Studio Mollan
Well-known member
- Joined
- Oct 26, 2011
- Messages
- 323
Hi guys,
Would be very glad for some input on this.
My API 2488 desk came with a ripped out multi track tape return. Basically a 24 channel submixer for the 24track tape recorder. The original design is not really worth reproducing as the sound quality in these were poor. Not at all like the standard input Channels of the API. so now I'm planning to build new and improved inputs for these, keeping some of the original features and adding some. Not the least the ability to get the output of the channels to the mixbus. From 24 to 48 inputs on mix. They will be summed using Classi API summing cards and injected to the existing mix bus in the API. As I know Jeff, Classic API, has done on his desk.
So.
Originally the monitor inputs were half wide versions of the standard input channels. I will build them in 500 series size. The 15 in connector will not be enough so i will have to wire an extra ribbon cable from each module to a new bus motherboard. It will be a tight fit but my prototypes shows it will work
The input channels will be based on the INX5 from JLM. And the Harrison Ford filter.
http://www.jlmaudio.com/shop/index.php?_a=viewProd&productId=128
http://strangeweatherbrooklyn.com/sales/harrisonfordfilter.jpg
They will have the following features.
Hi/Lo pass filters
* 4 echo buses on two pots
* Pan
* Fader
* Solo
* Direct out
* Stereo mix feed
* Outputs to all 8 submasters on the API.
Switches for:
* Individual on for the 8 submasters (subminiature toggle switches)
* Pan on for submasters
* Direct out on
* Stereo bus on
* Echo pre/post, global for all echo buses
* Echo: Either 1+3 or 2+4
* Solo on
* Filters on
The input goes straight to the Harrison Ford filter. Output from Harrison filters will serve as an Balanced Insert Send.
The balanced input on the INX5 will be the balanced Insert Return. After the balancing stage there will be a pre fader send point for the Echo sends, then fader before the output amp of the INX5.
The output amp will feed the Direct output transformer, Ed Anderson 2623-1. The output amp will also feed the post fader Echo send, Solo bus, Pan pot and all 8 submasters. The submaster pan switch will make it possible to use the channel pan pot to pan between ODD-EVEN numbered submaster buses. A-B, C-D etc.
I have copied the schematic from the original API 528 input module for all pot/resistor values. I really don't know if that will work well within the INX5 so help needed here. I have lots of high quality 10kA pots that i would love to use!! Enough for the whole 24 channels actually so that would be great!
The INX5 has options for the two OP- amps. Either NE5332/OPA2604 or DOA 2520 style. I would like to use 5332 to keep labor and cost as low as possible. The output of the INX5 is driving a lot so maybe a DOA would be better there?
Next posts will show schematics.
Hopeful to get some input on this.
Regards
Emil
Studio Möllan
Would be very glad for some input on this.
My API 2488 desk came with a ripped out multi track tape return. Basically a 24 channel submixer for the 24track tape recorder. The original design is not really worth reproducing as the sound quality in these were poor. Not at all like the standard input Channels of the API. so now I'm planning to build new and improved inputs for these, keeping some of the original features and adding some. Not the least the ability to get the output of the channels to the mixbus. From 24 to 48 inputs on mix. They will be summed using Classi API summing cards and injected to the existing mix bus in the API. As I know Jeff, Classic API, has done on his desk.
So.
Originally the monitor inputs were half wide versions of the standard input channels. I will build them in 500 series size. The 15 in connector will not be enough so i will have to wire an extra ribbon cable from each module to a new bus motherboard. It will be a tight fit but my prototypes shows it will work
The input channels will be based on the INX5 from JLM. And the Harrison Ford filter.
http://www.jlmaudio.com/shop/index.php?_a=viewProd&productId=128
http://strangeweatherbrooklyn.com/sales/harrisonfordfilter.jpg
They will have the following features.
Hi/Lo pass filters
* 4 echo buses on two pots
* Pan
* Fader
* Solo
* Direct out
* Stereo mix feed
* Outputs to all 8 submasters on the API.
Switches for:
* Individual on for the 8 submasters (subminiature toggle switches)
* Pan on for submasters
* Direct out on
* Stereo bus on
* Echo pre/post, global for all echo buses
* Echo: Either 1+3 or 2+4
* Solo on
* Filters on
The input goes straight to the Harrison Ford filter. Output from Harrison filters will serve as an Balanced Insert Send.
The balanced input on the INX5 will be the balanced Insert Return. After the balancing stage there will be a pre fader send point for the Echo sends, then fader before the output amp of the INX5.
The output amp will feed the Direct output transformer, Ed Anderson 2623-1. The output amp will also feed the post fader Echo send, Solo bus, Pan pot and all 8 submasters. The submaster pan switch will make it possible to use the channel pan pot to pan between ODD-EVEN numbered submaster buses. A-B, C-D etc.
I have copied the schematic from the original API 528 input module for all pot/resistor values. I really don't know if that will work well within the INX5 so help needed here. I have lots of high quality 10kA pots that i would love to use!! Enough for the whole 24 channels actually so that would be great!
The INX5 has options for the two OP- amps. Either NE5332/OPA2604 or DOA 2520 style. I would like to use 5332 to keep labor and cost as low as possible. The output of the INX5 is driving a lot so maybe a DOA would be better there?
Next posts will show schematics.
Hopeful to get some input on this.
Regards
Emil
Studio Möllan
