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Could this be Peace In Our Time? [message #78262] Fri, 01 November 2013 15:11 Go to next message
Bill Epstein is currently offline  Bill Epstein
Messages: 1088
Registered: May 2009
Location: Smoky Mts. USA
Illuminati (2nd Degree)
In 1974 I built a Dynaco SCA-80 and partnered it with an AR Xa and ADC whatevers with 10" woofers. When I completed the build and saw the chassis sticker that said "no user serviceable parts inside", I thought, Amen to that. I had no idea what dots I had connected!

Today, 39 years later, I removed the attenuation cap from the 4 Pis, fired up the Single-ended, direct-heated, direct-coupled, parafeed 45 amp (thanks to Steve Brown, who still helps me color inside the lines) and cued up 88 Basie Street on the somewhat modified and greatly tweaked HW-19 MK IV with JMW 9T arm and ZYX R50 cartridge. A transcendent experience!

Only the RCA Cunningham tubes have been around longer than me Laughing and nothing else I've heard sounds as much like the timbre and texture of real instruments as the 4 Pis.

It took until today to remove that capacitor because the first time, without it, having just received the new "C" horns, I thought they sounded stifled and old-timey. With the cap they were brighter, no doubt, but I felt it was needed. Several days ago, when I replaced the 15 Ohm Mills MRA-12s across the DE-250s with the Duelund CAST resistors, I knew the time had come to 'bag the cap'.

The Duelunds make the treble more defined but also, and in equal measure, the mid-range and bass. Therefore, I assumed that removing C2 would smooth the frequency response and hoped none of the goodness would be lost. That's exactly what happened.

These Graphite Rod, epoxy-coated resistors are game changers and short of replacing the coils with di-lithium crystals I don't know how these speakers could get any better. The ZYX cartridge gives me a soundstage that for the first time orients the keyboard of a Steinway in front of an orchestra correctly but it couldn't do that for RCA LSC-2581, Van Cliburn and Reiner Brahms 2. With the Duelund CAST, the piano now comes into sharp focus. The timbre of the opening French Horn is also greatly improved.

Has anyone else found the Double Bass line as recorded on 88 Basie Street annoyingly prominent at times? The ZYX improved the low bass texture but it took the Duelund to integrate it properly, volume wise, into the band. Better yet, even when that Upright Bass is barely audible in the mix, I can still feel the vibrating strings!

As if that wasn't enough goodness for one day, when I opened the front door to go to lunch with friends, waiting on the stoop was the package from Music Direct with Zeppelin's Mothership. I've just finished cleaning the 4 LPs and only listened to Side One but am amazed how a recording engineered to sound good on a Delco 5 Button Radio has been spruced up to sound great on this killer stereo of mine!

Looking at the thread just below and all the requests for 4 Pi plans I'm smiling at what a treat is in store for the builders. You guys have no idea!

Re: Could this be Peace In Our Time? [message #78263 is a reply to message #78262] Fri, 01 November 2013 15:47 Go to previous message
Wayne Parham is currently offline  Wayne Parham
Messages: 18670
Registered: January 2001
Illuminati (33rd Degree)

I love the way you describe yourself, Bill. You're born to write, that's for sure.

Yeah, the measurements show the Rs resistor needs to be there in most cases, and even where it doesn't need to be there, it doesn't hurt. The C1 capacitor provides a little too much top end, which is OK but I think I'd rather have a slight downward tilt than a slight upward one. The older radial horns had just enough off-axis attenuation to make power response set right with the capacitor installed, although that did tend to make 'em slightly bright on axis. But in the case of the newer H290C, directivity is more uniform so we don't have that issue anymore.

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