Correct parts for my first crossover? (Markwart)
I just picked up a pair of vintage Altec 604-8Gs last weekend and one had the wrong model crossover. After some a little research i decided on one designed by Jeff Markwart (Jeff Markwart's Corner - Phase Corrected Crossovers) It gets great reviews and I like DIY projects. I've hardly ever soldered anything, let alone built a crossover, but I like to try new projects. I've been reading up on how to read schematics and how to assemble them. I think I have a really basic understanding. :)
The schematic.
http://www.hostboard.com/forums/hbmc.../2016/07/5.jpg
This part is a little confusing. What parts are represented here as P1? Is it an l-pad or a resistor?
http://www.hostboard.com/forums/hbmc.../2016/07/6.jpg
Here's the parts in my cart, are they all correct? I know I have to double up everything.
http://www.hostboard.com/forums/hbmc.../2016/07/7.jpg
Re: Correct parts for my first crossover? (Markwart)
P1 is a potentiometer. Its slightly different than a L-pad. Like he says, you can just use one leg of an L-pad instead of a pot
Re: Correct parts for my first crossover? (Markwart)
Quote:
Originally Posted by
Elitopus1
P1 is a potentiometer. Its slightly different than a L-pad. Like he says, you can just use one leg of an L-pad instead of a pot
A little late to the game here, but I too am working on this crossover and am having trouble understanding how to wire the L-pad.
Do I connect the R4 resistor to ground leg, and then from the 30ohm leg go to positive? Leaving one leg free, correct?
Re: Correct parts for my first crossover? (Markwart)
Usually when hooking up an L-pad the positive wire (signal in) goes to #1, the driver gets #2 wired to its postive terminal, and #3 goes to the negative side of the xover or speaker terminal.
http://www.hostboard.com/forums/hbmc.../2016/11/2.gif
In Jeff's drawing it looks like its only hooked up to two of the L-pad connections. I would contact him directly and ask how to hook it up. I have spoken with him before and he is very nice and helpful.
I am planning on building this same xover for my Urei 604G's. I am going to use a fixed resister in place of the L-pad. When I asked Jeff about this he said a 10 ohm resister is a good value to start at
Re: Correct parts for my first crossover? (Markwart)
Quote:
Originally Posted by
Elitopus1
Usually when hooking up an L-pad the positive wire (signal in) goes to #1, the driver gets #2 wired to its postive terminal, and #3 goes to the negative side of the xover or speaker terminal.
http://www.hostboard.com/forums/hbmc.../2016/11/2.gif
In Jeff's drawing it looks like its only hooked up to two of the L-pad connections. I would contact him directly and ask how to hook it up. I have spoken with him before and he is very nice and helpful.
I am planning on building this same xover for my Urei 604G's. I am going to use a fixed resister in place of the L-pad. When I asked Jeff about this he said a 10 ohm resister is a good value to start at
Thanks for the response!
I contacted Jeff, and as you stated, only two of the pins are used. R4 goes to pin #2, and pin #3 goes to the mid point of R1 & R2.
I'll post photos when I'm done and give you my impressions. The supplies from PE is supposed to be delivered tomorrow!
Re: Correct parts for my first crossover? (Markwart)
Completed the crossovers tonight and installed them.
I used Dayton resistors; Solen caps; Jantzen inductors; and Belden 9497 wire.
Well. Simply put. The crossovers are game changers. Dramatically better. End of story.
My front end is a Scott 296 restored by Craig at NOSvalves. Jolida Tube DAC as my source.
Seriously, these are the best speakers I've heard.
Re: Correct parts for my first crossover? (Markwart)
Hey thanks for the review of these! I am planning on building the same xovers for my 604G. Also planning on using basically the same components as you (and then maybe changing out the caps for oil caps later).
I'm glad to hear yours are sounding so good and look forward to building mine;)
Re: Correct parts for my first crossover? (Markwart)
Also building the Jeff Markwart XO and was confused by the L-pad wiring, thanks for posting the question, also to the members of the board that clarified the issue.
Re: Correct parts for my first crossover? (Markwart)
Quote:
Originally Posted by
tysencahill
Completed the crossovers tonight and installed them.
I used Dayton resistors; Solen caps; Jantzen inductors; and Belden 9497 wire.
Well. Simply put. The crossovers are game changers. Dramatically better. End of story.
My front end is a Scott 296 restored by Craig at NOSvalves. Jolida Tube DAC as my source.
Seriously, these are the best speakers I've heard.
Hey since you have these completed and in use I have a question. At what setting do you keep the HF pot? Like is it wide open or do you have to attenuate the horn a little? The reason I ask is because I am building the crossovers without the L-pad. Just curious what size resistor I am going to have to use. Jeff mentioned 10 ohms but I cant imagine needing that much.
Right now the xover I have my 604G hooked up to has no HF attenuation. They are just simple 2nd order xovers with two inductors and two caps. With no attenuation the HF and LF are pretty balanced. That could change when I get the drivers recharged. I might have to mess around with the resistor values then
