After completing the breadboards of the Duelund CAST crossovers, I took them for a test drive and was really impressed with the overall sound quality, tonality, and level of emotional engagement I was hearing from the Coronas.

There's a couple of things about the Duelund CAST copper breadboard crossovers that really impressed me, the first being how much more musical information was coming through compared to the stock Altec N800E crossovers, which filtered out a lot more musical information than I had realized. 

The Duelund CAST copper breadboard crossovers also revealed how truly impressive the earlier Altec 803A low-frequency drivers were compared to the later 803Bs. The 803As are more agile, more resolving, and have more clarity than I've heard in the low-frequencies from either the Altec 803B or Altec 515B 15-inch low-frequency drivers in my other vintage Altecs. A nice surprise. 

When I bought my Corona 832A loudspeakers, I had a choice of buying a pair with either the 803A or the 803B low-frequency drivers (both had the 802D compression drivers up top), but based on Keith Aschenbrenner's (Auditorium 23) praise to me about the 803A drivers’ additional resolution and agility in the low-frequencies, I went with the 803A drivers. I’m so glad I did; as they are a revelation in low-frequency performance with the Duelund CAST copper crossovers.

I consider the 803Bs to be terrific drivers in my Stokowski Altecs, and as much as I love them, there's no denying the 803As deliver a more agile, more detailed, and more nuanced bass response. 

The overall clarity of the 803A drivers was impressive, and I could hear an abundance of beautiful overtones, harmonics, and pitch definition that were completely missing with the stock N800E crossovers of my Coronas.

Now I understand a lot better Keith Aschenbrenner's praise of the Altec 803A drivers. They really are something special, and the Duelund CAST copper magic has set them free to perform as they were intended to. 

It impressed the heck out of me to hear what a huge difference the Duelund CAST copper capacitors and inductors made in the N800E circuit, with so much more musical information coming through, and their utterly natural live-like tonality was an absolute delight. 

The Duelund CAST copper components brought that same sort of transformation to the high-frequencies through the Altec 802D compression driver and Altec 811B HF horn, with that pairing sounding very detailed and with a beautifully rich "live-like" tonal balance.  

However, the additional clarity and resolution I was hearing in the low-frequencies with the 803A drivers was somewhat diminished in the high-frequencies with the 802D compression driver and Altec 811B high-frequency horn combo by comparison, due to the presence of the L-pads in the circuits.  

Both the high and low-frequency circuits of the crossovers have one Duelund CAST copper 3.5 mH inductor and one Duelund CAST copper 10.5 uF capacitor each, and the only difference between the low and high-frequency circuits were the presence of the 16 Ohm L-pads.   

I came to the conclusion that the L-pads reduced the amount of musical information coming through the high-frequency part of the circuit relative to the low-frequency circuit.

The L-pads were less smooth and liquid sounding, reduced the clarity, and were just less nuanced sounding overall compared to the clarity and natural tonality of the Duelund CAST copper capacitors and inductors on their own in the low-frequency circuit.  

So while I'm nitpicking at the L-pads performance in the circuit, still the overall performance of my Coronas with their Duelund CAST copper breadboard crossovers was an extraordinary improvement, and was easily some of the best sound I’ve ever heard from a pair of Altecs.

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