Crossover Help Needed With ANOTHER Pair of ALTECS

[voice of the theater]

Still one last question I remembered before I do this upgrade....



In this photo I count what appear to be 7 (ground?) lugs--does anyone know if these should be connected with wire like people are doing with the Model 19's (or is it possible to tell from the photo or from Richard's schematic?)? Also, no one has chimed in about my earlier question regarding leaving the 470 uF capacitor alone instead of replacing it--any thoughts? Thanks again.......

[zelgall]

The only thing I can see 7 of are rivets. I'll go out on a limb and assume that there are circuit traces on the flip side of the board (that I've never seen) which will have the ground. The 19s are point to point wired with the attachments at actual lugs. There are pictures on this site of the 19 Xover.
The 470uF cap is for the protection circuit and is probably OK.

[voice of the theater]

The only thing I can see 7 of are rivets. I'll go out on a limb and assume that there are circuit traces on the flip side of the board (that I've never seen) which will have the ground. The 19s are point to point wired with the attachments at actual lugs. There are pictures on this site of the 19 Xover.
The 470uF cap is for the protection circuit and is probably OK.

Yes the circuit traces are on the flip side of the board. As you mentioned, I'm sure they have the ground so I'll leave the rivets (lugs) alone in this crossover. Good--one less thing to solder!

[westend9]

Still one last question I remembered before I do this upgrade....



In this photo I count what appear to be 7 (ground?) lugs--does anyone know if these should be connected with wire like people are doing with the Model 19's (or is it possible to tell from the photo or from Richard's schematic?)? Also, no one has chimed in about my earlier question regarding leaving the 470 uF capacitor alone instead of replacing it--any thoughts? Thanks again.......

An easy way to access the quality of the ground plane (lugs to plate) is to put a meter across varoius points and measure resistance. From the pictures, I think everything looks secure and no oxidation between metals. I have been known to give contact points like these a very quick squirt of Deoxit Gold or any other deoxidizing spray that is at my disposal.

I think you're being a little too apprehensive about desoldering the caps, it is very easy. There are lots of online soldering/desoldering tutorials but I could sum it up in a few words: Place soldering wick on soldered connection, place tip of iron on top of wick, watch solder flow onto wick. You might need to flow the solder a couple of times into the wick, I usually have a cutter on hand to trim the wick that contains the solder off of the roll. Lacking the courage to do this, and considering future replacement with the originals, you could cut the leads and twist together. It's your gear but if you want it done right, you should take the old caps off the boards and solder in the new ones. Maybe practice on a piece of something that has little value, even a piece of solder.

As I posted, my call would be to replace the 470uf electrolytic. There is no sense in keeping an aged cap in the circuit when I have an iron heated and the cost of a replacement is less than a dollar. I believe the cap is in the protection circuit so is not going to alter the sound, it is just a ticking time bomb.

[RonSSS]

Personally, I would remove the protection circuitry....unless you have some sort of mondo power amp and kids who like to crank the volume all the way.

Ron

[voice of the theater]

Personally, I would remove the protection circuitry....unless you have some sort of mondo power amp and kids who like to crank the volume all the way.

Ron

Great idea--there's no way that I need the protection circuitry as these speakers are so efficient I doubt if I ever put much more than 10 watts per channel through them--they blow you out of the room if you go past that. Anyone out there know how to bypass the protection circuitry? I doubt if it will effect the sound but it just makes sense to not have the signal go through any more circuitry than is necessary.... Not sure if this schematic will help as it leaves out the protection circuitry..... (click on images for full size)

[SD-50]

Just wanted to contribute to this thread with a tweak poached from John Krutke's Zaph Audio site. It's simple resonance trap and does not require any soldering to try out. Did it to my A7s two weeks ago and found a subtle but worthwhile improvement.
Using alligater clips place a .1uf cap across the woofer's inductor. The schematic shows an example, inductor L6 with capacitor C12 across it. I'd be curious to hear comments from anyone who gives it a try.
Cheers

[voice of the theater]

Great idea--there's no way that I need the protection circuitry as these speakers are so efficient I doubt if I ever put much more than 10 watts per channel through them--they blow you out of the room if you go past that. Anyone out there know how to bypass the protection circuitry? I doubt if it will effect the sound but it just makes sense to not have the signal go through any more circuitry than is necessary.... Not sure if this schematic will help as it leaves out the protection circuitry..... (click on images for full size)

OK, I asked if anyone out there knew how to bypass the Model 14 crossover protection circuitry FIVE AND A HALF YEARS AGO (in this same thread--see above quote) AND I GOT AN ANSWER THIS WEEK! lol I guess patience really is a virtue. This forum has been SO helpful with me learning how to optimize, update, and recap etc. my Model 19's, Model 14's, and Santana II's--this is the first question I've ever asked here (that I can remember anyways) that "stumped the panel" for five and a half years. Well, I finally got my answer from (user name) Lansing 4112 who is part of the Audiophile Nirvana team. He sent me this link in response to my question:

Model 14 Mods - Audiophile Nirvana

I have finally bypassed the protection circuitry in my Model 14 crossovers! In post number 56 of this thread (page 6 of thread) I comment on how much better my Model 14's sound after recapping the crossovers with Solen caps (thanks to help from Earl K, GM, Altec Best, Aditya, etc. etc.). I comment on how the high end and clarity are both significantly/noticeably improved after replacing the 30 year old caps!

Well, now that I've finally bypassed the protection circuitry on the Model 14 crossovers, this week, I am happy to report that these things sound even better without having the signal pass through that 35 year old protection circuitry. There is a lot to that circuit--a good chunk of these crossovers (much of the electronic circuitry) comprises the protection circuitry. By bypassing it, I am left with just the basic crossover circuitry--much less unnecessary "gobbledygook" (technical term) for the signal to pass through. I am really impressed that the 14's now have even greater clarity (and they just plain sound clearer/cleaner) and a more defined sound than they did before the "bypass"! Also, very surprising, I'm getting more low end out of them. Apparently, having the signal pass through the 35 year old protection circuitry was having a derogatory effect on the low end of these speakers. I said after I re-capped the 14's that they rival my two pair of Model 19's. I did some extensive listening last night and this morning after completing this bypass, and with the increased clarity/more defined sound and enhanced (restored) low end from this bypass, it is now too close to call IMO which speakers sound best on most recordings--the 19's or the 14's. In fact, there are a couple of recordings that I did an A/B comparison (same song on the 14's and 19's) where the 14's actually bested the 19's! That has never been the case prior to this bypass--up until now the 14's at best sounded comparable (but different) to the 19's on some recordings and inferior on others. Now, post bypass (and of course 5 years post recap), I have recordings that sound better on the 19's, some that sound better on the 14's, and many that are too close to call---they sound amazing on both the 14's and 19's and it's really a tough call which speakers most recordings sound "better" on! THANK YOU TO EVERYONE HERE WHO HAS HELPED ME ON THIS JOURNEY WITH THESE AMAZING SPEAKERS!

DSCN4206.jpgDSCN4223.jpgDSCN4218.jpg
PICS OF BYPASS (1st pic is pre bypass, 2nd and 3rd are the two crossovers bypassed) As you can see, I've recapped these crossovers with Solens, and have bypassed the treble "pot" to reduce the amount of circuitry the signal passes through since the optimal range for the treble pot, according to Altec, is in the maximum range and they do sound best with that pot turned "all the way up". I use the mid pots so those are still connected---in their optimal range (about halfway up), the balance of bass to mid to treble is excellent. In a recent thread in this forum, someone asked which of the three versions of the Model 14 stock crossover sounds best, based on reports I've heard of some of the versions of this crossover sounding too "shouty", I'd say this version is probably the best. Sounds AMAZING! (this version is the one with the 10 uF and 2 uF caps)

[Nickd]

Thanks guys, after more study, I think I have a plan to update my series 1's to match the series 2 crossover ( 2uf & 10uf cap)

Earl K, the schematics and measurements are a big help. If I loose the .67mh coil it looks as if the nasty peak at 2k will drop a bit. I will also change out the caps. To series 2 values.

Voice of the theater, thanks for the the listening notes and comparisons. Helps verify that smooth rise is actually preferred.

As much as I appreciate the guys restoring and reviewing a pair of 14's, I think they may have been using the 1st gen crossover with the "restorative peak" for their listening before going active.

Looks like the Altec team did indeed improve the design in the later gen 2 versions. Nice to know.

[voice of the theater]

An easy way to access the quality of the ground plane (lugs to plate) is to put a meter across varoius points and measure resistance. From the pictures, I think everything looks secure and no oxidation between metals. I have been known to give contact points like these a very quick squirt of Deoxit Gold or any other deoxidizing spray that is at my disposal.

I think you're being a little too apprehensive about desoldering the caps, it is very easy. There are lots of online soldering/desoldering tutorials but I could sum it up in a few words: Place soldering wick on soldered connection, place tip of iron on top of wick, watch solder flow onto wick. You might need to flow the solder a couple of times into the wick, I usually have a cutter on hand to trim the wick that contains the solder off of the roll. Lacking the courage to do this, and considering future replacement with the originals, you could cut the leads and twist together. It's your gear but if you want it done right, you should take the old caps off the boards and solder in the new ones. Maybe practice on a piece of something that has little value, even a piece of solder.

As I posted, my call would be to replace the 470uf electrolytic. There is no sense in keeping an aged cap in the circuit when I have an iron heated and the cost of a replacement is less than a dollar. I believe the cap is in the protection circuit so is not going to alter the sound, it is just a ticking time bomb.

I ordered all the parts for all 6 speakers today, locally. They told me to expect a phone call in about 5 days when the capacitors, etc. come in. It added up to about $160.00 for all 6 speakers but I figure that's only about $50 a pair so I'm happy. As soon as they call I'll pick up the caps and solder them into the first speaker for testing (A/B comparisons) the same day. I didn't even know that the 470 uF was an electrolytic cap. I'm glad you said something. I just called and had them add two 470 uF 100v electrolytic capacitors to my order. The ones in there now are 50 volt, I assume there's no problem switching to 100 volt is there? They are 470 uF, same value as the ones that are in there now....

So, the lugs/rivets are ground lugs/rivets? Should I solder a wire between all seven rivets just to be sure I've got a good common ground (similar to what I'll be doing with my Model 19's)? Or is this not necessary with these crossovers?