Gyraf Calrec EQ - PCB Rev 5

[quote author="thedug"]
The schematic from the pdf at gyraf has some(most) of the tanlums in a different direction. The component diagram is the same as the board, but the schematic has the polarity oppositie. Should I follow the board or the schematic. What should I do if the cap isnt' labeled? Should they all be backwards?[/quote]

I hope my re-draw is correct, but I used the stuff from the Gyraf page. Would be bad if the documentation has such errors in it.
http://www.groupdiy.com/index.php?topic=18257

[quote author="thedug"]Also, there is a 100uF cap in series with a 100nF film cap near the 47uF electrolytic. The baord says 22uF but the parts list and pdf have 100uF. Will there be any problems with using the 100uF?[/quote]

Hmm, I used 100 uF in my re-design. But electronically I'm an absolute greenhorn, so I don't know if that's correct.

Hi there, just saw the latest post and, having realised how long it was since I looked at the forum, I caught up on some of the latest threads, some interesting mods - I like the idea for a bypass for each band.

I finished one Calreq (Rev5), which I included in a mad filter matrix for a college project that's been gathering dust since graduating in the summer.

Having originally bought two sets of PCBs, I'm beginning to think the new year'll be a good time to get the second going and correct a few errors I made with the first build. This might be helpfull to those newbies out there - the first one I built as a complete electronics novice, so it was a pretty steep learning curve, from all sides; getting parts reading the schematics the whole nine yards.

Anyhow, probs I encountered included;
1. not reading everything thoroughly ! :roll: see my prev post - all the info I needed was there on Gyraf's schematic.
2. the polarity of a few of the caps is reversed on the sreen print on the PCB I had, but were easily corrected by following Gyraf's schematics.
3. Magnus' parts list uses 16v caps and the other ccts on my 'matrix' required an 18v supply - as a novice I only discovered the mismatch when the caps on the Calreq started popping
As Gyraf stated 35v caps work fine and using them allowed me to integrate the Calreq with my other ccts
4. I thought I'd found a source for the Neg log pots, but they're no good and obviously not 'true' audio taper - I'll try the Omeg ones for the next.

Apart from those, it all went great and the EQ itself (bearing in mind my error with the pots) sounds real nice, very clean too.

The only dissapointment - a MINOR one because of my intended application - was the ammount of cut/boost for each band. It would've been nice to be able to make this more, but I figure that's do-able - and if Sonicwarrior's mod works ok (couldn't find a 'final' answer in the discussion between Sonic' and SSL'), that'd provide the solution for me.

A long post, I know, appologies if it's irrelevant/in the wrong thread/rambling on needlessly, but thanks to Gyraf and The forum users for providing so much detailed info - it's a great DIY project and the results are well worth it
:grin:

Thanks for the info. :thumb:

[quote author="Al Stitch"]
2. the polarity of a few of the caps is reversed on the sreen print on the PCB I had, but were easily corrected by following Gyraf's schematics.[/quote]

The schematic is a bit confusing in my eyes: Is plus where the small line is?
(Else my drawings are wrong)

[quote author="Al Stitch"]
It would've been nice to be able to make this more, but I figure that's do-able - and if Sonicwarrior's mod works ok (couldn't find a 'final' answer in the discussion between Sonic' and SSL'), that'd provide the solution for me.[/quote]

Do you mean the band-bypass switches? :?

I am currently working on my (first) calreq.

pots are mounted, now i am stuck with the 22uF electrolytics (not the tantal one).

on the "left" board (with OUT pad on the right lower side when the pots looking away from you) i have multiple 22u but some of them are labeled as i know (with +) but others just have a DOT.

so ? what is what there; same applies to the other pcb.

any help appreciated.

..look at the layout .pdf-file..? ..consult the schematic..?

Jakob E.

I guess plus is wherever a marking is.
The plus is at someplaces overlayered with some white areas, I guess (I see no dots, only plusses with missing lines).

I guess plus is wherever a marking is.

Click to expand...

No, I don't draw it like that. There should be a "+" - but sometimes placed where the hole is drilled (or silkscreen is avoided close to drilled holes).

Use the layout as reference...

Jakob E.

[quote author="gyraf"]There should be a "+" - but sometimes placed where the hole is drilled (or silkscreen is avoided close to drilled holes).[/quote]

That's what I've guessed (using other words and you are telling a reason).

And these plusses that are overlayed by the hole drilling or whatever is what I meant with "Marking".

:thumb: