I managed to complete the component layout for one of the N801-8A type crossovers I?m building for my Santiagos.
The existing N801s will be removed and the new x-over boxes will be fastened to the back of the enclosures over the existing cutout using the screw holes for the N801s. To test I?ll leave attenuator/equalizer network in the cabs and then relocate to the new x-over back box.
If all goes as planned this design will allow me to passive bi-amp or bi-wire or bypass the passive components for active bi-amping.
Still waiting for my hookup wire to arrive.
Greg
Looks good except the coils are in the same plain and a little close to each other. General rule of thumb is to orient the coils so the centerline through the coils are at right angles to each other. Keeps the magnetic field from the adjacent coil from inducing an electrical current in it's neighbor. Depending on how much power your using, it may or may not matter. Any chance one of those coils can be stood up?
Other than that, it's a nice build.
BillWojo
Originally Posted by xinu
Hello Greg !!
What find of hook up wire are you waiting on? What lengths and amounts do you intend to use, to each driver, and internally inside the crossover box? ALL this is critical with ALTEC , if you seek optimum results.
Have a look at what I have developed, over the last sixty years plus of liistening to ALTEC speakers here :
RE: when the going gets weird -- - drlowmu - High Efficiency Speaker Asylum
Some general comments :
(1) The adjustment pot in the N801 is NOT good enough, its small wiper to winding contact area causes a LOSS of fidelity, adds unwanted high frequency distortions, when compared to either a high power pair of DUAL GANGED pots, or, best of all, a single FIXED value resistor, soldered in place.
The stock ALTEC pot, is mid -fi, at best when in use, and it ( ALL POTS in crossovers ) should be eliminated IF you seek real quality reproduction.
(2) The N 801 calls for 18 uF caps as I recall, Your caps as shown, are inadequate!!
A single cap will NEVER do the entire frequency range properly, typically, a 18 uF cap, being large in value, will SCREW UP the highs, .... the highs will be MIA.
You must ALWAYS use more than one film cap, if you intend to get a linear response from your ALTEC , and not a High-Frequency degrade.
A decent progression to try BY EAR, is the main film cap ( how about an industrially - priced, not audiophile - priced WIMA DC LINK MKP4 series cap, with 4 terminals ) plus a bypass "trio" to start, as follows: 0.68 uF ( try a 500 VDC Russian K75-10, improves dynamics ) , a 0.033 uF ( Russian Teflon ) and a 0.01 uF ( try a WIMA FKP1). I have used, by ear, as many as seven added film caps, to get the response I wanted. By EAR you do this !!
(2) Wiring needs to be superb, from the amp to the driver's terminals.
My favorite cost-effective wire is Mil Spec, m22759/11 in 12 and 14 AWG.
You MUST maintain full transfer efficiency.
Cut the leads off those inductor coils 1/2 inch out of the winding, scrape off the varnish insulation, and THROW AWAY the long stock inductor leads. That coil wire MAY be OK to wind a coil, but it certainly is NOT OK to properly carry the signal inside a crossover, to associated parts !!
Make all your crossover leads double 14 AWG mil spec wire, inside the crossover, to hook up Ls and Cs. See my above URL, for the other cogent wiring instructions / tips for quality.
(3) Use GOOD solder, and solder in a safe open environment, hopefully out of doors, or with a mask and a fan going inside.
Three solder choices in this order (1) Wonder Solder - Ultra Clear - "Signature", from Mike Percy (2) vintage toxic Ersin Multicore ( 60-40 ) and (3) Alpha Realiacore 15, in that preference - order.
Well, this should get you going on the right foot.
Ohh, I almost forgot. THROW AWAY every one of those four speaker jack terminals.
They are
(1) not needed or wanted at at crossover level component.
(2) They are NOT any wheres near good enough, each one DEGRADES the music versus a properly wired SOLDER JOINT !!
(3) You wrap the one wire around the other, at least one or two timers, to obtain surface area contact, and you solder it well.
(4) There should be ONE set of speaker - level Jack terminals in the audio system, at the amplifier's output. They MUST be Cardas' Silver ones, and the shorter ones. ( Mike Percy ). They will pass the signal quite well, with the least loss, and are actually better than MOST amp builds I see.
(5) That switch in the crossover is a huge NO-NO also, no wheres near good enough. Get rid of it !! No free lunch. Avoid switches whenever you can, at crossover-level builds.
(6) KISS rules in ALTEC land !!!
If you have additional questions, feel free to ask me and I'll do my best to respond.
You didn't expect me to give you an " atta boy" when it was not yet deserved, did you???
Have FUN, I do !!
Dr. Low Ohms ......... Jeff Medwin
Last edited by LowOhms; January 22nd, 2017 at 08:32 AM.
Hi Bill - Great observation regarding the coil positioning. I found this interesting site on the interweb Placement of coils in crossover networks and according to the measured results I should be OK with the coil placement in this layout. I would have preferred to have one of the coils positioned upright and rotated 90 as you did in your Z19 layout but I had to compromise. I wanted to use a 16 AWG coils and couldn't find a reasonably priced box with the dimensions I needed. So I compensated by going for length.
Last edited by xinu; January 22nd, 2017 at 10:04 AM. Reason: correction
Wow, I appreciate your input and experience with this Jeff.
First off, I should say that this project is a bit of an experiment. I’m not sure what my end game is at this point. I wanted to build something that I can use to test and listen to the results with passive and active bi-amping. Obviously if I end up preferring active bi-amping, x-over caps, switches, jacks and coils are no longer in circuit and the focus would be directed upstream in an active box.
I wanted to build something that I could easily configure between active and passive without heating up a soldering iron so to speak. So I won’t be tossing the speaker jacks for now
If I don’t hear an improvement going active then I will devote more attention to optimal passive components and loose the L-pad, no-no switch and jacks. I suppose if the passive design is sub-par to begin with that could point me in the wrong direction. I sure hope what I'm building is as good or better than the 40 YO Altec components in there right now?
I’ll follow your coil wiring tips and consider adding bypass caps.
Re-wiring the XO to drivers and XO hookup with value priced Connex 16awg copper wire
Looking for insight not ‘atta boys’.
Thanks,
Greg
Last edited by xinu; January 22nd, 2017 at 10:56 AM. Reason: correction
I have that same coil chart pic saved too. Lol. I used that when I built my 604G xovers. I know if you keep the coils far enough from each other that their orientation doesn't matter. I still flipped one of my coils on end just in case.
What I was also curious about but did not find a chart was coil and cap orientation to each other. I'm guessing that positioning, as well as the positioning or resistors, doesn't matter as much as the coils.
I used 18uf Jantzen caps for my N801 rebuild. I have heard good reviews of those Axon caps you are using too. They should sound 100 times better than your original caps. Good luck
Thanks Elitopus. Curious - did you hear an improvement as soon as you hooked em up?
Yes I heard a huge imrpovement. I recapped one xover first and compared them. The stock xover sounded dead and veiled compared to the recapped one.
I eventually took the L-pad out of those crossovers too. Those are in my A7 system. I switch between Altec 802D and Emilar EA175 drivers. I run the 802D unpadded. I use a 8 ohm resistor with the EA175's
Hello Greg,Wow, I appreciate your input and experience with this Jeff.
First off, I should say that this project is a bit of an experiment. I’m not sure what my end game is at this point. I wanted to build something that I can use to test and listen to the results with passive and active bi-amping. Obviously if I end up preferring active bi-amping, x-over caps, switches, jacks and coils are no longer in circuit and the focus would be directed upstream in an active box.
I wanted to build something that I could easily configure between active and passive without heating up a soldering iron so to speak. So I won’t be tossing the speaker jacks for now
If I don’t hear an improvement going active then I will devote more attention to optimal passive components and loose the L-pad, no-no switch and jacks. I suppose if the passive design is sub-par to begin with that could point me in the wrong direction. I sure hope what I'm building is as good or better than the 40 YO Altec components in there right now?
I’ll follow your coil wiring tips and consider adding bypass caps.
Re-wiring the XO to drivers and XO hookup with value priced Connex 16awg copper wire
Looking for insight not ‘atta boys’.
Thanks,
Greg
I LIKED your reply.
Let me state things another way.
A passive design, PROPERLY IMPLEMENTED, is absolutely the best possible approach .
The simplest implementation of the ALTEC system, using the best parts, well-thought-out layout, becomes the " ultra high fidelity" winner, as far as getting best sound POSSIBLE out of ALTEC.
You need to use the best possible sounding amplifiers to run the ALTEC. And there is always only ONE, by definition, that is the best sounding.
You need to use adequate low-loss wiring, for maximum transfer efficiency, and
You need to do the crossover with the best sounding parts known to you, to get the best results.
Yes, by all means, the caps on a vintage ALTEC crossover are the FIRST things to throw away, usually 18 uF Callins manufactured, and yes - certainly SHOT by now !!
Value priced Connex 15 AWG wire will become very very expensive, as it will easily lead you astray.
The suggestion I made, Mil Spec m22759/11 12 is the very BEST solution I am aware of in 2017, cost-verses-performance wise.
This wire suggestion was used as described, by Serious Stereo in the October 2016 RMAF show, driving GPA 604s in their custom-designed MLTLs. Stereophile Magazine reviewer, Herb Reichert, wrote the room up as one of his two most favorite to visit and hear, in the entire RMAF 2016 show....with 100s of demo rooms.
If using a short amp-to-crossover run, 14.28 feet or under ( three Bob Fulton Lengths ) you need to use TWO 12 AWG Mil Spec in parallel, for each polarity. If its over three Fulton lengths, you need to go to three 12 AWG in parallel. Short lengths and two in parallel ( effectively 9 AWG ) , sound better, using State Of The Art equipment, than longer runs with three in parallel.
Biamping is a whole can of worms. If a person can not afford to optimize a Passive set-up, as I was trying to show you to do, how can they pull off a more complex one, using TWO sets of amps, and double the appropriate wiring, for each channel, and truly determine what sounds best?
The answer is, one can't.
But then, why bother, no need to !! Serious Stereo got it right in 2016 at RMAF. It was the best possible sounding amplifier available, to power a ALTEC speaker, using good wire, and a GPA 604 crossover using the best possible crossover layout and parts choices, that won the show. In October, I was there, in Denver RMAF for three full days, and I extensively heard that result.
Just copy that proven, but KISS approach, I say !!!
Jeff Medwin ..... LowOhms.
Last edited by LowOhms; January 22nd, 2017 at 08:51 PM.
Of course there is only one "best" by definition. What sounds best is a matter of opinion though.
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