Broke down. Got a duplex.

**Alien_Shore** · January 14th, 2024, 06:24 PM

@Earl K

Here's a quick / dirty schematic from that sim network:

604e Sim network design

Let me know if something looks weird or you have any questions...

**Altec Best** · January 16th, 2024, 03:13 AM

Mike very nice schematic.. Draw them things up nice these days .

**Earl K** · January 16th, 2024, 08:39 AM

Thanks muchos Mike!

John, Good to see you ( & Todd ) back here !

regards <> Earl

**RonSSS** · January 16th, 2024, 07:12 PM

Very nice to see you back Altec Best!

**Alien_Shore** · January 17th, 2024, 05:29 PM

So good to hear from old friends!! Hope y'all are doing well.
I'm going to take a look at my project drawer and see if I have those coils laying around and I can breadboard that network. Now I'm interested to see if it sounds better than the GPA one I'm using now.

**Phil-G** · January 20th, 2024, 11:40 PM

i was starting get that 'Omega man' feeling

GM · January 25th, 2024, 12:14 AM

I know what you mean.

There's some folks missing from the DIYaudio forums and I lost an entire family of friends (61-99 yrs old) among others, though thankfully none of my own.

**Alien_Shore** · October 2nd, 2025, 01:48 PM

Waking up another old thread...

Since Great Plains Audio is now long-gone, I feel like I can finally post this.
Back in 2013, I drafted this schematic of their N604-8A network they used to sell.
I purchased one and still use it to this day on my 604e. It's a nice-sounding network and well-built as you'd expect.
I am really sad that no-one took over what Bill H was doing at GPA...

**dbale** · October 13th, 2025, 03:44 PM

Hey Mike, thanks for posting the schematic of the GPA N604-8A. When I got my 604-8H-III’s over 11 years ago Bill included a pair of these crossovers. Upon receiving them I wondered why there was a wire removing L1 and C1 from the circuit. I called Bill and he said that they removed the wire and put a 33 ohm resistor in it’s place only for the 212-8A driver.

I really like how they sound and never felt the need to try something different.

**Altec Best** · October 21st, 2025, 11:37 PM

Mike they are still around.. Bill sold it and they moved back to the Los Angeles area. It is now called Great Plains Acoustics LLC. Prices are a bit crazy now. Wish I grabbed a bunch from Bill when his woofers were $240 ea. and the 604’s were $950ea. And left them in their boxes for a rainy day !