Greets!
What's a 604-16LN? Only 'oddballs' I've seen are -168x, -16xx.
Hi guys,
Getting back into audio after a number of years absence and am going to start restoring/dialing in my Big Reds. They are bone stock with M/L xovers on the back. My version uses the 604-16LN, not too common from what I can find. One thing I have noticed is the highs aren't really there as I think they should be, could be my aging ears but there just isn't a lot of sparkle to them. I noticed a little trash on the throat screens..perhaps a cleaning is in order .
I haven't pulled the xovers apart again but I am now wondering about different versions to accommodate the 16 ohm 604. I have only seen one schematic published for the M/L xover and it isn't mentioned what the impedance is. I'll attach the drawing I have and a few pics of the driver.
I haven't ever taken one of these apart, is there anything to watch out for in dismantling the 604? Will I be able to get to the throat screen?
Thanks all, I hope I can get the highs back, after all, they were used as studio monitors for many years.
cheers
PS could someone please confirm if the attached schematic is for the 16 ohm xover? From what I read, I think there WAS just the 16, but want to make sure. thx
DSCN2935.jpgDSCN2939.jpgDSCN2934.jpgDSCN2930.jpg
Last edited by kilohertz; November 23rd, 2022 at 06:36 PM.
Greets!
What's a 604-16LN? Only 'oddballs' I've seen are -168x, -16xx.
Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.
Exactly. maybe Low NoiseOriginally Posted by GM
I'm guessing they are old enough to be Alnico, but not sure how to tell without dismantling. Are there any special instructions for taking these apart or do I just start removing screws layer by layer?
Cheers
LN = Less network
HPLN = High Power Less Network
Last edited by Old Guy; November 23rd, 2022 at 09:32 AM.
Your neighbors called. They like your music.
Les Nesman?
Sonic Barbarian
I'd rather have Lonnie Nanderson
I talked to Bill at GPA about the screens on my 604s, and he said that you would have to remove the horn to get at the screen, this would be very difficult for you do yourself. I would have a go at cleaning them with a long cotton swab and some soapy water or isopropyl alcohol, and then some gentle sucking with a bit of flexible tubing hose inserted into a vacuum hose, so that you only get a fraction of the sucking power of the vacuum and you can throttle it with your hand.
If that doesnt fix your highs, put a multimeter on your 604s and check the resistance. Good to do that anyway.
My bet is maybe one of the parts in the xo is the culprit. Move the wipers on the attenuators back and forth several times to "clean" them. Or better yet, if you can get some deoxit or something on them that would be good. And then put the MM on the various parts of the xo to see if they are all in spec.
- - - Updated - - -
from Altec Big Red Monitors - Page 2
I could say with the absolute confidence that bigger portion of that coil goes toward junction of 20 ohm resistor and 2.3 uF cap. Not vice versa as it was shown in this schematic posted above.
Corrected M_L_604_Xover.jpg
I swear i thought turkeys could fly!...
Not all vegetables make good leaders.
I was looking at GPA's parts list today for another reason and saw the 604-16LN and 604-16HPLN listed there.
Parts – Great Plains Audio
the 604-LN has the same LF as the 604E
There is no HF listed for it, so maybe it is the same as the 604E - 34852?
Or maybe the HPLN - 35153?
They both have Note 11, "For superior HF reproduction, use original diaphragm. If high power handling is required, and excellent HF frequency response is also needed, use diaphragm #26421 (16 ohms). Call us if you need advice on the proper selection of a diaphragm for your particular application."
I dont understand what "Less Network" would mean in context of this driver? Weren't the crossovers a separate p/n anyway?
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