calrec PQ1549 help thread

[Jonas K:strand]

thank you syn! for your reply! ive searched the forum and come across some interesting things but still. i dont think it is the gainproblem. it is just slightly higher when eq is flat than on bypass. and gives distorsion so easy. i test it on the outputjack on a dx7 synt so i dont think its to high in..? should be line. and everything seems to be right and on place on the pcb.

and this buzzing sound, ive tried the thing in three different powerjacks now and the character of the buzz is different from place to place. ive went through the pics of calrecs here but cant find even one where its possible to se how everything is hooked up on the ins outs switch, and so on.

ooh now i have something more... when i touch the chassis just litely theres a little crackling sound... doesnt this sound like some groundingstuff?

feels fantastic not to be alone even after the PCB!
i believe in life after the PCB. /jonsd

 

[syn]

Cool.There should be no sound when you touch the chassis...What PSU are you using? Have you connected audio ground to chasses and to mains ground?

 

[gyraf]

..and check supply line voltages, if it distorts easily..

Jakob E.

 

[Jonas K:strand]

hi! thank you for this! the suplyline is lika... jumping between 0 and 18. its a little bit strange and... is something on the psu wrong maby? the sound is still istorted... hmm...

after a hysterically long nite... ive got rid of the bussing sound... you see... i think i got the output soldering right. and the rest is... haha! as you would say - guesswork.

this is how i have it soldered right now...
notice that im GREEN but laugh if you have to-

output - board + to pin 2
- to pin 1
and ground to pin 3

input - + to pin 1
- to pin 2
and chassi ground to pin 2 also... dont know why... but it took away the buzzing sound, so i thought it was cool!

the chassiground is also conected to the middle pin on the switch where also the ground on psu is conected. and on the upper pin on the switch i have the ground on the calrec card besides the psu input... woaah...

the switch is not working at all... but thats i minor problem neow that i have this distortionthing... please help.

 

[madreza]

Hi all

Once Again I have problems !
this time it's with the Calrec EQ I've just built

the signal disapears when reaching the 47K resistor near the low shelf switch ( the one with (Qdb) written near it ! )

I've built 2 channels and have the problem on both :shock:

any idea is welcome !
thanks

 

[JayDee]

once again...

double check ALL parts , check pcb / soldering , check wires.

I guess thet 90% of all errors are wrong soldering.

gyraf pcb with correct parts and wire (and psu) works fine!

 

[capnspoony]

Hi

I just completed my calrec and have a few questions. It buzzes very loudly when it is not in bypass mode. All of the frequency/gain/q controls change the tone of the buzz like it was a guitar or something however it passes no audio.

Once I load my power supply with the calrec eq my negative voltage drops to -6.3 vdc and my positive drops to +13.8 vdc. The power supply measures +-15 on other circuits I've used with it so I know its not the power supply.

All interconnecting wires have been checked and are ok. I've checked my solder pads etc.

any ideas would be lovely thank you!

-Richie

 

[capnspoony]

Ok! Found a lose wire on the link insert point and another cold solder joint next to an opamp jumber wire and now it sounds like a "motorbike" as mentioned above.

The only time it sounds like a motorbike is when the high q is out and the high shelf is out.. Also it only happens when I give the unit 0 or negative gain on that high band.

The power supply changed values also. Now giving +8vdc and -14vdc

Everything else is working great.

--Richie :roll:

 

[gyraf]

+8 and -14 is obviously wrong

Check everything again.

Jakob E.

 

[madreza]

Hi all, me again :grin:

I managed to solve a few problems on my Calrec
I have 1 Channel working fine ( sounds great )
the other one works perfect except when I engage the Hi Q button
on the Hi frequency !!!
I get a kind of feedback or oscillation from 0db gain up. It gets higher in frequency as the gain goes up. the frequency pot also changes the oscillation frequency !
anyone knows what can cause that ????

Thx

 

[madreza]

UP

 

[madreza]

Nobody can help me ?

 

[jdr]

a kind of feedback or oscillation from 0db gain up. It gets higher in frequency as the gain goes up. the frequency pot also changes the oscillation frequency

I had the same problem when I was troubleshooting mine, only with the high-mid band of one channel. I remember that it was caused by a solder bridge. I can't remember where the bridge was for sure :? - it was something like 18 months ago and I didn't take any notes, but I think it was around the solder pads for the pots and the "Q" switch for that band.

John

 

[gyraf]

Yes, check for the "usual suspects" (this is why I didn't reply earlier)

Jakob E.

 

[madreza]

I know ! I should be able to do it by myself !
but I can't help ! I'm far too lazy :grin:
I've desoldered everything that might be shorting but I still have that feedback. I'm gonna dig it more tonight !
Can this feedback be made by a defective part ?

anyway thanks for your help !

 

[PimD]

I've had the same problem.
Just recheck all your solder connections, and make sure that you don't have any solder bridges. That was causing my problems. (just as jdr)
and like he said, look around the pots and switch for that band, and maybe even look at the corresponding IC for a bridge.

Pim

 

[capnspoony]

Okay.. Well unit is up and running and sounds great! My last question is: Does anyone know where to get circular pushbutton caps with a square "shaft"? I haven't been able to locate a link or find them in mouser or digikey. I don't really know what the specific name of the part is even called.

best

Richie

 

[louder]

Hi Richie
look at canford audio,under alps.
i had the same question.
best regards
pedro

 

[capnspoony]

thanks pedro!

 

[louder]

Hi
this is eq week for me.
after the 3d,i finnished the 1549,and with stelar results.
no smoke,no noise,all fine at first fire up.
as for the sound,i need time,but as soon i have my opinion,i`ll tell ya all.
thanks jakob for this (and others) project.wish i could do the same for this forum.
the very best regards
pedro