the schematics are available online. I also can email them to you when next in Seattle. I was in same boat and decided rather than modify I would just update the caps, etc NOT the inductors as they rarely go bad and the stock factory are pretty good
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I was cruising the internet today looking through all things Apogee when I came across the website audio-reality.com that had a full page on various Apogee speakers which included manuals and crossover schematics. The schematic for the Stage speaker was there. Thanks so much for offering to come to my rescue. I never thought until you mentioned it to put ‘schematic’ together with Apogee in my search. I was hung up on ‘crossover’.
I also in the process came across a website forum devoted entirely to Apogee users that had been mostly active a few years back. One topic that the forum members addressed regarding the Stage was whether or not to also bypass the high/normal switch. Several recommended this based on the positive sonic benefits and concerns about oxidation on the contacts when the switch was closed. Did you do this?
So now I’m ordering the capacitors, I’m leaving the inductors alone, I’m not sure about the resistor just yet and I’m breaking out my soldering gun.
One thing to be aware of is that modern film caps have a lot lower ESR than they used to. With so many caps in parallel, it may be worthwhile to measure the ESR of the original assembly (I see 4 or more caps in parallel) and make sure you replace with equivalent ESR, or add R as needed.
You can use Dayton DATS or a jig for Room EQ Wizard to do this.
They used to believe that ESR was a big contributor to the sonic characteristic of capacitors, but that's been pretty much disproven. Whatever the reason it isn't there.
I’ve had difficulty finding a schematic of the Stage crossover so when I finally stumbled across it today I thought I’d post the link for anyone else looking for it.
After a long saga with my Apogee Stage update I thought I’d post my final upgrade.
I’d previously partially updated the crossover replacing the original electrolytic capacitors with equivalent value Dayton 1% capacitors and the sand cast resistor with an equivalent value Mills. I didn’t replace the inductors or wiring. I used the Dayton’s because at the time I didn’t think I could fit any other high quality capacitors into the rather restricted crossover space and I figured this would at least bring them back to their original sound. The difference in the high frequencies was audible, but very modestly so, as a slight reduction in the harshness or graininess at higher volumes but even comparing the original with the modified side by side it was something you really had to listen carefully for. A bit disappointing and certainly not what I recalled as their original sound.
Then I saw a posting from bdp24 who suggested I contact Danny Richie at GR Research and get his input and crossover expertise. Without having the speaker on site to test(because I just couldn’t trust these heavy but fragile speakers to shippers) Danny couldn’t create a newer more accurate crossover but with the schematic he could recommend upgrades to existing components. With his philosophy that everything in the signal path matters and components have dramatically improved in the past two decades, this is what I did.
i removed all the components and completely rebuilt the crossover board. On the woofer section I replaced the old 1.98 mH 12 AWG air core inductor with a 2.0mH 16 AWG Erse XQ air core inductor that Danny felt because of the higher purity copper would perform far better than the original. The four 20uF capacitors were replaced with two 39uF 250v Erse PulseX metallized polypropylene film capacitors plus a 0.1uF Sonicap. For the tweeter circuit the replacements for the three 20uF and one 10uF capacitors were two 25uF Sonicaps and one 20uF Sonicap. The resistor was a Mills and the small 0.0288 mH inductor was replaced with a custom wound inductor of the same value. The 1.46 mH inductor was replaced with a 1.5 mH 16 AWG Erse XQ air core inductor. All the wiring to the woofer and mid/tweeter was replaced with 16 AWG 99.99% oxygen free copper wire. I decided also to replace the mixed metal washers on the speaker foil connections with copper washers. The solder was Cardas Quad Eutectic silver. In the end I happily discovered that all these components did fit into the original crossover space with some judicious planning.
Danny said the capacitors would take some time to break in but when I compared the first completed speaker with the Dayton mod the difference was dramatic. Nothing subtle here. It would take pages to describe all the ways it was better but the three most obvious were the lack of any strain and harshness at high volumes, the utter clarity at lower levels and the greater solidity and tonal quality of the bass. It’s what I remember about them when they were new but it’s also quite possible that they are actually even better now. I would have loved for Danny to have them in his lab and create something even better than this, but truthfully they are so satisfying now it’s something I don’t think about anymore.