Altec crossover upgrade

[zekk]

Thanks to Bill and Fran for the response to my query.
Appreciate it.

Zekk

 

[zekk]

Those audio caps that we normally used have current rating in VDC.
These GE motor run oil caps are rated in VAC !?
Is that OK ! I managed to get a pair of GE 25uf 370 VAC.

 

[Billfort]

Yes, it's fine. The DC rating of of these is higher than the AC rating and in reality, they will only be seeing a few watts - especially when considering the 100db/w/m efficiency of the 604s.

 

[zekk]

Thanks Bill!

By the way, I'm using your design for the corner cab and the music is phenomenal . The only different is the triangle ports (formed by newspaper cutting) with a depth of 3 1/2". Any comments ?

Zekk

 

[Fran604g]

Hey All,

I ran the sides today. Here's a pic to give you an idea of the size of these bad boys. They're .5" polycarbonate.

 

[jaymanaa]

Yes, it's fine. The DC rating of of these is higher than the AC rating and in reality, they will only be seeing a few watts - especially when considering the 100db/w/m efficiency of the 604s.

Speaking of caps and crossovers, what do you think a good value to start with would be if I add a small HF horn on top of my 511s?:scratch2:

 

[Fran604g]

Hi all,

I assembled the crossover boxes and started to fit the inductors. I still need to mount the copper cardas binding posts for inputs, they'll go in the rear.

I found a guy that does laser work and he said he can etch plexyglass, so the tops are going to have a vintage style Altec Lansing 604-8G logo on them.

I'm thinking that for the outputs, I'm going to run wires out through a grommet in the rear panel and not use binding posts. :scratch2:

Hopefully this weekend, I will be able to start soldering everything up and take them for a spin!

Fran

 

[Russellc]

Speaking of caps and crossovers, what do you think a good value to start with would be if I add a small HF horn on top of my 511s?:scratch2:

Jay, did you get my PM? I sent it during an ice strom so I will send it again, basically inquiring about a schematic you are using on your altec crossovers, I am trying PaulC again as well.

thanks in advance,
Russellc

 

[Russellc]

Whoops

 

[Russellc]

The A7's were later changed to 1200 hz for better power handling.

If 800 hz, you can KISS and buy the 2-way 800 hz crossover by Eminence from Parts Express. It would be difficult to build a better crossover any cheaper. Add a 100 w 8 ohm L-pad between the crossover and horn driver.

Hi PaulC, was wondering, and also asked Jaymana about a cross over for his altecs that I thought you had helped him with. I have ordered the the PE 800 hz crossover and dayton caps to upgrade it, but this will have no compensation for the woofer, an Altec 416 8C, nor ( and more importantly) compensation for the 802 8G. Would greatly appreciate a schematic if possible. Also got the 8 ohm 100 watt pots as well

Much appreciate any help

Russellc

 

[Paul C]

I had answered your PM, and asked you to send me your email address so that I could send you some attachments.

 

[Fran604g]

Yet another update...

Hi all,

I finally got around to the other part of this project, removing the stock crossovers and bi-wiring the cabinets in anticipation of the new crossovers.

I also installed an ultra bright blue LED in the back of each of the cabinets, just for fun, to match the crossovers. I tried to capture the effect with my POS Easyshare camera, but I can't manage the shutter speed and f stop with this particular camera, so I'll have to wait till my son comes over with his.

I also discovered that I need to add to the black material inside the cab that hides the pretty pink insulation.

Anyway, forging ahead here, albeit slowly!

Have a great weekend, folks!

 

[Russellc]

I had answered your PM, and asked you to send me your email address so that I could send you some attachments.

Sorry, I didnt get the pm...have pm'd you the two emails I use, thanks a million!

russellc

 

[jaymanaa]

Jay, did you get my PM? I sent it during an ice strom so I will send it again, basically inquiring about a schematic you are using on your altec crossovers, I am trying PaulC again as well.

thanks in advance,
Russellc

Here's the 500hz version that I used for 511s.

http://www.audiokarma.org/forums/showpost.php?p=794062&postcount=63

Good luck and keep us posted.

 

[Paul C]

Russell is using a 416C, so he can leave off the Zobel network (R3, C5).

The added parts for the horn compensation are R1, R2, C1.

If more top end is needed, he can add a 1, 1.5, or 2 uf cap between the L-pad terminals 2 and 3.

R1 and R2 don't have to be 40 w unless using with very high power amps. If using a low power tube amp like Jay, 10 w resistors will do just fine.

To make a 6 ohm 40 w resistor pack, wire four 6 ohm 10 w resistors in series-parallel. Ditto the 16 ohm 40 w, four 16 ohm 10 w resistors in series-parallel.

 

[Russellc]

Thanks to Jaymana and PaulC, I've got some soldering to do, I will report back how it compares to the ancient 501 8B's I have been using. I am confident it will be an improvement.

Thanks guys,

Russellc

12/25: here's a pick of the modded PE crossovers, havent added the compensation yet.

 

[Fran604g]

Hi all,

I partially wired the crossovers yesterday. Next is mounting the inductors to the bases along with a terminal strip. Also, I'll be finishing the case backs that need the input binders, LED terminal strip and output wire hole.

Man, time flies when you're having fun!

(Hope I didn't make too many mistakes)

Happy Holidays!

 

[jaymanaa]

Excellent! I'll bet it'll sound as good as it looks too. Are you keeping track of hours?:thmbsp:

 

[Fran604g]

Hi Jay,

Yeah, kinda.

I'm at about 8-10 hrs. with programming and setup on the CNC and mill. I'm sure you know how tuff it is when you start and have to stop after an hour or so ,then pick it up 2 days later.

I'm really psyched, I haven't done anything like this in so long that I'm wishing I had never stopped.

Man, how can thirty-five years evaporate so quickly? :tears:

If I only new then, what I know now....

 

[Fran604g]

Hi all,

First of all...Thanks Bill and Jeff, for their contributions to my 604's!! I couldn't be happier! :tresbon: Without both of you, I would never have been able to do something like this.

I finished wiring the crossovers today, and I am currently trying them out.

They sound beautiful.

They certainly sound more precise than the stock 604-8K's I've been using for years. The mids and highs seems to be right were they should be.

I notice that the attenuation for the highs is a lot more subtle than the stock 604-8K xovers, also. There isn't as much latitude from one end of the L-pad to fully open.

I have a pretty dead room, so I've attenuated the HF fully, and I'll listen to it this way for a few days. I haven't actually finished them, but they sound so nice, I don't want to take them out of the system just yet. I'll post more pics when I get them buttoned up in the coming weeks.

I'm thinking it's probably time to concentrate on Christmas now!

Merry Christmas, Everyone!!

Peace and Love,
Fran and Family