GroupDIY

Project Specific Discussions => Filters/Equalizers => Topic started by: JayDee on February 26, 2005, 01:27:27 PM

Title: calrec PQ1549 help thread
Post by: JayDee on February 26, 2005, 01:27:27 PM
Hi,

don´t know if there is an official calrec help. If not this may be the first topic?

I am building a stereo calrec. One is sounds great, on the second the hi shelve isn´t working. When I track the signal at the freq pot (e.g.) there is no change in freq. All other band work quite well. What are the parts I have to check? No cuts , no shorts , both (left & right) look exactly the same.

cheers
jaydee
Title: calrec PQ1549 help thread
Post by: nrgrecording on February 26, 2005, 07:05:31 PM
Hi.

If you bought alphastat potentiometers... i would check these first. I got at least 2 or 3 wrong assembled or labeled pots every delivery :?
Does the opamps IC3, IC5, IC6 gets power? If you used IC sockets you could try to change IC3,5,6 with IC10,11,12 if theres something different then, you could try to replace the opamps. (if you don't have LM833 at home, NE5532 will do)
Because you got one channel working... have you compared the resistor values (colour codes) with the other channel?

Frank.
Title: calrec PQ1549 help thread
Post by: JayDee on February 27, 2005, 10:12:10 AM
Hi Frank,

that´s what I did before already. But it´s always good to do it twice.

I sloved the problem meanwhile.

It was a short around the 6n8 by IC5a. Now the other half of my calrec is working too and it sounds very good.

I will do more tests and compare it to other EQs soon.

Thanks for help.

Cheers
Title: calrec PQ1549 help thread
Post by: nrgrecording on February 27, 2005, 10:17:21 AM
it works... super! :thumb:
Title: calrec PQ1549 help thread
Post by: cwatkins on February 27, 2005, 09:55:02 PM
I had mine working perfect, I went to put it into the box 2 days ago,
and darned if I didn't mess something up.

Now I've spent several days trying to figure out what I've done,
I had that thing fully tested too, everything worked. (I haven't built the other side I'm waiting patiently on the board, hopefully that will help me troubleshoot.)

But I sure am learning ALOT about filters.

All the features work still, it's just 2 filters are a hair too loud. The bypass isn't perfect, and I had the thing bypassing without a chain in gain.
Title: calrec PQ1549 help thread
Post by: cwatkins on March 01, 2005, 11:03:10 PM
Ok, It's been several more days, I've tried swapping everything I can think of and I still have the same issue.
All IC's have power, I swapped all IC's.
Here is what everything looks like with the pots at null..
(http://www.rockthemountain.com/~watkins/audiopics/calrec-prob1.jpg)
I can of course move the dip or the peak, the dip is the low mid, and the peak is mid-hi, the q, changes the peak crest.
(http://www.rockthemountain.com/~watkins/audiopics/calrec-prob2.jpg)[/img]
I can not drop the mid-hi lower than it is wrong in gain, only to about where it should be for bypass and I can't boost low and higher the same way.
I had this working so I had a flat bypass line, but I have fowled it up somehow, I have pretty much changed everything more than one, the back of the boards looking pretty used at this point.
but I can't seem to solve the basic problem, and I'm not sure how I introduced it in the first place, because, it was working, all it did was move around in a  box a little.
I have:
swapped with each other the 33u's.
swapped the 22p's
removed the pots, twice, moved them around.
replaced a switch.  
swaped with each other, then replaced completely the 22n's on
7a and 8b.
swapped with each other, then replaced completely the 68n's on 9a and 10b
swapped some 100n's.
swapped the 47ufs with each other.
freq is flat at 20k leading into 8a.
6k8 contains offending frequency. at volume (think it was by itself.)
removing 10k from bal - still seems to be the proper volume level between
bypasses relitivily.

Hopefully I can build anotherone right off the bat and be back to where I was, but, then if I break it again, I'm at a loss, there a few differences, in the rev's, but I figured I would have stubled on it by now and I'm pretty sure everything was in there right, cause it was working, so, what would cause it to go wrong like that?
Title: Calrec 8.1k resistor
Post by: paxworth on March 11, 2005, 01:25:21 PM
I have searched all over mouser, newark, and digikey but I cannot find an 8.1k resistor.  Does it have to be exactly that number?  I have found an 8.2k resistor.  Would that work?
Title: calrec PQ1549 help thread
Post by: gyraf on March 11, 2005, 01:32:36 PM
Yes.
Title: calrec PQ1549 help thread
Post by: paxworth on March 11, 2005, 02:52:59 PM
Yes the number has to be exactly 8.1k or Yes an 8.2k resistor will work?
Title: calrec PQ1549 help thread
Post by: gyraf on March 11, 2005, 03:08:35 PM
Yes, 8k2 would work..
Title: calrec PQ1549 help thread
Post by: Gustav on March 23, 2005, 09:36:32 AM
according to magnuses partslist you need


6x22u/16V radial
3x100u/16v radial

This fits with revision 4 as found on the Gyraf page, but on revision 5 you have to add one 22u and deduct 1 100u.  

I have marked the changes,,,and could someone help me with which way to turn the 22u ? the + must have been over a hole in the silkscreen.

(http://www.lavfrekvent.dk/pictures/calrec%20schem.JPG)

Gustav
Title: calrec PQ1549 help thread
Post by: thedug on March 23, 2005, 02:33:39 PM
I also noticed, and pointed out in another thread, that the 33uF are reversed on the board from orientatin in the schematic.
Title: calrec PQ1549 help thread
Post by: Gustav on March 23, 2005, 04:04:53 PM
Quote from: "thedug"
I also noticed, and pointed out in another thread, that the 33uF are reversed on the board from orientatin in the schematic.


ugh.
Ive really been trying to trace the schematic through the PCB, but I just cant, so I havent caught anything like that.

Could you point me the thread ? Im almost done soldering all this stuff up..

Gustav
Title: calrec PQ1549 help thread
Post by: thedug on March 23, 2005, 04:09:59 PM
I'll check when I get home, but I am pretty usre that most of the 33uF caps are backwards as compared to the schematic.

For the 22uF it is the same as the 100uF. It just got rotated and downsized. Just from memmory I think it is + to the left of the board, i.e. connect to those contacts.  

Doug
Title: calrec PQ1549 help thread
Post by: thedug on March 23, 2005, 10:06:56 PM
I think I've found other descripancies in the schematic. If this thread is correct, http://www.groupdiy.com/index.php?topic=75664#75664, then the default positions are show wrong.

Also, for a specific example of the 33uF tantalums, check out the tantalum on the just below the HQ switch for the low-mid. The schmatic shows the - terminal connecting to the 24K and 43K resisters. But the board has the + terminal connecting to those resisters.
Title: calrec PQ1549 help thread
Post by: Gustav on March 24, 2005, 07:31:01 AM
Quote from: "thedug"
I think I've found other descripancies in the schematic. If this thread is correct, http://www.groupdiy.com/index.php?topic=75664#75664, then the default positions are show wrong.

Also, for a specific example of the 33uF tantalums, check out the tantalum on the just below the HQ switch for the low-mid. The schmatic shows the - terminal connecting to the 24K and 43K resisters. But the board has the + terminal connecting to those resisters.


Unfortunately schematics are totally greek to me, so I can only go by the PCB drawings. Ill see if I can get someone at work to guide me through it when easter vacation is over. No hurry, Im still waiting for benkler to come back with a shipping price for a case.  :roll:

Gustav
Title: calrec PQ1549 help thread
Post by: Gustav on March 24, 2005, 01:08:53 PM
Ok.
This is for verification only, nothing is certian here.

Could someone verify that the red circles indicate discrepancies between schematic and PCB silkscreen, and the green circles indicate agreement ?
Im not done building yet, so I have no way of knowing what is correct, and I dont know wether to trust the schem or the PCB layout.

(http://www.lavfrekvent.dk/pictures/PCB1.JPG)
(http://www.lavfrekvent.dk/pictures/PCB2.JPG)

Gustav
Title: calrec PQ1549 help thread
Post by: thedug on March 24, 2005, 01:34:36 PM
I'll try to have a look tonight.

I'd really like to hear what Jakob has to say because, people have built these based on your boards and they work.

Also, I have found other problems with the schematic too. Check out the 4PDT switches. The schematic says that they are in their default position, yet there are some poles that are connected to the wrong pin.

Doug
Title: calrec PQ1549 help thread
Post by: cwatkins on March 25, 2005, 03:06:42 AM
Mine is together and working.  Both sides.
After mucho trouble with it. switchwise I ended up using panel mount
so I just used the same format accross and it worked.

Todo...

The gain is still wrong, if off = 0 db. then bypass = 0. then
eq in will = around +8db.  While this isn't a show stopper I'd just like
to confirm everybody elses works this way because both sides of mine are
identically flawed if so. And I literaly ripped one set of boards apart trying
to find a problem and that problem too.

everything else is perfect, I tested each q perside, the tracking on each of the pots, with the q, with gain.  Only one of my pots was a hair different.  very happy.  Put the knobs on today.  the noise floor is -93db with the +8db eq in. it gets flat as a pancake.

Yeah, orientation was a pain, there was 1 I had to guess on then later kind of guessed out because it is only in rev 5. it's the 22u around the insert point.  (having to look upside down here.)

But all of then have a little of the + except one of the rev 4 pdf if you look really close.

Course I'm still a newbie and it's not like I had built it before, but I do have the two sets working identically and it is a *****en eq. I like the pultec's high and low end better for mastering sudletly but everything else and inbetween, this thing rocks.
Title: calrec PQ1549 help thread
Post by: Gustav on March 25, 2005, 03:24:14 AM
Quote from: "cwatkins"


Yeah, orientation was a pain, there was 1 I had to guess on then later kind of guessed out because it is only in rev 5. it's the 22u around the insert point.  (having to look upside down here.)


Could you draw the orientation into one of the pictures I posted ?

Quote from: "cwatkins"

But all of then have a little of the + except one of the rev 4 pdf if you look really close..

Yep, I could read the +'s on the boards, but the problem is that some orientations on the board differ from the one in the schematic. Did you just follow the rev4 PCB layout (which is the same as rev5 for the 33 u orientation) ? or did you follow the schem for this ?

Also, how does this thing sound ?

Gustav
Title: calrec PQ1549 help thread
Post by: Gustav on March 28, 2005, 11:07:01 AM
Dont forget me   :shock:  :cool:  :oops:  :razz:

Gustav
Title: calrec PQ1549 help thread
Post by: gyraf on March 28, 2005, 11:24:58 AM
I don't think there's any altered orientations between these two versions..

Jakob E.
Title: calrec PQ1549 help thread
Post by: Gustav on March 28, 2005, 01:14:51 PM
Quote from: "gyraf"
I don't think there's any altered orientations between these two versions..

Jakob E.


Ok.Ill just try to fire it up with the 33u as they are now then....

Thanks !

Gustav
Title: calrec PQ1549 help thread
Post by: cwatkins on March 28, 2005, 06:32:38 PM
It's sounds great, They are matched well and then I tested with white-noise in stereo at different Q values, the low-end was the only Q that was a little different, and I'm sure it was a pot variance.

I put the 33u's in as show in the PDF, I put the top on and racked it this morning, I can draw but I visually checked the top board. (hard to do upside down).  The PDF was what I used to verify, because that you can use 300%+ zoom in and see a piece of the + in the picture, on the circuit board you got a viarable place on the drill hole and sometimes you could see the + and sometimes not on the board.
I don't think I saw any conflicts, that would have prompted a post.
I'll unrack it again and re-re-verify, don't suppose that could account for the gain variance?

is anyone getting a db gain when the eq is engaged at a flat response curve?
Title: calrec PQ1549 help thread
Post by: Emperor Tomato Ketchup on May 05, 2005, 12:10:58 PM
Has anyone ever resolved these questions?  I just finished one channel of the EQ, with Gustav's latest board (rev 5?) stuffed according to the silkscreened legend.  Everything works, but I also have the extra gain everyone else does.  So the two unresolved calrec issues seem to be:

1. Extra gain.  Has anyone tried swapping the 5.1K's for 1.5K's?  However, I might actually use this gain to my advantage, as a make-up gain when cutting dB.  I plan on putting an attenuation pot on the output (unless there is a better approach availible for output gain control).

2.  Backwards polarized caps.  Tracing the layout I find two elecrolytic and two tants that don't agree with the schematic.  They are the 22u and 33u located beneath the lo-mid Q switch, and the 22u and 33u located below the Hi freq dB pot (33u not on latest rev).  Gustav, I can't see the pics that you posted earlier.  Is this what you found too?  Finally, are there any issues with these caps being backwards if they aren't seeing a strong DC bias?

An by-the-way, the EQ sounds absolutely wonderful.
Title: calrec PQ1549 help thread
Post by: cwatkins on May 06, 2005, 12:48:19 PM
No, I haven't tried swapping.
and haven't solved the issue.

The only thing that seemed to concern me is gain structure issues,
I'd like to hear the EQ with the right staging and the bypass working.

It becomes kind of a pain with such a gain boost when using it as a insert on a daw.
Title: calrec PQ1549 help thread
Post by: Gus on May 08, 2005, 11:13:03 AM
I just looked at the schematic the gain part is easy.  You have to much gain with the eq in?

  Look at the top right of the schematic make the 100K pull down on the opamp a 10k to 100K audio pot connect the 22 ohm to the wiper your done.

  I would try a 10K pot and a 220uf cap.

EDIT 05-11-2005 The above it not good information.  I did not read the schematic correctly I looked at it fast and thought I saw a unbalenced output

However I was talking on the phone with a member of the lab tonight.   There might be an answer to the gain issue and a possable cool mod soon.
Title: calrec PQ1549 help thread
Post by: Emperor Tomato Ketchup on May 21, 2005, 02:07:24 PM
I just traced the board layout myself and noted that the 5.1K resistors on the negative input of the op-amps are not replaced by the 1.5K resistors.  The 1.5 K resistors on the board are part of the hi/low shelving circuits and are correct.  

The 5.1K resistors in the schematic are actually 6.8K, 5.1K, 6.8K, 20K on the board.

I have ran my EQ through a spectrum analyzer and everything works correctly.  My overall gain from inserting the EQ is 6.5 dB with a flat response.
Title: calrec PQ1549 help thread
Post by: cwatkins on May 21, 2005, 02:45:43 PM
Ok, like in the original schematic.

But, why is it +6.5db at all, should these not be modded since
this isn't a module in a consnole to have no gian whatsoever when
engaged?

we know the 5 resistors now, right, I'm not a designer, but
should it not be a very simple addition of the bands with higher resistor
values to compensate?
Title: calrec PQ1549 help thread
Post by: Emperor Tomato Ketchup on May 21, 2005, 04:07:22 PM
I'm pretty much lost on this one too.  It is a terrific box and I am quite happy with it as is.  It's more about understanding how it ticks that's keeping me going.  I also struck out with an attenuation pot.  I tried a variable attenuator similar to what NYDave used in his passive summing mixer (fixed 2K series resistors on + and -, 10KA pot as shunt).  The problem was that the output distorted when I rolled back to just below unity gain.
Title: fried component
Post by: Nele on June 24, 2005, 10:32:47 AM
After a while one of my two calrec channels stopped working. I traced the signal and the problem appeared to be in ic 10A/12A. To the test the ic I dropped it in the output stage of the working channel but I accidently put it in the wrong way.. As I powered up the unit smoke appeared from around the opamp. Figuring I had blown up the opamp I replaced it, but now the unit is distorting! The smoke probably came from another component but I can't see which one.. Any ideas?

The problem on the other unit turned out to be a tiny solder blob shorting the opamp... So now the tables are turned.. the initially working unit is fried and the broken unit is fixed!

adios,
corneel
Title: calrec PQ1549 help thread
Post by: gyraf on June 25, 2005, 04:52:03 AM
check powersupply lines. change opamps one at a time.
Title: calrec PQ1549 help thread
Post by: Nele on June 30, 2005, 03:28:05 AM
I changed the last two op-amps (11 and 12) and the unit is working again! Strangely enough when I re-inserted the 'fried' opamp(s) there was no distortion anymore, just a decrease in output gain.. In the end one op-amp turned out to be faulty but I replaced the last two to be safe.

Thanks Jakob for your help and designing this unit! :sam:

Adios
Corneel
Title: calrec PQ1549 help thread
Post by: gyraf on June 30, 2005, 04:07:06 AM
Good that you got this fixed.. :razz:

Your problem can very well have come from the unit being fed 48V phantom power by error. The output opamps won't survive this (like many other line-level devices) - so you better keep your phantom under strict control.

Jakob E.
Title: calrec PQ1549 help thread
Post by: Nele on June 30, 2005, 04:28:27 AM
As I'm not using the XLR's inputs on my desk but balanced jacks (non phantom-powered) that wasn't what happened here. The only thing I did was accidently reverse the output op-amp in it's socket. This caused a lot of smoke and seemed to fry the opamp.. After replacing the opamp there was still a lot of distortion in the channel but after replacing the opamp prior to the output opamp (11a/12b) everything was fine. Time will tell if something else has been damaged but at the moment the unit is behaving very nicely.

Adios,
corneel
Title: calrec PQ1549 help thread
Post by: gyraf on June 30, 2005, 06:08:42 AM
:thumb:
Title: calrec PQ1549 help thread
Post by: cannikin on July 01, 2005, 12:28:06 PM
Might have found my issue.. :shock:
Title: calrec PQ1549 help thread
Post by: cannikin on July 01, 2005, 09:51:50 PM
Ok I didn't find my issue...  :mad:

I am getting absolutely no audio passing through my stereo calrec.  Bypass works.   :roll:

I have checked everything - solder bridges, cold joints, wrong value resistors, cap polarity, replaced IC Sockets.  De-soldered, re- soldered. Made another Mini-PSU.  Nothing.....   :sad:

I have no idea whats happening..  I put a 1kHz signal through the unit and traced it.. around the 1k5 resistors the sound gets really weak. In the Low/Low-mid Pcb I'm not getting any signal to trace.

One thing that I also notice, is that when I hook up my VM to try and read any voltages vdc anywhere with reference to ground.  I get Negative readings.   Example: If I measure Zero out the Mini-PSU with Neg. Probe (black) and the +18 from the Mini-PSU with the Pos. Probe (red)  I get a reading of -18vdc.  then if I take the POs Probe a measure the positive side of a tant or electrolytic I get Negative readings (like -500mV).  I have no idea what the next step is.....  :cry:

One last question, Im not using the bypass LED..  Do I need it to complete the circuit?   Thanks.
Title: calrec PQ1549 help thread
Post by: gyraf on July 02, 2005, 04:39:51 AM
- check that your +18 is actually working at the PSU, 7818 pin3. Then check that it reaches the PCB's (measure at all IC's pin8).

- bypass led is not needed for the EQ to work.

Jakob E.
Title: calrec PQ1549 help thread
Post by: cannikin on July 02, 2005, 09:53:21 AM
Quote from: "gyraf"
- check that your +18 is actually working at the PSU, 7818 pin3. Then check that it reaches the PCB's (measure at all IC's pin8).
Jakob E.


Thanks Jakob.

I checked +18 as you suggested and its definitely NOT +18.  the reading is fluctuating all over the place.   Across 7818 & 7819 I'm unable to get a constant reading.  

For the bridge rectifier is 1.5A OK?  

I'm going to check my Toroid and make sure thats wired correctly too.
Title: calrec PQ1549 help thread
Post by: gyraf on July 02, 2005, 10:03:39 AM
Quote
For the bridge rectifier is 1.5A OK?


Yes.

Measure your voltages with reference to 0V. Check that the 7818 has good input voltage (>+21V). Check that the +voltage reservoir cap is good, connected and working.

Jakob E.
Title: calrec PQ1549 help thread
Post by: cannikin on July 04, 2005, 05:15:14 PM
thanks Jakob

I had my PSU wired incorrectly.  now I'm getting voltage through my unit.
I switched to 15v PSU.  

Pin 8 of my 5532 is reading 13.78Vdc  (too Low?)

I'm still not getting audio through either unit.   Did a third check of solder bridges .. found nothing suspicious.

Other than that..... Any thoughts as to a next step?
Title: calrec PQ1549 help thread
Post by: gyraf on July 05, 2005, 02:17:56 AM
- Check if any of the opamps gets hot. Replace if one is hotter than others.

- double-check all electrolytics that touches the +15V rail, one may be reversed..

- Look for DC at all opamp outputs - if there's more than say 100mV, something is wrong either in that stage or in a previous one.

- Trace signal through the unit. Look at the schematic - and check signal after each eq stage.

- make sure that all ic's gets both + and - supply (measure from top, directly on pin) Also check that none of the opamps has pins bent underneath them when inserted in sockets.
Title: calrec PQ1549 help thread
Post by: cannikin on July 06, 2005, 01:58:20 PM
HI jakob,

I want to thank you for all your help.  I found my issue by tracing the signal- it was such a silly over-site, I'm embarrassed to post what it was :oops:

Sounds great!

One thing I noticed is that if the High Freq Pot is "all the way up" and db Pot at 80%.  the unit will squeal.. ouch :roll:

I'll re-check everything.. but the unit is still quite usable.. thanks again.
Title: calrec PQ1549 help thread
Post by: Gustav on August 11, 2005, 07:01:18 AM
I finally got my two channels powered up , sent some signal through and have a minor things.

1.The bypass switch on one channel has no "click"  :?  - It doesnt work, even if I hold it in. Anything I could check there, or do I "just" need to replace the switch ?

2.Ive seen this mentioned somewhere, but cant find it in any of the threads linked from the Calrec meta - I have a boost with the eq in set flat. Was there any solution for this ? Its not a big deal, but for A/B I would like it to be even.

Gustav
Title: calrec PQ1549 help thread
Post by: JayDee on September 27, 2005, 01:40:36 PM
I also have a boost while all pots are flat. But I don´t really like it as I think the gain is a bit too high in general.

What do you guys think will be the best way to reduce the gain.

Attenuation at input ?

Changing amplification at output ?
Title: calrec PQ1549 help thread
Post by: cwatkins on September 27, 2005, 02:02:31 PM
I've been dealing with it in the daw.

I'd still like to know a mod way to fix it, because h/w bypass is useless
This way.  If there could be a simple attenutor knob when ingaged, that would rock, that way you could match to bypass..

But I'm not smart emough.
Title: calrec PQ1549 help thread
Post by: gyraf on September 28, 2005, 03:20:50 AM
How much of a boost is present with controls flat and balanced input and output?

You could try changing the two 10K series resistors at the balanced input to something larger - say 22K should take you down 6dB etc..

I have no proto of this unit around anymore, so I'd appreciate if you could report back with a solution..

Jakob E.
Title: calrec PQ1549 help thread
Post by: cwatkins on September 28, 2005, 01:13:03 PM
Hmm.  Ok, should try that, it's after bypass so that should be cool.
I tried changing the 10k in the bal opamp feedback loop, but I don't understand it well enough..
Title: calrec PQ1549 help thread
Post by: Emperor Tomato Ketchup on September 28, 2005, 01:26:24 PM
Jakob,

I'd love to have a gain adjust on the output of mine, as makeup gain/attenuation for the unit.  I also lack the design skills to do this.  Do you any suggestions?  Perhaps placing a rheostat where the 10K series resistors are?

Thanks,
Chris
Title: calrec PQ1549 help thread
Post by: gyraf on September 29, 2005, 02:38:41 AM
Not a really good idea, as you need very good tracking of the two resistors to acheive good CMRR on the balanced inputs..
Title: calrec PQ1549 help thread
Post by: Emperor Tomato Ketchup on September 29, 2005, 09:45:15 AM
So would a stepped attenuator switch loaded with metal film resistors be OK then?

Thanks,
Chris
Title: calrec PQ1549 help thread
Post by: gyraf on September 29, 2005, 10:44:39 AM
yup, I don't see why not. It will change input impedance though - but this may not be a real problem..

Jakob E.
Title: calrec PQ1549 help thread
Post by: cannikin on October 29, 2005, 10:20:23 AM
Hey Gyraf,

Can you help me..

I'm trying to figure out how to wire some switches off the board.

I have no idea where to start, I have been looking at the schematic but I can't see it ...

First, what switches should I use SPST, DPST.. etc..
Title: calrec PQ1549 help thread
Post by: Zee1usa on October 29, 2005, 04:24:04 PM
Quote from: "Emperor-TK"
Has anyone ever resolved these questions?  I just finished one channel of the EQ, with Gustav's latest board (rev 5?) stuffed according to the silkscreened legend.  Everything works, but I also have the extra gain everyone else does.  So the two unresolved calrec issues seem to be:

1. Extra gain.  Has anyone tried swapping the 5.1K's for 1.5K's?  However, I might actually use this gain to my advantage, as a make-up gain when cutting dB.  I plan on putting an attenuation pot on the output (unless there is a better approach availible for output gain control).

2.  Backwards polarized caps.  Tracing the layout I find two elecrolytic and two tants that don't agree with the schematic.  They are the 22u and 33u located beneath the lo-mid Q switch, and the 22u and 33u located below the Hi freq dB pot (33u not on latest rev).  Gustav, I can't see the pics that you posted earlier.  Is this what you found too?  Finally, are there any issues with these caps being backwards if they aren't seeing a strong DC bias?

An by-the-way, the EQ sounds absolutely wonderful.





This is what I have found also. "the 22u and 33u located beneath the lo-mid Q switch"  the + is labeled wrong on gustav pcb and perhaps the pdf since I believe his pcb was printed from that . According to the schematic it is reverse of the + printed on the pcb.


Jacob & Gustav may want to take note of this if they havent corrected this already. If you could take a minute and confirm this and let me know if i am just blind.

Also there are a few + that did not show up on the pcb, but looking at the schematic will show you the polarity in which they should be oriented.

 :cool:
Title: calrec PQ1549 help thread
Post by: Gustav on October 29, 2005, 04:40:58 PM
Hey Guys.
I dont remember what I had circled on the drawing, but I ended up just following the PCB layout PDF, and I have a kewl stereo eq with no problems. It does have the gain thing, but it hasnt caused me any problems, If it gets too hot I just back of the sends on my DAW insert points.  :?

Gustav
Title: calrec PQ1549 help thread
Post by: gyraf on October 31, 2005, 03:04:35 AM
Yes - don't worry too much about the wrongly-polarized caps, as they all are placed at spots with no DC potential. We'll try to fix it at the next update (which could take a while..)

David,

To use "external" switches, you'll need to consult the schematic AND the PCB layout..

Chris,

How did the attenuated-font-end turn out ?

Jakob E.
Title: gain problem fixed!
Post by: on November 15, 2005, 03:03:55 AM
Just to let everyone know who's having gain problems, the fix that jakob gave up top fixes the problem of extra gain. I swapped the two 10k's with 22k's, and I have the same gain with the eq engaged as I do when it is bypassed. Woo hoo! thanks jakob.

Erik Wofford
Stapes Audio
Title: calrec PQ1549 help thread
Post by: gar381 on November 15, 2005, 01:31:19 PM
Erik

Which 10k's did you swap??

GARY
Title: calrec PQ1549 help thread
Post by: gyraf on November 16, 2005, 03:22:24 AM
Thanks for the feedback, Erik!

Gary - look earlier in this thread: it's the two resistors in series with the input at the balanced input stage.

Jakob E.
Title: calrec PQ1549 help thread
Post by: gar381 on November 16, 2005, 07:50:09 AM
thanks Jakob

GARY
Title: calrec PQ1549 help thread
Post by: sleepingtiger on January 31, 2006, 05:15:14 PM
Hey Everybody,

I'm finally getting around to putting together a single channel of the PQ1549. I'm having a lot of trouble getting it to work and am wondering if any of you have suggestions...

I've narrowed it down to the negative power rail. The PSU (I'm on my second and it's an old lab supply) is working fine. I'm getting +/-15 until I plug into the pcb. At that point the negative side drops to around -1 volt. I've checked and re-checked everything that I can think of along the power rail. The positive side stays at 15 and the positive voltage shows up at pin 8 of each of the ic's. The unit passes no audio (except in bypass) but the led lights both green and red when the switch is pressed. I've replaced the diode and the caps that are right off the power supply and checked continuity and I'm stumped...

Any ideas?...

Thanks a bunch.
Title: calrec PQ1549 help thread
Post by: gyraf on February 01, 2006, 02:51:28 AM
Your -15V obviously is shorted to something. Reversed opamp/diode/electrolytic?

Jakob E.
Title: No power after the diodes
Post by: anneflyr on February 21, 2006, 06:44:23 PM
Hello

I am building a singe channel calrec into a rec.channel. Got a 15 v PSU.

I pluged the PSU in with wrong polarity first, fried one 22 uf. Got that fixed, but no there are no power after the diodes. Can't find them in the schematics. Is it possible that they are wrong rotated?

Andreas
Title: calrec PQ1549 help thread
Post by: gyraf on February 22, 2006, 07:55:13 AM
If you're asking if the layout is incorrect, then no. Look at the pcb layout in the pdf-file - it should be quite clear what it does.

Jakob E.
Title: hey Jacob
Post by: anneflyr on February 22, 2006, 09:57:41 AM
Thanks for fast reply Jacob

Sorry, but I been looking trough my electronics books and I don't understand what the diodes do.

I have traced trough the whole unit, but can find any errors. Checked caps, resitors and tried to look for shorts. I have changed the diodes and they are rotated the way the PCB says. Something is defenetly wrong.

When I connect power and messure voltage on the power ins on the calrec pcb the voltage slowly, but stedly goes up from 4 volts on both + and-. After about 3 minutes the two 22 uf caps explodes. It looks like the are caring them selfs up.

Any ideas for where to look?

A
Title: calrec PQ1549 help thread
Post by: gyraf on February 22, 2006, 10:18:18 AM
Quote
When I connect power and messure voltage on the power ins on the calrec pcb the voltage slowly, but stedly goes up from 4 volts on both + and-. After about 3 minutes the two 22 uf caps explodes. It looks like the are caring them selfs up.


Then your supply voltage is either FAR too high - or you've connected powersupply with reversed polarity - or you've reversed polarity of the electrolytics.

Check, check, and recheck..

Jakob E.
Title: calrec PQ1549 help thread
Post by: anneflyr on February 22, 2006, 05:56:17 PM
Thanks again

I have to thank you for this build.

I still wounder what the diodes do, can you tell me?

I will check, check and recheck

I now have gotten the voltages steady but at only 8 volts. the supply when not connected is 15,1 on both + and  -

Have checked polarity on the caps, now I'll check for shorts
Title: calrec PQ1549 help thread
Post by: gyraf on February 23, 2006, 05:33:00 AM
Quote
I still wounder what the diodes do, can you tell me?


They protect all the IC's from wrong polarisation of the PSU. Had it not been for those, then ALL your IC's would be dead by now.. And they also helps to filter psu a bit.

Jakob R.
Title: planning a build
Post by: EEMO1 on September 14, 2006, 04:10:44 AM
im planning to build one stereo unit.

 is there any point using switches instead of pots? i have my hands on decent priced 2x24 / 4x24 switches.

 how can i calculate the resistor values to match the potentiometer curves or better yet, calculate resistor values for certain frequencies/decibels/q etc?

 thanks,

eero
Title: calrec PQ1549 help thread
Post by: gyraf on September 14, 2006, 04:33:58 AM
Quote
how can i calculate the resistor values to match the potentiometer curves or better yet, calculate resistor values for certain frequencies/decibels/q etc?


It's a standard state-variable filter - you should be able to find formulas in any filter-cookbook

Jakob E.
Title: hey
Post by: EEMO1 on September 14, 2006, 04:43:16 AM
thanks, so it's possible. :D
Title: calrec PQ1549 help thread
Post by: enthalpystudios on September 14, 2006, 04:47:50 AM
dude..  2 and 4 by 24 switches.... at a decent price?   is this that EU online store with guitar fx diy and stuff like as well?  because i can never remember that site

billy
Title: hey
Post by: EEMO1 on September 14, 2006, 05:20:59 AM
yeah, it is. one of my local stores or at least used to be... no pickup anymore.  :sad:
Title: calrec PQ1549 help thread
Post by: gyraf on September 14, 2006, 05:47:24 AM
A link??
Title: here's the link
Post by: EEMO1 on September 15, 2006, 02:11:18 AM
http://www.uraltone.com/kauppa/index.php?cPath=15_53

 bought a couple of them already.
Title: calrec PQ1549 help thread
Post by: dinesh on February 13, 2007, 03:48:48 AM
Hi There,

I am getting problems in my Calrec eq. I have built 3 channels & all are sounding like motor bike ( low freq. oscilation) with no input. I have checked my PCBs with schematics & found some changes, Some reversed Caps & some diffrent resistances. Two 1M resistances are also wrongly placed.

Can anyone send me the correct PCB layout & schematics?

Thanks & Regards

Dinesh
Title: calrec PQ1549 help thread
Post by: gyraf on February 13, 2007, 04:22:37 AM
The stuff on the gyraf site is already correct and is been kept up to date. check your powersupply for oscillation, and check your wireing.

Jakob E.
Title: calrec PQ1549 help thread
Post by: Jonas K:strand on March 27, 2007, 02:39:08 PM
okipoki! im building this one chanel calrec eq as my first bigger thing and hmm... till today only the bypass sounded but i found this little "link or set point" (i think it said) and i put a little link there and the thing started sounding.

ive had it on without this link for some time... can this have damaged any components? the thing has a bussing sound in the highs now and the sound gets distorted when i tweak on a line signal from a synth, not really sure i wiered things the right way on the ins and outs and ground and ooh... seems like youre on your own after the PCB´s

to here! but not further! or its just things that everybody should know...

are there any threads on this? i mean... it should be!

/jonas
Title: calrec PQ1549 help thread
Post by: syn on March 27, 2007, 03:02:54 PM
Quote from: "Jonas K:strand"
... i put a little link there and the thing started sounding. ive had it on without this link for some time... can this have damaged any components?
I don't think so. You just didn't pass the signal from one point in the circuit to another... The link was meant for Hi-Lo pass filter insert point or a gain stage if i remember well from the posts that  i had read...

....the thing has a bussing sound in the highs now and the sound gets distorted when i tweak on a line signal from a synth, not really sure i wiered things the right way on the ins and outs and ground and ooh...
Shouldn't be sounding the way you described...Are you overloading the input of the Calrec? What about input resistor,"You could try changing the two 10K series resistors at the balanced input to something larger - say 22K should take you down 6dB etc.."quote-Gyraf... Try to look for the misplaced components, shorts of all kinds....Magnifying glass with a lamp is very helpful for this sort of problems, if you are not using one already....

...seems like youre on your own after the PCB´s
as you can read you are not

are there any threads on this? i mean... it should be!


cheerz

/jonas


use the "search" function it is very useful.  I know very little about electronic, almost nothing, but reading the forum and using the search function i've complited the Calrec project with success.
Title: calrec PQ1549 help thread
Post by: Jonas K:strand on March 27, 2007, 06:07:44 PM
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
Title: calrec PQ1549 help thread
Post by: syn on March 27, 2007, 06:53:50 PM
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?
Title: calrec PQ1549 help thread
Post by: gyraf on March 28, 2007, 02:02:42 AM
..and check supply line voltages, if it distorts easily..

Jakob E.
Title: calrec PQ1549 help thread
Post by: Jonas K:strand on March 30, 2007, 10:13:40 AM
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.
Title: calrec PQ1549 help thread
Post by: madreza on September 14, 2007, 06:46:04 PM
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
Title: calrec PQ1549 help thread
Post by: JayDee on September 15, 2007, 01:59:38 PM
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!
Title: calrec PQ1549 help thread
Post by: capnspoony on October 02, 2007, 06:59:11 PM
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
Title: calrec PQ1549 help thread
Post by: capnspoony on October 02, 2007, 07:33:45 PM
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:
Title: calrec PQ1549 help thread
Post by: gyraf on October 03, 2007, 02:27:45 AM
+8 and -14 is obviously wrong

Check everything again.

Jakob E.
Title: calrec PQ1549 help thread
Post by: madreza on October 21, 2007, 06:30:04 AM
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
Title: calrec PQ1549 help thread
Post by: madreza on October 21, 2007, 03:38:53 PM
UP
Title: calrec PQ1549 help thread
Post by: madreza on October 23, 2007, 05:32:51 PM
:cry:  :cry:  :cry:  :cry:
Nobody can help me ?
Title: calrec PQ1549 help thread
Post by: jdr on October 24, 2007, 01:49:37 AM
Quote
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
Title: calrec PQ1549 help thread
Post by: gyraf on October 24, 2007, 04:16:07 AM
Yes, check for the "usual suspects" (this is why I didn't reply earlier)

Jakob E.
Title: calrec PQ1549 help thread
Post by: madreza on October 25, 2007, 08:20:15 AM
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 !
Title: calrec PQ1549 help thread
Post by: PimD on October 25, 2007, 08:46:20 AM
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
Title: calrec PQ1549 help thread
Post by: capnspoony on November 15, 2007, 11:45:38 AM
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
Title: calrec PQ1549 help thread
Post by: louder on November 15, 2007, 01:51:07 PM
Hi Richie
look at canford audio,under alps.
i had the same question.
best regards
pedro
Title: calrec PQ1549 help thread
Post by: capnspoony on November 15, 2007, 02:46:10 PM
thanks pedro!
Title: calrec PQ1549 help thread
Post by: louder on December 03, 2007, 05:33:58 PM
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
Title: calrec PQ1549 help thread
Post by: gyraf on December 04, 2007, 04:55:15 AM
:thumb:
Title: calrec PQ1549 help thread
Post by: rbaker on December 22, 2007, 04:33:46 PM
I have a stereo unit and it has the extra gain problem (Didn't see the post about altering the resistors)  I'll do that when I open it up again.

Also I'm having a problem with the high frequencies.  On one channel, it absolutely does nothing..

On the the left, it does nothing unless the shelf is engaged and then its basically just a level adjustment (not frequency dependant) if I boost, it boosts the whole signal.  If I cut, it cuts the whole signal.

I remember being overly careful about solder bridges, but I'll check again.  Any ideas of where to look or what might cause this to happen?
Title: calrec PQ1549 help thread
Post by: gyraf on December 23, 2007, 05:18:06 AM
..it could be anywhere in the hi-freq filter or -add/boost section (see schematic)
Title: calrec PQ1549 help thread
Post by: rbaker on January 21, 2008, 10:59:20 PM
so I finally had a chance to open it up...

On the channel where the high freq was acting like an output fader, it turns out I missed two jumpers.  :oops:

Now that channel is working great.

On the other channel where the high frequency just doesn't work whatsoever, I looked for solder problems and there wasn't anything I could find--(I cleaned on semi-suspicious solder joint but it didn't help)

I noticed when the unit is not bypassed and I press the high shelf switch it makes a pop sound in the audio (the functioning channel doesn't do that)

Also I changed the resistors (22k) you mentioned for unity gain, and it definitely helped but I still have about 3.5db of extra gain.  Is there any problem with increasing this resistance further?
Title: calrec PQ1549 help thread
Post by: josh on March 09, 2008, 08:13:21 PM
Couple more questions if everyone doesnt mind.  If I might be a pain, the answers to the questions are hardly as important as to how you know the answer please? :thumb:

1. each "high" board has a balanced input and balanced output (according to the Calrec.pdf) and a third section marked (OUT) on the boards.  What is this?  
2. the "low" board has no markings for the input section, and the place I thought was the input is marked on the Calrec.pdf as the -+0 18V PSU.  Does that mean the input is part of the 6 pin connector on the "low" board but not the high?  Why?
3. the mini-psu I built specifys +-15V output, but the Calrec.pdf is labling the boards with +-18V?  Does that matter?

I read every thread and every link in the Meta last night.  Apparantly I am the only one thrown by this, but it really doesn't make any sense.
Title: calrec PQ1549 help thread
Post by: syn on March 10, 2008, 04:12:55 AM
1."out" is where you place jumpers connecting two boards, those tracks actually carry the "output" signal...
2.Calrec.pdf markings are O.K. just follow them...
3.+/-15v is cool, you'll lose some headroom due to the lower voltage rails,
i think around 1dB ...

1.pink: PSU
2.blue: jumpers that connect two boards together
3.green: audio input and output (to XLRs)

(http://www.syntech.co.yu/calrec.jpg)

hope this helps...
Title: calrec PQ1549 help thread
Post by: josh on March 10, 2008, 04:31:05 PM
I love you man.

I have an 18V toroid, but I bought it for my pico comp.  Do you suppose I should just get another one and use the heavier supply?  1db isnt much then again.....
Title: calrec PQ1549 help thread
Post by: syn on March 11, 2008, 04:10:33 AM
Josh

         Regulators will have plenty to regulate from, if you use 18V dual secondary toroid. From memory 1549 needs around 150mA per a chn.
Using that toroid will give you +/-18 VDC after a decent PSU (like jlm ac/dc or power station) just check its power rating...
Title: calrec PQ1549 help thread
Post by: josh on March 11, 2008, 08:44:55 AM
I built the mini-psu that gyraf posted.  It's p2p on verobaord so I hope it works.
Title: calrec PQ1549 help thread
Post by: syn on March 11, 2008, 11:00:22 AM
I think that you'll be regulating from ~25V down to 15V if you made the
PSU as on the Gyraf's schematic. 78/79-15 will need to drop ~10V and they might need heatsinks. You could change regulators for 18V version
of them and have less heat dissipation... Triple check as I don't use
78xx series and I’m not very familiar with their "real world" performance...
Title: calrec PQ1549 help thread
Post by: guitarmaker on March 11, 2008, 12:21:34 PM
I used the mini PSU and regulated to 18vdc no problem.

Steve
Title: calrec PQ1549 help thread
Post by: josh on March 14, 2008, 06:03:59 PM
I looked through the help thread but didn't see any explanation as to what this is?  
Can I really use it as an insert point with only 2 solder points?  
Am I to jumper those points for normal opertaion then?

What about the led.  Can I connect a regular led until I find one of those multicolor jobbies?  I'm not seeing which is + and which is - from the schemo though.  Anyone know?

I am 1 hour away from being done guys!
I would take a photo but some asshole stole our camera out of my wifes purse when she was at work the other day.  So that's a no-go.

Regarding the psu, I think I'll put some sinks on there, no biggie.
Title: calrec PQ1549 help thread
Post by: louder on March 14, 2008, 07:05:17 PM
Hi Josh
i don`t understand your first question.
as for the leds:
the led has 3 legs.the midlle leg goes to the midlle hole in the board.the other two legs ,one in one hole,and the other to the other hole.
best regards
pedro
Title: calrec PQ1549 help thread
Post by: josh on March 14, 2008, 07:34:23 PM
Hardy Har Har (http://www.therpgsite.com/forums/images/smilies/flop.gif)

I'm just going to assume you are drunk and are just checking to see that you can still type?  :sam:  :thumb:
Title: calrec PQ1549 help thread
Post by: josh on March 22, 2008, 01:06:57 PM
Ok everyone.
I am all done.  It's not working.  Now I am going to admit what I don't know so please be nice about it.  I don't know how to check voltages.  What points and what they are supposed to be.  

Can someone help me with this please?  I've never had to, so far my GSSL and G9 both worked upon first power up so I never had to try and look.

I really assume that my psu is mucked up because I built it on veroboard p2p and all.  It's a bit of a mess under there.  So, what voltages should I have coming out of the psu?  I did go ahead and use the 2x18V power toroid I had because I didn't want to order anymore parts right now.

As I mentioned above, I dont know what the "link or insert point" is supped to be, I jumpered those 2 points together since there was a line connecting them like all jumper points.  Is that correct?

And SYN!!!  that diagram was exactly perfect man, thanks alot for that.  It was exactly what I needed to know bro.   :thumb:
Title: calrec PQ1549 help thread
Post by: syn on March 22, 2008, 04:52:42 PM
Quote
As I mentioned above, I dont know what the "link or insert point" is supped to be, I jumpered those 2 points together since there was a line connecting them like all jumper points. Is that correct?

     
link is "link", can be used as the "insert point" to the calrec circuit.
correct.


good luck
Title: calrec PQ1549 help thread
Post by: Harpo on March 22, 2008, 06:07:32 PM
Quote from: "josh"
I really assume that my psu is mucked up because I built it on veroboard p2p and all.  It's a bit of a mess under there.  So, what voltages should I have coming out of the psu?  I did go ahead and use the +-15V power toroid I had because I didn't want to order anymore parts right now.

what is your transformers secondary? (+-15V power toroid doesn't make much sense, as a transformer is AC not DC). You'll need a 2x15V AC secondary or a 30VAC center tapped one (2x12,5VAC is the lower limit, 2x24,5V is the upper limit, producing lots of heat) to get a simple (without voltage doublers, ...) +/-15V DC supply, the calrec is asking for.
Assuming yours is a 30V center tapped transformer, your meter will read ~30V AC across the transformers outer secondaries. With the transformers center tap connected to 0 (or the connected inner windings of your dual secondary connected to 0), the 2 outer secondary wires connect to the AC leads of your bridge rectifier. Across your +/- leads of your rectifier you will measure about 40V DC or ~20V DC between +/0 and 0/- before the voltage regulators. Take care, that 78xx and 79xx have a different pinout and don't mount these regulators unisolated to the same heatsink as the metal sink of these have different potential. These regulators will need a load connected to their output to work properly. This can be eighter a resistor (maybe 1k5 resistor with led in series between +15V/0 and 0/-15V, indicating a current draw of 10mA for each rail) or your calrec or whatever circuit.
Title: calrec PQ1549 help thread
Post by: josh on March 22, 2008, 08:49:55 PM
Sorry Harpo, I'll stop casually throwing aroud terms I dont fully understand.  The voltages coming out of the PSU board are listed as +/-XX, not the toroid.

I'm using the Amveco 62054-P2S02  http://www.amveco.com/pdf/Amveco_Catalog.pdf#page=25
My mistake, it's a 2x18 power toroid.  

I haven't heat sunk the regulators yet.  I was going to have one of the guys at work make some custom sinks once I got everything working good.  I wont connect them.  I think I follow what you are saying about loading them, sort of....  
http://www.gyraf.dk/gy_pd/calreq/minipsu.pdf
do I need to make a change to this circuit?  I built it exactly as it shows and connected Red/Brown to 0, and Blue to AC and the Green to the other AC (does order mattter there?).  Coming out the other side I have Red/Yellow going to N, and Black/Violet going to the unmarked pin on the IEC.  Then I have the IEC gound running over to the Input XLR mounting bolt, and both Input XLR pin #1 are going to that bolt as well.  That's my star ground.

All this is correct, isn't it?

I would just post a picture, but someone stole our camera when my wife accidentally took it to her work.  We were supposed to go out and pick up another one tonight, but she's mad at me and we're not going anywhere.
Title: calrec PQ1549 help thread
Post by: louder on March 22, 2008, 09:18:47 PM
Hi Josh
forgive me for saying this,but i think from your description above,you need a ground connection for the ps.
shouldn`t you connect the 0v(rectified) to ground?
best regards
pedro
Title: calrec PQ1549 help thread
Post by: Harpo on March 22, 2008, 10:23:26 PM
from your datasheet reference your transformer wiering is Ok. (you can ohm it out to assure they didn't change their colour scheme) Assuming your transformer is working as shown your meter will read ~36V AC across the outer transformer secondary windings (blue/green). As long as no load is connected, this voltage is probably a little higher and it also will vary with different line voltages. This voltage (this is still AC voltage, so it doesn't matter if you reverse the blue and green secondary wire to your rectifiers AC pins, 50/60Hz later it will be the otherway round anyway) get rectified by a bridge rectifier, resulting in about 50V DC peak across the +/- pins of your rectifier (raw DC-voltage=AC-voltage * 1,414 - 2* 0,7V Diode drop). Between these +/- rectifier pins are your 1000uF reservoir caps, wired in series with your red/brown center tap/0 connection in the middle. (It won't work without this connection) Take care of orientation for these polarized caps. You almost have splitted your feeding raw DC voltage in about 2* 25V, the positive half feeding pin 1 of 7815, the negative feeding pin 2 of 7915. Connect pin 2 of 7815 and pin 1 of 7915 to 0. With connected load (your calrec or prementioned resistors) you will get +15V at pin 3 of 7815 and -15V at pin 3 of 7915 with reference to 0. These regulators will need a heatsink with previous quoted 150mA load per rail and burning 10V differential voltage between reg.in/out. A 100nF cap between close to regulators out and 0 improves stability and transient response, another one between close to reg.in and 0 may be needed if distance between reservoir cap and reg.in exceeds some inches. Although good practice, protection diodes across your reg.in/out and between reg.out and 0 are probably not needed.
Your star ground scheme seems correct. Make shure the IEC ground (safety ground) is always and safe connected to your case.

... now to your camera problem, ... :razz:
Title: calrec PQ1549 help thread
Post by: josh on March 22, 2008, 10:27:06 PM
Digesting.......

I will work on this and report back here with my findings.  Thanks so much for your help so far.
Title: calrec PQ1549 help thread
Post by: Harpo on March 22, 2008, 10:47:23 PM
You already have scrapped off the isolation paint at the wire ends of your transformer ?
Title: calrec PQ1549 help thread
Post by: josh on March 23, 2008, 12:43:37 AM
oh crap!  That's not pre-tinned ends?  That could be part of the problem my friend....

(http://www.therpgsite.com/forums/images/smilies/duh.gif)
Title: calrec PQ1549 help thread
Post by: Jonas K:strand on June 12, 2008, 10:17:03 AM
hi! im wondering if anyone can do some paintjob on the attached picture below. im not sure how to solder the audio ins and outs to the pcb. thank you! /jonas

http://www.pylons.se/kstrand/songs/calrec_eq.jpg
Title: calrec PQ1549 help thread
Post by: Harpo on June 12, 2008, 11:56:26 AM
Quote from: "Jonas K:strand"
hi! im wondering if anyone can do some paintjob on the attached picture below. im not sure how to solder the audio ins and outs to the pcb. thank you! /jonas

http://www.pylons.se/kstrand/songs/calrec_eq.jpg

maybe this way (http://www.hausverwaltung-heger.de/al_leck_trick/calrec_eq_wiering2.jpeg)
edit drawing see following post
Title: calrec PQ1549 help thread
Post by: Jonas K:strand on June 12, 2008, 06:16:30 PM
yes! maby that way. and the black wires circles means i connect it to both those pins aha? and the black cables are from the same ground point on the pcb? mhm? harpo. you are a kind person. /jonas
Title: calrec PQ1549 help thread
Post by: Harpo on June 12, 2008, 08:16:48 PM
Quote from: "Jonas K:strand"
yes! maby that way. and the black wires circles means i connect it to both those pins aha? and the black cables are from the same ground point on the pcb? mhm? harpo. you are a kind person. /jonas

? if you -not neccessarily- use shielded cable like cat-5 or mic cable, connect the shield to the pcb side only. If you don't use shielded cable but 2 single wires for xlr-pin2 to pcb +signal and xlr-pin3 to pcb -signal, drill these tightly together for each in/output, leaving the 0V pin in the middle of your in-/out pcb plug unconnected. Pin 1 of the xlr's connect to your case. Connecting your case/safetyground to supply-0V is a matter of taste. This drawing tidy up (http://www.hausverwaltung-heger.de/al_leck_trick/calrec_eq_wiering2.jpeg) hopefully makes it more clear.
Title: calrec PQ1549 help thread
Post by: Jonas K:strand on June 13, 2008, 08:00:35 AM
wow. thank you! and this is for balanced ins and outs? right?

/jonas
Title: Need help with my second Calrec.
Post by: living sounds on October 12, 2008, 06:20:40 PM
Hi everyone,

my first Calrec is working fine, but I've got a very hard time getting the second one to perform correctly. The PSU supplies voltage close to +/-15, which drops almost one Volt after the diodes. So all the opamps get +/-14V at the proper places, there's no detectable offset at any other pins. The unit passes audio, but the signal looses a little bass and much high end. What's even worse is that the low mid gain pot will change the gain of the whole signal, so much so that there is no output when turned all left. I've checked every connection multiple times, checked the components, changed some opamps etc. for more than half a day now and cannot find the problem. I read someone had a similar problem with a missing jumper, but those are all properly installed. Is there any obvious thing to look at from the schematics that would be in line with this outcome? Could the pots somehow be the wrong type (I checked them soldered in versus the ones in the second Calrec, and they behave the same). Is there an obvious component failure to check?

Thanks!
Gregor
Title: calrec PQ1549 help thread
Post by: living sounds on October 13, 2008, 10:44:57 AM
Anyone? I'm running out of options...
Title: calrec PQ1549 help thread
Post by: gyraf on October 13, 2008, 11:36:13 PM
If a single band's boost/cut pot affects overall gain instead of just the selected frequency range, then that band's filter isn't filtering.

Look at the schematic, compare to PCB, find and check the filter parts in question.

If you're absolutely sure there's no shorts (check with ohmmeter, not only by eye) - then look for order-of-magnitue errors in component values.

Jakob E.
Title: calrec PQ1549 help thread
Post by: living sounds on October 14, 2008, 10:34:57 AM
Thanks Jakob, I've found and adressed these problem(s) now. I had checked and eliminated all accidental connections before, but there were two bad solder joints. Turns out self-etching the boards for this build wasn't the best decision to make...

Anyway, this EQ sounds absolutely faboulus, better than anything else I've ever used, including my Pultec (which will get better inductors now). Thanks for this great project!

There is just one minor flaw left to fix with my Calrec: On one channel the amplitude is at unity gain although it should be at around +6 db at the output (like it is on the other channel) with a balanced connection. Both channels are identical in parts. The output is balanced (I've measured), but the ampitude is too low. The signal to noise ratio of this unit is 10 db worse than the other one, there's hum and a high frequency sine tone at 8 khz (at -82 db peak). It also adds a minimal high end (shelflike) boost vs. the bypass. I've tried to trace the signal to see where the loss might occur, but couldn't to it. My voltmeter won't show any AC on the opamp rails, either measuring between +/- on inputs and outputs or to ground when running a 1k sine wave through the circuit (which I can measure on the in- and ouputs). How can I determine at which part in the circuit the problem lies?

Thanks again!
Gregor
Title: calrec PQ1549 help thread
Post by: Harpo on October 14, 2008, 11:54:09 AM
Quote from: "living sounds"
On one channel the amplitude is at unity gain although it should be at around +6 db at the output (like it is on the other channel) with a balanced connection.

Hi Gregor,
did you measure only balanced (between +/- signal out) or between gnd/+ signal out and gnd/- signal out? For the 2nd option both measured values should be the same, case not, there may be a short between pin 1/2 of Op-amp BAL- or its connected traces, setting this inverter to a voltage gain of 0 (your missing 6dB). Just an idea.
Title: calrec PQ1549 help thread
Post by: living sounds on October 14, 2008, 12:15:54 PM
Harpo,

thanks for answering. The output is balanced correctly, with the measurement between ground and + or - reading exactly half of the measurement beween + and -. I'm trying to trace the problem in the signal path, but that's sorta tricky...
Title: calrec PQ1549 help thread
Post by: living sounds on October 14, 2008, 01:01:41 PM
Fixed it! There was another broken trace near the input. I'll never use a self-etched board for this kind of project again.

EQ sounds absolutely fabulous and the noise is around - 100db now. I've used 5532 for the (de)balancing and the low end and LM833 for the rest. Elma silmic II as electrolytics. Will post pictures and soundbytes soon.


Gregor
Title: Re: calrec PQ1549 help thread
Post by: Mylithra on November 13, 2008, 06:11:14 AM
Hi all,
Just had a quick BOM question.

6,8n/63V RM 7,5 or 10mm

is that 6.8nF or is it saying either a 6nf or 8nf may be used?

Also the BOM only specifies Poly. Is that polyester or Polypropylene
Title: Re: calrec PQ1549 help thread
Post by: gyraf on November 13, 2008, 08:04:44 AM
6,8nF always means six-point-eight nanoFarad
Title: Re: calrec PQ1549 help thread
Post by: Mylithra on November 13, 2008, 11:59:40 PM
Also the BOM only specifies Poly. Is that polyester or Polypropylene

Or does it even matter?
Title: Re: calrec PQ1549 help thread
Post by: gyraf on November 14, 2008, 12:29:22 AM
..if it really mattered, it'd be specified...

Jakob E.
Title: Re: calrec PQ1549 help thread
Post by: MrZpliff on November 14, 2008, 05:18:01 AM
A small, but a problem nontheless...

one of my calrec - channel is dead when BYPASSED .. when IN it works like dream  :)

I can't think of anything else than a broken bypass-switch or a broken trace on the pcb....

It's a little hard to pull it out of the rack... so any tip before I do it is most welcome.

Thank's
Title: Re: calrec PQ1549 help thread
Post by: Mylithra on November 14, 2008, 07:23:11 AM
Thanks Jacob,
I know it seems like a dumb question but Id rather be safe than sorry.
Title: Re: calrec PQ1549 help thread
Post by: Mylithra on November 19, 2008, 01:09:53 AM
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.
Title: Re: calrec PQ1549 help thread
Post by: Mylithra on December 01, 2008, 01:22:29 PM
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.)
Title: Re: calrec PQ1549 help thread
Post by: gyraf on December 02, 2008, 06:32:09 AM
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.
Title: Re: calrec PQ1549 help thread
Post by: raffaelebonetti on December 05, 2008, 02:51:13 PM
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
Title: Re: calrec PQ1549 help thread
Post by: Dr nEon on December 06, 2008, 06:34:56 PM
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.









Title: Re: calrec PQ1549 help thread
Post by: guitarguy12387 on December 09, 2008, 12:10:04 AM
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!
Title: Re: calrec PQ1549 help thread
Post by: Mylithra on December 10, 2008, 12:11:53 AM
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)
Title: Re: calrec PQ1549 help thread
Post by: Mylithra on December 15, 2008, 12:37:56 PM
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.
Title: Re: calrec PQ1549 help thread
Post by: Mylithra on December 25, 2008, 12:39:18 AM
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?
Title: Re: calrec PQ1549 help thread
Post by: gyraf on December 29, 2008, 06:30:03 AM
Check the PCB?
Title: Re: calrec PQ1549 help thread
Post by: Dr nEon on January 08, 2009, 05:44:36 AM

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
Title: Re: calrec PQ1549 help thread
Post by: Dr nEon on January 09, 2009, 10:17:43 AM

..any offers, guys?

sorry to bump!

nEon.
Title: Re: calrec PQ1549 help thread
Post by: Mylithra on January 09, 2009, 01:34:27 PM
I just wired pin 1 to the chassis on both input jacks on mine. I suppose the way you have it, its already floating.
Title: Re: calrec PQ1549 help thread
Post by: MatthewF on January 11, 2009, 08:22:29 PM
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;

(http://www.forbesart.plus.com/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
Title: Re: calrec PQ1549 help thread
Post by: Mylithra on January 12, 2009, 12:13:35 PM
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.
Title: Re: calrec PQ1549 help thread
Post by: Mylithra on January 16, 2009, 11:09:14 AM
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.

(http://goose-tracks.com/thegeekgoose/images/Caltop.jpg)
(http://goose-tracks.com/thegeekgoose/images/Calfront.jpg)
(http://goose-tracks.com/thegeekgoose/images/Calracked.jpg)
Title: Re: calrec PQ1549 help thread
Post by: lelabal on January 27, 2009, 08:30:05 AM
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
Title: Re: calrec PQ1549 help thread
Post by: lelabal on January 27, 2009, 08:35:26 AM
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?

(http://www.diyzone.net/images2/nc12-0221-15.JPG)
Title: Re: calrec PQ1549 help thread
Post by: 3nity on January 27, 2009, 09:36:34 AM
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...
Title: Re: calrec PQ1549 help thread
Post by: MatthewF on January 27, 2009, 09:51:12 AM
Hey Mylithra, that looks great!

I'm finishing off something very similar right now. Are those Omeg ECO pots you've used? If so, could you possibly tell me the Canford order numbers for the switches? The reason being that the Alps switches I have don't sit central in the holes on Purusha's case.

Cheers!

Matthew
Title: Re: calrec PQ1549 help thread
Post by: Mylithra on January 27, 2009, 11:35:14 PM
Heh.. Thanks..
Yes.. Those are Omeg Eco Pots, but the switches are the ALPs SPUN switches. And Yeah.. they dont line up 100% when the switches are soldered flush to the board. I ended up de-soldering them (Hakko 808 is a godsend), lining them up, then soldering them back in. The only thing I ordered from Canford for this was the push button caps. Those are the round ones made by Re'an.


Hey Mylithra, that looks great!

I'm finishing off something very similar right now. Are those Omeg ECO pots you've used? If so, could you possibly tell me the Canford order numbers for the switches? The reason being that the Alps switches I have don't sit central in the holes on Purusha's case.

Cheers!

Matthew
Title: Re: calrec PQ1549 help thread
Post by: lelabal on January 30, 2009, 01:06:11 PM
Hi there,
I've been working on my non-working board problem and I've discovered a strange behavior that might help finding the solution:

On the non-working board, when I power it up, I get signal for about 1 second, and then nothing. So I've tried to play around with the EQ controls and repower it: it's definitly wet well processed signal that show up for 1 second at each reboot ! So I guess the EQ works but for a short time and then nothing...

If it was a short-circuit or a bad solder issue, I would have no signal at all, even at the boot. Am I right ?

It can not be a PSU problem as the first board works perfectly.

Thanks for your time.
Title: Re: calrec PQ1549 help thread
Post by: briomusic on May 18, 2009, 04:19:52 PM
I finally got my CALREC eq to work (thanks to some hands-on help from a good friend) and I also noticed a jump in gain with all the band's level controls flat. as I quite like to have a gain control on an eq to compare with the untreated signal, I was thinking of inserting a dual gang pot instead of just changing the 10k resistors to 22k. so I tried the following mod:(http://img.photobucket.com/albums/v426/brio/calreclevelctrl.gif)
This allows me to have resistances from 10k-32k and to make up for moderate cuts and/or boosts. Is this kosher or am I comitting untold crimes on input impedances etc? if - due to pot tolerances - I have a different resistance on the plus and minus rails, what would the effect be?

ETA: I ended up using dual rev log 100k pots (instead of 22k) for the gain (same as the ones spec'd for frequency) to get the required range.
Title: Re: calrec PQ1549 help thread
Post by: gyraf on May 19, 2009, 03:42:27 AM
Quote
Is this kosher or am I comitting untold crimes

You mess a bit with the input CMRR because of the inherent tracking error of the pot, but if you don't need to feed it from long lines through noisy environments, I'd say it'll be fine...

You could make the series input resistors 4K7 in stead of 10K to get a larger gain range.

Let us know if it turns out right..

Jakob E.
Title: Re: calrec PQ1549 help thread
Post by: syn on May 19, 2009, 03:53:08 AM
...or use a 2deck MBB rotary switch. to keep CMRR happy, select the values of the resistors to match as close as possible...
Title: Re: calrec PQ1549 help thread
Post by: briomusic on June 06, 2009, 06:50:02 PM
sorry for question

is this a full parametric eq with variable "bell" /q
or a semiparametric eq?

thanks in advance
 ???

somewhere in between.... :P
the q is switchable between two alternative values for each of the four bands.
the narrower setting (higher q) is very 'notch-like' and IMO more suitable for cutting frequencies.
additionally the top and bottom bands can be switched to shelf, in which case the corresponding q button is inactive.

it's also a great sounding box  :)
Title: Re: calrec PQ1549 help thread
Post by: SIXTYNINER on June 07, 2009, 08:39:02 AM
briomusic thanks for post

by a first look this eq seem similar to standard eq ,
as default on soundcraft ts12-600-1600-2400....,DDA QMR,DMR.... ,  mackie 8 bus, allen & heat,soundtracs ,d & r......
"mid level" mixing consoles.....
i think if a "discrete opamp" as in api can replace the 5532 ic of this project
this eq can be very interesting....

Please: MR. jacob do you think it can be a good idea (and possible)try to developing this
good project with discrete opamp?

someone have just trYed to design a discrete opamp replacement for 5532?
thanks in advance
6T9R
Title: Re: calrec PQ1549 help thread
Post by: thedude on July 13, 2009, 07:18:39 PM
Hi! I've finished my calrec eq now and done some quick testing and everything seems to work. The only thing left now is the knobs!! Do anyone have any suggestions on some knobs for this baby?? It would be nice with some knobs that gives it an expensive look and feeling :). Have not found the buttons for the alps switches, where can i buy these?

At last i have a question about the power transformer. I've used a torroid from hairball audio, and mnats power supply board. Everything works fine and i get the right voltages and everything(+/- 18V DC) but when i measure from the center tap to ground i get 25v AC. I feel like i miss some basic knowledge about transformers?!?! Since the PCB "0" goes to the output will this bring any trouble in the next unit in the chain whit some current that might destroy something in other units. Im a little lost here and i think its important to fully understand theese things.

Cheers!
Title: Re: calrec PQ1549 help thread
Post by: Audioman on September 04, 2009, 03:14:13 PM
Hi All,
I have i question about the input connector of the calrec pq 1549 ,
I have see on the board labeled balanced input are use a two pin connector why ??
Can i take the zero volt from the output connector ???
Please let me know
Thank you all
Fabio
Title: Re: calrec PQ1549 help thread
Post by: Audioman on October 31, 2009, 09:35:32 AM
Hi All,
I have an electronic problem wit my Calrec eq on the hi frequency section
The problem is :
when i gain the max db on the pots hi frequency with the switch shelvin not pushing and the switch Q pushed the sound seems to be autooscillation and when you push the shelvin switch the problem disappear !!
i have no idea of  where is the problem but i have change all the tantalium and all the electrolitycs and all the ic's NE5532
I have ceck also all the soldering point and it was all ok no short
Please let me know if you have any idea
Title: Re: calrec PQ1549 help thread
Post by: SIXTYNINER on October 31, 2009, 10:03:02 AM
wrong resitor value?
any test "guide" with "voltages" ?
 :-\
Title: Re: calrec PQ1549 help thread
Post by: gyraf on October 31, 2009, 12:10:38 PM
No test guide with voltages available - wouldn't make sense.

Check and recheck resistor values.

For input ground, re-use output ground.

I don't think much will be gained by using a discrete opamp here - better reserve that for the Sontec-type circuits.

Jakob E.
Title: Re: calrec PQ1549 help thread
Post by: Audioman on October 31, 2009, 12:32:04 PM
Hi Guys,
Now i re-ceck all the resistor value and i cross my finger :-)
Then I tell you the result
Thank you for support !!!
Fabio
Title: Re: calrec PQ1549 help thread
Post by: Audioman on October 31, 2009, 04:54:28 PM
i'v re check all the resistors and the value are correct
Any idea ???
Let me know
thank you
Fabio
Title: Re: calrec PQ1549 help thread
Post by: Audioman on October 31, 2009, 05:30:01 PM
After some audio test in my studio the only problem on my calrec is :
only on the high frequency section when i gain max db at the highest frequency possible if i push the switcj Q the autooscillation appear and if turn down the frequency pot at 8k the autooscillation disappear !!!
Any idea ?????
let me know
thank you all !!
Fabio
Title: Re: calrec PQ1549 help thread
Post by: mks on January 22, 2010, 10:48:51 AM
So I finished stuffing the boards and built the PSU. My fear now is regarding the capacitor voltage ratings and would really appreciate some advice there. The PSU is the recommended 18v and I assembled the eq using the recommend 16v caps on the calrec. I've also read about the cap that would see 36V.

My questions are:
- Do I really need to replace every cap with a higher rating?
- or are there just a few caps that I need to replace (such as the one seeing the 36V)?
- or do I need to build a 15v power supply (even though a cap sitting across + and - would still see 30v)?

Any help would really be greatly appreciated as I didn't expect this problem with the BOM and silkscreening being incorrect.

Marc
Title: Re: calrec PQ1549 help thread
Post by: kazper on January 23, 2010, 05:35:35 PM
Option #1
Replace all 6 of the 22 uf caps to a voltage rating of 63V
Option #2 Replace the one near the shelve switch and power everything with 15V or less.

Good thing you reminded me, I need to replace some caps myself because of this on mine that I'm going to be finishing here real soon. I'll just order some 63V caps all around and call it good.
Title: Re: calrec PQ1549 help thread
Post by: mks on January 24, 2010, 09:29:00 AM
Thanks Kazper!

Glad my message was of some use too you too. Really good to have confirmation that it's only those 6 caps that need replacing and none of the other 16v caps. I was worried there were going to be more. Now I should have the build finally completed this week!

Thanks again and hope the build goes well for you,

Marc
Title: Re: calrec PQ1549 help thread
Post by: muffy1975 on March 04, 2010, 06:28:24 PM
For the dual 100k reverse log pots can you use dual 100k linear pots. What effect would this have?

Michael
Title: Re: calrec PQ1549 help thread
Post by: syn on March 05, 2010, 05:55:40 PM
Uneven distribution of frequencies through the wiper travel. You might or might not care. It will work.
You can buy 100k rev logs @ http://www.audiomaintenance.com/acatalog/potentiometers_carbon.html.
Cheers
Title: Re: calrec PQ1549 help thread
Post by: mokkinger on March 10, 2010, 12:36:42 PM
Hi Guys,

I finished my stereo calrec today... actually I bought the PCBs half done from someone, and they´re two different revisions of the PCB. but I don´t think this will really make a difference, no? (one is rev.4 and the other one is rev. 5)

so the rev. 5 works fine, sounds good from what I can tell after 5 min of testing;
The rev. 4 has a problem... bypass works, but when I switch the EQ on it only works for 4 seconds, then dies... I tried to measure all the currents, and hereby noticed that it works again for about 4 seconds if I short + and -... what is this?? i already checked for bad solder joints and connections, but didn´t find anything. could this be a broken capacitor or some reversed cap?

thanks for a hint!
Title: Re: calrec PQ1549 help thread
Post by: muffy1975 on March 14, 2010, 11:02:12 AM
Hey,

can you tell me if you did anything special when building the REV 5 Calrec? what is there to look out for and what are the common build problems when building these eqs?

Has anyone posted any build tips that work?

Michael

ps Mokkinger sorry to hear of your Eq trouble with Rev 4. Hope you get this fixed. Sounds like a reverse cap that's now damaged or a missing jumper. :-\

Can I ask you how you built the Rev 5? I am about to build one or two units and am worried that there is trouble ahead.
Title: Re: calrec PQ1549 help thread
Post by: syn on March 14, 2010, 12:11:58 PM
.... and am worried that there is trouble ahead.

Don't be, just build it as it is. A small mistake is reversed tantal on the silk, schematic is OK, I think
mid section-s.Also read the thread for the "balanced unity gain" resistor change. Even if you don't look at these small mistakes the unit will work, on power on.
Title: Re: calrec PQ1549 help thread
Post by: MatthewF on March 14, 2010, 03:22:45 PM
Indeed, I've built two channels with rev. 5 PCBs and both worked nicely. There's an issue with the voltage rating of one particular electrolytic cap which I've detailed on page 8 of this thread, but as Syn said, the boards work as they are - there isn't too much to worry about.

I ended up adding balanced line receive / drive boards on the input / output, but this was not a fault fix - it was actually necessary in my case to accommodate limitations of other kit connected before and after the EQ. If every source / load the EQ sees is balanced, all should be cool.

Matthew
Title: Re: calrec PQ1549 help thread
Post by: Jonas K:strand on March 30, 2010, 07:07:41 AM
hi! what is likley to have hapend if the 16V cap (the one that gets 30V) has blew?
what should i change first? any ideas? are some of those expensive tantalums probably broken now?

thank you for your help! /jonas
Title: Re: calrec PQ1549 help thread
Post by: gyraf on March 30, 2010, 07:17:43 AM
If you blew a tantalum cap, you probably reversed it's polarity. Put in a new one - observe correct polarity.

Jakob E.
Title: Re: calrec PQ1549 help thread
Post by: Jonas K:strand on March 30, 2010, 09:04:54 AM
hi! maby i was unclear... i ment the one that sits between +ve and -ve, written about on page 8 or so.
so nothing was placed the wrong way... only had to low voltrating... and blew! hmm...
how to think? where to start? thank you! /jonas
Title: Re: calrec PQ1549 help thread
Post by: gyraf on March 30, 2010, 10:52:22 AM
just replace with a 50v-type, and try again...

Jakob E.
Title: Re: calrec PQ1549 help thread
Post by: muffy1975 on April 04, 2010, 09:41:37 AM
Hi All,

OMG it has worked first time. I used 16V tantalums and the electrolytics were

22uf 63v
47uf 50v
100uf 25v

At the moment I am giving the unit 16volts. Can I give it 18V with my capacitor choices?

I followed the overlay for the polarity of the caps and have had no problems.
Where there wasn't a + on the PCB I presumed that the hole was covering the + sign up.

Thanks team for a nice sounding eq. Every bit as good as my TC Electronic parametric.

XOX
Title: Re: calrec PQ1549 help thread
Post by: juanjovincenzo on April 09, 2010, 01:54:33 AM
Hi guys!

two simple questions!

1.-For Calrec EQ PQ1549. what is the best opamp: LM833 or NE5532??? and

2.- The PCB Layouts Rev # 4 http://gyraf.dk/gy_pd/calreq/calreq.pdf (http://gyraf.dk/gy_pd/calreq/calreq.pdf), the copper PCBs are 100% functional to self-etch?

and thanks Jakob for this DIY thread

PD:Please, Jakob maybe you have the PDF file of the PCB copper layout of your Gyraf 4x Intrument Splitter to self etch??? if is possible to post it?  and Is your Tube HeadPhonesAmp DIY Project http://www.gyraf.dk/tmp/Tube_headphoneamp.pdf
 (http://www.gyraf.dk/tmp/Tube_headphoneamp.pdf) 100 %  functional?

Thanks again

Mucha suerte
Best regards
chao
Juanjo
Title: Re: calrec PQ1549 help thread
Post by: gyraf on April 09, 2010, 03:57:56 AM
1.-For Calrec EQ PQ1549. what is the best opamp: LM833 or NE5532??? and

2.- The PCB Layouts Rev # 4 http://gyraf.dk/gy_pd/calreq/calreq.pdf (http://gyraf.dk/gy_pd/calreq/calreq.pdf), the copper PCBs are 100% functional to self-etch?

3 - Please, Jakob maybe you have the PDF file of the PCB copper layout of your Gyraf 4x Intrument Splitter to self etch??? if is possible to post it?  

4 - Is your Tube HeadPhonesAmp DIY Project http://www.gyraf.dk/tmp/Tube_headphoneamp.pdf  (http://www.gyraf.dk/tmp/Tube_headphoneamp.pdf) 100 %  functional?

1 - I like the LM833 for this.
2 - The Calr-eq PCB's are checked and working (the same files are used for the OEM PCB-service)
3 - The 4x instrument splitter never had a layout - the circuit is simple enough to just mount on a piece if stripboard/veroboard
4 - The Tube headphone amp: The circuit is known working, but I haven't tried using the PCB's. It should be simple enough to get working - If you use them, please report back!

Jakob E.
Title: Re: calrec PQ1549 help thread
Post by: juanjovincenzo on April 09, 2010, 01:31:22 PM
Thanks JaKob I will try with the LM833!!
best regards
Juanjo..
Title: Re: calrec PQ1549 help thread
Post by: JBVries on April 09, 2010, 05:42:16 PM
I'm having a heck of a time finding 63v polyester caps, can I use a higher voltage rating? It won't hurt the integrity of the EQ will it? Thanks.

-JB
Title: Re: calrec PQ1549 help thread
Post by: syn on April 10, 2010, 03:54:55 AM
63V is a common value, but yes, you could use larger if they can fit (space) on the board. Farnell, Digikey, Mouser should have those. Farnell sells Wima MKS series...
Title: Re: calrec PQ1549 help thread
Post by: muffy1975 on April 22, 2010, 07:27:27 AM
Team,
 ;D

I have 2 channels working straight off the bat. Tight.

I would like to correct the 10k input resistors but I see there are 4 10k resistors connected to the input IC. Which are the two that are in series? IS it the two 10k resistors on the far left of the schematic that are connected also directly to the 47uf caps.

Don't want to change the wrong ones.

Help me ???

Thanks in advance

Michael

Title: Re: calrec PQ1549 help thread
Post by: muffy1975 on April 22, 2010, 07:32:38 AM
I finally got my CALREC eq to work (thanks to some hands-on help from a good friend) and I also noticed a jump in gain with all the band's level controls flat. as I quite like to have a gain control on an eq to compare with the untreated signal, I was thinking of inserting a dual gang pot instead of just changing the 10k resistors to 22k. so I tried the following mod:(http://img.photobucket.com/albums/v426/brio/calreclevelctrl.gif)
This allows me to have resistances from 10k-32k and to make up for moderate cuts and/or boosts. Is this kosher or am I comitting untold crimes on input impedances etc? if - due to pot tolerances - I have a different resistance on the plus and minus rails, what would the effect be?

ETA: I ended up using dual rev log 100k pots (instead of 22k) for the gain (same as the ones spec'd for frequency) to get the required range.


IS it the the two 10K resistors before this chaps idea of the 22k pot?
Are these the two 10K resistors that are also directly connected to the 47uf caps?

Michael
Title: Re: calrec PQ1549 help thread
Post by: Harpo on April 23, 2010, 04:01:44 PM
IS it the the two 10K resistors before this chaps idea of the 22k pot?
Are these the two 10K resistors that are also directly connected to the 47uf caps?
Yes. Increasing resistance lowers gain of this stage.
With Rin varying between 10K and (10K+22K rev.log stereo pot=32K) this diff.amp has gain varying between 0dB and -10.1dB.
With Rin varying between 10K and (10K+100K rev.log stereo pot=110K) gain range is varying between 0dB and -20.8dB.

Rearranging some connections giving gain varying between +/-10.1dB (with 22K lin stereo pot) or +/-20.8dB (with 100K lin stereo pot), keeping 0dB unity gain at pot center. Linear taper stereo pots have far better tracking and are easier to source than stereo pots with negative logarithmic taper, if you want to go this route (but CMRR will still be degraded).
(http://www.hausverwaltung-heger.de/al_leck_trick/calreclevelctrl_edit.gif)
Title: Re: calrec PQ1549 help thread
Post by: jyrki3101 on April 29, 2010, 01:45:01 PM
HI, I'm a little concerned about my standard Alpha(pcb) 16mm pots that I'm planning to use in my calrec EQ. Are those good enough in quality for this project?
I've been tryin to contact Omeg for pots that others have used, but haven't got any response from their company! Also, On their web page those ECO? pots has so MANY options for bush, shaft and spindle types, and I cant figure out the exact specs for the pots. That's why I can't make an order from Omeg.
IF someone has those pots (left overs) on the shelf, I would really like buy !!!  But kind of help would be greatly appreciated !
P.S Just wondering , Is there another company that sells Omeg pots for calrec EQ ?
With Kind Regards, jyrki3101
email:  [email protected]
 
Title: Re: calrec PQ1549 help thread
Post by: muffy1975 on April 29, 2010, 01:54:18 PM
HI,

alpha pcb pots are fine in my opinion and those cheap rev log pots from ebay ( 10 for £10 ).
The alpha pots have a great action too!

Michael

ps check out the sontec EQ if yo want a real quality eq unit
Title: Re: calrec PQ1549 help thread
Post by: syn on April 30, 2010, 01:51:20 AM
HI, I'm a little concerned about my standard Alpha(pcb) 16mm pots that I'm planning to use in my calrec EQ.

jyrki3101
             just use them, if they are in working order.They are good as any.
Title: Re: calrec PQ1549 help thread
Post by: jyrki3101 on May 01, 2010, 10:40:13 AM
HI, I'm nearly finished with stuffing the boards on my dual calrec EQ.
But just one more question , or someones opinion about this issue.
I noticed some differencies(like some other members too) between the schematic and Pcb layouts(gyraf). A couple of 22uF el.caps and 33uF tants are reversed in the pcb layout.
SO, WHICH ONE SHOULD I FOLLOW, SCHEMATIC OR LAYOUT ???
With kind regards, jyrki3101
Title: Re: calrec PQ1549 help thread
Post by: muffy1975 on May 02, 2010, 10:04:52 AM
Read through the thread. It's there I promise
 ;)

Title: Re: calrec PQ1549 help thread
Post by: musicman4327 on July 25, 2010, 01:39:41 AM
Howdy all.  I am modifying the 1549 slightly and have a question about the design.  I am guessing the extra 100nF caps are for power stabilization for the IC's but my question is how/where do these go.  Should I bridge them between the + and - DC pins or inline or what?  I know they have to be within 1/2" of the IC I just don't know how to put them in.

Also, seems Mouser don't have LM833's in stock.  Any place that might have 'em?
Title: Re: calrec PQ1549 help thread
Post by: spongebob on October 14, 2010, 08:04:03 PM
hey there,

builded mine with alpha rev-log pots. c-curve....but the scale of frequencies is expotetial.....30 to 50 hz till the middle of the pot and 50 to 450 from the middle to end....is that normal? or did they sold me linear pots?

Title: Re: calrec PQ1549 help thread
Post by: Bonke on October 26, 2010, 11:10:05 AM
Hi all!
I have just finished a single calrec eq. There is something wrong without a doubt. I was wondering if you guys could guide me in the right direction?
In bypass mode audio passes through just fine.
When eq is on it sounds distorted, the sound fades away and comes back.
When I enable the switch on "Lo-Mid freq" and turn the gainpot it sounds like an old MOOG or something.  :-\

You can here two recordings of the eq here: http://web.me.com/bedahenke/Stuff/stuff.html (http://web.me.com/bedahenke/Stuff/stuff.html)

Henrik

Title: Re: calrec PQ1549 help thread
Post by: Bonke on October 27, 2010, 06:27:08 AM
By the way, is this correct?
(http://web.me.com/bedahenke/Stuff/calrec_PSU_files/Skarmavbild%202010-10-27%20kl.%2012.06.16.jpg)
Title: Re: calrec PQ1549 help thread
Post by: Harpo on October 27, 2010, 06:37:28 AM
Join yellow and blue with 0V/center tap. Red and gray connect to the AC mounting holes.
Title: Re: calrec PQ1549 help thread
Post by: Bonke on October 27, 2010, 06:49:29 AM
Thanx a bunch! :D
Title: Re: calrec PQ1549 help thread
Post by: Bonke on October 27, 2010, 07:17:24 AM
What have I destroyed if I wired as mentioned above?  ???
Could that be the solution to my distortion-problem?

Have to get moving to the studio to check it out!

Henrik
Title: Re: calrec PQ1549 help thread
Post by: Harpo on October 27, 2010, 07:45:16 AM
What have I destroyed if I wired as mentioned above?  ???
probably nothing, worst case the transformer.
Be aware, this transformer now will hate you for the next couple of days and will induce a whispering
'this guy wanted to fry me. Don't buy his records'
to every recorded track running thru connected boards. :o ;D
Title: Re: calrec PQ1549 help thread
Post by: Bonke on October 27, 2010, 08:09:40 AM
I will rub it in some nice warm Deoxit and give it a massage. Hopefully it will forgive me! :D

Henrik
Title: Re: calrec PQ1549 help thread
Post by: Bonke on October 27, 2010, 01:51:10 PM
I solved my distortion/oscillation problem. ;D
Title: Re: calrec PQ1549 help thread
Post by: gyraf on October 28, 2010, 05:52:09 AM
I solved my distortion/oscillation problem. ;D

Any details (to help others in a similar situation later?)

Jakob E.
Title: Re: calrec PQ1549 help thread
Post by: cromwell on October 28, 2010, 08:19:08 AM
Hey guys,

sorry but I didnt find it, where can I find the Rev. 5 Layout for selfetching.

Thanks for your help.

Cromwell
Title: Re: calrec PQ1549 help thread
Post by: gyraf on October 28, 2010, 08:58:48 AM
rev#4 is the newest - http://www.gyraf.dk/gy_pd/calreq/calreq.pdf

If there is a #5(not sure), it might just be a slight adaptation for manufacturing..

Jakob E.
Title: Re: calrec PQ1549 help thread
Post by: Bonke on October 29, 2010, 10:32:13 AM
I solved my distortion/oscillation problem. ;D

Any details (to help others in a similar situation later?)

Jakob E.

I can not post!!!!!!!!
Tried a thousand times.
Title: Re: calrec PQ1549 help thread
Post by: Bonke on October 29, 2010, 10:33:27 AM
I can only post one or two lines otherwise there is an error. Maybe I have to split it up. Thats why I couldnt post my full answer.
Title: Re: calrec PQ1549 help thread
Post by: Bonke on October 29, 2010, 10:35:35 AM
My problem was a couple of fried ICs and a solderbridge. I swapped all LM833 to 5532 and all bands except hifreq worked.
Title: Re: calrec PQ1549 help thread
Post by: gyraf on October 29, 2010, 10:36:27 AM
..there currently is a database-problem with exotic characters in posts...

Jakob E.
Title: Re: calrec PQ1549 help thread
Post by: Bonke on October 29, 2010, 10:37:36 AM
Then I found the solderbridge near the hifreq pots and the oscillation was gone. Changed back to LM833 on the hifreq board.
Title: Re: calrec PQ1549 help thread
Post by: Bonke on October 29, 2010, 10:38:47 AM
Anyone who has any thoughts about different ICs in this great Gyraf project? Sorry about all the posts.
Henrik
Title: Re: calrec PQ1549 help thread
Post by: Bonke on October 29, 2010, 10:40:55 AM
..there currently is a database-problem with exotic characters in posts...

Jakob E.

Yes but i tried without any exotic characters whatsoever. Anyway, now my answer is there in 10 different posts.  ;)
Title: Re: calrec PQ1549 help thread
Post by: Bonke on October 30, 2010, 05:19:27 AM
Can somebody please confirm if these are the ones to change to 22kOhm for unity gain?
(http://web.me.com/bedahenke/Stuff/calrec_unity_gain_files/Skarmavbild%202010-10-30%20kl.%2011.13.59.jpg)
Henrik
Title: Re: calrec PQ1549 help thread
Post by: Harpo on October 30, 2010, 06:42:31 AM
Can somebody please confirm if these are the ones to change to 22kOhm for unity gain?
Yes, change both to 20k for a balanced out config.
Title: Re: calrec PQ1549 help thread
Post by: Bonke on October 30, 2010, 04:53:05 PM
Nice!
Thanks alot Harpo!

Henrik
Title: Re: calrec PQ1549 help thread
Post by: Graph on July 05, 2011, 09:50:29 AM
Hi, i am planning to build a stereo diy Mastering, Calrec, since its four bands i guess it can be used pretty well.

For this i need 2 channels in stereo connection, i guess this would be quite easy using instead of 2 gangs potentiometers, 4 gangs(2 for each channel) so adjusting channel 1 will affect channel 2 if channel 2 is linked to channel 1 potentiometers. The same with all switches and other pots.

The problem is i cant find correct 4 gangs of 100k neg log values. Audio maintenance is selling 4 gang 47k and 470k 4 gangs, will these give inaccurate frecuency response and should try finding a 100k 4 gangs neg log pot from another store?

Thank you!
Title: Re: calrec PQ1549 help thread
Post by: gyraf on July 05, 2011, 10:09:17 AM
It is VERY hard to find quad-matching pots accurate enough for this purpose.

The only probable route may be switched resistors on a quad deck switch..

Jakob E.
Title: Re: calrec PQ1549 help thread
Post by: Graph on July 05, 2011, 10:32:41 AM
It is VERY hard to find quad-matching pots accurate enough for this purpose.

The only probable route may be switched resistors on a quad deck switch..

Jakob E.

Okey, but are there any inexpensive switch(like lorlin rotative) which can give like 4/6 positions with 4 poles? or should i consider using relays?

Thanks jakob!
Title: Re: calrec PQ1549 help thread
Post by: gyraf on July 06, 2011, 01:12:00 AM
No, not that I'm aware of - it's one of those things that can't be done on a budget.

Though maybe the uraltone switches mentioned somewhere around here are available in 4x23?

Jakob E.
Title: Re: calrec PQ1549 help thread
Post by: briomusic on July 06, 2011, 04:13:26 AM
No, not that I'm aware of - it's one of those things that can't be done on a budget.

Though maybe the uraltone switches mentioned somewhere around here are available in 4x23?

Jakob E.

There are indeed:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=260693714311&ssPageName=STRK:MEWAX:IT#ht_1449wt_702 (http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=260693714311&ssPageName=STRK:MEWAX:IT#ht_1449wt_702)
Have used two of his 2-poles for output level in my TG-1 built, where they have been working fine for over a year now, but I have no idea what kind of contact materials are used.
Title: Re: calrec PQ1549 help thread
Post by: gyraf on July 06, 2011, 10:28:13 AM
They're decent enough (if still the same, made by the same company) - silver-on-bronze.

Jakob E.
Title: Re: calrec PQ1549 help thread
Post by: Graph on July 07, 2011, 12:33:08 PM
Greeat! Thank you jakob and briomusic!

Title: Re: calrec PQ1549 help thread
Post by: Graph on September 01, 2011, 07:22:03 PM
Greeat! Thank you jakob and briomusic!
I am about to order rotary switches, latching, resistors & PCBs.

10k linear pot, should i use dual 10% 10k linear for stereo? or i will need 1% resistances too in a 2pole?

Thanks for all the help
Title: Re: calrec PQ1549 help thread
Post by: G-Sun on November 29, 2011, 01:41:59 PM
Where do I find a psu-pcb with bom for a 2ch Calrec?
Title: Re: calrec PQ1549 help thread
Post by: gyraf on November 30, 2011, 12:02:18 AM
Any 2x15-18V/100mA powersupply will do fine for the Calreq - make that 200mA for a stereo version.
Title: Re: calrec PQ1549 help thread
Post by: G-Sun on November 30, 2011, 03:01:14 PM
Any 2x15-18V/100mA powersupply will do fine for the Calreq - make that 200mA for a stereo version.
Thanks!
I have many questions, and don't feel I understand enough yet. Please see:
http://www.groupdiy.com/index.php?topic=46750.msg586962#msg586962
What would be a typical choice? (Farnell)

Edit: I guess I'll go for an JLM AC/DC Ver. 4 kit :)
Title: Re: calrec PQ1549 help thread
Post by: G-Sun on December 01, 2011, 01:47:24 PM
I'm planning my complete part-list. One thing I don't understand:
Looking at the front-panels here: http://www.groupdiy.com/index.php?topic=756.msg10112#msg10112
It seems like the Calrec has four bands
I intended to by a case from Purusha http://www.diy-racked.com/diy-talk/viewtopic.php?f=7&t=18
But his cases are five-band.
What's the correct bom/ pcb / case combination?
Title: Re: calrec PQ1549 help thread
Post by: G-Sun on December 07, 2011, 09:43:29 AM
Is this the right pot for the Calrec eq?
http://www.audiomaintenance.com/acatalog/om-01-072_extended_info.html

Another question:
I see Purusha is selling cases for a 2ch Calrec with 5 bands. What pcbs and bom is for that one?
Edit, found this : http://www.groupdiy.com/index.php?topic=27972.0 :)

A feature question:
Does the Calrec have HPF? Or is the lower band shelving/peak?
Is there a list of Q and band-types somewhere?

Thanks!
Title: Re: calrec PQ1549 help thread
Post by: pedroplanet on December 09, 2011, 09:23:50 AM
Quote
Another question:
I see Purusha is selling cases for a 2ch Calrec with 5 bands. What pcbs and bom is for that one?
Edit, found this : http://www.groupdiy.com/index.php?topic=27972.0

that's the sontec case, not calrec
Title: Re: calrec PQ1549 help thread
Post by: G-Sun on December 09, 2011, 01:42:35 PM
that's the sontec case, not calrec
Ahh thanks! Didn't notice the name difference..
Is it much different in design and sound from the Calrec?
Title: Re: calrec PQ1549 help thread
Post by: Lucin Niega on December 15, 2011, 05:45:17 AM
Does anyone have the pcbs for this project that they would be willing to part with? I want to build a single channel.
Title: Re: calrec PQ1549 help thread
Post by: G-Sun on December 15, 2011, 05:49:36 AM
Does anyone have the pcbs for this project that they would be willing to part with? I want to build a single channel.
http://www.groupdiy.com/index.php?topic=10776.0
Title: Re: calrec PQ1549 help thread
Post by: Lucin Niega on December 15, 2011, 06:37:45 AM
Does anyone have the pcbs for this project that they would be willing to part with? I want to build a single channel.
http://www.groupdiy.com/index.php?topic=10776.0

Thanks! 
Title: Re: calrec PQ1549 help thread
Post by: dBDawg on January 10, 2012, 05:35:36 PM
Hi guys. I'm new to the thread and somewhat to DIY. I recently built the calrec 1549 project, but put it in a API-500 series format. (yes, I dished out some $ here, but what the hell, why not go for it) Everything works fine but it is noisier than expected. I used the schematic but didn't look over the PCB close enough and noticed there's some components I didn't include, i.e.

1) the diodes (I'm concerned now. I can't logically figure out why there there but don't want to dismiss them)
2) all the 100n and 22u caps grounded to the power rails

3)In addition to that I added an op amp just for ease of layout.

I realize the pwr voltage is slightly lower, but didn't think it would attribute to noise like this. Am I wrong? Other than problems attributed to trace layout, any ideas as to helping with the noise problems? All the above?

Thanks in advance for any help.


Take it easy and if it's easy take it twice.

Title: Re: calrec PQ1549 help thread
Post by: gyraf on January 11, 2012, 11:13:43 AM
Quote
2) all the 100n and 22u caps grounded to the power rails

You will need these - this circuit likes to oscillate if local supply power is not kept calm

Maybe try hanging them on the underside of the PCB from each of the IC's power supply pins to ground?

Jakob E.
Title: Re: calrec PQ1549 help thread
Post by: ricardo on January 11, 2012, 11:01:00 PM
Quote
2) all the 100n and 22u caps grounded to the power rails

You will need these - this circuit likes to oscillate if local supply power is not kept calm

Maybe try hanging them on the underside of the PCB from each of the IC's power supply pins to ground?
Second that.  It's likely your "noise" is hash from oscillation & marginal stability.
Title: Re: calrec PQ1549 help thread
Post by: ncoak on February 21, 2012, 02:49:09 PM
hey folks,

i have a quick question - i'm building a single channel unit, using toggles instead of pushbutton switches for both q and bypass/shelving switches. mostly for aesthetics :)

i've figured how to wire them and all (off board), just wanted to verify that the pots/switches are not in the audio path in this sort of design - i.e. that the quality of the pots/switches, and the wire connections to the board i'll be making won't affect the sound. i should be able to use no-frills unshielded ribbon cable for these connections without any issues, correct?

i'm assuming that since it's ic based, the pots are simply adjusting the control voltage to the chips...however i'm not at the point where i can really study the schemo/pcb layout and fully comprehend what's going on, but i'm getting there (i think)...

any insight would be greatly appreciated!

thanks
Title: Re: calrec PQ1549 help thread
Post by: Harpo on February 21, 2012, 06:37:49 PM
.. just wanted to verify that the pots/switches are not in the audio path in this sort of design ..
Except your mains power switch every pot and switch in this design is in the audio path.

Quote
i'm assuming that since it's ic based, the pots are simply adjusting the control voltage to the chips
Your audio signal is the voltage that this state-variable-filter design responds to. This is not a VCF or switched cap design. The ICs used in this design are opamps (a bunch of transistors, diodes, caps and resistors built by a piece of silicone chip).
Title: Re: calrec PQ1549 help thread
Post by: ncoak on February 21, 2012, 06:51:52 PM
ah, i see - that was the impression i was getting by following the signal path, but i figured i must have been mistaken. guess i wasn't!

thanks very much for clearing that up.
Title: Re: calrec PQ1549 help thread
Post by: dBDawg on February 28, 2012, 10:35:07 PM
Here's my version of the 1549, 500 style.

Thanks for the help guys
Title: Re: calrec PQ1549 help thread
Post by: ncoak on February 29, 2012, 12:39:19 AM
very nicely done!
Title: Re: calrec PQ1549 help thread
Post by: ncoak on May 27, 2012, 02:38:47 PM
hey folks,

just wrapping up my calrec, everything seems to be working as planned - dead quiet and boosting/cutting as expected. only issue is the frequency distribution; i used (what i believe to be) 100k revlog pots as specified, the ranges are spot on for each band (30-470Hz, 180-2.3kHz, etc.)...but i get much more resolution in frequency selection at the ccw end of the pot turn - at the cw end there is virtually none. for example, in the high mid band, 7.5kHz is about a half millimeter turn away from 5kHz...slightly problematic!

it seems all the frequency pots display this behavior - is it possible there is something i've slipped up on circuitwise, or more likely i was sold some phony revlogs?

outside of that it works/sounds great, really looking forward to putting it to use.

thanks for any tips!

Title: Re: calrec PQ1549 help thread
Post by: ncoak on May 27, 2012, 08:40:24 PM
here are a few pics:

(http://www.analog-to-digital.net/SANY0453B.jpg)

as you can see opting for toggles and off board pots complicated things a bit  ;)

(http://www.analog-to-digital.net/SANY0455B.jpg)

mounted the pcb upside down to facilitate a left-to-right/low-to-high layout - this introduced an interesting wiring dilemma - i opted to flip the back panel of the case as well, running the power switch lines under the xlrs but keeping the in/out audio cables shorter. if i were to do it again i'd likely go with the original layout.

the psu was my first attempt at a self-fabricated circuit, mounted it upside for easy access just in case...works like a charm.

(http://www.analog-to-digital.net/SANY0458B.jpg)
Title: Re: calrec PQ1549 help thread
Post by: gyraf on May 29, 2012, 05:39:17 AM
Beauty!
Title: Re: calrec PQ1549 help thread
Post by: ncoak on May 30, 2012, 01:34:57 AM
thanks jakob! using it in my vocal chain, sounds great. fun and easy build and learned a lot along the way...really appreciate the work you've done making these projects available.

assuming everything else on the board is up to spec, is it safe to assume i have some mislabeled c100k pots? can't think of any other explanation with regards to the freq distribution issue, unless i'm missing something. guess i'll pick some up from another source and plug them in...glad i used the screw terminals  ;)
Title: Re: calrec PQ1549 help thread
Post by: ricardo on May 30, 2012, 03:25:37 AM
.. is it safe to assume i have some mislabeled c100k pots?
Unsolder the pots and measure the resistance from each end with the pot set to 50%.  Compare this to a good volume control pot which should be Log.
Antilog pots will have the high & low resistance the other way round compared to a Log pot.
Title: Re: calrec PQ1549 help thread
Post by: pedroplanet on June 09, 2012, 10:27:26 AM
Does anybody have a front panel layout that could share with me?
I searched the forum and all the links are broken  :-\
Title: Re: calrec PQ1549 help thread
Post by: mariaaudiodesign on August 22, 2012, 05:54:36 PM
Hello Guys... I have a big problem whit my 1549 EQ...
I'll Check Thousands times the PCB and shematic... for  I don't see it the problem...
Hi and Lo section is not working...
LO section Work Like minimoog or something....
Hi section no change absolut anything... I will reed all forums...

Please...
Can you tell me Rev. 4 does it work...

Thank you!!!
Title: Re: calrec PQ1549 help thread
Post by: gyraf on August 23, 2012, 12:28:31 AM
Rev. 4 works.

oscillation is a common problem - reported several times in this thread. My guess is wrong component, bad solder, or broken copper track...

Jakob E.
Title: Re: calrec PQ1549 help thread
Post by: audiophreak on January 23, 2013, 12:54:21 PM
Helloooo   ;D

   Would some kind soul verify that AL-03-001 and AL-03-005 switches from AML are the ones for this project ??

  Thanks,
              Chip
Title: Re: calrec PQ1549 help thread
Post by: audiophreak on March 05, 2013, 06:58:46 PM
Hi All  ,
         Here is a  2u face plate graphic in Illustrator I've done for this project , waiting for some shelve / Q symbols from braeden here - http://www.groupdiy.com/index.php?topic=51403.msg654531#msg654531

   or I may just try my hand at it  ;D    just posting to get some feedback / suggestions , I will post the Illustrator file once I've  verified it works and all  measurements and clearances are correct.

  its has pieces of a graphics from benlindell and Scale-O-matic
 
Title: Re: calrec PQ1549 help thread
Post by: Junction on March 18, 2013, 07:29:09 AM
Audiophreak, are you intending on doing a front panel from this artwork, I need a panel myself and wonder if you would do an additional one?
Cheers
Michael
Title: Re: calrec PQ1549 help thread
Post by: audiophreak on March 18, 2013, 05:53:47 PM
Hi Junction,
                I dont produce the panels myself,  I'm doing this artwork graphic but I send the Illustrator file to Chae a Prodigy Engineering here - http://www.groupdiy.com/index.php?topic=43688.0 - along with my Par metal case front panel for Laser engraving , and I Drill the holes myself.
    When I finish this graphic I'll post it and the Illustrator file here for all.
Title: Re: calrec PQ1549 help thread
Post by: positrons on April 24, 2013, 05:37:07 PM
Hi everybody :
this is my first post and this is my first project .my Calreq EQ dos not work and I need your help.
I am completely novice in electronics and if I ask some simple questions, it is because of that and thank you to all of you.
also my English is not good and I am sorry about that, I am trying to improve it.

ok, at first I should said that the problem is when I push the bypass button to activating EQ , I dont have any sound and I only have some kind of noise like woooooooo!!!!!
I dont know I should start finding mistakes from where !!!I checked all part of PCB and I found 3 extra shorts connections and I fixed them but it is steel has the WOWWW sound instead of music.

please tell me, what can I do for finding problems ??any voltage measurement ??where?? testing resistors, Caps and ICs ???is it possible to say voltage of every pin of ICs and I check it to know that witch part has problem??

I made power supply board with 7918 and 7818 and in my output of power supply, I have 17.5 DC voltage .has it any problem or it is ok??
Title: Re: calrec PQ1549 help thread
Post by: gyraf on April 26, 2013, 11:37:36 AM
Should work from +/-10V and up to +/-18V.

Try tracing signal through the circuit - look at the schematic - and find the place(s) where you loose your signal. Then check for component integrity, traces and soldering around that area.

Jakob E.
Title: Re: calrec PQ1549 help thread
Post by: positrons on April 27, 2013, 03:56:13 PM
Should work from +/-10V and up to +/-18V.

Try tracing signal through the circuit - look at the schematic - and find the place(s) where you loose your signal. Then check for component integrity, traces and soldering around that area.

Jakob E.

Thank you jakob for your answer,I found something in circuit that I cant understand it from schematic.in my circuit ,these three area are connected too each other when I test it with multimeter(Red,green,Blue) therefor ( 0 and B-) will be connect to each other.it should be like this or there is a problem here??I checked soldering very carefully around here and  22u cap and 100K resistor, both of them are OK .....(http://upload7.ir/images/07979203070969634222.jpg)
Title: Re: calrec PQ1549 help thread
Post by: gyraf on April 28, 2013, 08:50:26 AM
You can see it from the layout: red and blue are (and should be) connected. Green should NOT be connected to these..
Title: Re: calrec PQ1549 help thread
Post by: audiophreak on May 01, 2013, 10:13:05 PM
Hi All,
     This is the latest revision of my 2U dual Calrec EQ front panel , I'm sending this out soon for laser engraving, all questions, comments welcome , "Q" and shelving graphics I had to make in Illustrator and buttons are Alfa 10.3mm dia.  , cut/boost and freq. graduations are for 3/4 inch  ( .750 ) dia. knobs.
 
Title: Re: calrec PQ1549 help thread
Post by: gyraf on May 02, 2013, 12:47:01 AM
Looks very good indeed.

1 - you may want an indicator lamp or led to monitor on/off status

2 - the fonts you're using has some VERY thin/spikey edges (serif's) - which can cause problems in cnc-engraving, less so in laser-engraving.

Let us see a pic if/when it's done!

Jakob E.
Title: Re: calrec PQ1549 help thread
Post by: audiophreak on May 02, 2013, 08:16:01 AM
Thanks so much Jakob !!

  I'm pretty sure I've spent more time on the front panel layout and graphics than stuffing the PCBs , PSU and  doing the metal work on the case  :o

    The power switch I plan on using is Illuminated , but can add one to another file and post that too.
  Good point on the Font style , I haven't had a front panel CNC'd yet, will keep that in mind, also I will be posting the actual Illustrator files , so fonts could be changed fairly easily. 

Thanks again, and Thank You for this and all of the wonderful projects and knowledge you've shared.
Title: Re: calrec PQ1549 help thread
Post by: positrons on May 09, 2013, 05:04:47 PM
You can see it from the layout: red and blue are (and should be) connected. Green should NOT be connected to these..

Thank you again.I found that and fixed it but steel have no sound and only WOWWWW....

is it possible to tell me how can I check the IC voltage to understand that they received right voltage or not??now all pins socket are about 17 volt(PSU is 18 Volt) ...is it correct or something is wrong??or if you have a better way please tell me,I dont know how should I check the component in circuit and I should start from where??
Title: Re: calrec PQ1549 help thread
Post by: gyraf on May 11, 2013, 02:00:28 AM
You need plus AND minus 12 to 18V for this circuit, referring to ground/0V.

Look up the IC data sheet to see where it wants its supply power.

Then measure all ic's to verify that the right pins have the right voltages (taking much care not to short power pins to anything else!)

Jakob E.
Title: Re: calrec PQ1549 help thread
Post by: geotone on May 11, 2013, 04:47:55 AM
Hey all,


I'm a newcomer to the DIY addiction, but fell for it heavily - I just ordered Gustav's PCBs and a whole bag of components for the 1549 - looking forward to solder-smoke filled evenings!

I have a question for Jakob though: since most of the stuff I plan to eq is unbalanced (synths and such), would it make sense to bridge the unbalancing/balancing in/outputs and connect plugs there directly, or is that wrong thinking on my part? I have seen the separate short thread on that, but wonder if there's a way to keep both options permanently.

Thanks!
Title: Re: calrec PQ1549 help thread
Post by: audiophreak on May 15, 2013, 03:02:18 PM
Hellooooo ,
                    would someone confirm that with the push-button switches on the PCB that the switch in the OFF / up / or non-pushed position that the Q is wide and the ON / down / or pushed in position the Q is narrow.
   
 sudden panic as I sent out the panel to be laser engraved   :P

 Thanks  :)
Title: Re: calrec PQ1549 help thread
Post by: gyraf on May 16, 2013, 05:28:34 AM
yep, pushed in is high Q
Title: Re: calrec PQ1549 help thread
Post by: audiophreak on May 16, 2013, 08:30:24 AM
Thank you Jakob !!!    :)
Title: Re: calrec PQ1549 help thread
Post by: positrons on May 16, 2013, 04:31:11 PM
Hi Jakob. :)
I found the problem of my circuit and now I have sound :D.one of the main reasons was soldering oil!!!
thank you for your helps very much.but there is a problem yet,when EQ is on I have a noise that i can only  hear it  in very high gain but it is a noise and it is not common,some noise like when you touch some parts of circuit  or supply board and when I do this, this noise  increases( noise is like zzzzzzzz sound)

EQ is not in the box yet I want to solve all the problems and after that put it in the box.please tell me what the main reasons for these kind of noise are??the quality of component(OP Amps, caps and pots) can be effective?(for example in PSU or EQ bands).?thank you again.
Title: Re: calrec PQ1549 help thread
Post by: gyraf on May 18, 2013, 01:55:21 AM
if you have buzz noise, that will be hum.

This is common when it's not mounted in a metal enclosure.

For testing, throw everything inside a grounded (connected to 0V) metal box and recheck.

If there is still hum, it must come from your power supply (assuming that it's not in your input signal). Then clean up powersupply.

Jakob E.
Title: Re: calrec PQ1549 help thread
Post by: josh on May 18, 2013, 03:35:43 PM
Hello everyone,

I built the psu gyraf put up here.
http://gyraf.dk/gy_pd/calreq/minipsu.pdf
thanks gyraf.

I'm not sure if I have the correct component in the 1A Bridge position.
Pic attached. 
The text on it is DB102 V718

Also, do you think I should heat sink the 78/7915's?
Would it matter if they are attached to the same sink?
Title: Re: calrec PQ1549 help thread
Post by: Harpo on May 18, 2013, 07:42:26 PM
I'm not sure if I have the correct component in the 1A Bridge position.
Pic attached. 
The text on it is DB102 V718
Different pinout http://www.datasheetcatalog.org/datasheets/70/193037_DS.pdf (http://www.datasheetcatalog.org/datasheets/70/193037_DS.pdf)

Quote
Also, do you think I should heat sink the 78/7915's?
Would it matter if they are attached to the same sink?
Depends on your transformers secondary voltage. Differential between raw DC in and +/-15V DC out times current load is transfered to heat.
Use insulation kits when attaching (especially to same condusting) heatsink. 7815 has 0V reference voltage potential at heat fin that might cause a ground loop, 7915 has input voltage potential at heat fin that could get shorted out to reference voltage, maybe blowing your rectifying diodes.
Title: Re: calrec PQ1549 help thread
Post by: josh on May 19, 2013, 02:00:24 PM
On hand, I have a packet of WL005F's
http://www.datasheetarchive.com/dataframe.php?file=DSAP0031288.pdf&dir=Datasheets-111&part=WL005F#

I think I know why I picked the wrong one...
Can you please tell me how you know which terminal is NEG on the Gyraf schematic?  POS is marked, what does that arrow mean please?

The trans is an Amveco 62054-P2S02, spec sheet says 18V at the secondary.
http://www.amveco.com/Miniature_Low_Profile_Transformers.htm
Title: Re: calrec PQ1549 help thread
Post by: Harpo on May 19, 2013, 03:02:29 PM
On hand, I have a packet of WL005F's
http://www.datasheetarchive.com/dataframe.php?file=DSAP0031288.pdf&dir=Datasheets-111&part=WL005F#

I think I know why I picked the wrong one...
Can you please tell me how you know which terminal is NEG on the Gyraf schematic?  POS is marked, what does that arrow mean please?
There is no schematic, only pcb trace side and component side shown at the minipsu.pdf. Arrow symbolizes bridge rectifier for this 4-pin device, containing 4 diodes in a BR arrangement. Negative side is opposite side of the positive side for the round shaped bridge rectifiers (or just follow the pcb trace to the center 7915 input pin).

Quote
The trans is an Amveco 62054-P2S02, spec sheet says 18V at the secondary.
http://www.amveco.com/Miniature_Low_Profile_Transformers.htm
Spec sheet doesn't say 18V at the secondary but dual 18VAC secondaries.
You connect both secondary windings in series, this series junction being the center tap connection that goes to '0V', located next to the AC solder lugs on pcb. With this now center tapped 36V AC transformer in front, each regulator will transfer the 10V differential between regulators raw DC in (about 25V) and 15V output voltage times current load (FI 10 dual opamps per channel, LED, ....) to heat, so better use heatsinks. Using 7818/7918 instead of 7815/7915 voltage regulators will give less wasted heat, but your opamps (whatever yours might be) have to be rated for this higher supply voltage, and the leftmost 22uF cap on calrec pcb has to be rated for at least this then +/-18V differential supply voltage, so better use a 50V or 63V rated part in this spot.
Title: Re: calrec PQ1549 help thread
Post by: josh on May 20, 2013, 03:45:34 PM
Quote
There is no schematic, only pcb trace side and component side shown at the minipsu.pdf. Arrow symbolizes bridge rectifier for this 4-pin device, containing 4 diodes in a BR arrangement. Negative side is opposite side of the positive side for the round shaped bridge rectifiers (or just follow the pcb trace to the center 7915 input pin).

sorry, when you know as little as I do, that's as schematic as it gets.
Yes, the (-) lead hits the center of the 7915 with the WL005F in place.  Thansks!

Quote
Spec sheet doesn't say 18V at the secondary but dual 18VAC secondaries.
You connect both secondary windings in series, this series junction being the center tap connection that goes to '0V', located next to the AC solder lugs on pcb. With this now center tapped 36V AC transformer in front, each regulator will transfer the 10V differential between regulators raw DC in (about 25V) and 15V output voltage times current load (FI 10 dual opamps per channel, LED, ....) to heat, so better use heatsinks. Using 7818/7918 instead of 7815/7915 voltage regulators will give less wasted heat, but your opamps (whatever yours might be) have to be rated for this higher supply voltage, and the leftmost 22uF cap on calrec pcb has to be rated for at least this then +/-18V differential supply voltage, so better use a 50V or 63V rated part in this spot.

I think I follow what you are saying here.
I have no idea where it came from anymore, someone on this forum, but I connected everything per the attached document.
plugged it in, and.... nothing.  1 channel works only in bypass, the other does not pass audio at all.

Anyone near Toledo Oh interested in helping me?
I'll buy you lunch!
Title: Re: calrec PQ1549 help thread
Post by: Harpo on May 20, 2013, 06:53:23 PM
..but I connected everything per the attached document.
Transformer primary windings black+violet and red+yellow joined for your local 115VAC mains ?
Your mains IEC socket might come with an internal fuseholder. Got the correct fuse fitted ?
Check if mains voltage arrives at your transformer with unit connected to your wall outlet and switched to power on by measuring voltage between the joined black+violet and red+yellow transformer wires with your multimeter set for reading AC voltage in the greater than expected 115V, so maybe 200V range if your meter is not auto sensing. IE black probe plugged into meters COM terminal, red probe plugged into meters V terminal. Black probe tip pointing at one junction, red probe tip pointing at the other junction. Order doesn't matter for AC voltage. When measuring, only use your probe tips, not your fingers! AC mains can be lethal. Got no multimeter, go buy one. They are cheap.
With confirmed mains voltage arriving at your transformer, check your psu with meter set for reading DC voltage in a greater than expected +/-15V, so maybe +/-20V range, black probe still plugged into meters COM terminal, probe tip at 0V reference voltage (keep it there), red probe still plugged into meters V terminal. With probe tip pointing at +15VDC psu output, meter should give you a steady readout of about (parts have tolerances) +15V. Probe tip pointing at the -15VDC output should give you a steady readout of about -15V.

Quote
plugged it in, and.... nothing.  1 channel works only in bypass, the other does not pass audio at all.
No supply voltage needed to operate in bypass. The bypass switch simply connects input with output. Just fix your solder connections for the not working channel, connecting to the correct XLR pins (XLR-in/out have mirrored pinout).

Quote
Anyone near Toledo Oh interested in helping me?
Naaa, you've already come so far. You'll take the final step yourself. This is DIY. ;)
Title: Re: calrec PQ1549 help thread
Post by: josh on May 20, 2013, 07:44:16 PM
Harpo,
I do have a multimeter :) and thank you for detailing out where to check, and more importantly.. HOW.
Thanks for taking the time to do that.  I will do what you said and report back my findings.

My SSL has a 2 Amp fuse, my G9 has a 5 Amp fuse, the Calrec I put a 3 Amp in there because I had one laying around, but I must confess that I have no idea what they are supposed to be.   :-[  what tells you this?
Title: Re: calrec PQ1549 help thread
Post by: Harpo on May 20, 2013, 07:53:47 PM
My SSL has a 2 Amp fuse, my G9 has a 5 Amp fuse, the Calrec I put a 3 Amp in there because I had one laying around, but I must confess that I have no idea what they are supposed to be.   :-[  what tells you this?
Scary.
I'd pick a 250mA [15VA transformer/115V AC mains*1.6 = 0.209A] slow blow fuse for your Amveco62054 with slow blow '/t' fusing characteristic.
Title: Re: calrec PQ1549 help thread
Post by: positrons on May 25, 2013, 05:15:34 PM
if you have buzz noise, that will be hum.

This is common when it's not mounted in a metal enclosure.

For testing, throw everything inside a grounded (connected to 0V) metal box and recheck.

If there is still hum, it must come from your power supply (assuming that it's not in your input signal). Then clean up powersupply.

Jakob E.

I understand that Jakob,thanks,I put it in something like a Metal box(a big metal sheet because I have not the box yet) and connecting ground to it and the noise disappear...after my university exams I will start making box and I will put the picture of complete unit here.thank you so much for your helps and your patience in answering our questions.you are a really,really nice guy. :)
Title: Re: calrec PQ1549 help thread
Post by: gyraf on July 30, 2013, 02:05:52 AM
You could calculate the needed resiasors for specific frequencies for the state-variable filters - or you could use two trimmers, set them to wanted frequency, dismount them and measure them for each wanted frequency.

Or you could just use the logarithmic step calculation "backwards"

But I'm not sure that stepping the frequency is such a good idea - often it's fine adjustments that is needed in eq's like this. 2x100KC pots are not impossible to find at all nowadays.

Jakob E.
Title: Re: calrec PQ1549 help thread
Post by: Harpo on July 31, 2013, 05:51:52 AM
I have observe the filter and need help to make sure, is anybody know if the filter component to calculate are like in the attached pics (only the mid section, but it looks like the same except the value for other band)?
The 22nF across opamp 8B output/inverting input (right side next to your red circled area) is part of the frequency setting network as well. Filters center frequency is 1/(2*PI()*SQRT((1000+1/(1/100000+1/15000))*22E-9*(1000+1/(1/100000+1/15000))*22E-9)), giving range 515Hz up to 7234Hz (when substituting the 1/(1/100000+1/15000) term with zero for the shorted out pots full CW setting) for this stage with perfect parts.
Title: Re: calrec PQ1549 help thread
Post by: Harpo on July 31, 2013, 07:42:59 PM
- low 47.7 to 446.6 but if I put the pot value 0.0001 (near short) the Freq 669.9
center peaking response from 1/(2*PI()*SQRT((1500+1/(1/100000+1/27000))*68E-9*(1500+1/(1/100000+1/27000))*(680+150)E-9))=29.43Hz
up to 1/(2*PI()*SQRT((1500+0)*68E-9*(1500+0)*(680+150)E-9))=446.62Hz.
The Calrec original schematic says 30Hz to 470Hz.

Quote
- high 1666.6 to 15603.4 and if I put the pot value 0.0001 (near short) the freq calculation 23405.1
center peaking response from 1/(2*PI()*SQRT((1500+1/(1/100000+1/27000))*6.8E-9*(1500+1/(1/100000+1/27000))*6.8E-9))=1028.35Hz
up to 1/(2*PI()*SQRT((1500+0)*6.8E-9*(1500+0)*6.8E-9))=15603.42Hz.
The Calrec original schematic says 1kHz to 16kHz.

Quote
I assume the equation is different for the low and high band, would You like to inform me how to calculate the high and low band freq?
Peaking response is the same, just substitute the different values for caps and resistors. Shelfing response is different.
Title: Re: calrec PQ1549 help thread
Post by: gyraf on August 02, 2013, 07:28:34 AM
for input transformer, a bridging type (like 10k:10k) would be fine

Jakob E.
Title: Re: calrec PQ1549 help thread
Post by: gyraf on August 05, 2013, 05:50:10 AM
1. what is the value of q when low and high of this eq (bell position)? Is there any formula to calculate the q and also which component in the schematic are for q control?

I haven't messed with the Q ever - the choices from Calrec seems very good indeed. The Q is set by the positive feedback over the two integrator stages - look up state-variable filters for calculations.

2. if use 5532, can I make the PSU higher, let says 20V? Do this will benefit to get higher headroom?

I don't think you'll gain anything real from this - but you could always try...

3. any idea what kind of output transformer is suitable for this circuit?  ;D ;D ;D

Driven from these opamps, I'd say just about anything around 600:600 Ohms or so - maybe LL5402?

Jakob E.
Title: Re: calrec PQ1549 help thread
Post by: Harpo on August 12, 2013, 05:43:39 AM
is that OK to use silver mica cap in the place of all tantalum and ceramic?
Sure ::), but you'd need a LOT of bucks and a GIANT box to fit them for a sub par result. (largest stocked value about 1nF. You'll have to fit 33000 of these caps in parallel to substitute a single 33uF cap, times 12 for a stereo build giving 396000 caps needed to substitute the 12 tantalum caps).
I'd use c0g/np0 for the cer.caps and low ESR electrolytics for the tants. YMMV.
Title: Re: calrec PQ1549 help thread
Post by: audiophreak on August 22, 2013, 10:38:57 AM
Hello Everyone ,
                          After a couple of months of hitting a brick wall on a dual 1176 Rev.D - I decided to clean my work bench and take a breather... well I couldn't stay away from DIY too long, so I went back to this dual Calrec 1549.

   I have to say that this, by far was the most difficult project to physically assemble ( for me anyway ), as I had the pot holes counter bored to recess the pot nuts.  I used the switches and pots from AML.  I actually needed 22k pots for another project and the only ones AML had with 3/8 bushing and 1/4 shaft has center detentes which I didnt need , so I disassembled the pots and swapped the wafers ( voids warranty )   so I have 10k Lin with center detentes for the +/-
  I used the LM833 as suggested by Gyraf , I have W492's and S800's with NE5532's , so I wanted to try the LM833's. I made the front panel graphic in Illustrator and Chae at Prodigy engineering laser engraved it. The knob grapgics are for 3/4" knobs and the the push buttons I got very cheaply from ebay and fit the ALPS push button switches - black anodized aluminum and are 0.310" or 7.88mm in diameter so they are smaller in Diameter than the ALPS button caps which gave a little more room for the knob graphics.

    I have posted the PDF of the final panel graphic , if you want the Illustrator file I will email it to you , but a word of WARNING -  the push button holes are as exact as I can get them , the switches have a little wiggle room and I had to de-solder and then re-solder them after mounting PCBs to the panel to get them centered - very much a PITA .

   It sounds great and I'm sure will be very useful,
                                                                               Thank you to Jakob and Gyraf and all who post and contribute,
                                                                                                                                                                                   Chip

here is a link to more pix -  https://goo.gl/photos/buXRjzi2oV9gWfvQ6
Title: Re: calrec PQ1549 help thread
Post by: audiophreak on August 22, 2013, 10:42:46 AM
 I could only attach one file - here's the PDF  of the panel graphics, cheers  :)
Title: Re: calrec PQ1549 help thread
Post by: gyraf on August 22, 2013, 12:02:28 PM
That's the best-looking Calreq I've seen yet...!!!

Jakob E.
Title: Re: calrec PQ1549 help thread
Post by: audiophreak on August 22, 2013, 03:27:23 PM
Thanks Nescafe, she sounds great and I have heard these described as  " surgical " and now know why  ;D

   Jacob, that means so much coming from the man who made all this possible. I have now completed all the DIY projects that you have given this comunity ( at least all the projects on your DIY page ). Thank you for years of enjoyment ( and a little fustration  ;D  )  , and gaining of knowladge ( tons more to learn ) , and great sounding DIY equipment.
Title: Re: calrec PQ1549 help thread
Post by: musika on August 23, 2013, 09:51:28 AM
Audiophreak,

Thanks for posting the completed Calrec PQ1549 !!!!   

Very Nice.
Title: Re: calrec PQ1549 help thread
Post by: ruairioflaherty on August 23, 2013, 03:08:42 PM
Outstanding looking EQ, well done. 
Title: Re: calrec PQ1549 help thread
Post by: ricardo on August 25, 2013, 12:39:46 AM
I mean only ceramic 11pF and 100pF using silver mica.....
NO.  If the 11p are the ones I'm thinking off next to each OPA, we (Calrec) swapped every single polystyrene 11p in the first M-series 75 channel desk for NPO/CGO ceramics.  This is the CORRECT part to use.  Mica/Polystyrene/Golden Pinnae are all substandard for this.

Guru Scott Wurcer posted some results in another forum that showed silver Mica introduced noise and polystyrenes are microphonic compared to CGO/NPO ceramics.  They are the BEST caps you can buy if their value & voltage fit.  There's an appendix in the John Hardy blurb on their 990 discrete OPA that shows chapter & verse.

Dunno where the 100p but similar considerations hold.
Title: Re: calrec PQ1549 help thread
Post by: musika on August 27, 2013, 08:40:17 AM
I found this website while trying to learn more about the characteristics of component materials.  This one talks about types of replacement passive components for the purposes of increasing the sound quality.

http://www.bext.com/replace.htm
 (http://www.bext.com/replace.htm)
Here is part of the article specifically about ceramic capacitors:

"Most caps found in audio equipment aren't used for coupling or power supplies, but for signal shaping. These smaller caps vary in quality as much as electrolytics and can benefit just as much from upgrading.

Ceramic disc capacitors were among the first small caps available and they're still used in a lot of equipment, especially guitar amps. They sound terrible, adding a screechy and gritty quality to the high frequencies that's quite unpleasant. They're also microphonic: a ceramic disc can pick up vibrations from the air or through the cabinet and add them (distorted) to the signal. When you find them in audio circuits it's a good idea to replace them with polystyrene (best) or polypropylene capacitors.

As always, there are a few exceptions. Ceramic discs are excellent for bypassing radio frequencies to ground; they're often found connected between the ground side of an input Jack and the chassis to help keep radio frequency junk out of the system. If you find ceramic discs used this way, leave them there. Ceramic discs are also sometimes used on circuit boards between the power supply pins and ground to keep radio garbage out of the active circuits. You can replace the ceramic discs with stacked film or polypropylene caps, but keep the discs around-if the new units aren't as effective, you may need to put the old ones back in.

Mica capacitors are even older than ceramic discs and aren't used much anymore. They behave a lot like ceramic discs and I replace them with polystyrenes when I find them. "
Title: Re: calrec PQ1549 help thread
Post by: gyraf on August 28, 2013, 04:05:35 AM
This seems like an over-simplified generalization to me. Use ceramics for opamp decoupling, poly for timing, and electrolytics where polys get too big - then you're at a good starting point. You can always experiment from there, just don't expect to hear big differences.

Jakob E.
Title: Re: calrec PQ1549 help thread
Post by: geotone on September 05, 2013, 02:10:57 AM
I finished the second channel of my PQ1549 yesterday. Both channels working first try, what a joy (and relief...)! Will post pictures once I get the case done, which might take quite another while.

Thank you Gyraf for this project, and thanks to Gustav for producing excellent boards. This forum is such an excellent resource.


/Geotone
Title: Re: calrec PQ1549 help thread
Post by: gyraf on September 05, 2013, 04:25:41 AM
Thanks for the feedback, Geotone - usually we only hear about problems here.

Good to have some posts that don't look so discouraging for potential builders...  ;D

Jakob E.
Title: Re: calrec PQ1549 help thread
Post by: reanimatorstudio on September 12, 2013, 06:02:10 AM
I'm drawing a frontpanel if you are interested. Nice mod would be to add a gain pot.
Title: Re: calrec PQ1549 help thread
Post by: Nescafe on September 22, 2013, 05:40:00 PM
I mean only ceramic 11pF and 100pF using silver mica.....
NO.  If the 11p are the ones I'm thinking off next to each OPA, we (Calrec) swapped every single polystyrene 11p in the first M-series 75 channel desk for NPO/CGO ceramics.  This is the CORRECT part to use.  Mica/Polystyrene/Golden Pinnae are all substandard for this.

Guru Scott Wurcer posted some results in another forum that showed silver Mica introduced noise and polystyrenes are microphonic compared to CGO/NPO ceramics.  They are the BEST caps you can buy if their value & voltage fit.  There's an appendix in the John Hardy blurb on their 990 discrete OPA that shows chapter & verse.

Dunno where the 100p but similar considerations hold.

This seems like an over-simplified generalization to me. Use ceramics for opamp decoupling, poly for timing, and electrolytics where polys get too big - then you're at a good starting point. You can always experiment from there, just don't expect to hear big differences.

Jakob E.

Thank You Ricardo and Jakob, really appreciate the explanation  :)
Title: Re: calrec PQ1549 help thread
Post by: Nescafe on October 07, 2013, 03:10:36 PM
Hi,

Is that correct that the shelving frequency calculation are:

Low: 1/(2*PI()*SQRT((1500+1/(1/100000+1/27000))*68E-9)  100000 is P4A

High: 1/(2*PI()*SQRT((1500+1/(1/100000+1/27000))*6.8E-9) 100000 is P1A

Thank You.
Title: Re: calrec PQ1549 help thread
Post by: gyraf on October 08, 2013, 01:41:08 AM
Seems about right - haven't been there myself.

Try doing the calculation and see if it's estimate fits real-life parameters?

Jakob E.
Title: Re: calrec PQ1549 help thread
Post by: Nescafe on October 08, 2013, 06:14:17 AM
Hi Jakob,

Yes, and I try to calculate for step switch, the peaking band is done but need to know the shelving, since this eq share the same pot for both peaking and shelving, compromise  ;D

Maybe I should PM Harpo my "Filter Guru"  ;)

Once again Jakob, Thank You for bring this EQ.

Thank U.
Title: Re: calrec PQ1549 help thread
Post by: Harpo on October 08, 2013, 06:50:32 AM
Low: 1/(2*PI()*SQRT((1500+1/(1/100000+1/27000))*68E-9)  100000 is P4A
Seems your SQRT() term is missing the RC factor at the 2nd integrator.
Looks like the low 'shelf' is still a bandpass, just the hpf part kicked down some octaves by paralleling the two series connected 33uFs to the 150nF||680nF.
Title: Re: calrec PQ1549 help thread
Post by: Nescafe on October 08, 2013, 07:59:03 AM
Hi Harpo  :D

So is that correct the low shelf should be:
 1/(2*PI()*SQRT((1500+1/(1/100000+1/27000))*68E-9*(1500+1/(1/100000+1/27000))*(1/((680+150)E-9))+1/33E-6)

And the high shelf formula is correct or using the second intergrator too 6n8 series 33u?

Thank You.

Title: Re: calrec PQ1549 help thread
Post by: Harpo on October 08, 2013, 09:58:16 AM
So is that correct the low shelf should be:
 1/(2*PI()*SQRT((1500+1/(1/100000+1/27000))*68E-9*(1500+1/(1/100000+1/27000))*(1/((680+150)E-9))+1/33E-6)
? number of opening and closing parenthesis will be the same and messed up cap value, so result might* be varying between 1/(2*PI()*SQRT( (1500+1/(1/100000+1/27000))*68E-9 * (1500+1/(1/100000+1/27000))*(680+150+33000/2)*10^-9)) and 1/(2*PI()*SQRT(1500*68E-9*1500*17.33E-6)).
*With the hpf part (0.40 - 6.12Hz) this far (8 octaves) apart from the lpf part, I doubt the 1/(2PI()*SQRT(RClpf*RChpf) for center frequency being valid here. Maybe 1/(2PI()RClpf) is giving you a closer result. I'd just build it and measure the response to prove one or the other wrong (or ask a filter guru, I am certainly not).

Quote
And the high shelf formula is correct or using the second intergrator too 6n8 series 33u?
The Sqrt() with only a single RC factor within these parenthesis cannot be correct.
The 6n8 isn't in series to 33uF. The 6N8 is in parallel to the series connected 33uFs, IE 6n8||33uF/2=16.5068uF and the 6n8 can be ignored as it will vanish in the 33uF parts tolerances.
Title: Re: calrec PQ1549 help thread
Post by: Nescafe on October 08, 2013, 10:17:43 AM
Got it, wrong lookin at 33u, there are 2 in series and pararel to the 680n & 150n, same mistake in high section. Thank U Harpo, will make and play with the freq table tonight.

(or ask a filter guru, I am certainly not).

For me You are a filter guru  ;)

Thank You Harpo, Gyraf and everybody
Title: Re: calrec PQ1549 help thread
Post by: vp on October 22, 2013, 05:27:47 AM
Hi,
I'm planning to build 4 channels of pq1549, but before starting I'm trying to find suitable stereo-rev-log pots.

Does anyone have experience using some cheap ebay ones? Such as these for example:
http://www.ebay.com/itm/6-pcs-C100K-Dual-Stereo-Potentiometer-Reverse-Log-Taper-/400389912481?pt=LH_DefaultDomain_0&hash=item5d391937a1 (http://www.ebay.com/itm/6-pcs-C100K-Dual-Stereo-Potentiometer-Reverse-Log-Taper-/400389912481?pt=LH_DefaultDomain_0&hash=item5d391937a1)

Thanks in advance!
Title: Re: calrec PQ1549 help thread
Post by: irfrench on December 13, 2013, 04:55:04 PM
Hi all.

I just wanted to say thanks for making this project available!  I recently decided to re-purpose an old rack mount unit into a channel of this EQ.

(http://media.tumblr.com/9b74e4f4fcfec9820ffc49d6aec277fa/tumblr_inline_mvlh01mgN21r2bfgn.jpg)

So I cleaned out the old guts, only to find that the PSU was already putting out a helpful +/-15v!:

(http://media.tumblr.com/5acd18f6e3d64ddcfca24ae291fa8e40/tumblr_inline_mvlhc8lWpy1r2bfgn.jpg)

Quickly populated the boards (thanks Gustav!):

(https://31.media.tumblr.com/343152d949849abba52acbecbfcf85bd/tumblr_inline_mxrkisR3ue1r2bfgn.jpg)

Tested, added the ICs, buttoned it up and added a front panel plate to hide the mess:

(https://31.media.tumblr.com/01344f7002cc8a9365eab96c211cc099/tumblr_inline_mxrkjtojAU1r2bfgn.jpg)

It fired up first time - which is always nice! - so I did some freq. sweeps to make sure all was working OK.  Damn this EQ is flexible!  I only ended up exporting the LOW band as I didn't want to spend ALL night getting plots; so here is a LOW band only set of sweeps!:

(https://31.media.tumblr.com/115ffec851f68c4fbc0fbacce94bda79/tumblr_inline_mxrknhGmhF1r2bfgn.jpg)

Thanks again to Gyraf for sharing this and to Gustav for still making the boards!

Ian

 :) :) :)

DOH! Just noticed that there isn't a non-Hi Q pair of measurements for Boost.  I'm sure you get the idea!
Title: Re: calrec PQ1549 help thread
Post by: 3nity on December 14, 2013, 10:17:16 AM
looks really good!
i always wanted to build a calrec EQ!
Title: Re: calrec PQ1549 help thread
Post by: audiophreak on December 14, 2013, 01:41:07 PM
very nice work irfrench  !!   :)
Title: Re: calrec PQ1549 help thread
Post by: mrkrawn on February 05, 2014, 06:08:53 PM
Hi guys

I just receive my calrec board rev 5 from gustav.
i just want to know what is the white film on the bottom?
can i solder on it or need to remove it
thanks by advance
Title: Re: calrec PQ1549 help thread
Post by: gyraf on February 07, 2014, 04:01:52 AM
the white coating on Grinder's pcb's is chemical silver - makes life MUCH easier. Just solder directly on it.
Title: Re: calrec PQ1549 help thread
Post by: solderboy on February 07, 2014, 02:48:20 PM
ok, finish with my build. unit ist running und sounds good so far. 2 smal problems:

- unit is to loud. saw other users got the same problem... can someon please show me the right resistors i have to change
- hi mid has a oscilator sounding problem, but only when i fully open the db pot

i was looking for the values of the resistors, seems everything is right. the directions of the caps are like in the rev.4 pdf...

someone?
Title: Re: calrec PQ1549 help thread
Post by: solderboy on February 07, 2014, 06:02:38 PM
ok, i changed the 2 resistors in serie next to the balance ic. but seems it´dosnt solved the problem with the gain????
Title: Re: calrec PQ1549 help thread
Post by: solderboy on February 08, 2014, 07:27:56 AM
nobody? help!!!!!
Title: Re: calrec PQ1549 help thread
Post by: Harpo on February 08, 2014, 02:04:20 PM
nobody? help!!!!!
Why are you surprised when you say exactly nothing to identify the fault ?
Quote
unit is to loud. saw other users got the same problem... can someon please show me the right resistors i have to change
'too loud' by what amount ? Factor 2 or +6dB would be easiest to come by with increasing the two 10K input resistor values that connect between input caps 47uF||100nF and opamp IC-input-pin2 and pin3 to 20K each. Different 'too loud' factor will probably be one or more wrong resistor value(s) fitted or a shorted or open connection somewhere on pcb.
Quote
ok, i changed the 2 resistors in serie next to the balance ic. but seems it´dosnt solved the problem with the gain?
So by a 50/50% chance you changed probably/maybe prementioned resistors to what value ? Still no number for the 'problem with the gain'.

With unit powered on and all boost/cut pots centered for +/-0dB, measure the AC voltage between input-XLR pins2/3 at a frequency your multimeter can handle, maybe 100Hz. With your maybe doubled up input resistor values to 20K in order to compensate for the last inverting output stage for balanced output, opamp IC-input-pin1 will measure half this measured amount in respect to 0V reference voltage. Same 'half of input AC voltage' for IC6A-pin1, IC8A-pin1, IC10A-pin1, IC12A-pin1, IC-Bal--pin1. If so, you should have overall unity gain, else check for correct feedback and input resistor values at the stage where measured voltage rises to your 'too loud' voltage.
Title: Re: calrec PQ1549 help thread
Post by: solderboy on February 08, 2014, 04:52:53 PM
Thank you Harpo!

And sorry for less descripton of the problem. by the way... my english isnt the best and it´s hard for me to finde the right words sometimes. i never got lessions in english... and your totaly right: what´s in my head is in my head and others can´t know it...

ok... i changed the wrong ones! i just saw in the pdf. that one ic is labeled as bal. and next to it i found to 10k resistors in series. nexttime i will take more time to follow the input. now i changed the right ones to 20k and this problem is gone...

Do you can also help me to locate the oslcilator sounding problem in hi mid? would be nice...
Title: Re: calrec PQ1549 help thread
Post by: Harpo on February 08, 2014, 07:55:42 PM
Halfway there. With unfortunately missing parts designators of all caps and resistors on schematic and silkscreen, the describtion of a parts location for an identification can get lengthy.
Double check for correct parts values of resistors and caps (some are in nF, some in pF range) connecting to IC7B, IC7A and IC8B as well as the frequency setting stereo rev.log pot P2, the Q setting switch and the 5K1 resistor back to the summing node at IC8A-pin2. Check or maybe reflow solder connections to all previously mentioned parts and/or remove unwanted shorts.
Good luck.
Title: Re: calrec PQ1549 help thread
Post by: solderboy on February 09, 2014, 10:27:30 AM
 :)
yeah, working fine now! can´t say what was the problem, think it was a unwanted solderbridge. also i canged the 2 resistors at the input to 22k to have really the same level like in bypass. nice sounding unit! by the way... can´t find any information about the db on each filter... how many + or - is it?

thank you very much hapo!
Title: Re: calrec PQ1549 help thread
Post by: mrkrawn on February 10, 2014, 04:41:34 PM
Hello boys
congratulation solderboy.
I will buid this eq with quad pot for stereo  in a few days.
I've read this help thread and i i want to now if there are really reverse caps on the board rev5.
I prefer ask to you before do a thing i will regret
thanks by advance
Title: Re: calrec PQ1549 help thread
Post by: solderboy on February 15, 2014, 09:18:32 PM
yes, it´s a 100k reverse audio log c-curve pot like in rev.4. for a mono pcb. i got the pots from "das musikding" in germany. they don´t have print contacts, but is working well. another ones i found here: http://www.audiomaintenance.com/acatalog/potentiometers_carbon_16mm_diameter_dual_gang.html but not tested yet.

i guess it will be difficult to find the pot in a quad option. if you find some please let me know. another option is to use 24 position rotary switches...

good luck!
Title: Re: calrec PQ1549 help thread
Post by: jicama on February 27, 2014, 02:11:21 PM
Ok Mr. Postman arrived with my next projetc, Im searching for all the compenents from Magnus Johansson BOM, I have 2 questions and I will be very greatful if someone can answer:

1. resistors values, -+ 5% tolerance will work? I went to the electronic store but half of them are 5% tolerance

2. Switches, it says on the list SPUN19035A and SPUN19036A with a Farnell code below 733118 and 733120 but those codes are SPUN191400 and SPUN194700, can I use those with farnell code??

Thanks in advance
Title: Re: calrec PQ1549 help thread
Post by: G-Sun on March 03, 2014, 12:43:32 PM

1. resistors values, -+ 5% tolerance will work? I went to the electronic store but half of them are 5% tolerance
I'm not an expert, but I guess +-1% metal film is the standard choice. Not hard to get.
Title: Re: calrec PQ1549 help thread
Post by: mokkinger on March 23, 2014, 01:35:06 PM
hi guys,
I have some questions about the calrec EQ. I have two sets of PCBs, finished, one working, and one with a fault, that I would like to find and fix (I didnt populate the PCBs myself, got them from someone on a german forum...)

the PCBs with the fault are self-etched by someone based on gyrafs layout rev2, and the problem is somewhere around IC9b / Low Mid section. I already checked twice for solder blobs, wrong oriented components, and swapped all the ICs...
once I put in IC9, the EQ hums, and only passes audio in bypass mode. once I bridge pins 2 and 3 (the middle ones) of IC 9b it works (I use an oscilloscope to see how the ES slopes change), but then the Lo-Mid Section is disabled...

anybody has a clue what could probably be the fault? where should I continue to nail down the problem?

also a more general question about the stereo EQ: I have one set of Rev. 2 PCBs (the one above with the fault, they look self-etched without silkscreening)), and one of Rev 4 I think, looking newer and more "professional"; they have some parts from different manufacturers (caps mainly)... does it make sense to use these two sets in stereo mode in one unit? from the osc I cant tell the difference until now, but I dont want to put all things together and then realize that L and R sound different...

thanks for help on the falut and for a recommendation how to proceed (desolder different components and use new / same ones on both?)

best,
mark
 
Title: Re: calrec PQ1549 help thread
Post by: gyraf on March 24, 2014, 03:34:37 AM
The versions are the same electrically in the pcb versions.

For your error, check continuity and isolation of tracks (and look through this thread for previous problem-fixings)

Jakob E.
Title: Re: calrec PQ1549 help thread
Post by: jicama on April 03, 2014, 02:46:23 PM
How come u need  to conect 2 pcbs with the out? Doesn't has to be input connecting out??
Title: Re: calrec PQ1549 help thread
Post by: gyraf on April 04, 2014, 03:47:40 AM
Does not compute. Please rephrase.
Title: Re: calrec PQ1549 help thread
Post by: jicama on April 04, 2014, 06:56:24 PM
Does not compute. Please rephrase.

In both  pcb's says out... I don't understand conecting 2 outs
Title: Re: calrec PQ1549 help thread
Post by: gyraf on April 05, 2014, 02:25:14 AM
look at the schematic, and then at the pcb layout.
Title: Re: calrec PQ1549 help thread
Post by: jicama on April 05, 2014, 04:38:05 AM
look at the schematic, and then at the pcb layout.

So is the same  connection, like one pcb divide it in 2 pcb's
Title: Re: calrec PQ1549 help thread
Post by: jicama on May 08, 2014, 03:13:04 PM
Hello there almost done with the Eq I only need to get the right pots, does any one knows if this will work?
http://www.ebay.com/itm/6-pcs-C100K-Dual-Stereo-Potentiometer-Reverse-Log-Taper-/400389912481?pt=LH_DefaultDomain_0&hash=item5d391937a1

I have dual 100k log pots, is it possible to wire one part of the pot  backwards?

Thanks for you help
Title: Re: calrec PQ1549 help thread
Post by: gyraf on May 09, 2014, 12:34:24 AM
Quote
I have dual 100k log pots, is it possible to wire one part of the pot  backwards?

Won't work.

Have you read the page about the project? Some options are mentioned there.

Jakob E.
Title: Re: calrec PQ1549 help thread
Post by: jicama on May 09, 2014, 09:43:48 AM
Quote
I have dual 100k log pots, is it possible to wire one part of the pot  backwards?

Won't work.

Have you read the page about the project? Some options are mentioned there.

Jakob E.

Thanks yes I just wanted to know if there was a simple way to conect a log pot and change it to reverse instead open it and change the mechanism I was searching but there is so many kinds of pots people sell on internet, some of them refers to reverse log tape C, others says is tape D, so I already ordered C100k  I hope they work,

Thanks
Title: Re: calrec PQ1549 help thread
Post by: gyraf on May 09, 2014, 10:52:55 AM
Dual C100K's should work fine...
Title: Re: calrec PQ1549 help thread
Post by: G-Sun on September 03, 2014, 05:15:14 AM
I could only attach one file - here's the PDF  of the panel graphics, cheers  :)
Thanks a lot for sharing. I might use this.
Very good looking unit :)

I have to get my pots and buttons sorted. Is it easy to order wrong dimensions?

The Q narrow-wide is upside down from what I first would assume. But that is because pcbs are mounted upside-down, right?

Anybody who wants a credit-logo on the front?
(Calrec, Gyraf, audiophreak?)
Title: Re: calrec PQ1549 help thread
Post by: audiophreak on September 03, 2014, 08:39:26 AM
I could only attach one file - here's the PDF  of the panel graphics, cheers  :)
Thanks a lot for sharing. I might use this.
Very good looking unit :)

Thanks G-Sun , as I'm sure you know its a labor of love :)

I have to get my pots and buttons sorted. Is it easy to order wrong dimensions?

not quite sure what you mean , if you're talking about the outside diameter of the push button caps , the Alps caps are 0.410" or 10.4mm and the ones I got off ebay are 0.310" or 7.88mm , I used the smaller diameter to have a little more room between the knobs - however I could have used smaller diameter knobs :)  the switch posts are 3.3mm ( measured 3.28mm)
*  with my panel graphic if you use the Alps switch caps, the hole for the High Shelf button will cut in to the High Freq. adjust graphic lines a little ( but not horribly )

The Q narrow-wide is upside down from what I first would assume. But that is because pcbs are mounted upside-down, right?

  when the Q switch is UP / not pushed in , the Q is wide - when it is DOWN or pushed IN the Q is narrow - so I put the wide graphic over the button and the narrow graphic below the button.

Anybody who wants a credit-logo on the front?
(Calrec, Gyraf, audiophreak?)

Thanks !!   I'm good though , This forum/place /home is just fantastic and I don't think I've been able to contribute much technically, so I'm happy offer the graphic here if any member wishes to use it  :) 
Title: Re: calrec PQ1549 help thread
Post by: G-Sun on September 03, 2014, 11:33:11 AM

Thanks G-Sun , as I'm sure you know its a labor of love :)
Quote
I have to get my pots and buttons sorted. Is it easy to order wrong dimensions?

not quite sure what you mean , if you're talking about the outside diameter of the push button caps , the Alps caps are 0.410" or 10.4mm and the ones I got off ebay are 0.310" or 7.88mm , I used the smaller diameter to have a little more room between the knobs - however I could have used smaller diameter knobs :)  the switch posts are 3.3mm ( measured 3.28mm)
*  with my panel graphic if you use the Alps switch caps, the hole for the High Shelf button will cut in to the High Freq. adjust graphic lines a little ( but not horribly )

The Q narrow-wide is upside down from what I first would assume. But that is because pcbs are mounted upside-down, right?

Quote
  when the Q switch is UP / not pushed in , the Q is wide - when it is DOWN or pushed IN the Q is narrow - so I put the wide graphic over the button and the narrow graphic below the button.

Thanks !!   I'm good though , This forum/place /home is just fantastic and I don't think I've been able to contribute much technically, so I'm happy offer the graphic here if any member wishes to use it  :)
Well, thanks for sharing! It's looking really nice, so I'll try to make mine as fine as yours.

Pots: I was thinking for lining them with the wholes. Is it standard dimensions or should I take special care?

BTW: How do I make such a fancy powerbutten?
Title: Re: calrec PQ1549 help thread
Post by: audiophreak on September 03, 2014, 02:15:44 PM
The power switch I got from Mouser - http://www.mouser.com/ProductDetail/Bulgin/MP0045-1E2BL012/?qs=%2fha2pyFaduhPnmJxD2BeVorYmT7BsVbo%252bMymC0TanDKywywohJ6r1Lp5PN55JARn

or

http://no.farnell.com/bulgin/mp0045-1e2bl012/switch-dpco-3a-250vac-blue-ring/dp/1332000?ost=MP0045%2F1E2BL012

still not understanding what you are saying about the pots , if you solder them to the PCB , the hole alignment is correct in my graphic. Its the push button switches that could be slightly off (  sides of the push button caps slightly rub on sides of hole in panel ) ..but desolder and reposition ( wiggle) of switches on PCB corrected this ,  not sure on how else to describe it. 

 Hope this helps  :)
Title: Re: calrec PQ1549 help thread
Post by: G-Sun on September 03, 2014, 02:30:45 PM

http://no.farnell.com/bulgin/mp0045-1e2bl012/switch-dpco-3a-250vac-blue-ring/dp/1332000?ost=MP0045%2F1E2BL012

still not understanding what you are saying about the pots , if you solder them to the PCB , the hole alignment is correct in my graphic. Its the push button switches that could be slightly off (  sides of the push button caps slightly rub on sides of hole in panel ) ..but desolder and reposition ( wiggle) of switches on PCB corrected this ,  not sure on how else to describe it. 

 Hope this helps  :)
Thanks!
Looking at the wiring for the switch. Is it just +-in and +-out? There seems to be 8 poles..?
Nice one :)

Pots: I guess it's no issue then. Thanks!
Title: Re: calrec PQ1549 help thread
Post by: audiophreak on September 03, 2014, 07:48:26 PM
use your DMM and meter the contacts out , that's what I did , basically th six in the middle  DPDT  and the top and bottom ones are 12v for the LED "On" indicator.
Title: Re: calrec PQ1549 help thread
Post by: G-Sun on September 04, 2014, 02:56:51 AM
use your DMM and meter the contacts out , that's what I did , basically th six in the middle  DPDT  and the top and bottom ones are 12v for the LED "On" indicator.
Ok thanks, then I understand.
12V? How did you supply that?
Diode drop times x ; 18V to 12V?
Title: Re: calrec PQ1549 help thread
Post by: frazzman on September 29, 2014, 06:09:57 AM
Hi all,
Just have an issue with a the Calrec mini PSU board. Basically I etched one to use for another projector (2x net EQ). Anyway, I used alternate regulators to get a 18v supply. The only issue is on my 30VA toroid, the secondaries seem to be a bit hotter than normal. So I end up with about -/+ 20V rather than 18v.

Question: is this within acceptable tolerance ? I thought opamps won't cope with this voltage ?

Any practical ways to get the voltage down with out having to rejig the whole circuit ... Could I drop it across a high wattage resistor ?

Cheers
Title: Re: calrec PQ1549 help thread
Post by: Nescafe on September 29, 2014, 06:17:37 AM
20V at unload condition? That is OK in most cases, try that with some load and measure again, BTW if You use NE5532 op amp that's OK (+/-22V Max).
Title: Re: calrec PQ1549 help thread
Post by: frazzman on September 29, 2014, 06:41:45 AM
20V at unload condition? That is OK in most cases, try that with some load and measure again, BTW if You use NE5532 op amp that's OK (+/-22V Max).

Thanks for the quick reply....yes at unload - actually closer to 21v

 It turns out I'm an idiot and I accidentally ordered a 30va 2x25 instead of 2x18...
Will 7818 and 7918 regs play nice with this extra voltage ?
The net eq is jam packed with ne5532s so I'm glad to hear they will cope with the surplus voltage...
Title: Re: calrec PQ1549 help thread
Post by: Nescafe on September 29, 2014, 07:09:38 AM
With 25V secondary I will worried more about heat dissipation, heatsink for regulator, make it as big as possible that the space allowed.
Title: Re: calrec PQ1549 help thread
Post by: Gustav on September 29, 2014, 12:16:18 PM
20V at unload condition? That is OK in most cases, try that with some load and measure again, BTW if You use NE5532 op amp that's OK (+/-22V Max).

Thanks for the quick reply....yes at unload - actually closer to 21v

 It turns out I'm an idiot and I accidentally ordered a 30va 2x25 instead of 2x18...
Will 7818 and 7918 regs play nice with this extra voltage ?

They will with quite a bit of cooling, but you should really get the right trafo for the job instead of putting so much strain on such a crucial part of your circuit.

Gustav
Title: Re: calrec PQ1549 help thread
Post by: G-Sun on October 02, 2014, 05:53:10 AM
So, getting my pots sorted:
10k lin: AML has these: http://www.audiomaintenance.com/acatalog/om-01-069_extended_info.html
but that's not center detent is it? And that's needed right?
So, Omega is my best bet then? Custom order http://www.omeg.co.uk/profile.htm
Yet, I don't see center detent as an option there, either.. ??

Dual 100k neg log is for fq and not center detent I presume.
( http://www.audiomaintenance.com/acatalog/om-01-072_extended_info.html )

Then I've noted 20mm diameter. That's correct, right?
The Omeg Eco-line was mentioned here (http://groupdiy.com/index.php?topic=2390), but that's 17mm diameter it seems (>> (http://www.omeg.co.uk/products.htm))
Maybe the P20 series then?
Title: Re: calrec PQ1549 help thread
Post by: Gustav on October 02, 2014, 06:04:54 AM
So, getting my pots sorted:
10k lin: AML has these: http://www.audiomaintenance.com/acatalog/om-01-069_extended_info.html
but that's not center detent is it? And that's needed right?
So, Omega is my best bet then? Custom order http://www.omeg.co.uk/profile.htm

Dual 100k neg log is for fq and not center detent I presume.
( http://www.audiomaintenance.com/acatalog/om-01-072_extended_info.html )

Then I've noted 20mm diameter. That's correct, right?
The Omeg Eco-line was mentioned here (http://groupdiy.com/index.php?topic=2390), but that's 17mm diameter it seems (>> (http://www.omeg.co.uk/products.htm))
Maybe the P20 series then?

Pot diameter doesn't matter. You can wire it up.

Center detent is in no way crucial.

Gustav
Title: Re: calrec PQ1549 help thread
Post by: G-Sun on October 02, 2014, 06:09:10 AM
Pot diameter doesn't matter. You can wire it up.

Center detent is in no way crucial.

Gustav
Thanks Gustav!

The bord is for one size of pots, right.
I understand the wiring-option, but are not the pots used for mounting the pcbs in the case
(and less soldering seems nice to )

And this is why I asked audiofreak about sizes as well. Pots and buttons needs to line up right.
So, if I have pcb-mount pushbuttons, I need pcb-mount pots as well, and they all need to be correct in physical dimensions. Or have I misunderstood?

Or, is case-mounted buttons and pots best? With wiring to/from board?
And then a dual unit is mounted with metal standoffs from bottom of the case?

I guess something like these are my buttons:http://no.farnell.com/alps/spun191400/switch-dpdt-0-1a-30vdc-latching/dp/1123855?ost=733118&rpsku=733118

And it needs to line up according to Chips frontpanel (attached)
Title: Re: calrec PQ1549 help thread
Post by: audiophreak on October 02, 2014, 11:20:10 PM
So, if I have pcb-mount pushbuttons, I need pcb-mount pots as well, and they all need to be correct in physical dimensions. Or have I misunderstood?

  as far as I know , this is correct. I have seen pix of at least one member who wired pots off board an used toggle switches instead of push buttons.

AML has the correct pots and push button switches for this project , the center detent is not necessary for the cut/boost.
Title: Re: calrec PQ1549 help thread
Post by: G-Sun on October 03, 2014, 03:14:08 AM
AML has the correct pots and push button switches for this project , the center detent is not necessary for the cut/boost.
Thanks a lot audiophreak! As you know I'll use your frontpanel-layout. So with this info I don't have to trace down every physical dimension of pots and switches.  You just saved me of some two hours work and a lot of worry :)

One thing: Switch cap size inner dimensions? Is this a standard thing, or?
I remember asking Collin about this a few years ago, for this project and these switches, but he had no idea.

And btw, pots: 20mm not 16mm, right?
Title: Re: calrec PQ1549 help thread
Post by: audiophreak on October 03, 2014, 08:18:48 PM
Yes , 20mm pots , I believe the switch post is 3.3mm square
Title: Re: calrec PQ1549 help thread
Post by: G-Sun on October 04, 2014, 03:02:02 AM
Yes , 20mm pots , I believe the switch post is 3.3mm square
Thanks a lot!
Title: Caps
Post by: G-Sun on January 11, 2015, 10:20:15 AM
Hi!

I'm ordering caps at Farnell, and have little idea if what I choose is wise or not.
Please tell me if anything looks like bad budget or quality decision:
100nok = 11.1 Eur = 13.1usd

Quote
Linje    Partnumber Ant.    Prod. delenr.    Beskrivelse    Price PriceTot
1    9708367    25    MCCB1C336M2DCB    MULTICOMP-MCCB1C336M2DCB-CAP, TANT, 33UF, 16V, RAD    kr 5,10    kr 127,50
2    1848399    12    EEUFM1H220    PANASONIC-EEUFM1H220-CAP, ALU ELEC, 22UF, 50V, RAD    kr 0,64    kr 7,68
3    1848463    4    EEU-FC1H470    PANASONIC-EEU-FC1H470-CAP, ALU ELEC, 47UF, 50V, RAD    kr 0,78    kr 3,12
4    1219466    6    EEUFM1E101    PANASONIC-EEUFM1E101-CAP, ALU ELEC, 100UF, 25V, RAD    kr 1,45    kr 8,70
5    9411674    25    MCCHU5220J5    MULTICOMP-MCCHU5220J5-CAP, CER, C0G/NP0, 22PF, 50V, RAD    kr 0,571    kr 14,275
6    1141797    5    F101K25Y5RP6UK5R    VISHAY BC COMPONENTS-F101K25Y5RP6UK5R-CAP, MLCC, Y5R, 100PF, 2KV, RAD    kr 0,92    kr 4,60
7    1006031    45    MKS2D031001A00KSSD    WIMA-MKS2D031001A00KSSD-CAP, FILM, PET, 100NF, 100V, RAD    kr 1,10    kr 49,50
8    1005997    5    FKS2D016801A00KSSD    WIMA-FKS2D016801A00KSSD-CAP, FILM, PET, 6.8NF, 100V, RAD    kr 1,40    kr 7,00
9    1006044    1    MKS4G022203C00KSSD    WIMA-MKS4G022203C00KSSD-CAP, FILM, PET, 22NF, 400V, RAD    kr 1,50    kr 1,50
10    1854848    10    ECQV1J683JM    PANASONIC-ECQV1J683JM-CAP, FILM, PET, 68NF, 63V, RAD    kr 0,94    kr 9,40
11    1890155    10    MKS4D031502B00KSSD    WIMA-MKS4D031502B00KSSD-CAP, FILM, PET, 150NF, 100V, RAD    kr 1,35    kr 13,50
12    1006039    5    MKS2C036801E00KSSD    WIMA-MKS2C036801E00KSSD-CAP, FILM, PET, 680NF, 63V, RAD    kr 3,20    kr 16,00
13    1215481    5    BFC236845104    VISHAY BC COMPONENTS-BFC236845104-CAP, FILM, PET, 100NF, 250V, RAD    kr 2,17    kr 10,85
Totalsum for varer:    Nkr 273,625
Title: Re: calrec PQ1549 help thread
Post by: G-Sun on January 15, 2015, 11:11:30 AM
Fuse:
Is 300mA slowblow fine for 230V/30A dual unit?
Title: Re: calrec PQ1549 help thread
Post by: musika on January 19, 2015, 02:32:01 PM
G-Sun,

Did you see this thread?

http://groupdiy.com/index.php?topic=58300.msg742807#msg742807 (http://groupdiy.com/index.php?topic=58300.msg742807#msg742807)
Title: Re: calrec PQ1549 help thread
Post by: cidw on February 24, 2015, 08:18:37 PM
Hello all,

I'm building this EQ for a college project, and I have a few questions.  I have 3 out of 4 filter sections on a breadboard, and I am running a signal from a Neutric audio analyzer through the circuit.  It can sweep and show the frequency response of each filter, which is very handy.

Question 1:  What is the intended signal level for the calrec?  Is it -10dBV or is it the more traditional pro line level?  The answer to this may be the answer to my second question.

Question 2:  While all the filters notch beautifully, when boosting some of them plateau at a certain point and stay flat at the top.  This is obviously not the intended response, or the notches would look the same.  Does anyone have any idea why this might be? 

I have referred to the original calrec schematic for the proper component values where the original schematic was in error.  I will post a corrected schematic after my project is complete.  I will also be required to design a new PCB layout which I will share for anyone curious.

cidw
Title: Re: calrec PQ1549 help thread
Post by: gyraf on February 25, 2015, 12:49:53 AM
Question 1:  What is the intended signal level for the calrec?  Is it -10dBV or is it the more traditional pro line level? 

Original intended level is a bit abstract, as this unit is cut out of the mixer's internal gain structure.

We have been using this eq at "classic" studio levels, that is, +4dB where there's still some 15-20dB headroom depending on your psu voltages.

The "flattening" of boost curves is probably clipping because of excessive levels - did you listen?

Note that the big cut/boost range of this unit makes it easily overloaded at full-level tone sweeps. In general, run eq sweeps at -20dB for necessary measuring headroom.

Jakob E.
Title: Re: calrec PQ1549 help thread
Post by: snaper on March 12, 2015, 06:03:14 AM
Maybe this was already covered, but...
Can I use DPDT and 4PDT toggle switches instead of those push-buttons?
Title: Re: calrec PQ1549 help thread
Post by: gyraf on March 12, 2015, 08:55:49 AM
yes
Title: Re: calrec PQ1549 help thread
Post by: snaper on March 12, 2015, 10:56:59 AM
yes
Maybe its just another silly question, but could be done this simply replace them pin-to-pin, no need to "cross wiring?"
Title: Re: calrec PQ1549 help thread
Post by: gyraf on March 13, 2015, 04:58:03 AM
That would depend on switch pin layout. Consult schematic?

Jakob E.
Title: Re: calrec PQ1549 help thread
Post by: snaper on March 13, 2015, 07:13:09 AM
Would like to use theses ms500 series Miyama ones :

http://www.miyama.co.jp/pdf/MS-500X-X-X.pdf
Title: Re: calrec PQ1549 help thread
Post by: jasonallenh on May 08, 2015, 08:15:05 PM
I'm about to start on a stereo pair of these. Did we decide that the 16V electrolytics are ok? It seems like some folks used them with no problems, but I suppose that is determined by your chosen operating voltage. I plan to run mine at +/-18, so I'd prefer to get it right the first time. All my Electros are at 50V, so I'm sure I'm fine.

I'm putting a Mouser Project BOM for this (I haven't been able to find one), so I will post it when I'm done. I've got to find a way to make myself useful around here!  :P

Title: Re: calrec PQ1549 help thread
Post by: jasonallenh on June 02, 2015, 01:26:46 PM
There is a 22uF electrolytic cap on the Rev 5 board that doesn't exist on the Rev 4... I'm assuming it was added as part of the insert point. Can I use a jumper in place of this I if I don't intend to use the insert point?

I ran out of the correct value... And I don't want to hold up build for two caps =\
Title: Re: calrec PQ1549 help thread
Post by: gyraf on June 03, 2015, 05:17:35 AM
I don't remember what that capacitor may have been - but I don't think any of them can safely be jumpered.

If you have any of larger value, just put that in...

Jakob E.
Title: Re: calrec PQ1549 help thread
Post by: jasonallenh on June 03, 2015, 09:22:31 PM
Thanks Jakob!

Title: Re: calrec PQ1549 help thread
Post by: unqlenol on September 18, 2015, 03:22:47 AM
Greetings all,

Loving this thread and this project and everyone's generosity and passion.
My PCB's are almost fully populated.

Would someone please  be kind enough to clarify a couple of issues:

1. Are the  two resistors highlighted in the attached pic  the correct ones ones to switch from 10k to 22k? I have looked at the schematic - I just want to confirm as there is a cluster of four 10k resistors at the input....not sure which two are the ones...

(http://i.imgur.com/Lq7o2aV.jpg)

2. What component is meant to go in the spot indicated in the pic below? There are no silkscreen markings to indicate a component or value...just two lonely solder holes that look like they are waiting for a cap.

(http://i.imgur.com/knpGuRz.jpg)

Please excuse my untidy board and the slightly cooked IC sockets!

Thanks in advance.

Nolan
Title: Re: calrec PQ1549 help thread
Post by: jasonallenh on October 02, 2015, 11:20:13 AM
unqlenol-

I don't know what that is for, but leave it empty... it will work without putting anything there.

=jh=
Title: Re: calrec PQ1549 help thread
Post by: jasonallenh on October 03, 2015, 03:14:22 PM
So I've completed two channels, and I've got some troubleshooting to do! I took a look at all of my IC voltages, and they're quite healthy, +/- just under 18V. I also fed the unit white noise and viewed the resulting processing with my DAW to see what is and isn't working. I double-verified my component values/locations/polarities, and they are are correct.

Channel one- I had the extra gain issue, replaced the specified 10K resistors with 22k, and it's PERFECT. This is definitely the way to go. My low filter, low mid, and hi mid are all working flawlessly. My issue is the high band. The gain control has no effect (meaning I also can't tell if the frequency select is working) and activating the shelf switch results in a pop and an almost complete loss of signal. I've double-verified my part values, and I know they are correct. I've also reheated some solder joints, and tried to clean off as much solder flux from the board as I can. Has anyone had a similar issue?

What could cause the full signal to pass through the hi filter unprocessed while also not allowing the filter to process the signal? Bad IC (I swapped ICs 5a and 5b and didn't see a change...)? A short somewhere in series with the gain pot?

Channel two- Not so close  :P The low and low mid are fine (seems like it is for most folks, too). The high mid band is allowing the full signal to pass unprocessed (like the hi band in channel one). The gain controls do nothing.

The high band seems to be influencing the signal all the way across the frequency range. Making changes to the high band actually allows me to get to 'flat' when using white noise, but not when the gain pot is at '0.'

I will certainly continue to check for shorts in the meantime... but any hints will be appreciated!
Title: Re: calrec PQ1549 help thread
Post by: jasonallenh on October 05, 2015, 03:00:43 PM
OK, so in looking at the schematic and I'm realizing that according to the schematic, the Shelf Hi switch is supposed to have two decks with no connection when ACTIVATED. On the PCB, there is only one? Is this correct? My problem is definitely in the vicinity of the shelf switch (ic5b/ic3b gets hot too). Im using the C&K 611-f4ueeau switch  (should be fine) but I'm missing something here...

Title: Re: calrec PQ1549 help thread
Post by: jasonallenh on October 05, 2015, 04:20:32 PM
I'm at my wit's end  :-[ It seems like everything I do has no effect... Hi band is still effectively bypassed until I hit the hi-shelf switch, then the signal drops out. I've been tracing the area around the switch and gain pots and can't find anything wrong. I'm just going in circles now.
Title: Re: calrec PQ1549 help thread
Post by: Harpo on October 05, 2015, 07:29:32 PM
OK, so in looking at the schematic and I'm realizing that according to the schematic, the Shelf Hi switch is supposed to have two decks...
It's a 4PDT (4 pole double throw, not two pole) switch.
Quote
... with no connection when ACTIVATED.
with only one of the 4 poles with no connection when ACTIVATED, the 3 remaining poles do connect to other nodes when ACTIVATED. Pg.2 of the schematic/pcb-layout pdf file doesn't show these minor errors from pg.1)
Quote
On the PCB, there is only one? Is this correct? My problem is definitely in the vicinity of the shelf switch (ic5b/ic3b gets hot too).
Shelf/peaking Hi-band is built around opamps 3b, 5a, 5b, 6a, 6b. These are dual opamps. How would you know only their b section gets hot?
Title: Re: calrec PQ1549 help thread
Post by: jasonallenh on October 06, 2015, 04:29:32 PM
Shelf/peaking Hi-band is built around opamps 3b, 5a, 5b, 6a, 6b. These are dual opamps. How would you know only their b section gets hot?
[/quote]

Because 3b and 5b are within the same LM833, according to the layout.  ;)

 Flipping the shelf switch still results in no signal passing. The gain knob for the high section has no effect. I'm wondering how one would go about bypassing the band (which is effectively what is happening). This would provide a hint. I'm looking at the 47k resister in series with the wiper of the gain pot...

I'm still doing my own footwork, but I don't have a lot of troubleshooting experience, so hints are sooooper-valuable. I'm going to test the PCBs for continuity- maybe a trace is broken.
Title: Re: calrec PQ1549 help thread
Post by: jasonallenh on October 12, 2015, 04:59:08 PM
I'm beginning to probe my circuit. When I hit the hi-shelf switch, the signal dissapears from one leg of the hi gain pot... I still have it at the wiper, and 5b, pin 7, so i'm not certain that this is wrong...
Title: Re: calrec PQ1549 help thread
Post by: jasonallenh on October 13, 2015, 01:14:37 AM
OK! Progress!

Pin 8 of IC 5B was shorted to Pin 7 through the  20k resistor's pad. these are super close together, so they are very easy to bridge.

IF YOU HAVE AN OPAMP GETTING PAINFULLY HOT, CHECK FOR THIS!

I cleared the bridge, and now the signal is passing through to where it is expected. It's really late now, so I can't run a white noise test to verify that the shelving filter is working. However, I imagine since the signal is now present at all three pins of the gain pot, the filter will be working as expected 8)

Now for Channel 2 :P

Right now, the high mid gain control has no effect on the channel, and with all gain knobs set to 0, there's a partial and uneven loss of signal. With the high shelf at max gain, the unit looks like it's at unity :o

My first guess is that the high-mid filter has a similar short since the symtoms (no gain, and a hot opamp) are similar. Stay tuned...
Title: Re: calrec PQ1549 help thread
Post by: jasonallenh on October 14, 2015, 12:36:11 AM
I did a white noise test with all my sweeps, and there is no issue! I've got one fully functional channel now =)

I hypothesized that the 'hot opamp' issue i had in channel one was similar in channel two, and I was right! :o

Once again, pin 8 (this time on IC 7a/7b) was shorted to pin 7. GUYS! if you have hot opamps, check for this! You're essentially mixing supply voltage with signal bus, thus the heat.

I corrected this issue, then replaced the 10 input resistors with 22ks for unity gain. NOW my problem is significant signal loss. Taking the unit out of bypass drops the signal waaaaay low. I'll read back through the thread (pretty sure this came up) to see what I can do next. Signal doesn't completely disappear, it just drops about 26dbs.

I'd still like some hints if anyone could help me out  ;)
Title: Re: calrec PQ1549 help thread
Post by: jasonallenh on October 20, 2015, 02:02:03 AM
Still probing!

I found another short-

Symptom- almost total signal loss between the two connected lugs of the hi and hi-mid gain pots.

Solution- a short. The short was located next to the INPUT IC. If you look at the silkscreen, there are the four pads for pins 1-4 of the input IC. To the right of that are four pads  exactly in line with each other. the first two  are supposed to have continuity, and the second two are as well. My short was between the 2nd and 3rd. If you have a great deal of signal loss in your unit... check for this one. The pads are VERY tight right here, so it's very easy to unintentionally short. I cleared it, and now the whole unit is working...

...except for the low band's hi-q switch.  If I have a boost or cut in this band and I press the hi-q switch, it acts like a bypass and the boost/cut returns to flat.

I'd ask for hints again, but I'm fixing this thing faster than I'm getting hints 8)
Title: Re: calrec PQ1549 help thread
Post by: jasonallenh on October 20, 2015, 02:02:37 PM
Woke up this morning, had a good 'ol fashioned bacon and eggs breakfast, and went to work. It took me all of a few minutes to find the last short and get the Hi-Q to work in my Low band. Two fully working channels!! 8) 8)

I circled all the traces that shorted throughout this project and kept a log of the symptoms associated with shorts at those locations. I'll be putting together a short guide for US builders... this project is too good to not be seeing more traffic!



Title: Re: calrec PQ1549 help thread
Post by: musika on November 04, 2015, 01:16:31 PM
Great to hear you will post some debugging notes on the Calrec EQ.  ...And glad to see you got this running.

What did you use for a front panel?  Or did you drill your own?
Title: Re: calrec PQ1549 help thread
Post by: jasonallenh on November 04, 2015, 05:53:57 PM
Great to hear you will post some debugging notes on the Calrec EQ.  ...And glad to see you got this running.

What did you use for a front panel?  Or did you drill your own?

Funny you should ask! My front panel should be arriving today. ;D ;D ;D

I found the FPD file on here somewhere (it all came as a .zip) and modified the design in FPD. I kept the scales (the same ones in Frank's design... I certainly can't take any credit for the panel, I only modified the existing design), got rid of all the infill ($$$), altered the labeling (really trying to cut it cheap here... I used "LMF" instead of "Low-Mid Frequency" less ingraving = less money), and added my logo, which I try to do for anything I build. I also modified drill hole sizes to match my pots/switches.

By the way, as a general troubleshooting rule for this project... TRUST THE DESIGN! all the silkscreen is right. Even those 'backwards caps' from earlier in the thread are fine as they are printed on the PCB. If you put the correct value components in the right places, this design works the moment you turn it on. Everything comes down to solder bridges. There are some pads that are impossibly close to each other, so you really have to be careful. I believe I am very good at soldering, and I still had four bridges total. 
Title: Re: calrec PQ1549 help thread
Post by: jasonallenh on November 05, 2015, 01:00:46 AM
Just a little glimpse... this is the first engraved panel I've ever gotten. It's BEAUTIFUL  :D
Title: Re: calrec PQ1549 help thread
Post by: tata on November 05, 2015, 04:57:09 PM
could anyone please help me adding a Q pot instead of the switch?
im planning to build this EQ but one Band per PCB, so it would be kinda 'modular' - here is my redrawn schematics (Hi-Mid Band):

http://beatbybit.com/gears/Calrec/sch_Calrec_Hi-Mid_separated.pdf

if there are any mistakes in it, please let me know

i already built one PQ1549 on Gustav's PCB, and i think i need more.. but a different layout, and some mods.
Title: Re: calrec PQ1549 help thread
Post by: musika on November 07, 2015, 07:20:42 AM
Very impressive panel.... I like the background color and the knobs that you selected.  Makes it a little easier to see what you are doing.  Thanks for posting this photo.
Title: Re: calrec PQ1549 help thread
Post by: jasonallenh on November 07, 2015, 03:05:30 PM
Very impressive panel.... I like the background color and the knobs that you selected.  Makes it a little easier to see what you are doing.  Thanks for posting this photo.

The knobs were tricky, the freq-select pots are 4mm D-shaft omegs, and the gain knobs were 1/8" bourns center-detented pots from CAPI-GEAR (I chose these because the center detent is much more accurate, so when the knob is centered, there is no boost or cut. others aren't quite that accurate).

That meant I had to source knobs that were visually identical while being mechanically (for different shaft sizes) different. I ordered a bunch of classic collet knobs direct from Elma -available in both shaft sizes- and they fit PERFECTLY. They also have a lot of cap colors available, with and without lines. I chose the colors based on the logo color scheme for my recording services logo-

http://www.ranchomolino.com/
Title: Re: calrec PQ1549 help thread
Post by: musika on November 08, 2015, 01:54:56 PM
Jason, 

This is great information on sourcing the pots for the EQ.  I had looked at the Omegs for the gain pots, but they didn't have the centers, and that's what I've been waiting on.  Now I just need the time to complete the builds.  I'll PM you about the front panel. 

Are the push caps round (what size did you use?)?  Hard to tell from your photo, they look somewhat cone shaped.
Title: Re: calrec PQ1549 help thread
Post by: jasonallenh on November 09, 2015, 01:42:44 AM
Yea. the gain pots were tricky... the leads aren't long enough, so I actually soldered jumpers on them to make them longer. The freq. pots were also an adventure... I couldn't source them cheaply, but I found a guy selling a ton of dual gangs with one rev log gang and one log gang. It was cheaper to buy double the necessary quantity and make the dual rev log pots than it was to order from omeg or import from AML.

The switch caps are C&Ks. These are also the pushbuttons I used. Datasheet here: http://www.mouser.com/ds/2/60/Fpush_1nov12-221205.pdf
Title: Re: calrec PQ1549 help thread
Post by: tata on November 09, 2015, 04:24:53 PM
The freq. pots were also an adventure... I couldn't source them cheaply,..

arent the Alpha dual C100k ones good? 6pcs is about 6 USD on ebay (thats what i use in my builds)
the pins dont fit directly to Gyraf/Gustav's PCB, but its not too hard to bend one row of the pins or add L shaped pins to the solder lug version of the pot.

a new PCB layout for this circuit would not be a bad idea, what you think? at least adding multipins to different pots, switches, etc.

(http://beatbybit.com/gears/Calrec/IMG_6952_pq1549_hi-mid.jpg)
my demo build of only 1 band, but with small switch and Alpha pots.
Title: Re: calrec PQ1549 help thread
Post by: jasonallenh on November 09, 2015, 05:05:14 PM
The freq. pots were also an adventure... I couldn't source them cheaply,..

arent the Alpha dual C100k ones good? 6pcs is about 6 USD on ebay (thats what i use in my builds)
the pins dont fit directly to Gyraf/Gustav's PCB, but its not too hard to bend one row of the pins or add L shaped pins to the solder lug version of the pot.

a new PCB layout for this circuit would not be a bad idea, what you think? at least adding multipins to different pots, switches, etc.

(http://beatbybit.com/gears/Calrec/IMG_6952_pq1549_hi-mid.jpg)
my demo build of only 1 band, but with small switch and Alpha pots.

Are those 1/4" shaft? I'd have never been able to match the knobs if I had went that route... I kinda painted myself into a corner with the bourns pots. I saw the alphas, but none with shafts under 1/4"
Title: Re: calrec PQ1549 help thread
Post by: tata on November 09, 2015, 05:08:29 PM
6mm, knurled shaft
Title: Re: calrec PQ1549 help thread
Post by: tata on November 24, 2015, 12:01:36 AM
if anyone knows a good way to replace the Q switch w/ a potentiometer, please dont hold it back..
a dual gang, high value pot? (1M and higher?)
Title: Re: calrec PQ1549 help thread
Post by: gyraf on November 24, 2015, 03:24:21 AM
If you really want adjustable Q, this will be a different EQ.

Maybe look at similar EQ architecture (state-variable filter) like the TC1140, the AmekM2500 or such.

Jakob E.
Title: Re: calrec PQ1549 help thread
Post by: Deepdark on November 24, 2015, 08:10:43 AM
Hi there.

May I know who sells the board now?  Thanks folks
Title: Re: calrec PQ1549 help thread
Post by: jasonallenh on November 24, 2015, 05:33:11 PM
Hi there.

May I know who sells the board now?  Thanks folks

PCB grinder was selling them, but ran out. I believe in a previous conversation, Gustav said he could get a new batch at a 10 board minimum.

=jh=
Title: Re: calrec PQ1549 help thread
Post by: Deepdark on November 25, 2015, 03:23:03 PM
Allright. If Gustav hadn't have time to release that one once again, I could always check by my side to print a couple of pcb's, if there is enought people interested in it
Title: Re: calrec PQ1549 help thread
Post by: ateshk on January 27, 2016, 02:03:16 PM
Hi,
I am building a stereo Calrec EQ. I finished both channels and I wired one to test. It sounds very low in volume and distorted. I have been looking for errors, I fixed a few solder joints and switched ICs but nothing changed.  Did anyone had any similar experience? or any suggestions for troubleshooting/fixing this?
Title: Re: calrec PQ1549 help thread
Post by: gyraf on January 28, 2016, 04:17:57 AM
ateshk,

Please read through this thread - you're not the first one to have some problems.

Jakob E.
Title: Re: calrec PQ1549 help thread
Post by: jasonallenh on February 13, 2016, 01:36:28 PM
Hi,
I am building a stereo Calrec EQ. I finished both channels and I wired one to test. It sounds very low in volume and distorted. I have been looking for errors, I fixed a few solder joints and switched ICs but nothing changed.  Did anyone had any similar experience? or any suggestions for troubleshooting/fixing this?

Go back and find my posts in this thread- I gave some specific solutions to common problems.
Title: Re: calrec PQ1549 help thread
Post by: ncoak on November 12, 2016, 07:12:31 PM
hey folks...4 years later and i'm out to fix the frequency distribution issue with my calrec, i'm at a bit of a loss.  on each band, the range is correct, but the frequencies are bunched towards the end position of the pot (in the high mids, for example, 5k is just a hair away from 7k). i thought maybe i had used linear pots by accident, but i bought some replacements, spent all day fiddling with them and arrived right back where i started.

anyone have any insight as to something else i'm overlooking that might be the cause of this? everything else works great, just can't dial in the correct frequencies. i'm using C100k dual pots as specified.

thanks in advance for any tips!
Title: Re: calrec PQ1549 help thread
Post by: jasonallenh on November 13, 2016, 11:47:17 AM
This sounds like you don't have rev log pots... Can you find the part number you used?
Title: Re: calrec PQ1549 help thread
Post by: kante1603 on November 13, 2016, 11:53:09 AM
This sounds like you don't have rev log pots... Can you find the part number you used?
That is what I thought too.


Best,


Udo.
Title: Re: calrec PQ1549 help thread
Post by: ncoak on November 13, 2016, 12:05:02 PM
and i as well! the replacement pots are alpha C100k....the "C" denotes rev log, correct?

got them here:
http://www.ebay.com/itm/6x-ALPHA-C100K-Dual-Stereo-Potentiometer-Log-Taper-pots-/170532518779?ssPageName=ADME:L:OC:US:3160
Title: Re: calrec PQ1549 help thread
Post by: kante1603 on November 13, 2016, 12:38:22 PM
and i as well! the replacement pots are alpha C100k....the "C" denotes rev log, correct?

got them here:
http://www.ebay.com/itm/6x-ALPHA-C100K-Dual-Stereo-Potentiometer-Log-Taper-pots-/170532518779?ssPageName=ADME:L:OC:US:3160 (http://www.ebay.com/itm/6x-ALPHA-C100K-Dual-Stereo-Potentiometer-Log-Taper-pots-/170532518779?ssPageName=ADME:L:OC:US:3160)
Hi,me again.


Taper codes are quite different by manufacturers,and it´s even important if it´s an old or newer code.
There´s a lot of info to find in the internet,here´s one (scroll down please):


http://www.resistorguide.com/potentiometer-taper/ (http://www.resistorguide.com/potentiometer-taper/)


You say the frequency are bunched towards the end position.May I ask what happens when you turn ccw,do they spread wider the more you turn to ccw?
If so then yes,you have a log. pot instead of rev.log.
I had something similar a while ago on a different project.


Good luck,


Udo.
Title: Re: calrec PQ1549 help thread
Post by: ncoak on November 13, 2016, 03:10:28 PM
right, the frequencies spread wider the further ccw it is turned - i knew this was likely indicative of the wrong type of pot, but read somewhere that C denoted revlog...that link clears it up, thanks very much. thought i was losing it!

will report back.
Title: Re: calrec PQ1549 help thread
Post by: kante1603 on November 13, 2016, 03:18:11 PM
right, the frequencies spread wider the further ccw it is turned - i knew this was likely indicative of the wrong type of pot, but read somewhere that C denoted revlog...that link clears it up, thanks very much. thought i was losing it!

will report back.
"C" often even indicated a center dentent position,just for info.
Not in your case of course.


Have fun,


Udo.
Title: Re: calrec PQ1549 help thread
Post by: PeteC on December 01, 2017, 07:44:28 AM
Hi just finishing up my 2 channel calrecs and due to test them this weekend.
One question

I haven't come across just a 2 pin balanced input like the one input Jacob's board before.
I am used to making 3 pin connections to xlrs on my inputs and outputs.

I am assuming I just need to ground the earth connection somewhere convenient on the board or chassis, and use the "hot" and "cold" xlr connections for the "+" and "-"  on the pcb.

Is this correct ?

cheers
Pete
Title: Re: calrec PQ1549 help thread
Post by: G-Sun on December 01, 2017, 08:31:46 AM
Yes, generally pin1 to chassis
(but I'm no expert)
Title: Re: calrec PQ1549 help thread
Post by: PeteC on December 03, 2017, 02:31:22 PM
All good - works a treat -
One channel up and running - now need to start on the second channel.

Studer 169 after that...

Cheers
Pete
Title: Re: calrec PQ1549 help thread
Post by: PeteC on December 03, 2017, 02:32:51 PM
Ah,
actually getting a bit of farty blocking distortion on some ( bass heavy settings )
But i think its just me driving the inputs too hard from the DAW send.

Pete
Title: Re: calrec PQ1549 help thread
Post by: PandaTornado on December 07, 2017, 09:26:38 AM
I have read quickly through this thread (sorry for being lazy) but could not see if anyone else had stumbled upon the same problem I have. Mine is almost done, everything has been checked and should run fine, however, as you can see from the attached photos, I am afraid that the solder joints on the upper channel will be able to get in contact with the lid of the case (risk for shorting the circuit).

Has anyone else had this problem? and more important, what was your solution? I will put some insulating tape on the solder joints of the pot close to the frontpanel as they propose the greatest risk, but it seems a little heavy to put it all over the circuit boards.

Does anyone know of any material that can be put on top of the boards, which is not harmed/altered/affected by the current running through the circuit and which works as an insulator? I have thought about using some antistatic plastic, but I do not know how it behaves then getting "powered".

Thanks in advance for your help.
Title: Re: calrec PQ1549 help thread
Post by: PeteC on December 07, 2017, 10:20:08 AM
Hi

I had the same issue on my recent 1073 build and used 1.5mm rubber sheet cut to size for the entire board just held in place by pressure between the board and the case and it works perfectly.   Lots available in cut sizes on ebay.

cheers and good luck with it
Pete
Title: Re: calrec PQ1549 help thread
Post by: PandaTornado on December 07, 2017, 10:53:38 AM
Hi Pete,

thats a great idea, I'll go straight to ebay to see what's there. Thanks for the advise :)
Title: Re: calrec PQ1549 help thread
Post by: antiehdas on August 16, 2018, 11:26:25 AM
Hello, I#m almost done with the pcb's of the gyraf calrec EQ. just one question, the 22uF electrolytic Cap on the one board is not on the pcb layout from the gyraf site. wich orientation is it ??? can somebody help me please, thankx !!!
Title: Re: calrec PQ1549 help thread
Post by: antiehdas on August 16, 2018, 11:27:19 AM
heres the pcb from gyraf
Title: Re: calrec PQ1549 help thread
Post by: musika on August 25, 2018, 10:11:21 AM
This is how I oriented mine... after looking at the schematic, the drawings are hard to read for that particular 22uf cap.  So I am not 100 percent sure either.  Maybe someone can verify.