LA3A 500 BUILD

[12volts]

So it's add a dash of color to taste?
I am finding a good bit of difference in the photo cells at an all dark state, guess I'll just match based on that.

Just a quick note on LDR matching.
The UK agents for Silonex say that matching these cells (NSL5910) is difficult even from the same production batch,
typically, 40% (this isn't a typo) variation between cells.


Frank B.

 

[nielsk]

One of units is getting only 1,5 dB compression max (same on meter). The other is fine. I can tell it is the EL side, if I pull the EL I get plenty of compression from ambient light and can use my finger to block the photocell, varying the compression (& meter). I swapped out the photocells & the op amp over the diodes, no change. Tested both in the other unit, working perfectly.
I tested for shorts / breaks from the photocell pins to CT4, & CT4 to the op amp pins, NPF.
Otherwise it is functioning normally, passing signal w/ plenty of gain
Any ideas?

Later: found a micro solder bridge on a set of the pads on the tiny op amp PCB... watch out for there, there are a few spots where pads are extremely close. All working now!
A schematic that indicates what components are on what PCBs would be very helpful
Dotted lines around sub-board areas w/ notation is an accepted approach

 

[peter purpose]

Bad ac boost transformer?

 

[buildafriend]

Hey guys, Sorry I could not read all 14 pages.

Is this project going to be available as a kit? I am interested.

 

[mulletchuck]

no.

 

[buildafriend]

Oh well that's a shame. I would love to build a 500 series LA3 kit if it was available.

 

[mulletchuck]

source the parts like everyone else did and build it.  that's what I plan to do after I build a pair of peter's 525s

 

[buildafriend]

Deal!

http://www.groupdiy.com/index.php?topic=47201.0;topicseen

 

[buildafriend]

source the parts like everyone else did and build it.  that's what I plan to do after I build a pair of peter's 525s

I just ordered two LA3 kits from peter (thank you) and I am going to move forward for the use of a really cool product. This will be a learning experience for me in 500 series land. So, I am sorry for any newb questions that I should have to ask in advance.

 

[ShandonSound]

Apologies if this is covered elsewhere on this thread (I have missed it if it was), but do I need stick the EL panel to the pcb or is it just held against it by being in contact with the LDRs?

Thanks!

 

[peter purpose]

The ldrs should hold it against the pcb, but nothing stopping you glueing it too.

 

[ShandonSound]

Thank you Peter.
Continuing my theme of elementary questions I'd really welcome an idiots guide to wiring T4?

Thanks again!

 

[peter purpose]

What wiring?  Just put the ldrs in the motherboard and the el panel on the small pcb.

 

[ShandonSound]

What wiring?  Just put the ldrs in the motherboard and the el panel on the small pcb.

Sorry for not being clearer, that's T4 not T4B. The board is marked with '2.5', '.31' & '5' and I have red , blue & black wires from the transformer. An idiot's guide would be very welcome!

Cheers!

 

[peter purpose]

oops.... Here's a pic of what you probably bought. Anything look familiar?
5 black - 2.5 red - .31 blue.

 

[ShandonSound]

That's the fella!

Many thanks!

 

[zayance]

Thank you sir , AND people around here for making it even more of a breeze to build this one 8)
1st is working perfectly, all good, 2nd one is waiting for one last bit and should be happy compressing....

 

[peter purpose]

Merveilleux

 

[sonic02]

Hi, I really need a step by step guide to calibrate this. Not sure if I have wired anything wrong, but I get no compression at all, even after turning the squash pot all the way. It just seems to add upper order harmonics to my 1khz test tone. Also, when the boost control is fully ccw there is no signal passing through, if I turn it up 1/4 of the way the boost is huge. Someone please help!

 

[peter purpose]

Well... please do check your wiring.
Dmp's post on page 7 should sort your calibration.