Igor

As far as I know, there's no any legal issues with it :)

Sooo....I will have some time this weekend to start PCB design.

Need some input from you, lady's and gents.

My guess is:

Choice of input transformers for mic pre;

Same mic input amplification stage like used in older consoles (3-transistor's circuit);

Optional DI (HI-Z buffer) before input transformer;

RM-8 or RM-10 layout for HF inductor;

AFAIK the LF inductor originally done on iron or nickel lamination, small size core like EI-24...
if someone can put lite on this?

As line out amp, I'd used prooven second half of BA-283....fat, Class A, etc...
This will make actually a bit different thing, not like already commercially available
and will reduce headache caused copy-paste-righters....etc.

Insert after micpre? Line input option?

And, replacement for Elma switch to something cheaper, as well as (maybe) use of Lorlin switches+resistors
instead of potentiometers?

Your input wellcome. I think this can be really nice project.

Ah, yes....just a thought....Lunchbox format card wit EQ only????


« Last Edit: November 12, 2009, 08:20:49 PM by Igor »
http://www.ij-audio.com
(new site hopefully will be up in July)


SSLtech

Re: DIY Helios EQ? Let's do it!
« Reply #1 on: November 10, 2009, 08:24:22 PM »
I think this might be a little too contentious.

Helios gear IS in current production, and Tony Arnold (in Europe) is known to visit forums such as this and voice his opinions.

If a version was attempted, I'd suggest some considerable changes and a COMPLETE avoidance of the term 'Helios'. It is a registered trademark and will bring down quite a lot of trouble, I've little doubt.

Keith
"A waist is a terrible thing to mind"
Quote from: PRR
Ah, but that was 1999; we don't party like that any more.

Igor

Re: DIY Helios EQ? Let's do it!
« Reply #2 on: November 10, 2009, 08:32:04 PM »
Aha, will change the topic name...to avoid debats :)
Thanx Keith!
« Last Edit: November 10, 2009, 08:34:43 PM by Igor »
http://www.ij-audio.com
(new site hopefully will be up in July)

Biasrocks

Re: DIY Hell-I-OS EQ? Let's do it!
« Reply #3 on: November 10, 2009, 08:39:49 PM »
Would love to have a couple of these guys.

An Olympic studio Helios opened up.


http://SharktankPro.com

"I'd rather use an SPX90 than a UA plugin....." Joe Barresi

Igor

Re: DIY Hell-I-OS EQ? Let's do it!
« Reply #4 on: November 10, 2009, 08:46:08 PM »
It can be good to know material and core size for LF inductor.
http://www.ij-audio.com
(new site hopefully will be up in July)

hobiesound

Re: DIY Hell-I-OS EQ? Let's do it!
« Reply #5 on: November 10, 2009, 08:57:19 PM »
LOL, I'm very interested. I've got a pcb layout for those amp cards and two sowter lustraphone copies waiting to be used. i even bought a small coil winding machine and i was just about to order some formers and core to try winding that low freq inductor. 

Greetings,

Thomas

Re: DIY Hell-I-OS EQ? Let's do it!
« Reply #6 on: November 10, 2009, 09:11:36 PM »
Ditch the mic pre. Keep the switches and pots.
« Last Edit: November 10, 2009, 09:34:56 PM by desol »

Biasrocks

Re: DIY Hell-I-OS EQ? Let's do it!
« Reply #7 on: November 10, 2009, 09:45:05 PM »
Ditch the mic pre. Keep the switches and pots.

Nooooooo, don't do it.

It's not like that mic input stage/transformer has anything to do with the sound of these modules.   ::)

Mark
http://SharktankPro.com

"I'd rather use an SPX90 than a UA plugin....." Joe Barresi

gyraf

Re: DIY Hell-I-OS EQ? Let's do it!
« Reply #8 on: November 11, 2009, 01:10:53 AM »
What value is the LF-inductor?
..note to self: don't let Harman run your company..

hobiesound

Re: DIY Hell-I-OS EQ? Let's do it!
« Reply #9 on: November 11, 2009, 04:39:30 AM »
i simulated the schematic a few months back with the values from various schematics and i got a value of 10H (this was confirmed in one of the posts here IIRC). I can't run the sim right now coz i'm at work so i don't know what the value is for the mid-band. But IIRC the mid-band inductor got varied in quite a few versions so there's no telling what the actual values were but i remember the values for the 2 tap inductor in one of the versions was more or less correct but i was planning on winding an inductor with more than 2 taps to match the values of the styroflex i have lying around.  

for people that want more info i suggest searching the B-B-B-Big helios picture thread on Pro Sound Web. I'm still looking for the schematic that was posted on vintageking for the 2004 helios reissue, i found the first page, but if anyone has the other 2 pages could they be so kind and email it to sureshotstudio -AT- gmail -dot- com .

greetings,

Thomas
« Last Edit: November 11, 2009, 04:51:30 AM by hobiesound »


Igor

Re: DIY Hell-I-OS EQ? Let's do it!
« Reply #10 on: November 11, 2009, 07:14:32 AM »
Yap. Every additional info wellcome.
http://www.ij-audio.com
(new site hopefully will be up in July)

Re: DIY Helios EQ? Let's do it!
« Reply #11 on: November 11, 2009, 10:47:08 AM »
I think this might be a little too contentious.

Helios gear IS in current production, and Tony Arnold (in Europe) is known to visit forums such as this and voice his opinions.

If a version was attempted, I'd suggest some considerable changes and a COMPLETE avoidance of the term 'Helios'. It is a registered trademark and will bring down quite a lot of trouble, I've little doubt.

Hmm. I agree about the name and i don't think the schematic should be posted. 

But, there are many in-production projects going on here. What's different about this? Why can't Igor do a H*** type? Others do other type's? The only reason there would be a problem is if TA had a fit (uh oh, being such a small project and totally modified) and that would be a real downer.. Sheesh. Besides, this would be a great addition to the 51x release! :)

Let's party!! Champagne?

I think Tony should helping us out!? He can have some champagne too?  :D


okgb

Re: DIY Hell-I-OS EQ? Let's do it!
« Reply #12 on: November 11, 2009, 10:59:17 AM »
I'm in for two of any version
GKB Audio / Greg Boboski

skal1

Re: DIY Hell-I-OS EQ? Let's do it!
« Reply #13 on: November 11, 2009, 11:10:16 AM »
I am in, depend on  how much those inductors are going to cost, i was waiting for someone to do this.

skkal1

Igor

Re: DIY Hell-I-OS EQ? Let's do it!
« Reply #14 on: November 11, 2009, 12:11:56 PM »
In case you wound inductors youself, $20 max for pair.
In case someone else do it....$40-50 maximum for pair of inductors.
http://www.ij-audio.com
(new site hopefully will be up in July)

Freddy G

Re: DIY Hell-I-OS EQ? Let's do it!
« Reply #15 on: November 11, 2009, 02:22:07 PM »
I'm in for a pair!
PRR wrote:
Use #18 wire for rock-n-roll, #16 wire for classical.

mata_haze

Re: DIY Hell-I-OS EQ? Let's do it!
« Reply #16 on: November 11, 2009, 06:02:32 PM »
WERE IS THE KIT???
 ;D ;D ;D ;D ;D

M.

Igor

Re: DIY Hell-I-OS EQ? Let's do it!
« Reply #17 on: November 11, 2009, 06:37:29 PM »
Ahem. Little by little. For now, I just have incomplete PCB design on my laptop
and waiting for oppinions etc.
http://www.ij-audio.com
(new site hopefully will be up in July)

Joechris

Re: DIY Hell-I-OS EQ? Let's do it!
« Reply #18 on: November 11, 2009, 07:15:35 PM »
Mabye Carnhill inductors from Audio Maintenance would be a good option. VTB 9043 for the bass, and VTB 9048 for the midrange. ca. 34€
Its hard to get the Bass cut/boost done without a expensive rotary, unless you limit the choice to two cut and three boost steps (read lorlin 6x2)
j
musicians vary +/-9dB depending on mood, drugs, and line-voltage. (PRR)



 

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