I'll see if any of my equipment here at work can do it, but this is a hybrid, so the audio amp section is essentially a 2254/1272. The attenuator and sidechain come from the 33609J.
All of the equipment here is RF related. I might be able to do IMD/IP2/IP3 type measurements at higher frequencies, like 10Kish. I can do some direct spectrum captures with some arbitrary CW input and measure each harmonic and figure things like that.. But again I don't think my analyzers go down into the Hz range.
I think I'm changing the gain scale to 1-10 and adding a switch for "fast" and "slow" compression attack. I just don't have room for another rotary switch/pot.
You'll also see the offset threshold switches. I rather dislike having to do that, but for 7$ a piece I guess I can't complain too much. I couldn't find any 24 position switches that were smaller except for the elmas which are hard to get and 50$+ each..
Ordered the front panel. Decided to make it blue. I'll do my own infilling to save 10$. Spray the panel with white spray paint, and then use a rag soaked in acetone, swipe it across the face. It should leave only what was in the engraved valleys. Or, use a small squeegee to wipe the paint across the face.
I haven't really worked on this the past week. I'm at a point where I need the front panel so I can mount all the controls and finish wiring. I got the chassis the other day, it was a par-metal second on Ebay, so I got it for a few bucks cheaper than their website.
I also got the remaining input transformers and the meters from Hairball. The frontpanel shipped today so I suppose I'll see it next week at some point. Getting kinda excited to get this thing together finally.
You can see the infilling in the pic above. I cleaned the panel with acetone, then sprayed white spray paint over it. Before it dried, I took an acetone soaked rag and wiped the paint off. It's messy but easy. I made a couple passes and let it dry. There was a paint film on the panel still, so another pass with a clean rag soaked in acetone took that off.
I did screw one thing up so far, and that is the boxes on the front panel. I made them just a little too wide so the screws that mount the front panel are much too close and partially cover the lines. Oh well, live and learn. The lettering is a little small too. I probably should have made it a tad larger. I also need to lengthen the wires connecting the right channel limiter recovery switch, they are a little short to reach it. The rest look to be long enough though.
I also want the knobs I bought to sit almost flush with the front panel. I'll need to trim off a little of the shafts on the switches and pots for this to happen with these knobs.
I have two issues right now, the left channel has about 5db more gain than the left. The meters are waaaay off from where they need to be and they are well outside the adjustment range even though the originals were supposed to be 1mA meters and these are 1mA meters.
So today before recording I need to try to figure out why one side has a little more gain. It also has a little higher noise floor too. Otherwise, listening it sounds pretty good. It can do a lot of compression before getting crunchy, and the compression stays very "round" sounding.
I built this to put on the drums, but I think it's going on the mix bus because the limiter works well and sounds pretty good.
gain problem was that the gain pots were mismatched. That's fixed.
The higher noise seems to be related to the JFETs on the front end. One of them on the channel that was noisy was sensitive to the touch too, so it needs replacing but I don't have any more. Time to order some.