Altec 1285-8B Crossovers

**Altec Best** · October 23rd, 2010, 09:23 PM

@Dsauro Hey Dave my crossovers arrived but they came with another external crossover on a small plate also Altec, #391049 was wondering if yours came with those as well.I think they are for the woofer but I'm not sure.

Dose anyone know what they are for ?

Here are some pictures to ponder Thanks !

**Altec Best** · October 23rd, 2010, 09:33 PM

More Pictures

**bfish** · October 23rd, 2010, 09:51 PM

Looks to be a later variation of the 30923 attenuator board. ArtJ hosts that layout;

http://img101.imagevenue.com/img.php...ecn50130923jpg

It's for the HF driver, the basic "flatten the midband to extend the HF" circuit.

**Altec Best** · October 23rd, 2010, 10:03 PM

Originally Posted by bfish

Looks to be a later variation of the 30923 attenuator board. ArtJ hosts that layout;

http://img101.imagevenue.com/img.php...ecn50130923jpg

It's for the HF driver, the basic "flatten the midband to extend the HF" circuit.

Thanks Brad for the info. Much Appreciated ! :2thumbsup:

**bfish** · October 23rd, 2010, 10:06 PM

You're welcome.

Good ol' Zilch has explored and (ab)used the circuit to some degree.

Search his posts for 30923.

**bfish** · October 23rd, 2010, 10:12 PM

Would you mind posting the parts values?

**Altec Best** · October 23rd, 2010, 10:20 PM

Originally Posted by bfish

You're welcome.

Good ol' Zilch has explored and (ab)used the circuit to some degree.

Search his posts for 30923.

Which forum he seems to be everywhere these days.I seen him on PE Techtalk this morning even.

**Art J.** · October 24th, 2010, 08:06 PM

Originally Posted by bfish

Looks to be a later variation of the 30923 attenuator board. ArtJ hosts that layout;

http://img101.imagevenue.com/img.php...ecn50130923jpg

It's for the HF driver, the basic "flatten the midband to extend the HF" circuit.

Hey Brad, wow, it shocked me that my old hand drawn diagram still exists.
I made a somewhat better one for the board later. Lets get rid of the old one

Altec3090430923 | Flickr - Photo Sharing!

**Altec Best** · October 24th, 2010, 10:23 PM

Hey Art, Thank You for posting that !!:2thumbsup:

**Art J.** · October 25th, 2010, 08:35 AM

I took a look at my old 30923 and it has the number 391427 on it.
It must be a batch number or inventory number. Who knows.
Yours is old like mine because it has the Callins capacitor.
They have been out of business for a long time.
Mine came from an early 70's model of the 9846 shown in the avatar.