calrec PQ1549 help thread

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I ended up ordering the pots from Omeg though Im getting 1 set more than I need so I may have an extra set once its all said and done.
 
Ive started my build out on this and have a question.
Here is the original SilkScreen layer I got from Gyraf's site:

http://goose-tracks.com/thegeekgoose/images/calreq1.jpg

Note the area in red has no silkscreening in it but the real board has some components there.  There were several Tant. caps and a couple of electrolytics that didnt have a polarity marking on them (I suspect there was but it was on a thru-hole) If Im following the schematic correct, Ive labled the 22uf as the direction its suppose to go in. Can anyone confirm that this is indeed the polarity on this part?

http://goose-tracks.com/thegeekgoose/images/calreq2.jpg

(edited imgs to links - jakob e.)
 
Yes, that's the correct orientation.

The reason why it's not in the PDF is that the pcb's are rev#5 (which has an insert point option) - and the pdf at Gyraf.dk is rev#4, before this small change.

The reason why it seems unmarked is that the hole is drilled where the +sign was in the drawing.

Jakob E.
 
Hello Everyone,

I am new to this forum, not to DIY. I have been moding and building guitar pedals. I have a few questions regarding the Calrec EQ. I am not sure what type of resistors to use (film, ceramic) and what voltage rating? I guess the usual 1/4W but I just want to be sure. i am collecting the components from the parts list on the Gyraf website, wich I think is rev.4

Does anyone have the rev. 5 parts list?

Thanks in advance,
Raffaele
 
Hi all!

Sorry for revisiting old territory,here, but I'm just looking for confirmation on something...

It's regarding the four reverse polarised tants/electros on the pdf .

I built my first calrec before this issue was raised , so I guess those caps are reversed on that build , but it sounds fine anyway...and jakob has noted that they are at zero dc potential spots..

But now I am building another Calrec on home etched boards (from the same rev4 pdf), and so I'd like to orientate those the caps the correct way around this time,just for good measure.

That would mean going with what the schematic says , not the pcb overlay. I know there's a discrepancy , and I think it's the overlay that is wrong , but I would really appreciate it if someone could confirm that the schematic is correct.

Many thanks in advance!

Cheers

nEon.









 
Hey guys,

I've looked around, but haven't found any answers.

I'm stuffing Gustav's Rev5 it looks like...

Is there any significance to the asterik (*) next to some of the parts or the parts that are in parenthesis?

Thanks!
 
guitarguy12387 said:
I'm stuffing Gustav's Rev5 it looks like...

There are some parts that dont have the polarity noted due to the silkscreening for the "+" sign ended up lining up right over a thru hole. If you check out the PDF from Gyraf's site, the silkscreen layer there can be see better than it is on the board. That will give you the polarity to all but 1 cap and I noted the polarity on that cap a few post back. There are also some parts on the Rev. 5 that arent on the original BOM due to Rev. 5 boards having an insert on them. (Dont take this list a gospel but I remember it being 2x 100n Poly caps, 2x 100K resistors, 2 x 22uf Caps)
 
Just finished testing my first set of Calreqs.
I used an MNATs adjustable PSU to power these. (LM317 LM337)

With the first unit, I had the same problem someone else had back in this thread, The high band wasnt working at all. Flipping the shelve swith would cause a pop. There is a jumper wire right behind IC 5a. The value 100n is for the capacitor right next to it but there is a jumper there. Once I installed that, it worked. I did have the +6 db problem but replaced the appropriate 10k resistors with 22k and that problem was solved.

On the 2nd channel, I ended up having 1 taintalum caps backwards, missed 2 jumpers and had 2 solder bridges a little flux cleaned right up. (pads are a touch tight but otherwise a great board Gustav)

My metalworking skills kind of suck so I have a Pursha case coming for this. Ill post up some pics once its in its new shell.
 
Id like to use terminal blocks instead of hard wiring the XLRs and the Power Supply but Im not certain what terminal block to get.

Would it be the 3.5mm, the 5.0mm or the 5.08mm block to fit Gustav's PCB?
 
happy nu year to y'all!

I've just started building another calrec eq ... this time I'd like to put an earth lift switch on the back ...a habit I've gotten into recently..

On the gssl and g1176 it was easy...Ovolts ties to xlr input pin1 , and these go via the switch to chassis star point.

However, I can't figure out how to do this with the calrec circuit , because there is no provision for input xlr pin1 to 0v ..on the pcb there are only pads for + and -  .

At the output xlr, pin 1 does connect to the pcbs 0v , but in my first calrec I don't think I also tied this point to chassis . Should I have done so ?  It works ok , but maybe I've got the whole thing floating?

Is the output xlr pin 1 the place where the calrec 0volts should be tied to chassis , and where the aforementioned 'lift ' switch be inserted?

Appreciate any help here guys!

All the best

nEon
 
Hi everyone,

I just noticed something while assembling the rev. 5 PCBs - unless I'm mistaken the 22uF cap next to the IC11b / bal- opamp appears to be sitting accross the +ve and -ve supply rails and as a result sees 36v. I nearly got caught out there as the BOM suggests 16v caps are good everywhere. The cap I'm talking about is the one circled in red below;

calrec_cap1.jpg


Apologies if this has been mentioned before, I didn't find it mentioned anywhere when searching.

Maybe it would be worth adding a 22uF / 50v cap to the BOM?

Cheers,

Matthew
 
Somewhere in this thread, this was discussed and I believe 35v parts were recommended in place of the 16v parts though 50v should work as well.
I just completed 2 channels using 35v parts where 16v where mentioned and they worked fine.. Just waiting on those little push button caps. :) Ill post pics once I have all the cosmetics completed.

I got a chance to use them this weekend on an acoustic guitar.. I thought they sounded pretty good but Im probably going to add some input transformers for a little more charactor.
 
Got the last piece in today. The push buttons from Canford. Here she is.
I got the case from Pursha. I choose to use NE5532s for the OPAmps, Nichion Audio for the Electrolytics and Kemet for the Taints.
the power supply is a simple LM317/LM337 that MNats made for the 1176. Got to use it this weekend and it sounded very smooth and sweet.

Caltop.jpg

Calfront.jpg

Calracked.jpg

 
Hi everyone ! In advance sorry for my english !

Just finished a stero Calrec, the first channel is working great ! This EQ rocks !

The second channel doesn't work, it's not passing audio, so I checked ICs voltages, everything is fine. Bypass switch seems to work as the led changes color when activated. So, I put a 1KhZ signal on it and tracked it with my scope.

Here is the weird thing, I get signal working fine until it passes through IC8a. It's getting in.. but nothing gets out of IC8a. (According to the layout, it's the point where the signal goes to the second PCB). I tried to change the LM833 about 3 times, I even tried with a NE5532. I desoldered the socket and soldered the IC right on the pcb, same problem.

It doesn't seem to be an IC problem because the second part of this IC ("input" on the schematics) works great. I tried to short circuit IC8a in and out and here's another strange thing: No signal ! So I get signal at the IN point and nothing at the OUT point  ???

Any idea ?

Thanks
 
oups, another thing that might help:

On the first unit which works fine, I used basics polarized electrolitics capacitors. In the bad unit, I used Nichicon electrolytics capacitors (MUSE series) which are not polarized, could it be part of the problem?

nc12-0221-15.JPG
 
why dont you try the first part of the working board with the second of the non working and vice-versa...you'll see whats the part of the boards really show problems...
 

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