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Old 2nd December 2011, 04:00 AM   #1051
qusp is offline qusp  Australia
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agree, for PTH soldering using such a fine conical tip is counterproductive. the tip doesnt hold heat properly and is more likely to damage the soldermask. Admittedly there is no large ground plane to worry about sucking the heat out of the tip, but it just seems something like a 1 or 2mm chisel is much more suitable. for some fine pitch smd i'll use a fine tip, but i tend to favor the much quicker flood and suck method for things like dac chips etc.normally i still stick with the chisel as most stuff i build has large ground planes

btw i need to make it clear that, THAT user's behaviour, posts, claims to the most extent are utterly ridiculous and contemptuous, but it does seem, given further reports that at least the initial problem may have actually started with a legit issue. further reports confirm that there is a point of weakness somewhere in the way the components in this area are coming together, if not the components themselves. It was these further reports, presented in a less abrasive and more reasonable manner that caused me to rethink the whole thing and take my current position.

I wasnt saying you need a 200 dollar meter to diy, but i do think there is a point of weakness in many of the cheaper meters when it comes to accurate measurement of AC (particularly music, so if possible sinewaves should be used for measurements) if there is a DC components present.

Last edited by qusp; 2nd December 2011 at 04:05 AM.
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Old 2nd December 2011, 04:01 AM   #1052
qusp is offline qusp  Australia
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Quote:
Originally Posted by agdr View Post
Probably no benefit for soldering the O2 up - it is just the tip I like to use. In the other direction though - unsoldering - the fine tip rocks for getting one lead of small resistors out. I can wedge the tip under the resistor lead right above a pad, give it a second to heat, then just lift the lead right out of the hole with the tip.
stuff that, get a second cheapie meter and use both

edit, i see this is for rechecking measurements across the resistor? not removing it?
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Old 2nd December 2011, 04:14 AM   #1053
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Quote:
Originally Posted by MrSlim View Post
Meh, guess I can stick with my $30 ebay clone... although this looks useful:
http://www.amazon.com/gp/product/B00...A1UB0766FG4V9I
To all: I think you can get brass scrubber pads at the grocery store that will do the same and cost much less. Just add a diy holder, like say... a can of your favorite beer that you've just finished. Put a large hole in the side, and add a couple of wads of aluminum foil inside top and bottom to align the brass at the hole.
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Old 2nd December 2011, 04:31 AM   #1054
qusp is offline qusp  Australia
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they ARE extremely useful though, i never have to replace tips on my hakko anymore; wet sponges blow
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Old 2nd December 2011, 08:02 AM   #1055
timpert is offline timpert  Netherlands
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Quote:
I see an entire page here that makes it look a lot like one needs a $200 DMM to make any diy progress.
That was not my intention. I was just reporting a particular fault that I have seen with a couple of very cheap meters. You can check it very easily if your particular meter has that fault by measuring a 9V battery with the meter set on AC. If it reads zero after a few seconds, then your meter is OK, and perfectly fit for circuit checking and fault finding. If it does not, then it is something to keep in mind in order to prevent drawing the wrong conclusion from the displayed value. It certainly caused me a headache, because I found out while using it, and I never would have thought this particular meter would behave this way. That was all I wanted to say.

It is totally unrelated to whether or not the meter is true-RMS, a meter that is not faulty will only measure the AC component when set to AC. It is true that a significant scale error occurs when the waveform is not a sine wave and the meter is not true-RMS, but that is besides the point ans also mostly irrelevant for the purpose of fault finding.

So the conclusion should be: even the most lowly, cheap DMM is a useful tool in checking your build, provided it is not faulty. Since I have a faulty one, and I have seen at least one more with the same fault, it never hurts to check yours. It only takes a couple of seconds, and it gives you certainty. Chances are >99% that your meter will be OK I guess.
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Old 2nd December 2011, 08:45 AM   #1056
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No offense to the smart folks here but in my experience with two amps the O2 can't drive HD650's and not eventually overheat the regs to the point they suffer reduced performance or even fail. Maybe I did build both my amps wrong, but if they're wrong why do they otherwise work flawlessly? I know we've got some knowledgeable people looking into things but it wouldn't be the first time someone falsely claimed the customer was wrong.

I can hear the V-regs getting hot because the sound goes all icky, probably a subtle effect for most to hear, but quite obviously wrong to my ears.

I think this amp can sound good and that's part of my frustration with this situation. Its good to see people are looking into the issue and hopefully we can see a solution soon.

Last edited by cheapskateaudio; 2nd December 2011 at 08:47 AM.
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Old 2nd December 2011, 08:46 AM   #1057
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^ No problem. I wasn't intending to point fingers. You've added some good info with your response. It's much appreciated. I've impulse bought several of those $5 meters, if for no other reason than they are handy to have around the house and garage. I've never put them to your test, though. I'll have to do that. Measuring audio and odd signal shapes isn't really what I had in mind, and there's been discussion in this thread about doing that already. I suppose I'm on a bit of a crusade to try and convince some that the diy ethos includes having and properly using some test equipment, however basic it may be. Thanks for indulging me.
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Old 2nd December 2011, 09:03 AM   #1058
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CSA, the regs do not overheat and fail. It just doesn't happen. They were specifically designed not to. I don't know what the power dissipation is with your headphones and your listening levels. But I gather you don't either. One of my mods indirectly targets your concern. agdr modded his O2 to have the regs mounted to the back panel. Maybe you should consider doing the same as he. That should definitely solve the dissipation problem, and it's just the sort of thing done around here on a daily basis (warts and all).
I just stated mine isn't functional yet. I'm not pretending it's the perfect design. RS himself said it's good for 98% of users, and that figure is probably holding true. Exceptions don't make the rule.
BTW, ya got a soldering iron and a cheapo DMM?
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Old 2nd December 2011, 09:28 AM   #1059
timpert is offline timpert  Netherlands
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Quote:
Thanks for indulging me.
You're welcome.

We are really on the same side here, I find it unimaginable that there are people willing to risk turning an expensive pile of parts into an expensive paperweight because they refuse to spend 10 on a cheap multimeter. As your only guidance in a world that is beyond the grasp of our senses, they are invaluable. I reacted to your remark, because it was not my intention to leave the impression that anyone had to spend , but apparently, the story seemed to be heading that way. I just wanted to set that straight.

@Cheapskate: could you provide some more info on your build? Especially the HD650 should be among the easier to drive phones for the O2, because of its high impedance and its resulting low current draw at a certain required power. Everything should stay cool, in any case cooler than with low impedance phones. Those phones require more current and less voltage, and current draw is what causes the regulators and opamps to heat up. That your O2 behaves like you describe is not to be expected when everything works OK. A picture of your board (top and bottom) would be very helpful, and also a list of substitutes you might have done because of availability. Did you do some measurements, like the supply voltage that the ICs get? And are you sure that the MOSFETS aren't faulty in some way? If the board is having a power supply issue, I would certainly like to scrutinize those as well.

If you measure the supply voltage of the power management circuit and compare it to the voltage of the opamps when the amp is playing with a load (cheap phones, as you might slip with a measurement pin and cause something to pop), then this will tell if the power supply is coming through like it should.
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Old 2nd December 2011, 01:00 PM   #1060
agdr is offline agdr  United States
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Quote:
Originally Posted by qusp View Post
stuff that, get a second cheapie meter and use both

edit, i see this is for rechecking measurements across the resistor? not removing it?
Hey qusp! No it was actually removing one end of a few resistors for a mod I did in another thread. I added ouput relays for fun and needed to lift up one end of all the 1R resistors. I had to lift out some more resistors when I changed my gain pairing from 2.5x/6.5x to 1x/2.5x.

You are right, the fine tips don't hold heat as well, but I like how they can precisely get on the small pads. Less trouble with solder bridging, at least for my somewhat shaky hands. I have actually been wanting an even finer tip. 0.4mm is the smallest for the stations I have, but that LF-2000 does have a 0.2mm tip available.
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