Re: Altec N1209-8A Network
Nice Work ! Thank You for your contribution ! :Thumbs up: What program did you use to draw up the diagram ? The layout looks the same as the 1201/M19 Crossover except for the zobel.But all the values seem to be different so not really the same.Interested to know the readings of the coils when you get them.
Very,Very Nice Thanks Again ! We want to put all the schematics in one place for easy retrieval.
Re: Altec N1209-8A Network
Finally getting around to refurb on my 1209s, so I yanked out the coils and measured them.
The schematic now is updated with the values. These measurements are only the averages from one unit that I've worked on so far. Will continue to perform tests on the other three I have and then update again if the average values move as the sample size increases.
I can tell from these values that I still have a lot to learn about these filters. They're pretty complicated. At first, I thought that L2 and C2 were essentially the 2nd order low pass, and that L3/C3 were the 2nd order high pass, but it's not that simple apparently...
Re: Altec N1209-8A Network
It would be interesting to power one from a nice SS amp, load it with 8 ohm resistors and measure the response. Do the same for the 1201 and see what the diff is.
A project I could tackle in the winter.
Ron
Re: Altec N1209-8A Network
Quote:
Originally Posted by
RonSSS
It would be interesting to power one from a nice SS amp, load it with 8 ohm resistors and measure the response. Do the same for the 1201 and see what the diff is.
A project I could tackle in the winter.
Ron
Good call - that will be some useful info.
I am waiting for parts to come in from PE, so in the meantime, I re-worked the schematic drawing to make it a bit more intuitive to look at, and added some specs.
Re: Altec N1209-8A Network
I finished re-furbing my 1209s today. As you'd expect, the sound is better. I'm noticing much clearer definition (particularly in mid bass), and the sound is cleaner (not as muddy) at the crossover point. The horns blend with the woofers better now. All in all, I completely re-wired two of the networks, and checked the inductor values on three units.
I won't bore everyone with another "crossover rebuild" thread, but here are a couple of things that may be of interest.
First, I gutted the network, leaving only the L-Pads and coils (which look and test out fine):
http://img29.imageshack.us/img29/3045/n1209gutted.jpg
Then, I rewired with all new components:
http://img195.imageshack.us/img195/8...09rewired1.jpg
The parts used (each crossover) were:
(2) MILLS 2 OHM 12W NON-INDUCTIVE RESISTOR
(2) DAYTON 7.5 OHM 10W PRECISION AUDIO GRADE RESISTOR
(1) ERSE 6.0μF 250v PulseX - Metallized Polypropylene Film Capacitor
(1) DAYTON 10.0 UF 250V POLYPROPYLENE CAPACITOR
(2) DAYTON 18.0 UF 250V POLYPROPYLENE CAPACITOR
I also tested all the rest of the inductors. The values posted in the schematic above are pretty much representative of the average across all three of the 1209's that I pulled apart. I tested each inductor five times and took the average of all the tests. Here is a shot of a typical test for L3 (the coil in the high-pass filter section):
http://img29.imageshack.us/img29/3866/n12098al3test.jpg
Fun project, and the garage is sounding better all the time. :)
Re: Altec N1209-8A Network
Nice work Mike! I love to see folks dig in and make some solder smoke!
I'm watching Tower Of Power's 40 anniversary concert on AXS through the A7's powered by 8 screaming watts of modified Heath W5M PP DHT power.
It jams!
Ron
Re: Altec N1209-8A Network
Many thanks Alien_Shore (Mike) for the posts...
I really like these types of threads.
Congrats
Re: Altec N1209-8A Network
That's what I told Mike.They are never boring ! They are all different in some way... Keep those threads a coming guys. :smile2:
Re: Altec N1209-8A Network
Tonight I did a bit more focused listening tests of the crossovers.
After a few cold IPAs from the beer fridge, I decided to let the big 816s out for a run.
Man, the old 416a are really, really nice drivers. I push them and those big bass horns just sound so incredibly good.
The 802-8gs on the 511s are another matter. Even with the big L-Pads in these crossovers, it is really hard to tame them down. I think I need to whip out the active XO and play around a bit with some bi-amping and see if it is just mismatching in terms of the wattage, or need to make some changes to the crossover itself.
Again, I don't know much about the original intent of the N1209 - it seems more like a general purpose XO for pro sound reinforcement (PA maybe?) And to be fair, I don't have them loaded correctly. The 416a is a 16ohm driver, so I probably need to just start over with some custom XO design for my garage :D I definitely am thinking that the 816/416 combo is a winner for sure.
Re: Altec N1209-8A Network
It is an efficiency problem... The 802's are way more efficient and add to the fact that the woofers are 16 ohm they are getting way less power, and there lies your problem IMHO... If the 802's were 16 ohm you would have a closer match with the efficiency..The woofers would then be getting more power than the 802's and since they are 6-8 dB more efficient or more (802) they would sound more tonally balanced.. IMO.. That's why it is always best to have a matching impedance..You will have less crossover issues and less crossover work to do to get them sounding equally balanced...
Re: Altec N1209-8A Network
Hello,
where can I find the schematic ? there is nothing to see and I have to rebuild A N1209-8A for our Cinema.
Thank you very much.
Re: Altec N1209-8A Network
I'm pretty sure the 1209 is the same as a 1201 except it has parallel 1/4 inch inputs instead of push button terminals.
EDIT: actually, they are different, and thanks to Earl K this thread explains the differences nicely: Altec crossover
http://www.hostboard.com/forums/hbmc.../2010/08/1.jpg
http://www.hostboard.com/forums/hbmc.../2016/07/3.jpg
1 Attachment(s)
Re: Altec N1209-8A Network
The schematic for the 1209-8A network above has an error in the HF lpad section. I?ve redrawn it after noticing that the original drawing shorts out the HF lpad.
Re: Altec N1209-8A Network
Thanks for spotting the error!
Here's the corrected version
http://www.hostboard.com/forums/hbmc.../2018/04/2.jpg
Re: Altec N1209-8A Network
It?s great you updated the original schematic, my correction was a bit crude. What app did you use to make this schematic?? Thanks Mike for doing the work on these.
Re: Altec N1209-8A Network
Quote:
Originally Posted by
dbale
It?s great you updated the original schematic, my correction was a bit crude. What app did you use to make this schematic?? Thanks Mike for doing the work on these.
LoL, I use MS Power Point. No problem, I enjoy adding to the knowledge base.
