johnheath

REDD EQ without the RS127
« on: August 12, 2019, 05:21:23 AM »
Hi all...

I have read through the topic of the REDD EQ with the added RS127 (Brilliance pack) and it seems just fine.

But... I am a bit interested in building the REDD EQ without the RS127 pack. This is for a small mixer project to use in rehearsal situations and it does not require a full EQ when I just need to be able too cut and boost 100Hz and 10kHz.

My question is if somebody here can advise me on how to revise the schematic compared to the one with the added RS127 pack?

https://groupdiy.com/index.php?topic=51030.0

Best regards

// John
Nothing is impossible - It just takes some more time


ruffrecords

Re: REDD EQ without the RS127
« Reply #1 on: August 12, 2019, 12:32:40 PM »
It is not too hard. You basically strip out the mid section and replace its resistor ladders with two resistors. When I can get to my printer later today I will mark up a schematic for you.

Cheers

Ian
www.customtubeconsoles.com
https://mark3vtm.blogspot.co.uk/
www.eztubemixer.blogspot.co.uk


'The only people not making mistakes are the people doing nothing'

ruffrecords

Re: REDD EQ without the RS127
« Reply #2 on: August 12, 2019, 03:36:27 PM »
OK, here you go; image attached.

Core of the EQ is an attenuator consisting of the 22K resistor and the 5K1 resistor giving a nominal insertion loss of 14.5dB. Bass boost is achieved by adding a series RL across the 22K and top boost is applied in the same way using an RC network. Bass cut is by series C (with parallel R) in series with input. Tip cut is achieved by a series RC across the 5K.

I have scribbled out the bits you don't need, added the 22K and 5K1 (they basically replace the mid ladder) and gone over a few lines just to make sure they are visible. Anything not clear just ask.

Cheers

Ian
www.customtubeconsoles.com
https://mark3vtm.blogspot.co.uk/
www.eztubemixer.blogspot.co.uk


'The only people not making mistakes are the people doing nothing'

madswitcher

Re: REDD EQ without the RS127
« Reply #3 on: August 12, 2019, 07:26:46 PM »
Hi Ian,

Just in case you don't read them that often,  I have sent you a PM about boards for your RED Eq.

Cheers

Mike

johnheath

Re: REDD EQ without the RS127
« Reply #4 on: August 13, 2019, 03:10:22 AM »
OK, here you go; image attached.

Core of the EQ is an attenuator consisting of the 22K resistor and the 5K1 resistor giving a nominal insertion loss of 14.5dB. Bass boost is achieved by adding a series RL across the 22K and top boost is applied in the same way using an RC network. Bass cut is by series C (with parallel R) in series with input. Tip cut is achieved by a series RC across the 5K.

I have scribbled out the bits you don't need, added the 22K and 5K1 (they basically replace the mid ladder) and gone over a few lines just to make sure they are visible. Anything not clear just ask.

Cheers

Ian

Many thanks to you Ian

I had calculated the 22k but it did not seem to add up in the end... the 5k1 to 0V should do the trick.

Best regards

// John
Nothing is impossible - It just takes some more time


 

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