Erik Mandaville

Per Tony: "I'm really impressed with this tweeter you've put together." That makes two of us. A clever and very affordable idea! Erik

Really beautiful work! The visual element really appeals to me, and I do wonder about the possibility of increased HF diffraction effects that MAY be associated with the inside edge of the grille that stands out-and-away from the surface of the baffle. If you don't notice a difference, or prefer to listen with the grilles removed, it doesn't matter. There are ways to reduce diffraction potentials, but installing felt or open-cell foam around that edge would really ruin the otherwise incredible look. Erik

An even cheaper but just as effective solution is to use common spade lug terminals. You can buy a small box of the them at a hardware store. What I sometimes do is yank off the insulation on the wire input end, and then bend the lug at a 90 degree angle. Use a small flat-head wood screw, screw to the board, and then wrap once around the upright section of the lug, crimp snug, then solder. For a neater appearance, you can trim the circular cross section which is usually crimped around a piece of wire down to a single vertical length about 3/8" high. cheap and effective. Erik

At www.tubesandmore.com Go to the menu on the left and scroll down to Hardward and Terminal Strips. Some different choices there for the solder lug type. I sometimes don't have any of the single lug types, and so will cut down one with two lugs for what I need. I hope this helps. Good luck -- you're really doing a nice job with them!

Daytons are great for the money, and I don't A/B them with anything. I forget about them and listen to music after driving myself crazy with cap and cable comparisons for too long. That is part of the hobby that I remember well, but just don't do too often these days. Erik

Here's something I did that is very much like the ALK universal, using reversed polarity in the mid-high section (due to slope) and a variable L-pad rather than the autoformer. I don't use the autoformer anymore.

Or this little network I made for a pair of monitors that I had first built a pretty high-order series network for (yuk). This simple cap and coil on the woofer is much better, much more open sounding, and around 3dBs louder with the same input than the other. I think high order has some real advantages, but particularly when used at the line level. I just installed some solder terminals (these are what I use in amp and preamp projects). Erik

And this: If you look closely, you can see some different ways of doing it, but there are a number of options.

And this:

kg4: There are a number of sources for solder terminal and barrier strip parts: www.tubesandmore.com (solder terminals) Mouser Electronics, and elswhere. Even Radio Shack has 5 lug solder terminals, but you can also wire caps directly to the barrier strip you're using on the board. Not all connections can be made that way, of course. The connection points can help keep wire in place and from sort of 'flapping in the breeze'. in the past I've used everything from rivets in masonite, to fine solid brass machine screws and nuts. Wow, it's amazing when I think I was doing that 18 years ago. Time goes by too fast. Lots of networks shown here and elswhere on the forum use them, and I'll enclose a couple of picture of my own as an illustration. The coils are hand wound on the first. Erik

The color of the wood you chose is too light. Darker woods such as ebony and mahogany will give you at least another 20Hz on the low end, not to mention an extra four or five inches in image width and depth. These are getting better and better, kg4. Are you using some sort of terminal post or solder tie point for connections between the components? Single or multi-lug solder terminal lugs work well, as do the right angle solder 'posts' design for use with barrier strips. Both have eyeholes that will accept small wood screws. Erik Great work!

Absolutely agree with enjoying the freedom of choice on this subject. I've made a dozen preamps without tone controls with the very idea that the added required circuitry would amount to a compromise. I've also used preamps designed by smaller-scale companies that sounded very good without them. I'm using a small solid state preamp right now with bass and treble controls, and its performance is unquestionably in keeping with the best all-vacuum tube (including rectification) line stages I've used that didn't have tone adjustment options. Others may disagree with that (although the ears in question are my own), and that's fine. There are also many high-end line stage designs that include bass and treble controls, so it seems we are in the position to make our own choice in the matter. I've also made and used ICs with horrible cap/foot specs, and found longer runs, particularly in the presence of high output impedances, to behave very much like turning a treble control to the left of flat. Clarity is important to me, as well, and having the ability to adjust highs and lows a bit is something I would rather do with than without. ANY circuit (regardless of whether it has tone controls or not) will add a certain coloration; we can choose the colors we prefer. Erik

As an FYI - There are lots of speaker builders who by choice leave the network OUT of the cabinet. The cabinet may have three sets of binding posts or barrier strip installed, however what is wired to them on the inside is not the input into the crossover, but rather the drivers, themselves. People often start with calculated values of L and C, and sometimes want to tweak or add compensation circuits to personal choice. I've done this many times; the speaker shown below has its crossover installed in a separate box outside of the speaker. For high order networks where space is a problem, inductor placement and proximity is more of an issue.

Great! They've seemed fine to me all along. I'm glad they're up and running and that you're happy with them. Erik

"I think he might first have to send the boards to the CMDF for miniaturation before he can put them in the speakers. " Is that where you sent yours?

Chris: The Eastern Provice where you were is so different in terms of topography from the mountains of Soutwestern Saudi Arabia. I wish could post the pictures I took in the Asir Highlands during a backpacking trip a friend and I went on when in high school. We flew from Dhahran to Abha, and from there hitched rides up into the mountains. It is comparatively green and cool; almost as if it were another country altogether. It sometimes rained in the afternoons and night, and, without a tent, we wrapped ourselves up in the shower curtains we brought for makeshift shelter/ground cloth/source of shade. We went mainly to try to find the wild baboons that live in the mountains. Towns and cities there are fascinating; but the desert is what I miss so much about the place I still refer to as 'home.' Erik

Dee: I think there is something to be said for the kind of simplicity of your current setup: greatly reduced distance between stages, less IC and related capacitance effects, that sort of thing. It seems there are a greater number of very good quality receivers and integrated amps being sold these days by modern companies, too. I also like the 4,000Hz crossover I'm using with the Klipschorns and Bob's tweeters. Erik

Hi, Chris: Yes, both Empty Quarter articles mention my dad, Jim. Small world, indeed! The 'Jack Mandaville' you mentioned is my uncle (my father's younger brother). Please send my regards to your mom, as well. Erik PS: I'm glad a few of you enjoyed reading the links. I miss desert traveling/camping in Saudi Arabia very much. The closest I've been able to come to that sort of remoteness in this part of the world was a 1985 trip my wife and I made, before we were married: a drive from Texas up to the Northwest Territories and back. The wildness up their is beautiful; just lots of really big 'beasties' snorting and grunting around our tent -- pretty spooky at times.

Chris: I'll be sure to ask my dad about this. Your trip sounds very much like what we had to do a few times a year to go home to visit family from high school and college; too much flying and jet lag. The last time I was there was in 1994, just before my parents left for retirement. My dad and I went on a week-long camping trip down near the border of Yemen so I could photograph some rock inscriptions in that vicinity, and I had published a couple of other stories based on that trip -- one of which your mom might have seen in an issue of Al Ayyam Al Jamilah. At any rate, my dad and his family did live in Ras Tanura for quite a few years. We spent the majority of time in Dhahran, but also a bit in Riyadh, as well. Erik

Nice work! I'm curious: What happened to your 2A3 amps and the AVVTs? Erik

And a link, if curious, to an earlier trip when I was little. http://www.saudiaramcoworld.com/issue/196706/camping.in.the.empty.quarter.htm That desert is very arid and very remote.

Neat! Pictures of what was once home -- changed considerably since my dad first moved there -- in the 1940s. For environmental interest see: http://www.saudiaramcoworld.com/issue/198903/crossing.the.rub..htm BTW: The title "Crossing the Rub' " had been provisional at the time -- the working title I used when I wrote the piece was "Through the Heart of the Empty Quarter" Enjoy your visit! Erik

Don't worry -- people talk about MANY brands of speakers on this forum that are not Klipsch. The new woofer looks good! Erik

IMO the space between coils is adequate. Nice work again. Erik

Great! enjoy your Klipschorns. I have K-horns, too, and there are people who have expressed about them essentially what you have referred to with regard to the 901s. Just no accounting for personal taste, I suppose. Erik