The Motown eq

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pucho812

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Wanted to share this.

another flowchart. Plus I wanted to start a discussion on the motown eq.
from what was said by John windt. The eq was passive and used similar tech as the langevin graphic eq. Faders were replaced with stepped attenuators and the eq consisted of 2 smaller eq’s wired in series. This allowed for the bands to not overlap. You will note there was a Fairchild line amp used for insertion loss however when it was decided that the tech department would build 40 of them for Motown, the Fairchild line amp was replaced with an opamp labs line amp plugin module. The transformers were custom made for Motown.
 

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Could have have some similarities with other graphic Eqs of the same era, like the Cinema Engineering Eq units:

1.-Cinema-Engineering-7080-B-Pair-Front_720x.jpg


https://retrogearshop.com/products/cinema-engineering-7080-b-pair
 
Info from Vintage King on the Motown EQ:
motown-studios-graphic-equalizer-pair-7479-vintage-7408881.jpg

https://vintageking.com/motown-studios-graphic-equalizer-pair-7479-vintage
The best EQs of the 60s were these custom made, 7 band Motown Studios Graphic Equalizers. They were very smooth units and were used in mixing and mastering for Motown Studios in their glory years.

A passive equalizer based on the Langevin EQ
  • Proportional 'Q'
  • Gain of +/- 8 dB of gain
  • Frequencies: 50, 130, 320, 800, 2000 5000, 12500 Hz
 
Info from Vintage King on the Motown EQ:
motown-studios-graphic-equalizer-pair-7479-vintage-7408881.jpg

https://vintageking.com/motown-studios-graphic-equalizer-pair-7479-vintage
The best EQs of the 60s were these custom made, 7 band Motown Studios Graphic Equalizers. They were very smooth units and were used in mixing and mastering for Motown Studios in their glory years.

A passive equalizer based on the Langevin EQ
  • Proportional 'Q'
  • Gain of +/- 8 dB of gain
  • Frequencies: 50, 130, 320, 800, 2000 5000, 12500 Hz
Whoops (or anyone!) do you have an idea about the topology or configuration of each filter here? how they are supposely conected (series, parallel...)?

opacheco
 
Whoops (or anyone!) do you have an idea about the topology or configuration of each filter here? how they are supposely conected (series, parallel...)?

opacheco

I have no idea of the circuit, but would love to know for sure.

In my engineering duties, being it recording, mixing or mastering I love to use simple EQs as much as possible, something that with the touch of only one knob takes to where you wanted to go.
Complex parametric EQs are my last resort, don’t get me wrong I use parametric EQs and I use them a lot, I don’t neglect any of the tools we have available, but if there’s an EQ that just does what I need with one knob I prefer to use that one first.
I’ve been using the plugin emulation of this EQ from URS for years, in orchestras and string sections if you want to remove “sawing” harshness from the strings just lower the 5khz knob, simple enough and it does wonders.

With all this I just wanted to say this should be a pretty sweet EQ and it would be great to have a schematic and know the circuit.
If Heritage Audio released the reissue it means the schematic exists
 
I have two Altec 9062a. I'm reading this thread interestingly because I'm currently thinking about what to do with the gain circuit.
I have a brief review on my blog. Since it is Japanese, please translate it automatically and read it.

『Altec 9062A パッシブグラフィックEQ』
awesome link. I translated to English. nice stuff.
Have you ever considered a tube make up stage?
 
awesome link. I translated to English. nice stuff.
Have you ever considered a tube make up stage?
Thank you for your reply.
DSC_3472.JPGDSC_3468.JPGI don't have any knowledge or skills about tube, so I think it will be a transistor circuit.
I haven't picked up the circuit yet, but I'll upload a photo that isn't on the blog.
The lowest and highest frequencies.
Precise inductors and capacitors are required to make a copy.
 
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