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View Full Version : L-pad value for ALTEC N-800-F crossover



tnc
02-06-2007, 08:45 PM
one of the shaft on my altec n-800-f is going bad. Does anyone know what is the value for this l-pad. Thanks.

X_X
02-07-2007, 08:37 AM
one of the shaft on my altec n-800-f is going bad. Does anyone know what is the value for this l-pad. Thanks.


Yes, they are 8 ohm. I'd guess the original had a wattage rating of about 50.

If you're shopping for L-pads, Vialet (sometimes spelled Violet) from Japan gets my vote. The Lpads from Madisound are nice, too. Link (http://www.madisound.com/cgi-bin/index.cgi?cart_id=2136073.29619&pid=1605).

Use a very small screwdriver and unscrew the set screw in the attn knob. Remove the nuts on the Lpad shaft. Open the back baffle and remove the screws holding the can in place. Drill out the rivets on the can, and if you have trouble with the black cutback adhesive- try putting the networks in the freezer until the adhesive becomes brittle- chip away the excess carefully using an awl of screwdriver. Check your caps values while you're at it. Have fun, and good luck!! ;)

Tom Brennan
02-07-2007, 09:24 AM
X X---Are you sure 8 ohms? My 800-Fs have 25 ohm L-pads. Note the 800Fs were meant to be used with 16 ohm drivers. Usually, some odd stuff went on though.

tnc
02-07-2007, 09:47 AM
So which is it 8ohm or 25ohm. How would I measure it from my existing network. I can unsolder the 3 tab but dont know how to measure it. Thanks.

X_X
02-07-2007, 09:55 AM
X X---Are you sure 8 ohms? My 800-Fs have 25 ohm L-pads. Note the 800Fs were meant to be used with 16 ohm drivers. Usually, some odd stuff went on though.

I know mine measure 8 ohms. I did think it was odd, but that's what it reads. I wouldn't be surprised to see anything, though- especially from the later periods. My networks had completely different caps inside. Do you have a schematic? I sketched one out...we should compare to be certain.

Zilch
02-07-2007, 11:08 AM
How would I measure it from my existing network. I can unsolder the 3 tab but dont know how to measure it. Thanks.Between terminals 2 and 3.

It will be zero Ohms at one extreme of the adjustment range, and the nominal value of the L-Pad at the other (CCW) extreme.

tnc
02-07-2007, 04:04 PM
I will measure mine and post the result here. Thanks everyone.

SMKSoundPro
02-07-2007, 04:13 PM
I also have a pair of Altec N800-f for the Valencias I am supposed to be working on for a friend. He slid them out of the back of his Tauris wagon and broke the knob of the l-pad off. He said no big deal. I say: it is a big deal.

I have not opened the can to find out the l-pad impedence, and am watching this thread to see your results and recommendations!

Good Luck!
Scott.

tnc
02-12-2007, 05:50 PM
I measured the old L-pad and I've got a reading of 15.2; Does that mean I should use a 16ohm L-pad to replace the old one.

Zilch
02-12-2007, 05:53 PM
Yes.

tnc
02-12-2007, 08:22 PM
Thanks Zilch.....