Is something new in preamp design possible? Albatross. Now in 51X. PORN.

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Igor

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Joined
Jul 17, 2006
Messages
2,193
Location
Israel
P1060373.jpg


The history behind is...

Some good years ago, I got a mind to build a pre-amp with the next characteristics:

- Cutting-thru-the mix, but pleasant sound.
- Low noise, low as possible, but very nice harmonic content;
- Can have both clean and colorful sound, depending on how it is "pushed";
- Headroom: more as possible
- Simple as possible to build
- Can be used with all possible output trafo configurations: gaped on 80-100 mA DC, ungaped, transformerless.


I started to dig around amplification modules. At this time, we built La-Vi console
http://www.groupdiy.com/index.php?topic=23907

And we built and tested about 30 of different amplification modules.

The result gave us the Albatross amplifiers family.
http://www.groupdiy.com/index.php?topic=23907.msg284128#msg284128

Than, I took the simplest possible, best sounding amps, simplest possible gain structure (2x amps, gain and output),
and did first Albatross proto, 4x4 beast.

The input trafos we wound by our-self.
There were 2 input trafo models, our simple (EI2425, 8414), and same idea as 10468,
same 2023 lams, but 8014 instead of "original" 50/50. Both sounded really nice, but different.

First Albatross had 3 transformers and transformerless switchable out options.

I uploaded some pictures taken with oldy Nokia, found at my home PC.
The rest should be somewhere at very old backup.

Photobucket album:
http://s251.photobucket.com/albums/gg291/diy33609/Albatross/First_Albatross/

Than, we built about 200 channels of pairs and eights, of course, without crazy 4-trafo option, for last 4-5 years.


Here is the album with some photos:

http://s251.photobucket.com/albums/gg291/diy33609/Albatross/

As a "drum" model, we did first eight with gaped output transformers and EI2425 inputs for Bardo Studios
http://www.bardostudios.co.il

We use these pre's in DB as well.

As a "pleasant vocal" model, I prefer output transformerless configuration with Neve'ish inputs.
Output stage at 45 ma, single-ended, into current sink, with nice blue axial Panasonic 'lyth cap.
Sits perfect on big piano. Cool for all kinds of brass etc.

As a "dirty" model, possible to use low primary inductance ungaped iron,
can be cool for all kinds of electric guitars and "grungy" things.

Than, came time to make it in 51X format.

Albatross trafo configuration can be done by 6 different ways at least.

Here are the "Neve'ish" version pictures.

alb_2.jpg


alb_3.jpg


pcb_small.jpg
 

edanderson

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Joined
Jun 4, 2004
Messages
637
Location
atlanta
how does the input transformer mount mechanically?  i can see that the pins on the carnhill solder into the small PCB that attaches via header to the switch PCB...  is there a bracket or something else to hold the transformer?

ed
 

kazper

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Joined
Jan 2, 2007
Messages
1,705
Location
Snohomish, WA USA
edanderson said:
how does the input transformer mount mechanically?  i can see that the pins on the carnhill solder into the small PCB that attaches via header to the switch PCB...  is there a bracket or something else to hold the transformer?

ed

I'm thinking it's the 4 Pin header connector above the PCB mounted toggle switches.

Kaz
 

gemini86

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Joined
Sep 22, 2008
Messages
2,476
Location
Eugene, OR USA
jensenmann said:
kato said:
51X is the new normal.  :p

I recently saw the Foo Fighters documentation and spotted a pair of 51X racks in Dave Grohls garage studio, filled up with some 9k-500s :)
Obviously this place here ROCKS

Wait, really?

ruffrecords said:
I notice you use an 8 way connector. Will this fit in a normal API 500 size rack?

Cheers

Ian

They'll obviously physically fit, but the 'neve-ish' one probably runs on +24, which is not API500 standard, but IS 51x standard.
 

Igor

Well-known member
Joined
Jul 17, 2006
Messages
2,193
Location
Israel
how does the input transformer mount mechanically? 
i can see that the pins on the carnhill solder into
the small PCB that attaches via header to the switch PCB... 
is there a bracket or something else to hold the transformer?

Please see the photo attached to this post. Trafo holds on its own side screws, 2 holes at aluminum bracket;
the small PCB used to interconnect input trafo with front panel PCB, input impedance jumpers/Zobel network are here too.

EA10468 can hold on 2 screws as well. BTW, excellent trafo.

I notice you use an 8 way connector.
Will this fit in a normal API 500 size rack?

18 way connector. OK, already figured out.

To disappoint Lunchbox and Windows 95 users:
this pre-amp will not work in normal Lunchbox, and I absolutely don't care about this.

Albatross needs +/-24V, 100 mA max. Amplifiers are optimized for this voltage.

I don't see any logical reason to run 24V powered 1073 etc in Lunchbox, on DC/DC converters.

It is the time to get the 51X rack from silent:arts if you still don't have it.

A pair of Albatross pre's can be racked in 1RU, there is the simple solution - PCB which holds
XLR's and 18-pin connector. I will offer them soon as well.
Here, +/-24V and +48 V power supply for pair of Albatross pre's can be done with single 2x25V, 30VA toroidal trafo.
For 2x24 and 48V PS PCB, there are some choices.

OK than...


There will be complete build support manual written by native English speaking person and detailed pictorial.
All trafo etc options will be explained in comprehensive manual.

I thought about kits, and they will contain the most important parts:
PCBs, bracket, bolts/nuts, front panel, switches, transistors, 6.3 jack, relays, high quality capacitors.
The rest - resistors, capacitors, diodes - sorry, we have no time for this. Transformers are not included.
The kit will be more than reasonable priced - target is USD190 +/- 10%, shipping included.
More orders, less price.
The rest you have to buy, including transformers, is in range USD 85...130.
IMHO, total of $275...320 is more than reasonable investment in great sounding pre'.

If there will be more than 30 orders, there will be black anodized aluminum, silkscreened fronts, amazing quality.

If you interested in Albatross kits, post on my WM thread (and keep this thread for tech questions):

http://www.groupdiy.com/index.php?topic=29771
 

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edanderson

Well-known member
Joined
Jun 4, 2004
Messages
637
Location
atlanta
thanks for the explanation igor; seems like my take on the 10468 could work with your PCB for the carnhill with a different right angle header combination.

great to see a new design!  and glad to see further embrace of the 51x idea.  though the word albatross has mixed associations in english:

http://en.wikipedia.org/wiki/Albatross_(metaphor)

ed
 
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