Studer 169 EQ in API 500 format

[strangeandbouncy]

Hi,


      just finished my second pair, again with 6 way switchable frequencies top and bottom, no mid. Again, I used two DOA's, with the one that should be for the mid-band re-wired as balanced input. The output is impedance balanced. My first pair has 2520's, and this pair has the OA10's. BOth sound really good, the 2520's are a bit more "forward" in the mids, and the OA10's are very silky smooth and warm sounding. I have also tried it with 5534's, and it sounded pretty amazing too. My favourite is the OA10 version. It is just a tad more subtle.

    For what it is worth,  I rarely use anything but one frequency top and bottom, normally 28Hz at bottom, and 19kHz at top.


    I am very fond of these eq's. They are very simple, and very effective.


  Kindest regards,


    ANdyP

 

[geoff004]

I just finished up 1 of 2 EQs and it seems to be working OK except:
when I turn the mid frequency knob full counter-clockwise I get some serious oscillation - almost sounds like feedback.
Any ideas?

I need to get a couple more caps to finish out my high and low frequency selection - I'll post pictures after I've got them both finished up.

 

[Tweekhead]

Hello!

I'm going to try to build 2 channels of these EQs, and I was wondering if anyone could help me out with a BOM for the transformer balanced input version of the unit. I looked at the component layouts and got all the values written down, but I'm very new to electronics and trying to learn to read schematics, so I'm not sure what spacing I would need to go with for the pcb foot prints, or voltages I should be looking for.

Thanks,

Arthur

 

[regularjohn]

My first pair has 2520's, and this pair has the OA10's. BOth sound really good, the 2520's are a bit more "forward" in the mids, and the OA10's are very silky smooth and warm sounding. I have also tried it with 5534's, and it sounded pretty amazing too. My favourite is the OA10 version. It is just a tad more subtle.

I really like it with the LME49710.  You have to add psu decoupling for em, but it's ultra transparent.  Definately one of my favorite EQ's for mixbuss applications.

 

[RedNoise]

Hello!
...if anyone could help me out with a BOM for the transformer balanced input version of the unit...
Arthur

Hi Arthur , are talking about ALL the components , or only the input transformer?

 

[Tweekhead]

Hello Rednoise!

I'm looking for all the components, as I ordered 2 of the Neutrik NTL1 transformers already. I'm so new to all of this I didn't realize I could build the unit without the transformer option until after I placed the order :-[ Lead time in the US is 8 weeks, so I ordered it from the UK, and it was pricey. I'm confident I could find all of the resistors, but I was looking for possible help on the capacitor selection. I've used Wimas in other projects and would like to use them on this, but again, I'm not sure which ones would be the best for the application.

Thanks,

Arthur

 

[audiox]

I looked at the component layouts and got all the values written down, but I'm very new to electronics and trying to learn to read schematics, so I'm not sure what spacing I would need to go with for the pcb foot prints, or voltages I should be looking for.

- resistors 1% metal film
- 100n power decoupling caps, ceramic multilayer 50V or higher R=5mm
- pF range capacitors, ceramic, any voltage R=5mm
- nF range capacitors, polyester, any voltage R=5mm
- 10u electrolytics, 25V or higher R=2.5mm
- 100u electrolytics, any voltage R=2.5mm

 

[Tweekhead]

Audiox,

Thank you so much!



Arthur

 

[geoff004]

I finished up my pair tonight and they sound great except:
with one of the EQs when the mid freq knob is full counter-clockwise and the mid gain is up about 3 o'clock the thing just puts out a loud tone.
I checked component values and solder joints and I'm not really coming up with any explanations.  I also switched op amps around and no change.
Any ideas?
Anyone???

I'll post pictures when my switch button-caps come in.

 

[Matthew Jacobs]

Hi Everyone,

I'm thinking of getting 2 of these boars from Gustav to make a stereo EQ.

Can I add another Mid band simply by adding another mid section in series? Sort of repeat everything in between C9 and R16?

Do I need to isolate each section with a 100uF cap?

I'm thinking of building a EQ that does Low Shelf, Mid, Mid, High Shelf

Is that possible? I think so, right?

J

 

[strangeandbouncy]

Hi,


    I think you might get some interaction between the mid-bands(?) if you try this . . . .iirc an earlier discussion.



    Kindest regards,



  ANdyP

 

[Matthew Jacobs]

Thanks ANdyP

I tried to search, but found nothing. Is it somewhere in this thread?

I know you just bypassed the whole mid section. Do you find you don't miss it?

I was thinking of using these boards to build a "mastering version" as the official "mastering version" doesn't have pinouts for DOAs.

I need to investigate having 2 mid bands, cause it's something I think I'd want...

JD

 

[dbeeson]

I've finished a stereo pair of these babies and they sound fantastic.  Very neutral, not harsh at all. I'm just wondering, I used the larger omeg plastic pots for the build and the knobs stick out a little further than I'd like them to.  I have the other pots that will fit better except the dual 22k...would it be ok to use a dual 25k there instead?  Once again, great build!

 

[Matthew Jacobs]

I used the larger omeg plastic pots for the build and the knobs stick out a little further than I'd like them to.

Is it simply that the shafts are little to long. If so you can easily cut them to length. I usualy put some electrical tape to seal the joint between the shaft and the body so that cuttings don't go into the pot. Yeah, but simply use a saw to cut the shaft.

JD

 

[dbeeson]

Yeah, it's not the shaft that is the issue.  I've already cut it down nicely, but the threads are really high on the pots so they stick out past the front panel.  They don't look that bad really. I just wanted a more professional look I guess.  So no go on the 25k?  I guess I could try it out.

 

[Matthew Jacobs]

Yeah, it's not the shaft that is the issue.  I've already cut it down nicely, but the threads are really high on the pots so they stick out past the front panel.  They don't look that bad really. I just wanted a more professional look I guess.  So no go on the 25k?  I guess I could try it out.

Put some washers behind the panel so that the pots sit a little further back...

 

[dbeeson]

ahh yes, but the issue is that the front panel will no longer sit flush with the lunchbox.  I'll try it out and see what happens

 

[Matthew Jacobs]

ahh yes, but the issue is that the front panel will no longer sit flush with the lunchbox.  I'll try it out and see what happens

Oh woah... didn't realize the the API 500 format was that tight... not much room for moving things around... is it because of the pin thing at the back?

 

[geoff004]

here's my pair.
There's still something a little funny with one of them, with the feedback and all.  I guess no one can help.
Anyhow, they're intended for tracking purposes.  Stuffed with the GAR1731 op amp and they sound real nice.

 

[3nity]

where you get those push buttons caps...??
if you compare the good one vs the not so good then i'd say swap the pot..
THanks..