Have the stock 604-8Ks and XOs, not satisfied with their performance compared to my extensively modified A7s cabs and XOs therefore will build new ones based on Jeff Markwart?s simplified 604H. Simplified 604-8H EQ Crossover
Went about replacing all of the grotty stock XO wiring with 14g Teflon silver/copper wire, one resistor was replaced metal-film type, cap just before the HF driver is bypassed with a small value Sidereal. It was a time consuming PIA but achieved a substantial improvement in transparency and dynamics making all the work worthwhile.
Gathering the components required, already have most of them, PIO and Teflon caps, Teflon silver plated wire, carbon film resistors, waiting on Solen Hepta-Litz inductors and inexpensive L-pads which should arrive late next week. Once the XOs are dialed in the L-pads will be replaced with fixed resistors.
Added pair of pics of the 604 XOs post mods.
Cheers
Ditto for drivers like Lowther that supposedly require 1000+ hrs of break-in; my response and subsequent banishment from an early audio BB was that by this time they were broke if they'd changed much, otherwise they would have designed them that way to begin with!Originally Posted by mah
GM
Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.
Well I dont know about electronic burn in but after a few days of listening I am burning in! The GPA crossovers are really good! Listening to some vinyl last night was sublime. Very happy with this purchase!
Those Callin caps in the XO pics are they still active or did you bypass them ? If they are still active they should be replaced. I can almost guarantee they are out of spec by now.Almost every Callins cap I had in my crossovers have all drifted from spec that I had measured..They don't last very long, after 20 years they should go into the trash.
The Callins are very easy to spot they say Callins on the side and they are black with red ends.
I'm real glad to hear that you're happy with your GPA purchase .
AFAIK, you're the first person to report back after buying that particular network ( I thought the price was really a bit of a steal, IMHO ).
Yeah I searched all over the internet prior to purchase trying to find anyone who had reviewed this crossover, especially used for Altec 604-8G. I had no luck. I think for $60 each already built they are a steal.I'm real glad to hear that you're happy with your GPA purchase .
AFAIK, you're the first person to report back after buying that particular network ( I thought the price was really a bit of a steal, IMHO ).
Hello AB
Not going to bother with replacing the stock caps at this point as I'm just about to built new XOs. Maybe at a later date will replace them just to hear what the mostly stock XOs sound like with new caps.
Cheers
Well if your building new crossovers then yeah I wouldn't bother, but they will still need to be replaced at some point if you plan on using them again.. I can almost guarantee a much better sounding speaker once they are replaced.
Good Luck on the new Crossovers.
Its funny I have a pair of GPA x-overs and they weren't my cup of tea, I listened to them for about a half hour. In my space with 8 g's they sounded muffled and rolled off.
mah,
Depending upon dilelectic , a film cap takes anywheres from 10 hours to 200 hours to fully break in. Usually 100 hours is pretty much there, except for teflon. Sometimes, a film cap will reveal their true characteristics, after break in, as being unacceptable. All one needs is a high resolution system, and some listening on their own, to discern such things.
Have fun in your search for audio truth, and most of all, learn to trust your own ears.
Jeff Medwin
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