Kleos - Dipole Line Array

[Hank]

Liking that poor man's solder mask. We're out here waiting for test results of this bad boy xover...

[Johnloudb]

Liking that poor man's solder mask. We're out here waiting for test results of this bad boy xover...

Good description Shouldn't be long now. Just waiting on some parts from mouser and will stuffing the other board and matching JFETs in the meantime.

[Johnloudb]

Okay, I'm done measuring 90 JFETs, hah!!! :dancenana: My test setup is below and it's really not too hard to measure them with a bit of practice. But, they are small and if you drop one it will bounce and be gone till you find it stuck to the bottom of your foot. I use needle nose pliers to move them with and it works pretty well.

Test setup with on JFET on the board -




My measured JFETs are attacted to a piece of metal tape that keeps them in place and labeled -

[JonMarsh]

Yeah, I had it easy working with matched NPD5565 monolithic duals in DIP8! Even if I needed to match a set of those (when paralleling for even lower noise than the stock part, which is pretty low), I had a LIF socket and fixture... ah, the good old days!

Hope your testing and selection goes smoothly...

[Johnloudb]

Yeah, I had it easy working with matched NPD5565 monolithic duals in DIP8! Even if I needed to match a set of those (when paralleling for even lower noise than the stock part, which is pretty low), I had a LIF socket and fixture... ah, the good old days!

Hope your testing and selection goes smoothly...

Yeah, more package options like a TO-92 for this would be very nice, but I guess there's not enough money in big parts since it's all about miniaturizing everything now days.

I am happily surprised how close I could match 24 pairs of these, within less than 0.1 mA for each pair. The Idss values were all over the place (12mA to 20mA) but were kind of in groups that hit the same values. I only need 12 matched pair but the other 12 goes to another who wanted a pair of boards.

John

[Johnloudb]

Got all the parts in except the four caps and four resistors that affect response, two caps that determine the shelving filter corner frequencies, and the JFETs and opamp. Next up need to clean the board with flux remover!

My Babies!

[Hank]

Atta boy, John! We eagerly await your measurements and listening impressions after some break-in time.

[JonMarsh]

Good progress... what Hank said goes double!

[wkhanna]

A work of Art!

[stampol]

nice!!!

[Johnloudb]

A work of Art!

nice!!!

Thanks Guys!!!

Hank and Jon,

Okay, you guys want measurements and listening impressions? I hear ya! I'm almost there, but had a bad weekend ... well just my aura all out of whack, and my inner and outer orbit is for sure not in sync. But, I did manage to put in the response shaping components on one board, but using Mapleshade Sil Clear (gooey silver contact conditioner ... highly conductive) as sort of a temporary solder. It seems to have worked really well, and then I can change components if I need to. Now installing that board in my box and going test and listen to it. More to come soon!

[Johnloudb]

Oh, for crying out loud!!! I just soldered two wrong (not matched) JFETs into the same spot! You'd think I'd have learned the first time, but no ... Just did the same damn thing over again. Fortunately the wrong JFETs didn't have a matched pair so still have all the matched pairs.

Just to update I've been having problems ... Obviously huh?!!! Just very preoccupied, distracted with other stuff and can't seem to concentrate or focus on audio. But trying to do that now!

[JonMarsh]

Take a deep breath, let it out slowly, and try to work at a relaxed pace. It's not easy sometimes, believe me I know!

[Johnloudb]

Take a deep breath, let it out slowly, and try to work at a relaxed pace. It's not easy sometimes, believe me I know!

Thanks Jon, will do that. You are the master at multitasking, no doubt!

[Hank]

Well, I'VE never made a component soldering mistake in my 40 years of solder-slinging. No sir, not one. Nope. Nada.
Not me.

Well, there was that one time...and oh yeah, the time I really...

Never mind ops:

Okay, serious advice: put down the soldering iron and go take care of one of those distractions. Chill for a day or two and take care of another distraction. Do something physical that will wear you out (keep it clean, here) completely. You're refreshed and then can get back to slinging solder with a smile.
"The Doctor is In: 5 cents"

[JonMarsh]

Good advice from the "Senior" Member... :W

[Johnloudb]

Well, I'VE never made a component soldering mistake in my 40 years of solder-slinging. No sir, not one. Nope. Nada.
Not me.

Well, there was that one time...and oh yeah, the time I really...

Never mind ops:

Okay, serious advice: put down the soldering iron and go take care of one of those distractions. Chill for a day or two and take care of another distraction. Do something physical that will wear you out (keep it clean, here) completely. You're refreshed and then can get back to slinging solder with a smile.
"The Doctor is In: 5 cents"

Wow, Hank we are totally on the page!!! I haven't even looked at this thread since I last posted! This last few days I've Installed a new car stereo, visited my XGF Nickie and ate out with her and her daughter last night. Okay now got to take care of the physical part tomorrow, plan on a walk and going swimming. Then I'll get back to work on the crossover.

Thanks for the advice, it was just what I needed even though I didn't know it, and still got to get my exercise in. 5 cents it is!

John

[JonP]

hurts to add a little organizational structure, especially if I think its simple enough to not screw things up... Say, matching the FET pairs on a block of antistatic foam, separating resistors, caps, etc by value.... you know. I often wish I'd had, the times I think it's not worth the time.

Sounds like you're primed for progress, though! Onward!!

OK... Now having read back in the thread.. I can see you already are organizing, as well as the lack of leads with the SMT parts. Ah well, don't mind me. Still interested in the layout SW you're using...

[Johnloudb]

Hi JonP, I'm not organized but working in steps to get that way. Most of my parts stay in the shipping box till they are put in the circuit, though I have some small parts orginizers that I use for variety of parts and supplies. I did have to be orginized about matching the JFETs and documenting their Idss values though.

The software I used is ExpressPCB.com software. It's easy to learn and really intuitive to use. It worked well for my circuit, but you are stuck with using their PCB fabrication facility unless you pay $60.00 for the gerber files after your first order. There are cheaper options out there, I think.

If remember correctly Sunstone gives you the gerbers for free after your first order.

John

[Johnloudb]

Finally got back to work and finished installing the JFETs today ...



OMG! what a fussy little op_amp! Hmmm ... I can hear the depth of soundstage and truth of timbre right now ... :W

Well, got to install both of the them as soon as I open the bag ...

[Johnloudb]

Here's that little fussy opamp I mentioned above! Got both mounted on the boards. This board is now ready to put in the box and test on a speaker! So, getting closer ... bit by bit ...



Here is the humidity tester that came inside the sealed ESD safe package holding the opamp. There were also THREE little moisture absorbing packets inside there too. Hmm ... I've never encountered a IC part sensitive to moisture like this one.

[Hank]

I've never seen humidity warnings on any electronic component and I've seen million of 'em in our plant and others. Hmmm.
Fire it up and get some serious listening/measuring/tweaking done and report back.

[Johnloudb]

I've never seen humidity warnings on any electronic component and I've seen million of 'em in our plant and others. Hmmm.
Fire it up and get some serious listening/measuring/tweaking done and report back.

As usual, I can't fire up a circuit and just have it just work, no sir! not a chance!

The positive voltage rail is pulling too much current somewhere in the circuit. I haven't found the problem yet.

I do have a thermally controlled resettable fuse in the unregulated supply, and it triggers at about 300 mA as I recall. The negative rail powers up for few seconds and then the fuse kicks in and the voltage drops. At the positive side the voltage hovers around only 3.3 volts and pulls 330mA, till the fuse kicks in. Something is pulling too much current, got to figure that out. A bad cap maybe? Some error in the circuit? Anyway, I'll keep investigating.

Yep, that is strange about the moisture sensitivity ... I haven't seen that either ... Hmmm.

[Hank]

Above the upper left corner of that fav op amp, do I see a dual-hole pad with empty holes? It sure would be easy to have a short with all the small spacings on an SMT board. Long-live through-hole decent-sized parts!

[Johnloudb]

Above the upper left corner of that fav op amp, do I see a dual-hole pad with empty holes? It sure would be easy to have a short with all the small spacings on an SMT board. Long-live through-hole decent-sized parts!

Yes, surface mount packaging sucks for DIY! But got use what they give ya.

There are a couple holes on either end of the opamp just for ventilation. I'm not sure if that's what you mean.

I hooked up the second board with only the opamp in it, and no JFETs installed. It also had problem, which I traced to a poor solder joint on the negative regulator that kept it from getting power. Easy fix so this board at least has the power supply and regulators working correctly!

I yeah, there could very well be a short or partial short somewhere, or a bad cap on the other board. I haven't done too much yet in trouble shooting it ... Not a pleasant thought as removing all the caps would be a nightmare!!! I could cut the positive power trace to rest of the circuit and isolate the problem - make sure the positive regulation stage is working or not.

Anyway, I'll see if I can get the second one up and running and test it on the speaker. Then for the first board I may have to repopulate a new board with new parts. Hope it doesn't come that and I can find the problem.

[Hank]

I didn't notice the op amp hole. I refer to the PCB - just above the upper left corner of the op amp - looks like a pad with 2 holes. I'd go over the entire board with a strong magnifying glass. I like this combo LED lamp and magnifier I bought from Parts Express: http://www.parts-express.com/desktop...opter--350-022 Have faith - you'll find the problem.

[Johnloudb]

Yep, there are two holes that are large pads to let air through the PCB, since the opamp is on bottom. On the left one hole is partially covered by a yellow cap. Those are the only holes in that picture and it all looks like it should. Yes, I hope to find the problem just as soon as I start looking again. I have have problems ... Trying to get ready for school in the Fall and more demands being placed on me by parents ... Like, "can you take mom to ---" plug in this or that appointment. Just a lot of change but should get back to work on it soon!

[JonMarsh]

Keep plugging away, John,... you know what I like to say, slow work takes time! Slow and careful it what it takes at times...

[Johnloudb]

Keep plugging away, John,... you know what I like to say, slow work takes time! Slow and careful it what it takes at times...

Thanks Jon, and slow people doing slow work take extra time! This shouldn't take so much time except that other challenges have had to take precidence, especially the last few weeks. But, expect to be back at this soon!

[Juhazi]

Things are moving along, slowly. But can see the light in the distance.

10-07-2010, 01:54 PM #8 (8)
The longest lightbeam in diy audio history? All the time in top 10 threads!
Go on, John!

[Hank]

Yep, we're rootin' for John.
-from the grandaddy of procrastinators

[Johnloudb]

Thanks Guys! Yep, I can still see the light in the distance ... I have good eyes! Or maybe I should say ESP? I have dreams about the future now and then too! "Rage, Rage, against the dying of the light"

Anyway, I checked out the problem board really good, and I was going cut the positive power trace to the JFETs to see if the regulation stage was working, but I can't find my Dremel tool. That would be perfect to cut the trace but I may have to use a drill bit.

John

[Johnloudb]

I never found my dremel tool but i used a 1/8" drill bit to cut the trace. How simple and worked great! Don't know what I was dreading, just thought it's make a mess but no, worked good. I then powered up the board and no voltage at at the positive voltage regulators and non of the regulator got slightest bit hot. The only part that got hot was the resetable fuse which kicks after a few seconds. I did hear a slight pop from the board after powering it up a couple times ... caps can pop and even explode. I suspect it's the positive electrolytic filter cap before the regulators that is bad.

Okay, we'll see what happens after I replace it. hard to get parts out but got to do it.

[Johnloudb]

I pulled out the cap with force, no way to get solder out ... solder sucker and solder wick both failed. I just tested with no cap there since it's not necessary. Still got a short and I can see non at all! All looks good. A mystery! I love a mystery! It powers up to 3.0 volts on the positive side, that's it.

On the negative side the power gets up to 9.0v as it should after the capacitance multiplier. But, then quickly drops as the resettable fuse kicks in. Anyway, it's got to be a problem on the positive side ... only way I can see it. I'll do some more checking tomorrow and figure out my next move. Maybe a broken regulator, or cap after the regulator? I don't know.

[Johnloudb]

There is short at the output of the positive regulator. So far I've pulled out three caps and cut the output of regulator. Short is still there and I see no reason reason for it. The opamp is fine and the capacitance multiplier is disconnected from any load and can't conduct current. The mystery continues and going to take another careful inspection again, and disconnect the op amp positive power lead again get those small caps out of the way and test for continuity again.

More soon ...

[Johnloudb]

Here the schematic for the regulated power supply. The red X's show where I have removed the caps. The red slash shows where I disconnected the regulator. Still there is a short to ground at the +15v node.

Opps! There should be an X through C101 as well.

[Johnloudb]

Anyhoo, I guess I will get the JFETs and filter components installed in the other board and get it working. I'm stumped on this one.

[JonMarsh]

Curious. Without seeing it on a bench in front of me, I'm at a loss to offer constructive suggestions... somethings have to be done in person!

[Paul W]

Short in the PCB itself?

[Johnloudb]

Okay, I think I'm going to post some close ups of the board where there is a problem and perhaps someone will see something. I think it has to be somewhere on the board, a short to the ground plane, maybe a board defect? Kind of hard to believe cause I don't think that happens too often and my other board is fine. I do have a couple extras for myself so, I can always use those. I'm going to check those now as well for a short.

[Hank]

I know this is frustrating, John. Check your unpopulated boards for a GP short. You might want to get a higher power magnifying glass also, or maybe an inexpensive USB microscope. http://www.parts-express.com/usb-mic...-lamp--360-510
Through-hole components forever!:W

[Johnloudb]

Thanks Hank!

I did get around to checking the unpopulated boards and they are fine. Will try to get some more done this after Fathers Day.

[5th element]

Some caps when they go bad can develop a short across them. If you've got a duff decoupler it could be the issue.

[Johnloudb]

Some caps when they go bad can develop a short across them. If you've got a duff decoupler it could be the issue.

Yeah, I pulled three caps that could possibly cause a short. About 5 or 6 posts back I posted a schematic showing what I've pulled out of the positive power supply.

What is a duff decoupler? But pretty sure I don't have one.

[5th element]

Oh right. A decoupling capacitor is usually a ceramic or electrolytic capacitor that is connected from any part of a circuit to common ground. Usually these are connected from the input and output sides of regulators back to ground. Sometimes you will see one used from the adjust pin of some regulators and ground.

To be honest I don't know what the failure modes of electrolytics capacitors are, but I've had ceramic ones go bad on me and when they do they've ended up as a short.

Without being there it's difficult to know what to recommend. Still, if you've got a short either a component is defective or you've got a small solder bridge somewhere that you haven't yet noticed.