helios 22113

[Squeaky]

I've also been working on a diy Helios-type mic pre using a 22113 output card, and I'm pretty excited about the possibilities as well. The version I have been putting together uses all BC-type transistors. I'm having trouble getting the pre-eq up and running (I also have a 2128 amp, filter buffer and the standard helios eq in the circuit). Currently, my version looks a little bit like one of the early Olympic proto-types, complete with vertical boards for the eq-capacitors. Anyway, during testing, I bypassed the front end (it wasn't passing signal) and wired straight from the input transformer (a Sowter) to the input of my 22113 card. As per the schematic I have, the feedback resistor is set at 680ohm on my board. The output transformer I am using is one of the Carnhill's wired 1:2.

The circuit fired up nicely and I was really impressed with the sound. I was using my test mike (an MD-421) and the signal sounded great, quiet and clear, and at pretty high gain with 680ohm resistor setting. I was using a voltage of a hair over 31V, I have a JLM Audio TREX2 and a 48V SMPS in the power supply, and you can dial up+24V and about +31.5V with the stock components. Apparently you can get a higher voltage with the TREX2 by changing out a couple of resistors.

Now to get the rest of it working.

 

[Rocinante]

Whoa im getting blind in my age. I dont know how I missed this.  Luckily the 2128 I built with the 22113 is working. It's working great as a matter of fact.  Engaging the eq is currently where im struggling.  But I believe I figureed out what I did wrong and sm waiting for parts to finally finish it.
Btw: the preamp sounds awesome.

I've also been working on a diy Helios-type mic pre using a 22113 output card, and I'm pretty excited about the possibilities as well. The version I have been putting together uses all BC-type transistors. I'm having trouble getting the pre-eq up and running (I also have a 2128 amp, filter buffer and the standard helios eq in the circuit). Currently, my version looks a little bit like one of the early Olympic proto-types, complete with vertical boards for the eq-capacitors. Anyway, during testing, I bypassed the front end (it wasn't passing signal) and wired straight from the input transformer (a Sowter) to the input of my 22113 card. As per the schematic I have, the feedback resistor is set at 680ohm on my board. The output transformer I am using is one of the Carnhill's wired 1:2.

The circuit fired up nicely and I was really impressed with the sound. I was using my test mike (an MD-421) and the signal sounded great, quiet and clear, and at pretty high gain with 680ohm resistor setting. I was using a voltage of a hair over 31V, I have a JLM Audio TREX2 and a 48V SMPS in the power supply, and you can dial up+24V and about +31.5V with the stock components. Apparently you can get a higher voltage with the TREX2 by changing out a couple of resistors.

Now to get the rest of it working.

 

[Rocinante]

Whew.  So I uhh finally took pics.  Thanks Gearsix, Ian, PRR, Whoops, and David.  It's actually a pretty damn good preamp.  I was pleasantly surprised.  I'll put the next one in a smaller case.

http://postimage.org/


http://postimage.org/


http://postimage.org/


http://postimage.org/

 

[Whoops]

Nice one Rocinante.
It looks good and I'm really happy that you manage to do it.

For study purposes do you think you could post a schematic of the way you did it?
I saying a overall schematic from the input tx - mic pre - EQ - output pcb - out transf

 

[Rocinante]

I certainly will my friend.  And thanks for the immeasurable help with this. Between you and Ian and Tiago I got all the help I needed to do it.  I'm proud of it. I have been and still am away with the family but will post a bunch of the documents I used to build it.  I am still happy and using this often. I have Neve and API and think this brings something all its own.
Thanks again comrade
Dylan

 

[Whoops]

I certainly will my friend.  And thanks for the immeasurable help with this. Between you and Ian and Tiago I got all the help I needed to do it.  I'm proud of it. I have been and still am away with the family but will post a bunch of the documents I used to build it.  I am still happy and using this often. I have Neve and API and think this brings something all its own.
Thanks again comrade
Dylan

Thank you so much Dylan

 

[muffy1975]

Hey,

have you excluded  C8 and R17 from your build?  If not, do you know these values?

kind regards and great work

Michael de A

 

[Whoops]

Strange I don't seem to have C8 and R17 on the other 22113 schematics I have.

Im sure Rocinante didn't use those components although it would be nice to know it's values.
By the way anyone knows why C8 and R17 may be needed?

Thanks

 

[Whoops]

22113 Schematic 1

 

[Whoops]

22113 Schematic 2

 

[Rocinante]

You know i don't think i did but now i gotta recheck. The document you are referencing wasn't available when i built it.  Aamof i searched forever for it.  I believe the version i came up with i cross referenced three different schematics which were all nearly the same.  Unfortunately all the rep pro images were gone which would've made things easier.

 

[Rocinante]

Here's what I came up with using modern transistors.



http://postimage.org/

Interesting find muffy1975!  I could never get info on the dual 22113.  Bus amp?

 

[Rocinante]

On a final note I implemented the preamp/eq using:

XLR  in >  Cinemag cmmi-10c  > 2128  > by-passable EQ filter via Ian's 69 boards > 22113 > cinemag cmoq2s > out

 

[abbey road d enfer]

Voltage drop resistor? Noise suppresion for emitter?  I don't really know but I've seen numerous designs from the 60s using that as well (ADI 44 and 21 come to mind) Honestly the answer is its in the 22113 schematic and so I included it. Im sure someone smarter than me can tell you?

IMO, it's something an engineer drew on a paper to indicate where the load should be connected, and a draftsman diligently copied it; maybe it passed PCB layout and production, and somedy figured out (I hope) that it's a mistake and the 600r should not be stuffed. If it was on the BOM, the purchaser must have cursed and vituperated, and asked if a 620r would fit.
As to using it for avoiding oscillation, no designer in their right mind would do that; it sucks the headroom of the stage.
You cannot neglect alsoi the possibility that it's been deliberately as a matter of deception.

 

[Rocinante]

IMO, it's something an engineer drew on a paper to indicate where the load should be connected, and a draftsman diligently copied it; maybe it passed PCB layout and production, and somedy figured out (I hope) that it's a mistake and the 600r should not be stuffed. If it was on the BOM, the purchaser must have cursed and vituperated, and asked if a 620r would fit.
As to using it for avoiding oscillation, no designer in their right mind would do that; it sucks the headroom of the stage.
You cannot neglect alsoi the possibility that it's been deliberately as a matter of deception.

You are not the first person to say something like that. Was it common to throw deceptive wrenches in the schematics like that back in the day?

I dont have an original line amp card but im pretty certain through the few pics i can figure out if its 'real' or not.
There was a claim that Sir Rupert used (although the person said stole) this scheme for his own upcoming console. It was contested and i believe that in the end it was said that it waan't and that it didnt matter cause everybody borrowed from everybody.
Nevertheless it adds to the lore and keeps it interesting.

 

[abbey road d enfer]

You are not the first person to say something like that. Was it common to throw deceptive wrenches in the schematics like that back in the day?

Yes it was, and probably is still today, although it's more difficult because of all the automated documentation. I would say most of these were genuine mistakes.

 

[Potato Cakes]

Do you have a schematic for the 2128 preamp section? Helios is one of the things I've never really used but since people seem so very excited about this particular sound, I'd like to build one sometime and see what I thought.

Thanks!

Paul

 

[Whoops]

Do you have a schematic for the 2128 preamp section? Helios is one of the things I've never really used but since people seem so very excited about this particular sound, I'd like to build one sometime and see what I thought.

Thanks!

Paul

Click the GroupDIY logo on the top left corner of this forum.
Then on the top row of the page next to were it says members , theres a white rectangular box that says "smart search"
Write on that rectangular box "Helios 2128" then Press Enter.

Those white rectangular boxes are really useful for internet users, what they do is that they will search information related to the words you  write there, it's pretty cool.

Give it a try!

 

[Potato Cakes]

Do you have a schematic for the 2128 preamp section? Helios is one of the things I've never really used but since people seem so very excited about this particular sound, I'd like to build one sometime and see what I thought.

Thanks!

Paul

Click the GroupDIY logo on the top left corner of this forum.
Then on the top row of the page next to were it says members , theres a white rectangular box that says "smart search"
Write on that rectangular box "Helios 2128" then Press Enter.

Those whit rectangular boxes are really useful for internet users, what they do is that they will search information related to the words you  write there, it's pretty cool.

Give it a try!

Every other time I tried that I got a pizza delivered to my house. This time it worked!

Thanks!

Paul

 

[Whoops]

Helios is one of the things I've never really used but since people seem so very excited about this particular sound, I'd like to build one sometime and see what I thought.

Thanks!

Paul

A lot of great records were made on Helios consoles,
Led Zeppelin, Bob Marley, Deep Purple, Rolling Stones, Joy Division, Eric Clapton, just to name a few.

The company had a short life compared to Neve or SSL, so the number of consoles produce was also much smaller, which makes these consoles and modules scarce and rare nowadays.

The Mic Pre has a particular sound and character and also the EQ is quite famous.

The looks were quite awesome also.

Not clean or transparent units, that seems to be precisely what I like and it seems a lot of people like them also for their personality.