calrec PQ1549 help thread

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antiehdas

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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 !!!
 

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musika

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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.
 

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erquere

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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

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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

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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

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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

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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

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gyraf said:
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

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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

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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

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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🤔
 

HyprDrivr

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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

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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

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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

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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

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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.
 

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