Altec 846A Crossovers

[Paully]

Are the values in the 846A crossovers the same as the 846B? It turns out the speakers I bought are 846A and not B. The Black goo looks nightmarish and I was toying with the idea of just completely building new crossovers. I understand, that at least with the B, some like to replace them with Model 19 crossovers. Thoughts?

Schematics are great if you have one!

Thanks!

[Zilch]

Use a 16-Ohm L-pad in lieu of the pot and resistor shown here:

[Paully]

Thank you Zilch. I have been reading your old posts on the 846A and B, they are very useful. I was a little peeved when I realized I hadn't bought what I had been sold. Hopefully the A isn't a worse performer than the B.

Anyway, I didn't realize there was so much going on in that little metal box for the A. Unfortunately I now have to return most of what I bought when I thought I had the B. Do you have any suggestions on how to improve the crossover? Either by using the 846B values or using a Model 19 crossover or would you just replace the old components in the 846A stock crossover and call it good? Thanks!

Paul

[Zilch]

I no longer have 806A drivers to test with here.

My recommendation for upgrading 806A Valencias with Altec components would be the same: new GPA 902-8A drivers and Model 19 crossovers, adjusting the lowpass components for 16-Ohm woofers. You may have to add a fixed L-pad to the HF to move the overall sensitivity into the optimum crossover adjustment range.... :dont-know

[Allanvh5150]

Use a 16-Ohm L-pad in lieu of the pot and resistor shown here:

10.5 milli farrad is a rather large capacitor....

[Zilch]

It's a capital "M" so it would be mega-farads, I believe, rather than milli ones.

[Robh3606]

Looks like U micro farads to me. Those coils sure are not Megas more like milihenries. Older notation I guess.

Rob

[Paully]

There are three inductors in a reasonable price range at parts-express, I just wanted to see if you or anyone here had an opinion should I just choose to go the replacement route. I don't know the DCR of the originals and if that would make a large difference. Two of the options are air core, one is iron core which would match up with the type originally used.

http://www.parts-express.com/pe/show...number=255-278
http://www.parts-express.com/pe/show...number=266-840
http://www.parts-express.com/pe/show...number=266-916

Once again I really appreciate the input for an Altec newbie.

Paul

[Zilch]

Use Iron core for the LF and air for the HF.

[Paully]

I appreciate your responses and patience!

Paul

[voice of theatr]

Is the GPA 902-8A driver essentially an Altec Model 19 h.f. driver? Does it have the radial phase plug (tangerine) and the extended high frequency response that the Model 19 h.f. driver has?

[Zilch]

Yes, but it'd be good if they published some curves, wouldn't it?

[Perhaps you'll tell them so.... ]

[voice of theatr]

I agree, it would be nice to be able to compare the curve for this driver to the original Altec version--I should try sending Bill an email...