Jordan JX92S Aurum Cantus G2si Part 2

I put the mini-monitors together and I must say they sound great. I brought them to a local audio meet and everybody had very nice things to say about them. Their only downside is they are not very efficient. They sounded pretty bad on a triode-strapped single ended KT88. Just not enough power for them. Once they were hooked up to a KT88 running ultra-linear, they sounded much better. I look forward to hearing them with my DIYTUBE ST35 EV once its complete.

Now for a confession... I find it hard to pass up a good deal. I came across the group buy for Jordans on the diyAudio forum and Parts Express had the G2si tweeters on sale again, so I just had to buy them.

This time around, I want to build the transmission line version of Jim Griffin's design and upgrade the crossover components. The components are the same for the mini-monitors and the tl's so it will be interesting to compare how the crossover components effect the sound compared to the enclosure.

I bought the upgraded parts from SonicCraft. Here's the BOM - they are an upgrade but not an extreme upgrade. I really wish I could afford Mundorf Silver in Oil caps, but they are just too much right now.

• 2 - AlphaCore 1.5mH 12awg ($100.16)
• 2 - AlphaCore 0.3mH 16awg ($24.38)
• 2 - Sonicap 6.8uF 200VDC ($28.40)
• 2 - Sonicap 5.1uF 200VDC ($23.20)
• 2 - Sonicap 15uF 200VDC ($44.60)
• 2 - Mills 8R 12W ($7.00)
• 2 - Mills 3R 12W ($7.00)
• 4 - Mills 2.5R 5W ($8.60)
• 4 - Dayton BPA-38SN HD Binding Post Pair Satin Nickel ($23.60)
• 2 - Aurum Cantus G2si Tweeters ($138.66)
• 2 - Jordan JX92S Group Buy ($253.00)
  

So the total excluding shipping and stuffing is $788.60. That comes in less than my original mini-monitors. That is why I cannot resists a good deal.

I don't really need the larger gauge inductor for L2, but the cost of buying a 20awg inductor from another source made the price the same. Because the 16awg inductor has lower DCR (0.129) compared to the specified 20awg (0.36), I had to change the value of R3 in the crossover.

Original resistance of shunt on tweeter: 0.36DCR + 1R = 1.36R
Upgraded resistance of shunt on tweeter: 0.129DCR + 1.25R = 1.379

In addition to the parts I ordered, it was recommended to me that I bypass C2 and C3 with a Sonicap Platinum 0.1uF capacitor. These guys are $29 each totaling $116. I decided to pass on these for now and use the Russian Telflon caps that Grainger Morrison (there is only one) gave me.

Finally, I'm considering making the enclosures using a very different construction technique this time. I want to make them using layers of Baltic Birch Plywood so that the front, top and rear would be striped and the sides would be the birch veneer. I could make the enclosures from 2 sheets of 5x5 BB so the cost really isn't that much more than if I used traditional construction techniques.

More on this later.