Crossover card for 4430s using 5234A

[Ed Zeppeli]

I picked up a 5234A with modified cards that are supposedly correct for the 4430. They look like they were originally cards for the 4345 according to the front label.

I understand that for the 4430 these are supposed to be 18db cards which I believe mine are. I have limited knowledge of crossover networks and would like if someone here could take a look at these cards to tell me if they have been correctly converted.

They do look different than the picture shown in this thread by Grumpy.

http://www.audioheritage.org/vbullet...ighlight=5234a

Note the missing C6 and C5 in my versions...



The board is 56182 B

I'm about to test out the 5234A but won't be hooking it up to the monitors until I know they are correct. I do have access to the schematic in the manual posted here.

Thanks for taking a look and please resist telling me to "dump it. it's a piece of crap" and/or "get an Ashley!" I know there is better technology out there but this is what I have right now to experiment with.


Best Regards,

Warren

[Don C]

Is that three capacitors in series at the top left? That's unusual. What are the values?

[Ed Zeppeli]

Yes. There are three tied together all reading 3n9 K.

The more I'm reading through the 5234A manual, I think I needed the 12db cards.

The unit came with the 80hz cards as well; unmolested.

Cheers,

Warren

[Ed Zeppeli]

According the the manual, C3 should be .0013 uF. That's the questionable one for sure. The other three caps seem to be correct.

[Ed Zeppeli]

I guess if I added it right, 3n9 in series should be .0013, right?

[Don C]

They don't sum when added in series, I think it's the sum of the reciprocals? The reciprocal of the sum of the reciprocals? it's been a long time since I supposedly learned this. I'd just try to buy the right cap for that.
http://www.mouser.com/ProductDetail/...rylXbliYxHg%3d

[Ed Zeppeli]

Google says to divide the individual values by the number of caps in the series.

[NickH]

1/cap value plus each cap value. So 1/c + 1/c+ 1/c= c3 series. Or if all 3 are the same value and you have 3 in series the total value is a third of the value of one cap.


Does that make since?

Nick

[Ed Zeppeli]

1/cap value plus each cap value. So 1/c + 1/c+ 1/c= c3 series. Or if all 3 are the same value and you have 3 in series the total value is a third of the value of one cap.


Does that make since?

Nick

Yes. So 3 3n9 in series would be .0013 uF right?

[Don C]

Yes.

[ivica]

They don't sum when added in series, I think it's the sum of the reciprocals? The reciprocal of the sum of the reciprocals? it's been a long time since I supposedly learned this. I'd just try to buy the right cap for that.
http://www.mouser.com/ProductDetail/...rylXbliYxHg%3d

a) if C in-series
1/Ctot= 1/C1 + 1/C2 + ...+1/Cn

b) if C in-parallel
Ctot = C1 + C2 +....+ Cn

c) if L in-series
Ltot = L1 + L2 + ...+ Ln

d) if L in-parallel
1/Ltot = 1/L1 + 1/L2 +...+1/Ln

[Ed Zeppeli]

Great. So now I just need to determine if this is a 12 dB card.

[Odd]

It may look like you have 12db cards for 4430.
Values.

[speakerdave]

. . . . The more I'm reading through the 5234A manual, I think I needed the 12db cards . . . .

That's right. Not as hard to find as the 18's. I've never seen blank ones, but you could cannabilize some common ones, such some 800hz. Someone apparently tried to adapt the 18dB cards you have. I don't know if it is possible.

[Ed Zeppeli]

Everything as far as resister and capacitor values seem to check out on my 'bastardized' versions but I am unsure how to physically check to see if it is in fact an 18db card.

Another source of confusion for me is that the 5234A manual says C5 and C6 are to be left blank but in this picture (as posted in the link in my OP) of the 4430 cards, there are capacitors in those spaces.