DIY equalizer based on Studer 169 (standard and mastering)

[druu]

Hi, i'm interested in building the mastering version of this EQ. I've looked through the thread but can't find anywhere to get PCB's? Gustav seems to only sell the 500 series version? Sorry if I've missed it.

Thanks

 

[druu]

I'm looking to start building one of these soon but wanted to use stepped switches in place of the normal lorlins. I'd like to build 21 step switches that provide 0.5dB increments either way of 0 on the gain switches but wondering if it's ok to just wire up 270r resistors in series each way for the gain controls? This will be used for mastering to a +/- 5dB range for gain controls @ 0.5dB increments is fine.

I'm not too clued up on circuit design but is there a specific range the pots need to be to fit the circuit? Eg. the HI GAIN controls seem to add up to 4.68k but if I was to use a 21 step rotary switch with all 270r resistors it would equal to 5.67k - is this ok?

Thanks in advance.

 

[dirtyhanfri]

Hi

First of all Thanks for the project Audiox

I'm building a stereo pair, etched my boards at home this weekend (newbie at home etching, but boards looks ok) and now I'm thinking in adding a mid band.

I've been reading this thread and had a look to the one about the 500 series version of this eq. But I'm not sure about how to implement it using 2 pole 6 pos. Lorlins. Should I calculate the resistor values for both switches for match the 10K pots? In gain Switch I'd like 1 db steps, could somebody give me some tip on how to calculate resistor values for this?

 

[audiox]

Please read through both 169 eq threads before posting. Not the first time I answer this question.

I'm not too clued up on circuit design but is there a specific range the pots need to be to fit the circuit?

Keep the original 4.7k and 22k.

but if I was to use a 21 step rotary switch with all 270r resistors

could somebody give me some tip on how to calculate resistor values for this?

The curve is not linear. Circuit simulator is your friend.

 

[druu]

Would it be possible to have more frequency selection if caps were soldered to the switches? Say 8 selections?

 

[dirtyhanfri]

A pic of my building

Finally I built the Mastering Version, sounds and work nicely, so clean (Noise at 50Hz is about -118 dbfs) so flat (up to 35Khz, there my unit looses the first db)

Now, I'm etching boards for the 500 series version. As adviced below it seems easier to replace pots with switches than make the mid band working with this...

Thanks again Audiox for making it avaible

 

[druu]

Has anyone tried adding rotary switches with the caps soldered to the switch for more steps? Any advice on how I could implement this?

 

[rmaier]

Check my post on page 11 of the thread on the 500 version of this eq:
http://www.groupdiy.com/index.php?topic=36522.200

 

[druu]

Thanks rmaier, I can see you've created stepped switches with resistors but just wondering if anyone has info on how I would go about using capacitors for the frequency selection on this particular version?

I might have to build the 500 series version into a 2U as you've done though, this will allow me to use some DOA's I have laying around.

 

[rmaier]

Actually, I did add frequencies to the low and high sections. I believe the 500 boards have spaces for additional caps, and I added a few on the switches as well. IFAIR, there's a fair bit of info about how to do it on the other thread.

 

[druu]

Would anyone happen to have the Gerber files for this project? Looking to get a few sets made but having the Gerber files would save me a bunch in manufacturing! Thanks.

 

[All Ears]

Hi folks,

I am hoping to embark upon this project soon and I wanted to have a transformer balanced input.

Any suggestion to what turns ratio / impedance ratio would be appropriate ?

Would any other mods to the front end be necessary ?

 

[Dr nEon]

Hi guys!

I'm building my second 169 eq... This time I'm using polystyrene caps in the High Freq section, for all five frequencies.

Can anyone tell me, for sure, which is the correct way round to orientate these, in this particular circuit, with regard to the outer foil?

There's only a handful of pages on the net covering polystyrene cap orientation, but the typical circuits used as examples are nothing like this one.

Looking at the schematic, where all the High freq caps join at the node with R25 (560r) , my instincts tell me that this side of the caps should be the inner foil, and that the outer foil should be on the side that goes to the switch terminals.
If it were the other way around, with all the outer foils of the unterminated caps connected together, I fear that it would act more as an antenna than a screen...?

I've no idea if my thinking is correct, though, and I would appreciate an education, here..

Since these caps are sensitive to heat, I only want to solder them in once!
 
Cheers guys

nEon.

 

[audiox]

I am hoping to embark upon this project soon and I wanted to have a transformer balanced input. Any suggestion to what turns ratio / impedance ratio would be appropriate ? Would any other mods to the front end be necessary ?

The API 500 version pcb already has the transformer option.

http://www.groupdiy.com/index.php?topic=36522.0

This time I'm using polystyrene caps in the High Freq section, for all five frequencies. Can anyone tell me, for sure, which is the correct way round to orientate these, in this particular circuit, with regard to the outer foil?

Generally, outer terminal to the lower impedance side.

In practice, the pcb tracks are much bigger problem... If you are worried about the interference, use a metal enclosure or a local grounded shield.

 

[tombaker]

Hi,
To repeat a request from above, does anyone have the gerber files for this?
I asked Gustav and he doesn't have them anymore and I'm looking to get a few done.

 

[glover]

Is there any easy way to add more bands for one channel or do I have to connect few PCB's in line ?

Wasn't that question, do know why I was thinking it it's PEQ and it's shelve EQ.

 

[pvision]

I'd be up for a couple of boards if anyone is making them

 

[steves.mastering]

Hi all

I know this has been asked before.... but does anyone have the etch files or gerbers or anything so I can get a stereo set of these to make a nice mastering eq?

Thanks

Ste

 

[dmp]

PDFs are on the first post. You can self etch them from the PDFs.

 

[steves.mastering]

So sorry... blonde moment by me.... i thought there was only the PDF for the control pcb... is there not another pcb to this?? wow thats awesome.

Sorry hadnt looked into this project yet, wanted to know i could get the PCBs ... and assumed it was like the GSSL.... main board and Control board.

anyway thanks, much appreciated =]