A holiday update:
And the project moves on, slow, but forward progress is being made. I have recently finalized the 625CR (control room) module. I have been working on it as time has allowed over the last few months. I think I mentioned I was at a spot with the other modules where I felt I could not continue without completing this module. That said, the PCB’s have been thru their final tweaks and Rev’s and are now 100% done.
There are a number of non-stock parts that I already have on order for the 625CR. All of the pushbutton caps (besides DIM) are a factory direct order along with the two required 5-x-interlocking switch banks. Those parts are due the first week of Feb. The center 4 independent pushbuttons are in the same order. These are very cost affordable, not C&K. The quality is still excellent.
The 2x24 Elma used for control room level has also been ordered. These have a custom lite torque setting specifically for a control room level application. The law on this dual switch is my own which I took some time and a few rev’s tweaking and fussing with until I got it just how I wanted it. You can see the level steps in the artwork pic below. The steps are highly accurate and with .02dB of the target except at the lowest 2 settings. They are better than .2dB there, which is close enough at –57dB. The Elma switches will be fully factory assembled with SMD R’s installed. They are using a custom version, .05% tolerance Susumu part that is touted as the best SMD metal film resistor made. The parts are not cheap and will street for about $150 but IMHO, they are hands down the best part that can be used for this application.
For the Elma switch, I have decided on a large 1” diameter blue anodized pointer knob. These are simply outstanding. I just love them.
I am waiting on my last quote for faceplate aluminum before ordering a production run. In the mean time, I have a small 9pc proto run that is being shipped out tomorrow for anodizing. Those will then be shipped off for silkscreen printing. I should have these 9pc back in 2-3 weeks or so.
Here is the finalized artwork for the control room module. The color theme across the console will be brushed, clear anodized aluminum. All printing will either be black or the blue as shown. Each module will have flood printed areas to highlight certain controls and whatnot. Overall, I am pretty stoked about the look.
So, now I am back to work on the input channel. I have done my first proto run and have some changes I want to make. There are a few circuit things but nothing real major. The biggest change is I have found a new line of pots I plan to use instead of the 51 series Bourns. They are the 9mm BI Tech pots. All of what I need are factory orders since no one stocks these in the configs I need. This alone will be a huge savings for each module. They are excellent long-life, conductive plastic parts and are literally a fraction of the Bourns parts.
Oh, I have also finalized, built and tested the headphone amp for the console. It is part of the right program booster PCB so I wanted to complete it before finishing the rest of the boards for the pgm boosters. It is based on Burr Brown INA137’s with BD139/BD140 output drivers. It is by far the best sounding headphone amp I have here. Distortion is very low when driving an old pair of Sony 24 Z phones. Better than most specs that I have seen. I am so happy with this that I am considering doing a standalone unit in a small clamshell enclosure. It’s a relatively inexpensive build and sonically a killer.
OK, back to the input channel’s 2nd Rev.
Happy holidays to all, Jeff
![Smile :) :)](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)