Altec crossover schematics?

[mcds]

Hi guys,

I'm a newbie here. I've acquired an Altec VotT using the N501-8A crossover for a 416-8C woofer and 902-8B hf driver combo. Is there a schematic for the crossover somewhere on the net? I suspect the internal components of the XO may be well past their best-before date and I'd like to see if upgrading any components would make sense.

TIA for your help.

[speakerdave]

I'm doing this from memory, please note, but I don't think you really need a crossover schematic. There are only two capacitors in that can (as I recall). They are both the same size and it is an odd size--that is, they were probably special-made, and in mine you could read the size on the capacitor. You will have to do some arithmetic to find a way to get VERY CLOSE to the same capacitance with available sizes. Note carefully how they're connected before you cut anything a way. While you're in there fuddling around you might try adding some bypass caps.

David

[Earl K]

I'm a newbie here. I've acquired an Altec VotT using the N501-8A crossover for a 416-8C woofer and 902-8B hf driver combo. Is there a schematic for the crossover somewhere on the net? I suspect the internal components of the XO may be well past their best-before date and I'd like to see if upgrading any components would make sense.

TIA for your help.

- You really don't need a schematic since you already have existing Altec crossovers.

- I'd recommend first buying either a dedicated LC or LCR meter from eBay. If you are in the US you'll be able to get one delivered to your door for about $70.00 . Do an Ebay search for either "Inductance" or "Inductance Meter" . This will bring up a handfull of returns for new product available online within the US. Typically, there are also a few Hong Kong sellers & a couple of Australian vendors of these speciallized meters. ( Get a meter that has more than a 20uF capacitance range , as its' top range ).

- Then , with meter in hand, you can measure the actaul inductance of the coils in your present crossover. Replace them with air coil types / if cost permits. You can also measure your existing capacitors ( from the 501-8a ) to see how they spec. out. Altec used PIO ( paper in oil ) types for decades. They are most likely dried out & developing funny sounding resonances. The Altec network have the capacitor value labelled right on each cap.

- Before buying new coils / post your findings here , so that the values can be scruntized for obvious mistakes ( or misreadings ) .

[CONVERGENCE]

Hi,

Why go through all this trouble. Just purchase an Altec N500 8H or N1285 8B.

These are recent Xo .I do believe with all the new type of capicitors and inductors etc...

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[mcds]

I'm doing this from memory, please note, but I don't think you really need a crossover schematic. There are only two capacitors in that can (as I recall).

I got that info before but that would mean that the woofer is being run wide open, and I find that a bit hard to imagine.

[mcds]

- You really don't need a schematic since you already have existing Altec crossovers.

Well, actually I'd like to avoid opening the crossovers but it seems I'll have to.

- I'd recommend first buying either a dedicated LC or LCR meter from eBay. If you are in the US you'll be able to get one delivered to your door for about $70.00 . Do an Ebay search for either "Inductance" or "Inductance Meter" . This will bring up a handfull of returns for new product available online within the US. Typically, there are also a few Hong Kong sellers & a couple of Australian vendors of these speciallized meters. ( Get a meter that has more than a 20uF capacitance range , as its' top range ).

Thanks for the tip, I'll get one of those.

- Then , with meter in hand, you can measure the actaul inductance of the coils in your present crossover. Replace them with air coil types / if cost permits. You can also measure your existing capacitors ( from the 501-8a ) to see how they spec. out. Altec used PIO ( paper in oil ) types for decades. They are most likely dried out & developing funny sounding resonances. The Altec network have the capacitor value labelled right on each cap.

The capacitors are what I was wondering about. I don't see a serial number on my crossovers and so can't determine their age, but I suspect that caps may be well out of spec. Do you have a recommenadtion what type or make of capacitor I could try?

- Before buying new coils / post your findings here , so that the values can be scruntized for obvious mistakes ( or misreadings ) .

I most definitely will ; thanks for the help.

[mcds]

Hi,

Why go through all this trouble.

Because it's fun?

[speakerdave]

I got that info before but that would mean that the woofer is being run wide open, and I find that a bit hard to imagine.

I wasn't clear in what I said. I didn't understand that you would be completely rebuilding the crossovers, replacing the inductors as well.

David

[Earl K]

Hi mcds

- I'd recommend you first open up your present crossover before worrying too much about selecting new cap types.

- In fact, personally, I'm more concerned about the quality of Altecs' older inductors than their original cap choices.
- For the horn circuit, I'd recommend you buy at least Solen / or Erse aircoil types from one of the online vendors . An 18 gauge coil will work just fine in that position. For the woofer circuit many mambers around here are satisfied with the Erse SuperQ coils ( they are a variation on using a laminate/transformer core ). These have very low DCR , which is an advantage in this position.

- Here's a pic that shows the typical parts that Altec was using back in the 70(s) & 80(s) .

cheers

[Wardsweb]

Hi guys,

I'm a newbie here. I've acquired an Altec VotT using the N501-8A crossover for a 416-8C woofer and 902-8B hf driver combo. Is there a schematic for the crossover somewhere on the net? I suspect the internal components of the XO may be well past their best-before date and I'd like to see if upgrading any components would make sense.

TIA for your help.

Maybe this will help.

[Wardsweb]

And if you have an attenuator build it.

[Art J.]

Here is a diagram I made for the other board
when I had mine appart. May be handy for reference.

http://xs75.xs.to/pics/06141/N-501-8a.jpg

[mcds]

Thanks very much for the info, folks. I have the 511 horn, so I'll go with the values for that. I'll report back when I have done the XOs.

One last question: are there any particular recommendations for the L-pad?

[Mr. Widget]

One last question: are there any particular recommendations for the L-pad?

I like the 100 watt L-pads that Parts Express sells. They offer both 8 and 16 ohm versions.

I know you don't need a 100 watt pad, but I have had many of the lower power pads fail over the years and have never had on the the 100 watt pads fail.


Widget

[mcds]

Thanks, I'll get one of those.