calrec PQ1549 help thread

[antiehdas]

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 !!!

 

[antiehdas]

heres the pcb from gyraf

 

[musika]

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.

 

[erquere]

Hi ! Im' almost done with the building of the calreq stero EQ, but there's a part I don't manage to find : caps for the ALPS Spun buttons, 6mm diameter, does anyone have found an alternative ?

Best regards

 

[audiophreak]

Hi ,
      I may have a set , and can give you some alternatives , not home at the moment but will check in the next couple days and let you know , very least can get you some part numbers.

Cheers

 

[peterc]

I have used caps from RS Components  before

https://za.rs-online.com/web/c/switches/tactile-switches-accessories/tactile-switch-caps/
https://za.rs-online.com/web/p/products/6821112/?tpr=4
https://za.rs-online.com/web/p/products/6821115/?tpr=1

 

[Slime_Lord]

Hi all, long time listener, first time caller!

I’ve gone through the entire thread and appreciate all the advice that everyone has provided.  I thought I would be in the clear when I fired my eq on but alas, it sounding funny.

I’m powering the EQ with a 15v power supply, the positive rail on all ICs hits around 15.5 v and the negative rail hits -14.7, nothing problematic.

When I run signal through, it’s completely distorted, almost in a hilarious way - honestly, it sounds cool but I’ve got my fair share of dirty outboard signal destroyers. 

The distortion almost sounds bit reduced and if the signal going in is lowered, only the transients are passing through the output. 

I’ve gone back over the board and corrected any bridges that I noticed, etc but there’s no improvement to the signal.  Is there any area on the board that I should concentrate on?  I have the feeling that there might be a resistor that’s letting too much signal through somewhere on the PCB and it’s clipping the signal somewhere.

I’m finishing the second set of PCBs this week and am hoping the other one works so that I can compare the 2.  I’m eager to get the first up and running though.  Any advice is greatly appreciated!

 

[gyraf]

http://gyraf.dk/gy_pd/calreq/calr_eq.gif

Look at the outputs of the opamps in turn - the signal goes through the input opamp, then 6A(out=pin1), 8A(out=pin1) 10A(out=pin1) and 12A(out=pin1)

When you know where you loose signal integrity, you have a place to start your search for err.

/Jakob E.

 

[Slime_Lord]

http://gyraf.dk/gy_pd/calreq/calr_eq.gif

Look at the outputs of the opamps in turn - the signal goes through the input opamp, then 6A(out=pin1), 8A(out=pin1) 10A(out=pin1) and 12A(out=pin1)

When you know where you loose signal integrity, you have a place to start your search for err.

/Jakob E.

Thanks Jacob, I followed your advice last night and was able to identify where the signal goes bad.  Turns out one of my op amps was bad, replaced it and now everything is working as it should!

 

[thewotan]

Hi!

I tried looking for some info on this with no luck, so I decided to post my doubt.

I'm about to start this build and I ordered these switches (the Alps recommended part is pretty difficult and expensive to get...):

https://www.mouser.es/ProductDetail/612-WBL2UEERQR05CLR

https://www.mouser.es/ProductDetail/612-WBL4UEEYQR05CLR


They don't fit the PCB, but I'm not too worried about that. Wiring them should work fine (attaching them to the front panel will be a different sroty though ;D), but I would like to be able to use the LED on the switches. I could wire them directly, but the light will stay on all the time...

I though about connecting the + of the LEDs to a voltage rail and them strapping the - to the pin on the switch that goes unconnected when pushed, but I'm not entirely sure that would work well, as I'm not entirely sure that that unconnected point goes to ground or not...

If this is not a valid solution, is there any other workaround?. Reading through the internet, I saw some comments about doing it with relays, but I couldn't gather much more info on that...


Maybe it is too much of a hassle, and I'm better off forgeting about the LEDs...

Anyway, any help is much appreciated.

Cheers!

 

[gyraf]

you will need a whole, uncommited (all 3 pins free), switch part to make LED light turn on and of with switch. You can not re-use a partial-used one (that is, only one pin free) from here, as they have audio flowing..

 

[thewotan]

Hey, Jakob, thanks for answering


That was what I was fearing... So for the DPDT switches I would need a 3PDT and for the 4PDT I would need 5PDT, right?

I might save these for future builds and use toggle switches instead

 

[gyraf]

yup..

 

[HyprDrivr]

Hello friends!

I am building a pair of these in one rack and need some advise on the PSUs
I have these of the shelf UMEC switching PSUs i have scavenged. +18/-18 300mA max per out.

1. Are these ok to use at all?

2. Can i use one for both EQs or should i use one for each? I seem to recall that one EQ should draw about 100mA.

 

[gyraf]

300mA should be plenty for both channels.

Check for switch-mode noise on completion just in case (I haven't tried to run these from smps supplies before)

/Jakob E.

 

[HyprDrivr]

300mA should be plenty for both channels.

Check for switch-mode noise on completion just in case (I haven't tried to run these from smps supplies before)

/Jakob E.

Thanks for the response.

Yeah, i have looked around but i cant find anyone have done that.
I will report back.

 

[HyprDrivr]

Hello friends!

So finally found som time to build this.
I have PCBs from Pusherman. Quality seems excellent, but earlier in this thread it is stated that there are some silkcreeening errors. I have compared to the silkscreening in the Gyraf documentation and they match perfectly so i assume this is fixed.

Does anyone have other info?

 

[gyraf]

IIRC it might have been something with the orientation of the inter-stage coupling electrolytic capacitors that does not match schematic. However, this is not important, as we don't pretend to be able to predict polarity of any DC that may be at those points. >pcb's are known working.

/Jakob E.

 

[Bernardo]

Hello, could someone tell me how are the switches?
the small ones are 2-pole 42mm dpdt, and the large 4-pole 52mm dpdt?
Thank you

 

[thewotan]

Hi there!

I just finished my EQ and I thought about sharing with the community to keep this great project alive and up to date. It worked (mostly) flawless from the beggining (which has to be the greatest feel ever...). I do have a problem with the bypass LEDs, which I'll comment on later.

I want to reassure everybody trying to put this together that with correct parts and soldering, the project works. Most (if not all) of the doubts I came across while working on this were solved in this very thread. Some errors I had (like ordering switches with integrated LEDs, because I thought it would be cool to have lights go on when things were pushed) were because I didn't took enough time to research by myself. So yes: read everything, several times, and if you can solder, you'll have a neat EQ in no time!

The BOM I used is the one on Gyraf's website. It is perfectly valid, but it does not reflect a couple of important aspects:

- The couple of resistors you have to change so you don't have a gain boost when engaging the EQ

- Electrolytic caps are rated at 16V, but you should use higher voltage caps (35V should be fine)

I got the PCBs and frontpanel from Pusherman (in the UK). Not very expensive, and the frontpanel is pretty great (it saved me a lot of trouble. I learned that drilling holes in steel is not very fun....). PCBs seem to match the layout on Gyraf's website and the components marked on the siilkscreen are correct.

For tantalum caps and the dual 100K neg log pots, I found that Tayda electronics was, by far, the best possible deal (Mouser didn't have the pots when I ordered most of the BOM, and you can find the Tantalums in ebay, but they are not as cheap...). I live in Spain, but Tayda's shipping fees are ridiculously cheap. I can't comment on the quality of the parts, because I'm a total noob, but they seem to do the work just fine and the sound is nice, so no problem for me


One of the "trickiest" part was getting the switches. You can find the suggested Alps in some places, but they are quite expensive. After my LED switches fiasco, I ended ordering some from Aliexpress, just to find when I soldered them that they were TOO high from the PCB and the board couldn't be mounted on the panel. Again, my fault for not taking the time to check and recheck everything. I ended ordering these:

https://es.aliexpress.com/item/32651661605.html?spm=a2g0s.9042311.0.0.55b363c0bO34tS
https://es.aliexpress.com/item/4000966504132.html?spm=a2g0s.9042311.0.0.55b363c0bO34tS

They fit perfectly on the PCB and they seem quite sturdy. Time will tell if I messed up, but so far, I think I'm good.

PSU is one of Volker's POSNEG supplies. Maybe it is a bit of a overkill for this project, but it's working great. BTW, I'm using +-15V, because in the LM833N datasheet the input voltage range is marked as 15v. I'm not totally sure if that's the maximum supply voltage range for the IC, but I didn't want to fry them all so I settled in 15V supply voltage.

One important thing with this project is to be very careful with shorted connections. There are a lot of very close solder pads, so when I finished soldering both PCBs I spent a while with a DMM checking the continuity was the same in all PCBs (asuming it would be difficult to bridge the same spot in two different PCBs). Checking with a magnifying glass could help as well, but checking continuity doesn't heart and I love the beeping sound

When I was done with that ¡, I followed Magnus' list of procedures before inserting the ICs (mainly, checking all the voltages are correct and mostly important, that the ICs sockets were getting the correct supply voltages). I slapped the ICs in powered up and it was the best f@#!ng moment of 2021!! Something I put together almost from scratch sounds pretty great

After that, all was just a matter of wiring it all together and putting it in the enclosure (I got a 2u Adam Hall enclosure from thomman). There it was when I found that drilling steel is no fun . It's not the best wiring in the world, but I think it could work. If any of you see any obvious mistakes, please let me know!. I didn't soldered yet pin 1 on the outputs to the enclosure (and I'm still not sure I have to do it....)


That Big fat ass wima cap is sitting on the downside of the PCB because, again, I didn't took my time to double check but I was getting... I did check voltage rating, capacitance, width, etc... But I didn't check how big it was, so I couldn't put two of them together...

On the next post I'll coment some little problems I'm having in hope any of you can shed some light on them