Mastering Lab Crossover for Altec 604E

[iso]

:screwy:Has anybody out here used Altec 604E with Mastering Lab Crossover. https://www.google.fi/url?sa=i&rct=j...05064038158883 (https://www.google.fi/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&docid=KNyXT9yTAUdjRM&tbnid=hwXiyA3oVew8yM:&ved=0CAUQjRw&url=http%3A%2F%2Fwww.audioheritage.org%2Fvbulletin %2Fshowthread.php%3F1595-Altec-Big-Red-Monitors&ei=LUO-U8CrA8jiywON_ILIBA&bvm=bv.70138588,d.bGQ&psig=AFQjCNG0kKa6sYK545pn_COAYrYaaK5qtw&ust=1405064038158883)On abowementioned scematic 0,15mH tap of 1,5mH inductor seems to be closer to end connected to 0,26mH inductor. On other scematic I have seen 0,15mH tap seems to be closer to end connected to 0,125mH inductor. Does anybody know which end of 1,5mH inductor is supposed to be closer to this .15mH tap.It is also nice to hear if this crossover is worth to try, or should I look something else.Best RegardsKimmo

[rgwalker]

:screwy:Has anybody out here used Altec 604E with Mastering Lab Crossover. .It is also nice to hear if this crossover is worth to try, or should I look something else.Best RegardsKimmo

I have owned several Altec 604 systems with a variety of production and DIY cabinets and crossovers including stock Big Reds, Urei 813s and Altec Model 17s. The ML xover was the holy grail for many years and luckily I didn't shell out $1500 for a pair when I could at the height of the boom in the early 2000s. However, I jumped at the chance to purchase a pair of Big Reds for $2500 from the original owner who was downsizing his studio. IMHO the Mastering Lab xover works best on what it was designed for and that's the Big Red cabinets. It does work well on other 604 systems but they are very expensive, and often in rough cosmetic shape, when you can find them. You can do better for much less $$$ with upgraded Altec, GPA or DIY xovers. I highly suggest building the Jeff Markwart upgrade of the Altec N1500-8A xover. I was blown away when I built a pair for 604Es in 5.5 cu ft Barzilay cabinets with tube ports.

[iso]

I highly suggest building the Jeff Markwart upgrade of the Altec N1500-8A xover.

If I have not misunderstood N1500-8A is for 8 ohm diver. However Markwart explains how to add series eq for HF in stock N1500-A crossover. He suggest to add 6uf cap and 8 ohm resistor parallel connected in series to HF driver and connecting mid point of resistor to ground by pot. 8 ohm resistor most likely meant 2 pc 4 ohm resistors in series like in 3rd order butterworth filter for 604B with 604E cone.

However 3rd order filter seems to have some advantages over modified 1N1500-A unit, as 604E LF cone seems to have audible resonance close to 2K and 3rd order slope will at least improve HF power handling. HF eq will most likely be benefical too. If cone is most obvious difference between 604B and 604E and hf units are fairly similar this might be good starting point.

Any ideas?

Best Regards

Kimmo