Racking Amek Einstein - Project COMPLETED!!!

[Go to second page to see the pictures of the completed project]


Hi Everyone,
My first project will be racking an Amek Einstein channel strip, Im just starting my way into DIY and electronics so I will need a lot of your help. Please give a hand, and have some patience with me.

The channel Strip has 2 separate channels with individual EQ, one channel is mic/Line and the other is the Monitor (tape return).

I have the schematics and diagrams for the module.

I also have a power supply.

My Goals are:
- Rack the module into a 1 unit rack , having the power supply externally
- Use the input on the channels, and have outputs before (insert send)  and after the fader
- Maybe modify the tape return channel to a mic/line input, since I have a couple of SSM2016 , the same chip used on the pre channel of this module.
- Getting rid from the Aux’s, Bus outs, Pan Pot, Mute switch , etc … Basically everything that I don’t need and is in the signal way


So Far:
-I have connected the Power supply to the card : -17,5v, 17.5v, 48v, 0v, chassis ground
-All the connection work, I can get audio going into both to the Mic and line inputs. Phantom Power is working also
-I can get the audio out of the module from the channel Insert send (unbalanced output)


My questions for the next steps are:

1) How could I take an output after the fader? Where should be the best place?

2) What should be the best way to Balance the outputs? Should I do this or keep it unbalanced?

3) Is the input on the Monitor channel the same as a Line input? What would be the easiest way to modify it to a Pre-amp?

4) I measured the rails of the power supply, and instead of  + 17.5v and  – 17,5v I have +17.2v and -16.9v . Is that any problem that the rails are not exactly 17.5 volts? Would the audio performance from the preamp improve ?

Schematics are here:

Page 1
http://i299.photobucket.com/albums/mm284/Amekeinstein/AmekEinsteinSchematicPage1.jpg

Page 2
http://i299.photobucket.com/albums/mm284/Amekeinstein/AmekEinsteinSchematicPage2.jpg

PCB Layout1
http://i299.photobucket.com/albums/mm284/Amekeinstein/einsteinsheet1.jpg
PCB Layout2
http://i299.photobucket.com/albums/mm284/Amekeinstein/einsteinsheet2.jpg

here are some pics of the module

if you dont run long cables then you can stay unbalanced.
Voltages look alright to me.
If you wanna go balanced go with the THAT chips simple and cheap!

Thanks for the reply 3nity,
what THAT chip should I use to balance the output?

Try the SSLtech Output Balancer board (OB-1)

www.beatbazar.com/guests/ssltech

THAT1646 best results for the money and great products!

Cool,
I will use your Balanced Output Driver Board .
Could I use the THAT1646 in that circuit?
whats the best place to buy them in europe?


Im still having some problems finding a way of getting an output after the fader, anyone can give some clues about that?


Thanks

WH

where are you trying to get audio after the fader?
visit wayne site: www.ka-electronics.com for THAT ic's

I just want to be able to distort the preamp if I need it, so it would be nice to have the fader so I dont clip the AD.
otherwise, it would be enough to get the output from the insert send.

But the schematic gets a litle bit confusing for me in Page 2 , after the insert return, so I dont know where could I take an output after the fader

Could I just use a pot after the insert send?

If you want a board for the That1646s, I have a couple of these somewhere:



I designed the board for the DRV134, but the That should work also. There's space for a Neutrik XLR connector on the board.

Best regards,

Mikkel C. Simonsen

Cool,
How many do you have? price?

what circuit is it ? is it like the SSLtech Output Balancer?


cheers

[quote author="Whoops"]Cool,
How many do you have? price?[/quote]
I have 4 of them left. They cost me about €2 each.

what circuit is it ? is it like the SSLtech Output Balancer?

Click to expand...

It's the standard circuit from the DRV134 datasheet. I just added space for a pair of electrolytics in parallel with the film caps.



Best regards,

Mikkel C. Simonsen

As long as the sends are available post EQ, it is often easier to use a send pot instead of the fader. You will probably need to remove the mix buss resistor, and to go into a THAT or AD balanced line driver chip, you will need a buffer amp as well, since they do not like to see a changing load. A 5532/34 at unity gain works well here. To tell you the truth, this is not a good preamp to overdrive, unless you are after very nasty chip distortion. Easier to use the fader buffer amp to drive the balanced output chip and not use the fader. To use a transformer output you will need an output driver stage.
You can also use a THAT / AD mic preamp chip (the most current version of the "2016" and way better, see: http://www.thatcorp.com/datashts/1500data.pdf) as a simple preamp for the 2nd path (tape monitor input). Go out of this into the tape monitor input just like an insert.....

thanks a lot for your reply

looking to the schematic it seems to me that all sends are post EQ, the problem is that there a lot of circuitry after the insert send and before the Aux send that I really dont need to have in the signal path.


I think you probably are right about this not being a good preamp to overdrive.

I gonna check the That 1500 thanks for that one. Maybe even replace the 2016 , if this one sounds better.
for the 2nd path (monitor input) I was thinking of bypassing everything before the EQ. Maybe do a small pcb with a pre circuit similar to the 1st path, and connected it straing to the Monitor EQ circuit.

whats the diference between a Line input and a Tape return/monitor input?

There is a "Langley" mic amp upgrade available for the Einstein E10;

Part number AML-16-010

http://www.audiomaintenance.com/acatalog/aml_electronic_products.html

http://www.audiomaintenance.com/downloads/einstein_mic_input_mod_fitting_guide.pdf

Colin
www.audiomaintenance.com

What upgrades does it provide?

The PCB was to big to fit inside a 19" rack case, so the only option was to cut the PCB.

After studying the schematic and circuit layout, I found a place before the Aux and Group outputs section that could easily be cut.
I fount the points in the circuit that I needed to link after the cut.

picture of the guide line, before the cut

I used a small metal saw for the cut. these are pictures after the cut

You can see the points that I need to link now. A,B,C and D written on the 2 board parts