EQN build thread

[shabtek]

are you using the dcdc converter or 51x

 

[zayance]

Well at noon, i fitted back one gear at a time my stuff inside the rack, don't have a lot but still..
And noise got back, but it's when my Mixxbuzz is next to the EQN's, the Gremlins are there, when alone in the rack
it seems no prob...hmmm
I'm running 51X without DC/DC

Or it has nothing to do with this, and again some Gremlins back there, from fitting things back again as before...

hate those Gremlins.....


EDIT: After taking the Mixxbuzz out, the Gremlins were still present in the EQN's but went away
after Bypassing EQ bands and the unit tottaly, and playing with that, so maybe some leaking Caps in there?


@dmp: Going back in the thread, it seems you maybe got same parts as me concerning the ceramic and tantalum links i've posted some time ago reply#175
Maybe some bad tantalums we got?

Anyway will get more into it this week-end.

 

[dmp]

I'm using 51x as well. A problem with a tant cap is a good idea. It seems like it could be a problem with DC not being blocked somewhere. Good luck and let me know what you find.

 

[peter purpose]

I have no idea what's going on here boys.

 

[zayance]

I have no idea what's going on here boys.

haha, me too, how comes? Will see tomorrow, today i had to repair my father's 1984 E30 BMW seat huh, what a PITA
nothing to do with EQN i know, i talk too much....

 

[dmp]

@dmp: Going back in the thread, it seems you maybe got same parts as me concerning the ceramic and tantalum links i've posted some time ago reply#175
Maybe some bad tantalums we got?

I checked my records and I only ordered the same ceramics as you from digikey - the tants I got from mouser. Since the ceramics aren't polarized I doubt that is it.

Just looking now, I think I might have C48 backwards...

 

[zayance]

Allright, so checked the unit with LAB PSU, and all seems in place, and right direction, no prob...
And there is no significant DC on pots nore in the circuit after most Caps,
All tantalums are ok etc.....

Anyway wanted to plug them back in the rack, as i was testing on LAB PSU
and to put a scope on the output and try to have a look of what's going on
after injecting different frequencys in there....
Plugged it back, with some other 500 stuff, and no weird sounds again...

Did i already mentioned i hated those Gremlins? Because i really hate them....


EDIT:
Sound is back , i have recorded it, get the same thing dmp?
One file is inside a percussive sound, it's more noticeable a little after in the file...
Second one is the sound alone, and i'm playin with it, the sound is the most noticeable when HF at 12Khz,
and volume of HF Band at a precise position BUT with the volume of Mid frequency up as well, in the file i'mplaying with the MF volume pot but with no frequency selected.
And playing with HF frequency also afterwards, and bypassing.....
For me seems it's an oscillation problem, now from where i don't know?

Right click save:

http://dl.dropbox.com/u/12562977/EQN%20Percussive.wav

http://dl.dropbox.com/u/12562977/EQN%20Noise.wav

 

[peter purpose]

How very odd..... did you connect the giggling pin to the laughing shaft?

 

[zayance]

not this week-end unfortunatly.....

 

[peter purpose]

 

[zayance]

Found on mnats Page:

I terminated the input to the EQN module with a smallish resistor I had lying around and listened again to the output. Even back in the 51X jig the noise was still there.

The noise didn't seem to change much regardless of frequency switch postitions. But it did, of course, disappear when the EQ IN switch was switched OUT.

Pulling out the BA284 amps one at a time saw the noise disappear. Having located the offending amplifier board I thought about what might be causing such a popcorn noise. After giving the board a good clean I removed the transistors and found there was one particularly noisy one. Problem solved.

Will try that....

 

[zayance]

Allright, found the bad amp, changed the transistors on it (all the rest was ok), problem solved....

 

[peter purpose]

Merveilleux

 

[zayance]

flabbergasting

 

[mnats]

Allright, found the bad amp, changed the transistors on it (all the rest was ok), problem solved....

flabbergasting

I wonder if there was a bad batch of these transistors? The coincidence is too weird that more than one and possibly three people have experienced a problem with them. dmp - what's the verdict?

 

[peter purpose]

Sounds like it Mako.

 

[atticmike]

can anybody tell me what the eq is based on?

 

[zayance]

can anybody tell me what the eq is based on?

Brrr.. wrong question 

 

[atticmike]

can anybody tell me what the eq is based on?

Brrr.. wrong question 

why's that ?

 

[peter purpose]

Tony is just being mean.... it's based on a Massey Fergusson tractor.






Mike, it's a 1084/1073.