REDD EQ, Helios 69 and Dick Swettenham

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myers1st

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Thanks Ian, yes, 56dB will be plenty and there are other preamps for when it is not.  Just wanted to consider the option before I lock in a front panel layout. 

So is it as easy as classic 10k pot > Helios In and Helios Out > Classic Return?

Ordering parts and will post progress with the project as I go!





 

Ted Krotkiewski

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Nov 4, 2018
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mike said:
I used a mean well external 24v wall wart type transformer (picked it as it's the same line as the Heritage Audio HA-73EQ uses) It's a cheap switching psu but it seems good and is noiseless.

Hi Mike.
Congrats on an absolutely stunning build!!

If I may ask, do you have a link for where to buy that Wall wart PSU that you used?
Thank you for your time.

Best.
//Ted
 

mike

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Ted,
I used Mouser part number: 709-GST25A24-P1J

For panel mount power entry, I used Mouser part: 502-721AFMS
 

HerbertR

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Hi, I ve nearly finished a Dual Version of Ian's Redd EQ. As for the MakeUp Stage I built the recommanded easy Fet Amp Circuit. First sound tests are awsome good. They EQ has a audible sound leaned on Helios EQs, really excellent colour. That EQ adds so much life and character.. ❤️
The Hi/LoShelf Combi with the Brillinace EQ is fantastic clever. Easy and versatile like a Channel EQ....

I will equip the circuit with Edcor 10k/10ks the next days. Frontpanel 19" is already designed and orderd from Franks (I am very excited what you think about..). Does anybody know if there is a Zobel Network necessary for that 10k/10k WSM Transformers from Edcor?
 

ruffrecords

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The Edcor WSM is really an output transformer. For a really good quality 10:10K input transformer at a reasonable price try the

OEP K30A06C


Cheers

Ian
 

HerbertR

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The Edcor WSM is really an output transformer. For a really good quality 10:10K input transformer at a reasonable price try the

OEP K30A06C


Cheers

Ian
Hi Ian, for a LA2A Build from Silent Arts I ve also used Edcor WSM for the Input because they are the recommanded ones, most used - because I think they are cheap and have lots of excellent "Iron" sound, and they do a fantasic job - without any shields. Totally quite, no hum, nothing....
Is there an other reason not to use them except of the missing shield? BR
 

ruffrecords

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Hi Ian, for a LA2A Build from Silent Arts I ve also used Edcor WSM for the Input because they are the recommanded ones, most used - because I think they are cheap and have lots of excellent "Iron" sound, and they do a fantasic job - without any shields. Totally quite, no hum, nothing....
Is there an other reason not to use them except of the missing shield? BR
Not really. Transformers don't care what you use them for and if you have used it this way before with good results then I say go for it. They can handle 10V rms which us +22dBu so they are unlikely to saturate.

Cheers

Ian
 

ruffrecords

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Nicely done. (y)

When it is finished, would you send me some photos of outside and inside so I can pass them on to my friend Pierre. He hosts a gallery of projects based on my designs:

EZgallery

Cheers

Ian
 

thakava

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Nov 19, 2011
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I've read through the posts here several times and still don't believe I have the entire picture if I go the helios line amp for makup gain.

Would it be 2128 straight to a 600:600 transformer? (I see this is already a no after more reading elsewhere)
or 2128 to 22113 to 600:600 transformer?
Or just 22113 to 600:600 transformer will provide enough makeup gain?

Also on the 2128 I don't understand what the FB "output" is exactly. Is it just a resistor to ground and the value sets the gain?
Looks to be so, and also could be replaced with a trimmer as well as R8 on the 22113 could be a trimmer to set gain?

As an experiment, I'm attempting to build the RS127 portion of the schematic on turret board/point to point.

Still waiting on the Carnhill inductor and a 10k:10k input transformer in the mail.

I'm thinking of keeping it passive, going balanced in, then straight out to di on a 1073 clone for now, but if I used an external PSU, I could have makeup gain.

I'm housing it in a small 6x4" hammond case similar in size to the original. Resistors are soldered directly onto the switch. Caps and inductors are the only things on the turret board and the carnhill inductor will be mounted to the case with standoffs. Transformer will be rear mounted.

Here's a pic of my progress so far while I'm waiting on parts!

imHf9s4.jpg
Very Cool! Been looking to make one myself! Would you mind sharing the parts/values?
Best//
Tom
 

mike

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Very Cool! Been looking to make one myself! Would you mind sharing the parts/values?
Best//
Tom
I used the values from the REDD EQ earlier in the thread. I just removed the Bass and Treble portions leaving only the RS-127 presence EQ.
 

thakava

I´m into gear...
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I used the values from the REDD EQ earlier in the thread. I just removed the Bass and Treble portions leaving only the RS-127 presence EQ.
Very Cool! What are the values of the caps? I have a few of the REDD EQ cards, looking at them, but not so sure which parts are solely for the Bass and Treble.
 

mike

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Very Cool! What are the values of the caps? I have a few of the REDD EQ cards, looking at them, but not so sure which parts are solely for the Bass and Treble.
Here's the turret board layout I made when I built mine - it doesn't include the line amp for makeup gain (you can use whatever you want or just use a di input on a mic pre. Also doesn't include input transformer wiring as that differs depending on what transformer you use. I used the Jensen JT-11P-1 input transformer.
rs127 layout.JPG
EDIT: Here's the schematic edit I made for myself (off of Ian's original) to recreate an RS127 only.
Note: The resistor value corrections are for real world resistor values vs. the ideal values in Ian's original. I used carbon comp resistors in my builds.
RS127 Corrected circuit.jpg
 
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mike

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I never actually posted final photos of these - I made a pair and they sound great!
I don't believe they (the RS127 only) are worth the effort and cost to build honestly - the full REDD EQ that Ian designed is not much more effort and you get a 3 band eq not just 1. Much better value for your time and effort. But they do work well and they also look pretty cool, haha.

rs127 pair.jpg
 
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