Crossover for the Za5.5tt MMTMM - AVS Forum
DIY Speakers and Subs > Crossover for the Za5.5tt MMTMM
AVI20's Avatar AVI20 08:46 PM 04-14-2014
I haven't built any crossovers before but am really good at soldering, I built the Zaph Audio 5.5tt MMTMM and want to build the crossovers. I have the schematic for them is there anything special I need to know? And should I buy all the parts for it from partsexpress?

AVI20's Avatar AVI20 06:19 AM 04-15-2014
Anybody?? frown.gif
Bud Heavy's Avatar Bud Heavy 01:44 PM 04-15-2014
Given Madisound sells a kit with the assembled crossover, could you buy the parts from Madisound?
Mrkazador's Avatar Mrkazador 02:22 PM 04-15-2014

If you're a newbie like I am, how does one figure out what wattage resistors you need? or air core vs solid core inductors? What AWG should the inductors be?


Bud Heavy's Avatar Bud Heavy 02:46 PM 04-15-2014
I have never designed my own crossover. There are books or you can ask google for help. Here is just one of many links:

http://www.diyaudio.com/forums/multi-way/189847-introduction-designing-crossovers-without-measurement.html
WVSyd's Avatar WVSyd 04:06 PM 04-15-2014
Simple math transfer functions in passive crossovers were how crossovers used to be developed.
And generic crossovers are still sold using that old technique.
However with computer modeling circuits can be developed that take into consideration the actual manner in which the crossover and reactive load interact.
Quote:
air core vs solid core inductors
They have different performance characteristics.
( including saturation and hysteresis )
http://www.electrical4u.com/what-is-inductor-types-of-inductors/
http://info.ee.surrey.ac.uk/Workshop/advice/coils/air_coils.html
http://www.die.ing.unibo.it/pers/grandi/papers/ciep00.pdf
WVSyd's Avatar WVSyd 04:49 PM 04-15-2014
RE:
http://www.zaphaudio.com/ZA5/ZA5.5tt-crossover.gif

Note: the comment This resistance is part of the inductor

This is the DCR of the inductor.
AVI20's Avatar AVI20 08:12 AM 04-16-2014
I wouldn't design them, I have the schematic of all the parts I need and where they go, I would just like to put them together and not buy the pre made ones they sell.
WVSyd's Avatar WVSyd 08:25 AM 04-16-2014
Madisound was founded in 72 and started advertising in AA and SB mags.
In my experience they were very good at modeling.
Speculation:
The inductors were chosen and their specific DCR was included in the model. *
The choice of an air core in the HF section and inductors with a metal core in the low pass section was intentional - based upon the characteristics of each ( w cost in mind )

* Make sure this is part of inductor selection
Bud Heavy's Avatar Bud Heavy 12:11 PM 04-16-2014
Quote:
Originally Posted by AVI20 View Post

I wouldn't design them, I have the schematic of all the parts I need and where they go, I would just like to put them together and not buy the pre made ones they sell.

I would either go with Parts Express or Madisound. I have ordered a lot of stuff from Madisound and they are great to work with if you give them a call.
djarchow's Avatar djarchow 01:08 PM 04-16-2014
You can get your parts from anywhere but as as others have mentioned, you need to be sure that you are getting close on the inductor DCR values to what Zaph used in his XO design. I would bet that when John chose values for the inductors, he used Madisound parts to do so. Also you should check to see if any resistors are doubled up to make the final value while still having the proper power handling.
AVI20's Avatar AVI20 02:03 PM 04-16-2014
Awesome. I'll give them a call and see what they can do. Thank you all for your help
AVI20's Avatar AVI20 07:22 AM 04-17-2014
So I called them and they can ship the crossovers unassembled. And they can ship the circuit board with or without it, which is a 20 dollar difference, should I just get all the stuff for them and build them on something else or use their circuit board?
WVSyd's Avatar WVSyd 07:34 AM 04-17-2014
It's your call...
Getting the board means you don't have to fabricate ( cut, drill hole, wire up etc ).

In your situation: Eliminating this gets you listening quicker biggrin.gif
Face2's Avatar Face2 07:55 AM 04-17-2014
If you have no idea what you're doing, you may be better off using their circuit board.
Mrkazador's Avatar Mrkazador 12:38 PM 04-17-2014
I say skip the crossover board so you learn how to read a schematic.
AVI20's Avatar AVI20 05:01 PM 04-17-2014
I love to fabricate stuff so that would be a plus, and I think I have a pretty good idea about what I'm doing, and what did you mean by skip the crossover? You mean their circuit board?
Mrkazador's Avatar Mrkazador 05:04 PM 04-17-2014
I edited my post, I meant to say crossover board (their circuit board).
AVI20's Avatar AVI20 05:28 PM 04-17-2014
Ok cool. And you guys would recommend buying the parts and building it rather than just buying the crossovers put together and ready to go?
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