REDD EQ, Helios 69 and Dick Swettenham

[Cyril Jones]

 

[Cyril Jones]

View attachment 103606

This is the Helios amplifier referred to above, my version compressed to a half size board also containing the voltage follower used in the Helios modules to drive subsequent stage of the Helios modules.. The pre-set potentiometer sets the gain when used as a stand alone amplifier rather than the microphone stage. Useful when used as the second post EQ stage. It is stable.
Cyril

 

[HerbertR]

Hi, I am also very happy with Ian's provided TL072 based Makeup circuit. Instead of the Fet TL072 I am using Burr Browns OPA2604 AP as direct replacement. These Burr Brown Opamps draw compared to the 072 a few more mA's - but these guys also sound in my opinion better - audible more detail. After the Opamp Makup circuit the signal passes in my build 10K/10K Edcors that gives an extra nice coloriziation.
At the Input I use an electronical debalancing board. I love this EQ, it is really fantastic, very powerful, gentle to play around. I also tried other R35 values what results in different Q Factors. Might be an option for a couple of engineers to trim the piece with broader Q and less gain to the ultimative cool mastering EQ. All pots/switches are stepped, perfectly ....Btw my unit shows a really good flat frequency response curve with about a decreasement of <1dB upper 14kHz to 20kHz (at neutral settings ), very happy with it. And the build did not break my bank....

 

[ruffrecords]

My latest REDD EQ design which I call REDDPLUS, uses a single string of resistors to set the boost and cut levels of all bands. You can add as many bands as you like just by adding a rotary switch and the appropriate R, L and C components for shelving or peaking responses. You can also design the resistor string for different boost/cut ranges. I recently designed and built a custom stereo mastering version with six bands of boost only in 0.5db steps up to 2.5dB.

Cheers

Ian

 

[bleachboy]

Wow, I’d be very interested in that one Ian ! I have only downloaded your previous Redd EQ design files, is this new mastering version available ?

Many thanks,

Louis

 

[ruffrecords]

Wow, I’d be very interested in that one Ian ! I have only downloaded your previous Redd EQ design files, is this new mastering version available ?

Many thanks,

Louis

Nothing is available yet. There is a long thread about the design here:

Passive Mastering EQ

Bear in mind this began in 2017. There was much discussion about what is should do and a lot of hurdles to overcome in its implementation but it basically works. I got distracted onto other things untill I was asked to build for a specific boost only stereo mastering EQ which I have built and delivered.. If I rememeber correctly it had six or seven bands; one high shelving and one low shelving plus four or five peaking mid bands. The boost range was just 0 to 3dB in 0.5dB steps but each band was stereo.

Cheers

Ian

 

[bleachboy]

Thank you Ian.

The more I look at all of you guys’ gorgeous builds on the last few pages of this thread, which I’ve read many times over the years, the more I realize with great sadness that I absolutely don’t have the skills to assemble a pair of these Redd Eq´s…
I use the plug-in version all the time, it started becoming a sort of secret sauce for me. I absolutely need those in my studio !

 

[TwentyTrees]

I absolutely don’t have the skills to assemble a pair of these Redd Eq´s…

...Yet! Everyone starts from that same place. If it's something you want to do, it's absolutely possible to work up to a build like this. The usual advice is to get your soldering skills honed in by starting on low-cost, low-risk builds like cables and guitar pedals, then try a preamp kit or two, and work up from there to a PCB-only project like this.

Believe me, if I can do it then you certainly can!

 

[ruffrecords]

...Yet! Everyone starts from that same place. If it's something you want to do, it's absolutely possible to work up to a build like this. The usual advice is to get your soldering skills honed in by starting on low-cost, low-risk builds like cables and guitar pedals, then try a preamp kit or two, and work up from there to a PCB-only project like this.

Believe me, if I can do it then you certainly can!

+1

You will find plenty of help here to get you started on your DIY adventure.

Cheers

Ian

 

[bleachboy]

Well I do a lot of cable soldering (big pedal board…), a couple of pedal mods and and I have (semi successfully, that’s for another thread) repaired a vintage mixing console, but that’s about it.

Is there an up to date BOM available for this build ? Also, can I just send the .png file of the circuit board to a company that builds them ? Or do I have to order the circuit boards from you directly ?

Thanks a lot !

 

[ruffrecords]

The boards are available to buy from me via my website:

Custom Tube Consoles - Ruff Records PCB Emporium

Documentation including BOM can also be found there:

Custom Tube Consoles - DIY

just scroll down and click on the REDDEQ folder. I have attached the assembly instructions to this post for you.

Cheers

Ian

 

[bleachboy]

Fantastic ! I hadn’t seen your new website.

 

[ruffrecords]

.Fantastic ! I hadn’t seen your new website.

Unfortunately I cannot access the old site to edit it to include a pointer to the new one

Cheers

Ian