A 7 Filter

[eric g]

Hi,
I rebuild an A7 500 with a 808 8A driver + 511B as HF speaker.
1? I search the shematic diagram of the original filter which should be a N500 or a N501, 500 Hz model.

2? What improvement or modification could be done to the original shematic to adapt the filter for HI-FI domestic use.

Thanks in advance for your reply.

[Frantic]

Eric do you have the N500-8 crossover? If so just clean and lube the L-Pad (Caig d5 and MCL or the "gold") if the caps check OK about 30-35 MF in the circuit... there are two.. rated 16MF each.. I wouldn't do anything.. Some folks don't like L-Pads and find a fixed value resistace that works for them...thou...


F1`

[Frantic]

Eric, I've got to preview my posts (hey I'm NEW at this) but ...please excuse me I should have type uf for microfard...... not MF....that's a big difference

F1

[Altec19]

Hmmm . . . I don't think I would care to meet a 30 "MegaFarad" capacitor in a dark alley!

Welcome, Frantic!

[eric g]

Hi,
Thanks to every body to take care of my case.

The problem is that I have NOT the filter N500 or N501, so I search the schematic diagram in order to build a filter.

When I say that I rebuild, I dont start from an existing A7 500 but from a pair of 808 8A +511B and probably a pair of 416 Woofer.

Thanks for further informations
Regards
Eric

[dgwojo]

I'd switch the diaphragm in the 808 horn driver to an all aluminum tangential diaphragm in place of the symbiotik one that comes stock in the 808 driver. This changeover will make the draiver a model 802, the 802 is a better choice for home use. Here's a link for a good calculator and wiring diagram on crossovers, good luck!!
http://www.mhsoft.nl/spk_calc.asp

[Art J.]

Hello Eric, here is a diagram I made of my N-501 with modification 30923
Contour Network for home use. It will tame down the 511b . I think this is what you asked for.
http://img1.uploadimages.net/974615Altec9846-8A.jpg
This is the system used in the 9846 Monitor and the Barcelona home speaker.
It can be used in A-7 with only different Zobel value for the base driver you choose.
Changing element will help as dgwojo said. This system uses element 34647 which
is hard to find. Hope this helps. Art

[eric g]

Many thanks Art J for the diagram..
BR
Eric

[Russellc]

Art I see on your diagram this is a 501 8A. I have in my A7 501 8B. It also has the pot in the high frequency. Do you or anyone know what the differences are? I have often wondered but have never seen a schematic for the 501-8A.

Thanks, Russellc

[Art J.]

Hi Russellc, I never see schematics either, that's why I had to disassemble the speaker
to see what they did and make my own. I'm setting up for bi-amping anyways.
The 501-8b has a different case but I don't know if the inside
is different. If you can open it up, you would be able to read the capacitor value
printed on it. If the two say 28uf, then its the same. If it is different, let me know and I can
back-calculate to see which alignment they used to get 500 cycles.