EQN build thread

[haima]

Sorry about that, but just for info, Digikey has free shippings worlwide for purchase over 65 euros, or dollars don't remember, anyway, those 30 dollars would have been for other things, like knobs yes  Smiley, but dont want to be a PITA just wanted to let you know if you missed that one

thanks zayance - but it must be worldwide except for australia!... i ordered a lot more than 65 euros - i believe it's always a flat fee of $30usd for australia

mouser on the otherhand is free shipping on orders over $200 aud - very handy!

 

[zayance]

Oh yes you're right i've just checked, when you change country to Australia you have one blinking message telling that, that's a real PITA.

 

[haima]

Onward: I haven't had a lot of time but I've been trying to figure out what could be wrong with my 8th module. If the mid band is off it passes signal perfectly, but if I turn it to any of the settings i lose my signal. I checked all my solder points and tried to trace the lines out but I can't quite figure why I would be losing all of them except for off. If anybody has any clues it would be greatly appreciated.

marc - do you have a card edge "harness" - like an external 500 series connector wired to XLRS and power - for the bench?

if you have one of those and a signal tracing probe/scope you should be able to follow the signal through the mid section and find out where it stops.

it's probably nothing too big, if it passes signal in the OFF position it would seem that it's something in the "BA211/A" section of the schem pete posted a few pages back. look for solder bridges, wrong parts etc around the midrange inductor, switch and caps? i would expect something there is shorting all your signal to ground perhaps?

 

[Marcocet]

Yip, that's been my guess. I do have a test rig set up and an oscilloscope. However I'm pretty new to the whole thing and haven't been able to find the trouble spot yet. I have learned that if i swap out the mid amp card the problem stays the same. I'm gonna have to spend some time figuring out how to track down the signal tomorrow. I'll let you know how it goes. Thanks!

 

[MM1100]

Nice job Peter! After several hours of work we have a beautiful sounding EQ. Don't laugh at the knobs ladies, they are only temporary. No issues.

 

[Brizco]

Thanks Peter! Finished mine yesterday...

 

[haima]

I have learned that if i swap out the mid amp card the problem stays the same. I'm gonna have to spend some time figuring out how to track down the signal tomorrow. I'll let you know how it goes. Thanks!

yes, according to pete's schem the signal always goes through that amp card, so it appears that part is fine. good luck tracing it - mine isn't done yet otherwise i'd be able to give you more specific places to probe...

BTW: looking good Brizco & MM1100!

 

[peter purpose]

And the pix start flowing in.... keep em coming.

Marc... Could you have the switch stop pins in the wrong place on the dodgy 8th?
Just a guess, as signal would go nowhere if you're the wrong side of the pins.

As for R29... stick 750R in there and adjust with the fader.
I haven't built any yet, so can't report.

 

[funkymonksf]

How is the input transformer being mounted on the PCB? Are you guys using an L shaped bracket or this something included in the kit that I'm missing. Just want to have all bases covered before I send out my mouser/digikey order.  Also, Marcocet would you mind sharing what size knobs you got? I think I'm going to follow the KILO route. It looks really good. I'd do it myself I just don't know the diameter size for the front panel markings.

The builds look great!

Thanks,
Brice Conrad

 

[Marcocet]

I can't remember exactly what the diameters were but they were easily measured with a ruler and the faceplate. 1/4" shafts on the switches and 1/8" on the pots.

As far as mounting the transformer I used 1" 4-40 screws and nuts. My local store didn't have washers that size but they're holding fine without them. I don't plan on moving the things around much.



As far as the stop pins I checked them and they're right, plus it's the 12 position switch so even if I was on the opposite side at least some of the settings would work. Gotta be something in the signal path that involved all of the on positions but not the off, I'm just having trouble sorting out exactly what those spots are. However I know I can get through it, just gotta keep looking at the schematics and layouts till my brain jumps into the right tracks.

 

[haima]

check out around those 4m7 resistors on the underside of the mid switch too - maybe there's a solder bridge or something amiss there?

 

[crisotop]

Would 1/8W be fine for the 4M7 mini resistors as well?

thanks,
Christoph

 

[briomusic]

Would 1/8W be fine for the 4M7 mini resistors as well?

thanks,
Christoph

yes, I think only 1/8 Watt is available in the required size which is 204 (the normal 207 resistors won't fit!)

 

[ultra-alex]

finished mine today.  
altough i went through some trouble with one of the amp boards, but all working fine now. thanks, peter!
cheers, alex

 

[dmp]

I'm looking for the ceramic caps and wondering if others have found these in the USA (mouser, newark...)
I can't find a few in the 5mm LS, and the .1uf in COG. 

CAPACITOR          Order #
10uf / 25v tant 74-199D25V10-E (mouser)
22uf / 25v tant 74-199D16V22-E3
10pf COG 2.5mm 140-500N2-100J-RC
180pf COG 5mm 140-50N5-181J-TB-RC
220p COG 2.5mm 66C6064 (newark)
330p COG 2.5mm 66C6073
470 pf cog 5mm 66C6083
100nf COG 5mm

 

[zayance]

I found them all at Digikey IIRC, they were Murata brand, with the right pitch and all, try again, be precise  , you know what, give me a minute i'll give you the ref of Digikey.

22uf / 25v tant : 478-4175-ND
10uf / 25v tant : 399-3640-ND
10pf COG 2.5mm : 490-3678-ND
180pf COG 5mm: 490-3695-ND, i just bend them to go to 5mm, same same
220p COG 2.5mm : 490-3638-ND
330p COG 2.5mm : 490-3723-ND
470 pf cog 5mm : 490-3738-ND
100nf COG 5mm : 445-4756-ND

Check if i'm correct again, maybe i did some typing mistakes who knows, and maybe there are some cheaper alternatives, but i was doing some order there so, and a little spare is always ok, will find it's need in other projects as well 

 

[dmp]

Ok, thanks! I found them right away on digikey (it's nice that they include LS in the search filter, which mouser does not!).

 

[zayance]

Anyway i gave you the links in case of, look up.

 

[dmp]

Thanks Zayance!
That 100nf is a pricey cap...

 

[zayance]

yep  :, if you get cheaper somewhere else, please share