regulator a little better, hot air might actually be the way to go. I didn't realize that there was actually a pad on the underside of the chip. Solder paste and hot air is probably the best bet for this one.
8 hours ago, HemiSam said:Good stuff, congo. I like the look of the Hakko micro handpiece / pencil. Might have to spoil myself with one of those.
HS
[whisper] Ditch Hakko... buy Metcal...[/whisper]
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Paid. Paypal primary address is correct. Thanks.
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I wonder, would it be possible/practical to split the Blue Hawaii power supply in the same way that the GRHV power supply is split? I only ask because the split configuration provides so much flexibility, and the BH power supply is so much more affordable than the GRHV for projects like this and the SRX+.
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Payment for flat rate shipping sent.
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Looks like Mr. Speakers has come to their senses and will be using a stax compatible plug on their Ether E headphones after all. I guess they couldn't sell their bullshit logic for a proprietary connector once they were called on it.
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I'd be in for 4 of the Song Huei pots. I intend to build the Mini SS Dynalo.
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I got my boards today. What paypal account do we send shipping reimbursement to?
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That is the most gorgeous slab of amp I've ever seen. There simply are not words...
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I'm on the home stretch as far as parts acquisition for this build, but I do have a question. For the 10m90S heatsink isolation, is rubberized silicone sufficient, or should I be using ceramic insulators?
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Not gonna lie, I wouldn't be thrilled if someone repaired something for me and sent it back with an invoice before quoting me a price or confirming whether I wanted to go through with the repair. Glad to hear you're satisfied, but to me that sounds like something that a shady auto mechanic would pull.
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Payment sent.
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The Headcase Stax thread
in Headphones
Posted
My 727 has that same transformer. It's a pity, I have to use a step down transformer.