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/vbulletin/showthread.php?30179-Crossover-card-for-electronic-crossover-4430&highlight=5234a

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

6560065601

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/Vishay-BC-Components/BFC241911302/?qs=sGAEpiMZZMsh%252b1woXyUXjwarXwENlZE5rylXbliYxH g%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/Vishay-BC-Components/BFC241911302/?qs=sGAEpiMZZMsh%252b1woXyUXjwarXwENlZE5rylXbliYxH g%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.

65605

[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. :confused:

http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=49330&d=1294612120

[HCSGuy]

It looks like you have 18db cards that have been modified. If you're not in a hurry, I can probably find a pair of 12db cards to trade, though they won't be the 4430 cards; they'll need to be re-populated.

[Ed Zeppeli]

I'm not in a hurry and upon further confirmation I'll likely take you up on your offer. Can you tell this by looking at the board components?

If these are indeed the 18db cards, I trust that using them would cause a dip in the crossover frequency and cause possible phase problems between the drivers.
Thanks,

Warren

[Ed Zeppeli]

Someone apparently tried to adapt the 18dB cards you have. I don't know if it is possible.

...or I could just take your word for it! :D

[speakerdave]

Sorry not to get back to you. I have a box of those cards around somewhere, but I haven't laid eyes on them yet.

I would think that if someone tried to make a 12dB circuit with an 18dB card (if that is even possible) it would not look like a "normal" version of either one.

I'll seriously look for those cards today.

[Ed Zeppeli]

That would be much appreciated Dave. Thanks very much. Please PM me what you would like for them and postage and I will send you my details.

Regards,

Warren

[speakerdave]

On looking at the photos you posted and some 12 and 18 dB cards I think those cards are probably OK. First, I think it makes sense that an 18dB card could also be used for a 12dB load. Second, there are things about those cards, like the labels, that make me think it is professional work, maybe even factory. How do the solders and traces look? If its amateur work, they're going to look abused. Are your 80Hz cards 12dB? If they are you could work out the schematics and compare and know for sure. It would be simpler, though, just to see how they work. The only real concern would be to know that the LF is not getting to the compression driver. But I believe you have protection capacitors in line with the switch in external mode in that speaker (check the schematic to make sure). If so, I would just try the 5234A with those cards and see how it sounds.

[Ed Zeppeli]

I'm away from home right now and as such don't have the cards in front of me for closer analysis. I remember that you could see that they'd been 'worked on' from the board side. They didn't look awful, just not factory. I will say that the 4430 label looks pretty good but it is just a sticker.

Thanks a bunch. I'll try them out when I get home and compare them with my 80hz 18db cards.

[speakerdave]

In my jumble of cards there are two versions of the 18dB card. Your cards and the cards you linked to are like the ones I have which I think are "later." The cards you linked to seem to be factory 4430/4435 builds, and if that is the case then that load in a later style 18dB card is correct.

I would deduce from this and earlier observations that your cards were made to order using what was on hand, 4345 cards and almost the requisite load, and that they are correct. Because of the make-do load for the .0013 capacitor I would guess it was done by a technician under pressure to get it done, rather than an amateur who would have had to order all the components and would therefore have all the exact sizes.

As I said, a deduction--but for me one I would think likely worth testing. The fact that they look worked on would result from having to strip out the 4345 components first and then solder in the 4430 loads. For me this would be enough to make me think they were probably OK and worth a try, but you need to decide for yourself.

[Ed Zeppeli]

Thanks Dave. I'll give them a try. Maybe I'll hook the high side up to the woofer first just to make sure no low frequencies are getting through.

I'll also see if I can dig up the 5235 manual here and see if their 4430/35 cards spec out differently. Perhaps there was an update as it appears there are C5 and C6 components in the ones pictured in the link whereas my manual (and cards) show nothing there.


Cheers,


Warren

[HCSGuy]

Is there such a thing as a "Vanity Jumper"? I have factory cards like the second picture you posted, and the components in C5 and C6 read 0 on my capacitor tester, and no resistance either direction from an ohmmeter; act just like a pair of jumpers should. Hope this helps...

[Ed Zeppeli]

Is there such a thing as a "Vanity Jumper"? I have factory cards like the second picture you posted, and the components in C5 and C6 read 0 on my capacitor tester, and no resistance either direction from an ohmmeter; act just like a pair of jumpers should. Hope this helps...

Oooooooh. The plot thickens.

Thanks