dmlandrum

Helios thread
« Reply #20 on: July 22, 2004, 11:49:46 AM »
Okay, which schematic do you need cleaned up? I'll give it a shot. I just guessed based upon your posts which you were looking at.
Darren Landrum

Be comforted that in the face of all aridity and disillusionment
And despite the changing fortunes of time,
There is always a big future in computer maintenance.


Helios thread
« Reply #21 on: July 22, 2004, 11:57:05 AM »
I find them all very readable (after the "make it big icon" appears in the bottom right )- but I haven't a clue what I need to look at...

sismofyt

Helios thread
« Reply #22 on: July 22, 2004, 11:58:04 AM »
There are three schematics.

This is the original 69 Helios:

www.vintageking.com/images/schem_V69-1973-1-Var-1.jpg

www.vintageking.com/images/schem_V69-1973-2-Var-1.jpg

It would be great if you could clean this :thumb:

This is the reissue, which doesn't look like the original 69. The two buffers aren't there and the amp cards are different. I wonder why :?

www.vintageking.com/images/schem_V69-2003-A3-Var-1.jpg
www.vintageking.com/images/schem_V69-2003-2-Var-1.jpg
www.vintageking.com/images/schem_V69-2003-1-Var-1.jpg

I think these are the ones we should try to clone. Maybe. I'm not sure. What do thers think? Maybe Sowter can make those two inductors? (One is multitapped). Would be swell if you can clean those as well.

This is the old one from Dan Alexander's site:

www.danalexanderaudio.com/OutboardPic/HeliosInputSchematic.jpg

www.danalexanderaudio.com/OutboardPic/HeliosChannelSchem.jpg

Hmm, that appears to be the same as the original 69 :? But running at -24V :shock: Hmm, me confused.

Hell, clean 'em all if you can :grin:

dmlandrum

Helios thread
« Reply #23 on: July 22, 2004, 12:00:11 PM »
It'll take some time, but I'll go for it. I'll post here when I'm done.
Darren Landrum

Be comforted that in the face of all aridity and disillusionment
And despite the changing fortunes of time,
There is always a big future in computer maintenance.

sismofyt

Helios thread
« Reply #24 on: July 22, 2004, 12:02:16 PM »
It's the reissue that's mostly unreadable, but I think we should not make that one. Yes, I said the opposite before. I'm typing, looking, thinking all at once. Real time simofyt :grin:

Ok. The old 69 and the Dan Alexander is the same.

SSLtech

Re: Helios thread
« Reply #25 on: July 22, 2004, 12:07:07 PM »
Quote from: "uk03878"
I am sorry but this (from Dan Alexanders site) wins hands down on looks

That's 10CC's old Helios. It was made a custom red to go in Strawberry Studios in Stockport. I worked on it a few times... it had at least one cigarette lighter (12V, out of a car) in it!

That was an awesome board, and at the time, Strawberry was an awesome studio! -unfortunately, it ran downhill in the 1980's, and by 1990 it was a pit, with a useless Quad-eight/Otari/Westrex/Mitsubishi console/machine package. Otari was making cold-sounding junk and badging it as QUad-Eight in those days...

Lotta history in that board... check out this thread on GM's forum:
http://recforums.prosoundweb.com/index.php/mv/msg/1178/0/16/2172/?SQ=f6a6568ae8a257298e84bf24f9af3bfa

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.

sismofyt

Helios thread
« Reply #26 on: July 22, 2004, 12:10:28 PM »
Looks like it's all -24V stuff.

Ahh, the multitapped inductor, only has one tap. And I think it's 220mH & 680mH.

Still need to figure out the L1, #L3857

NewYorkDave

Helios thread
« Reply #27 on: July 22, 2004, 12:18:44 PM »
Quote from: "sismofyt"
I don't understand why there's a 36V zener diode parrallel with a cap in the ampcards when the they running +24V


Overvoltage protection ("crowbar")?

dmlandrum

Helios thread
« Reply #28 on: July 22, 2004, 12:18:48 PM »
http://studioconsul.net/techtalk/helios/schem_V69-1973-1-Var-1.png
http://studioconsul.net/techtalk/helios/schem_V69-1973-2-Var-1.png

The others look hopeless. I couldn't do anything to make the component values readable. Maybe someone else has some tricks.
Darren Landrum

Be comforted that in the face of all aridity and disillusionment
And despite the changing fortunes of time,
There is always a big future in computer maintenance.

sismofyt

Helios thread
« Reply #29 on: July 22, 2004, 12:21:22 PM »
Yes, I thought of that Dave, but is that really neccesary? Doens't he trust his PSU? Depending on the fuse/PSU, the zener might blow instead. I think it's a bad idea. Edit: It's current limited through a resistor.

Consul, I think we can make it without better schematics. I was concerned about the 69 reissue, but I think that's not the one to clone.

I'll try to figure out what value that inductor may have tonite or tommorrow. Perhaps NYCDave will give a hand?


soundguy

Helios thread
« Reply #30 on: July 22, 2004, 02:27:00 PM »
I guess this seems like a good time to bring this up-

A friend of mine has an Island Studios helios limiter, taken from a console.  He uses this thing on pretty much everything he does and Id bet most of the guys here reading this have heard his records.  Ive been playing phone tag for weeks with him, but hope to see him soon to photograph the insides of that box.  Kind of exciting, I always thought that the Island boards just had repackaged AD&R compex limiters in them, I have seen at least one helios board that must have been licensed from AD&R.  According to my friend, its not a compex, it definitely doesnt sound like mine.  Ive never heard a compressor do what that thing does.  Stay tuned, hopefully in the next few weeks I'll have more info on this one, kind of exciting.  

dave

chips are good with dip...

Mark Burnley

Helios thread
« Reply #31 on: July 22, 2004, 02:35:55 PM »
Dave,

I'm all ears (literally!  :grin: ), that sounds amazing- I've been looking for internal shots of that for a long time.

Great stuff.

 :thumb:

Mark
O_O tape is life O_O

dmlandrum

Helios thread
« Reply #32 on: July 22, 2004, 02:44:03 PM »
All I know is, seeing those pictures of the old Helios consoles is making me want to build all of my gear as one large console again, instead of inidividual rackmount pieces.

I'm with sysmofit on this one. I'm not fond of rackmounting. Now I just need to figure out how to fit a G9 into a different style of case.

Those extruded Hammond cases look good.
Darren Landrum

Be comforted that in the face of all aridity and disillusionment
And despite the changing fortunes of time,
There is always a big future in computer maintenance.

Bear

Helios thread
« Reply #33 on: July 22, 2004, 04:43:34 PM »
Quote from: "sismofyt"
The preamp alone sans EQ would not be that hard to make with that new Sowter trannie. And not very expensive either.


Damn, you know I'm starting to think I need to win the lottery to keep up with building gear, much less buying it.  Still, I want to be the coolest home studio on my block, so I think I must.  

Bear

[So anyone have the inductor spec's?]

Helios thread
« Reply #34 on: July 23, 2004, 04:07:19 AM »
Quote from: "Consul"
All I know is, seeing those pictures of the old Helios consoles is making me want to build all of my gear as one large console again, instead of inidividual rackmount pieces.

I'm with sysmofit on this one. I'm not fond of rackmounting. Now I just need to figure out how to fit a G9 into a different style of case.

Those extruded Hammond cases look good.

That's exactly what I am thinking...
Using a 3 unit card frame case as a base for vertical modules based on Eurocards - and going to two panels wide for those which need more space.
Bolting the case into a desk
Maybe three layers....
Top layer - mic pres
Second layer - limiters, compressors
Third Layer - Faders

ijr

Helios thread
« Reply #35 on: July 23, 2004, 05:53:41 AM »
(edit: post deleted)
"The ear is the only judge of tonal balance."
Radio Designer's Handbook, 1953, p.632.

sismofyt

Helios thread
« Reply #36 on: July 23, 2004, 06:42:33 AM »
I think we can figure out the missing inductor values allright. I'm gathering information about the 69 module. I'll have something by this weekend. Don't put to much into my posts on this thread, it was just loud rambling :green:

I've also found some transistor subs. It be cool if we could do a sim on the amps. The two amps seem to be the same with different gain arrangement.

I wonder why the re-issue is so different from the original :?:

I'm also wondering where the famous 1dB @ 100Hz bump is hidding. Probably in the trannie? I don't think it's that important anyway. The EQ is all passive and could be used with any 20dB gain makeup. The input Lustraphone trannie is important though. I hope Sowter made a good copy. I would have no way to check, as I don't know anyone who has an original Helios. Jules @ Gearslutz have some and I'll bet he'd do a shootout as his place if any brits make a clone :razz:  :thumb:

Dave, that's great! That is kinda exiting!

It be cool to do a real Helios look, so if anyone wanna do the layout, it be tres bien :grin: I'll redraw the amp schemaitcs and do a pcb layout.

Stay tuned!

I know what you're saying Consul. Afterall the reason we use outboard is because the console (pardon the pun!) sucks.

uk, I don't think these 69 Helios modules will fit in a modular scheme as they're running -24V. I don't know of any comp that uses that. It will be interesting to see just what is inside that comp Dave mentioned :cool:

Helios thread
« Reply #37 on: July 23, 2004, 06:45:05 AM »
Quote from: "sismofyt"

uk, I don't think these 69 Helios modules will fit in a modular scheme as they're running -24V. I don't know of any comp that uses that. It will be interesting to see just what is inside that comp Dave mentioned :cool:

I was planning on having multiple PSUs in the back of the rack
And Audio going to a patchbay....

Helios thread
« Reply #38 on: July 23, 2004, 06:50:34 AM »
From the Helios history...
"In 1994 I loaned him a Type 78 to clone, while I continued to maintain and support those that were still in use throughout the world, later he returned my Type 78,  complete with drawings for the first prototype, in the meantime I had contacted various respected Engineers/Producers,  they felt that the best sounding Mic/EQ was the ones that he first built using a Lustraphone Input Transformer which utilised the Centre Tap as a 20dB pad, this was the main Type 69 Mic/Pre plus Passive EQ, although not as versatile as the Type 78 they all felt the Type 69 was without doubt the best sounding.

April 1997,  I approached Dick to clone the Type 69, but he stressed that due to unforeseen circumstances he had not had time to complete the type 78, and also to find  the finance and the time involved to work on both Types was impossible, we agreed that I should clone the Type 69,  3 months later, we sent Dick a Type 69,  he agreed that it was such a perfect clone, it had even inherited the problems of the  original.

i.e.  1 Db 100 Hz boost,  with its EQ switched out,   the unit ran at . 775 as opposed to today?s standard of plus 4dB, it also oscillated when on full Mic Gain,  but the sound was identical.

We solved these inherited problems one at a time, by making comparison checks with the originals at each stage of the modifications."

I put the emphasis in bold - it looks like they got rid of all the "problems" i.e. the EQ boost, .775 level

sismofyt

Helios thread
« Reply #39 on: July 23, 2004, 06:55:43 AM »
No, I don't think they got rid of the eq bump. I think they did what they could to be sure it stayed there.

This is the George Shilling review:

A brief history lesson: the late Dick Swettenham was a maintenance engineer at Olympic Studios in its late 1960's heyday. In the early 1970's he built a rather wonderful desk for Olympic and subsequently a number of Olympic clients' private studios. When Island Records wanted Swettenham to build a desk for Basing Street Studios legend has it that his Olympic employers were none too happy, so he left and went into business with the Helios name. As time went by, gear fanatic and music producer Tony Arnold started to buy old Helios consoles and acquired seven of them for export to the US. With a c.1973 desk built for Eric Clapton as his reference, Arnold set about replicating Helios modules carefully including all the faults of the original to begin with. In the course of his research he found that the original desks' 20dB pad used a centre-tap from the Lustraphone input transformer. These sounded better than later Helios desks, which used Beyer transformers with resistors rather than a centre- tap for the pad. Arnold approached Sowter to copy the Lustraphone transformers. He then built a console for Elvis Costello and Chris Difford's Helioscentric Studios and put in 20 original Helios modules and 18 new modules. Over a period of over two years incremental modifications to correct problems with the original modules were carried out on the new ones. Each time these were carefully compared to the originals to make sure none of the modifications had any detrimental effects. Cyril Jones of Raindirk helped with some aspects of problem solving. Having acquired the Helios name, Arnold set about perfecting the EQ1 modules we now have here.

The originals' unreliability was always a bugbear for Arnold, so the new units are built to military specifications by CLI who amongst other things makes tyre-warmers for Formula One racing teams. The front panels are dipped in paint and the discrete circuitry is bulletproof. Modules from subsequent production runs will feature phantom power (which is already included in the rack version).

The lunchbox comprises a flight case with two vertically mounted Input/EQ modules alongside a panel with 6 bantam sockets for mic and line inputs and outputs - very convenient if you encounter bantam patchbays, a nuisance when you occasionally don't - and an IEC mains socket. There are no LEDs or lights anywhere. And with everything on the front, there is no need to open the back of the box.

The Input section features a three-position toggle switch for mic/padded mic/line input and a stepped control for gain.

I had a couple of the original modules in a lunchbox for comparison: the old ones sometimes sounded slightly smoother. This is probably due to the new ones' extended high-frequency response, which if audible, is not necessarily preferable to my ears. But any difference is extremely subtle. One vast improvement over the originals is in the build quality and reliability - crackly knobs are understandable on something almost 30 years old, but the originals were notoriously unreliable.

The stepped gain fixed 10kHz high frequency band is gentle and open, wonderfully enhancing clarity without introducing harshness. It goes in 2dB steps from -10dB to +10dB, although I have an inkling which way it will generally be turned. The Mid band comprises a selection of eight switched frequencies from 0.7 to 6kHz. A toggle switches boost or cut, with an uncalibrated pot giving a roughly 10dB range. Gain for the Low frequency band is also controlled by uncalibrated rotary pot giving a maximum boost of approximately 10dB at 30, 80, 120 or 240dB. These are 'boost only' frequencies. The frequency selector becomes an attenuation switch below zero, with cuts in 3dB steps down to -15dB at a fixed 75Hz shelf. I thought I might miss the ability to cut low-mid frequencies, being something of a fan of subtractive EQ, but with the Helios, boosting always sounds so good that I quickly adapted to this way of working. One Helios aficionado I spoke to testified to the glory of "F'BAAF" (Full Boost At All Frequencies) on the Helios desk he had used! On the low frequency gain pot there is a click at the off-extreme. The originals had a low-frequency boost of 1dB even when the EQ was bypassed. For purists this has been retained, but the click position gives you the option of switching it off. A high-pass filter gives 15dB/Octave cut at 40 or 80Hz, which is bypassed if the EQ is bypassed. A proper phase switch circuit is incorporated, the original design for this being something of a bodge.

By modern standards the features and control are limited. But here the sound is everything. You know you're in heaven when just about any setting sounds good, not just one compromise setting, which can be the case with many desk EQs. I recorded and processed all sorts of sources and the Helios always imparted a wonderful openness and clarity. If I were to own just one input module the EQ1 would certainly be near the top of the list.

A giant from a previous era returns in style, and in a portable package to take wherever you go.

 

Copyright ©2000 George Shilling


 

Related Topics

  Subject / Started by Replies Last post
1 Replies
2370 Views
Last post February 23, 2005, 08:57:03 AM
by ciminosound
8 Replies
3136 Views
Last post July 17, 2005, 08:11:46 PM
by soundguy
5 Replies
3149 Views
Last post January 12, 2009, 06:18:12 PM
by skal1
202 Replies
58180 Views
Last post February 10, 2019, 09:42:41 AM
by beatnik