DIY equalizer based on Studer 169 (standard and mastering)

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HI,

  just gotta share. Some eq we use for it's flavour - NeveyNeve for instance. SOme are tight - da Pultec for instance. Some are just darn flexible, smeary and with a signature - SSL 4000 etc etc etc. Some are just plain different. I am a big fan or Peter's LA-Z, My Helioses, API's, Pye's etc, and wouldn't dream of leaving home without them.

 
    HOWEVER . . . .


  This is just transparent. Plain and simple. I dunno how else to describe it. I think that you could possibly change the signature with different DOA's, but it''ll still be transparent!



        ANdyP


   
 
strangeandbouncy said:
I am getting a 6dB loss, and cannot for the life of me see why. I am connecting cold to shield in and out.

strangeandbouncy said:
Still don't know why I am down 6dB. It doesn't seem to be a bal/unbal issue.

Most likely your output is balanced with a simple inverting op-amp stage. With that kind of circuit you get "0dB" between hot and cold but "-6dB" between hot and ground (or cold and ground).
 
Hi Audiox,


  Thank you so much for this! There is no balancing simple inverting op-amp stage, just one 2520 as DOA 1. only 1 op-amp in total! I am now using 2503 (actually a profile 4808(?)) as 6dB make-up and balancing. I have no suitable input transformer to hand, so it is possible that there is something there, but surely, pin 3 tie to pin 1, and pin 2 hot should surely be fine(?).


    yet again, thank you!


    ANdyP
 
strangeandbouncy said:
There is no balancing simple inverting op-amp stage, just one 2520 as DOA 1. only 1 op-amp in total!

Not in the 169 but inside the device that is driving the unbalanced input of the 169.
 
Hmmmm, . . . .I did try NOT shorting pin 3 to ground, didn't I? Hmm, now I'm not so sure! I'll have another stab in the morning, and report back to moonbase.


  Hmmmmm.


    Kindest regards,


      ANdyP
 
Ok,


    I have checked and double checked. I am not shorting out 1 leg coming in. Even if I connect a transformer balanced output across pins 1 and 2 of the input, I am still losing 6dB!!!! On the face of it, it MUST be a balancing issue, but I'll be damned if I can find it! To make it worse, I have an API 553 EQ which is also unbalanced in/2503 output. It does NOT lose 6dB in the same slot, same wiring. AAAagh! Good news is that I do have a working eq. Bad news is I don't know when I am gonna be able to sort this out! Hectic busy mixing, and i NEED this eq now. FOrtunately, it is amazing with the 2503 makin' up the difference. I'll wait for my Carnhill 10k:10k to arrive before bothering any of yous with this any further . . .


    Kindest regards,


        ANdyP
 
Oh Blimey!


  just when I thought I could relax a little . . . Just inserted it pre my desk instead of as an insert in "tools, and it's got 6dB of GAIN now, where it was unity as i/o. Must be a balancing issue. B@llocks.


    B@llocks and Help, actually! I cannot see how it is possible NOT to short one leg, and connect cold to ground. It doesn't matter whether I do it externally or internally to the Lunchbox. I am obviously missing a point somewhere. I have even strutinised the Schemo for a 553 which is also unbalanced in, tranny balanced out.


    I am feeling rather sheepish right now . . . !


        Baaaaaaaah,


        ANdyP
 
Is this a good first eq project?  I've built several Synth modules and a mic pre.

Or would the Neuman W492 be easier?
 
It's pretty easy.  the only wiring that you need is In, Out, and Voltage.  Go for it! 
 
Hey guys,

Just to be sure (as I'm new to all this stuff), the switches I want are the CK1060 and the CK1059. That is, assuming I wanted to go with the silver contacts and blah blah blah...

Those would be correct switches to use though?

Thanks in advance, and sorry for the rookie question! ::)
 
nickeveslage said:
Just to be sure (as I'm new to all this stuff), the switches I want are the CK1060 and the CK1059.

I think your order codes are correct (for pcb mount / metric / shorting 1x12 and 2x6).

nickeveslage said:
That is, assuming I wanted to go with the silver contacts and blah blah blah...

Silver contacts work fine because they get cleaned when the switch is rotated.
 
Hello.

I´m wanting to do a version using pots instead rotaries for the gains. 5K lin for the highs and 22k lin for the lows. Is this correct ? can someone confirm ?

Also, which will the best way to implement an "EQ bypass" switch here ? any ideas? 

Thanks so much !
 
Silvas said:
I´m wanting to do a version using pots instead rotaries for the gains.

Such a project already exists:

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

Silvas said:
Also, which will the best way to implement an "EQ bypass" switch here ? any ideas? 

Bypass is included in the 500 version of the Studer 169 EQ.
 
audiox said:
Silvas said:
I´m wanting to do a version using pots instead rotaries for the gains.

Such a project already exists:

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

Silvas said:
Also, which will the best way to implement an "EQ bypass" switch here ? any ideas?  



Bypass is included in the 500 version of the Studer 169 EQ.


Wow ! I missed that one !

What i want is to put this eq after the so called "$5 preamp" with INA217 and hear how the combination turns out...i´m working on a proto layout.


Thanks !
 
Silvas said:
Hello.

I´m wanting to do a version using pots instead rotaries for the gains. 5K lin for the highs and 22k lin for the lows. Is this correct ? can someone confirm ?

Also, which will the best way to implement an "EQ bypass" switch here ? any ideas? 

Thanks so much !

I have 20 K Pots successfully used in my Version. Bypass is also described in this Thread, anyway.
Input to outer Lug
Output middle Lug
Eq input on other outer Lug

hope this helps...
 
I´m looking for the best way to implement the bypass, since i´ll be using the unbalanced EQ input but i´m leaving the output balancer...maybe there´s an "electric" way of bypassing the EQ, instead a "mechanical" one (switch or relay connecting input to output) ?

For now, the idea is putting a switch or relay to do the bypass and connect the unbalanced signal so it is routed just before the balancer, not sure how to do it the best way.
 
Relay based bypass is a solution or double switches and dual deck rotary switches. I think some schematics are around for relays. The sidechain board for the GSSL is balanced and has a relaybased bypass, if I'm not mistaken...
 
My idea is to bypass the EQ, which is unbal in/bal out, and is located after the pre, which is unbal out, so, for now, i think i'm doing it with relays. Don't want switches, to keep things neat. That's 3 relays, one for polarity (located at the bal. output), one for selecting the EQ in (from pre / from dedicated unbal eq in), and another for the eq bypass. It's just an idea i have ATM, but i'm cooking a proto in the future and hear...Thanks guys !

 
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