Crossover Upgrade

[voice of the theater]

I just put the common wire to all 4 lugs and connect it to the negative side of the speaker wire. I found out the clarity and HF/Mid range has great improvement. However, it doesn't help to improve the bass. Altec Model 19 is using 15" woofer. But you cannot notice any bass from the speaker. I wonder how we can help to improve the bass.

I'm finally ready to do this ground lug connection upgrade on my Model 19's. Unionville connected the four ground lugs and then ran a wire to connect them to the "negative side of the speaker wire"? If I understood a previous thread correctly, don't I just need three short lengths of wire to connect the four ground lugs (one wire connecting ground lug #1 to #2, second wire to connect lug #2 to #3, third wire to connect lug #3 to lug #4)? If I solder the three wires to the four ground lugs i.e. connect the four ground lugs, isn't one of the lugs already connected to the "negative side of the speaker wire"? I don't need an additional wire connecting one of the lugs to the "negative side of the speaker wire",do I? Also, what kind of wire should I use to connect the ground lugs? Is speaker wire ok? Any gauge/type of wire recommended?

Pulled the crossovers out today to attempt the mod. There isn't much room to work in there!! I can't see how I can get my soldering iron in there & not melt some of the components. I looked long & hard at it for quite a while & decided that it's better left alone.

What I did try was to connect the wires to the HF control & bypass the pot. This made a huge difference to the top end....a lot more than just having the pot on full. A lot more detail, & a crisper sound overall. I did find that I had to pull the mids back a touch, as the horns were a little overbearing with this setting, particularly on vocals.

Just read this post in a previous thread--Is there going to be enough room for me to safely solder wire to these four ground lugs? Anyone out there including anyone who's done this mod (Altec Best, etc.), any answers to these five questions? Any tips on how to safely solder to the lugs without frying anything? I want to get this right the first time and don't want to fry my Model 19 crossovers. Thanks in advance for any help on this upgrade.......

[Altec Best]

First of all what are your plans ? Complete Upgrade ? If so then,Clean the pots with De-Oxit 5 first then solder the new resistors in,then the ground lug bypass then the caps ! If you solder in that order you'll be fine.Test your iron so it gets just hot enough to melt the solder. Good Luck ! We should have another satisfied customer !

Then they should look something like this. In the first photo there is a ground wire that also runs along the side of the yellow wire if you look close it goes from the one ground lug to the other one on the other side.I forgot to draw a orange line on that one too.

[cradeldorf]

Good luck with the upgrade Vott.

[voice of the theater]

First of all what are your plans ? Complete Upgrade ? If so then,Clean the pots with De-Oxit 5 first then solder the new resistors in,then the ground lug bypass then the caps ! If you solder in that order you'll be fine.Test your iron so it gets just hot enough to melt the solder. Good Luck ! We should have another satisfied customer !

Then they should look something like this. In the first photo there is a ground wire that also runs along the side of the yellow wire if you look close it goes from the one ground lug to the other one on the other side.I forgot to draw a orange line on that one too.

Thanks a lot for the photos AB--now I can actually see that you have the ground lugs connected with three short wires, as I guessed. So for that part of the upgrade that's all that's involved is the three wires, right?

To answer your question, I'd like to do this upgrade in stages if at all possible. I've already cleaned the treble and midrange pots with contact cleaner (and I've experimented with bypassing the treble pots since I always leave the treble pots turned "all the way up" anyways). Next, I want to connect the four ground lugs in one Model 19 speaker to see what improvement that makes. Then I can do an A/B comparison and will probably notice the improvement everyone's talking about -- and in that case I'll immediately connect the four ground lugs in my other three Model 19's. After both pair of Model 19's have the ground lug upgrade, I'd like to listen for a while (to get used to the "new" sound) and eventually will probably try the caps upgrade in one of my Model 19's (but save the original caps just in case) and do an A/B comparison with a speaker with the original caps. If I notice another improvement, I'll put new caps in both pair of Model 19's (I'll use Solens--you recommended them and I talked to Bill at GPA a few months ago about it and he recommends Solens too....).

Do you think I'll be able to get to the ground lugs to (safely) solder the three wires to them without removing the original caps? Any advice on that?

Not to turn this into a "wire thread", but does anyone know (AB?) if I can use speaker wire to connect the four ground lugs or is there another kind of wire/guage that is better for this part of the upgrade?

[SOOTSHE]

"Do you think I'll be able to get to the ground lugs to (safely) solder the three wires to them without removing the original caps? Any advice on that?"

My experience was that I didn't trust myself to solder the ground lugs while the original caps were still in place. Once you've got the crossovers out & can see what you're looking at, you'll be able to make that call for yourself.
Because I didn't feel I could do the ground lugs without removing the original caps, I decided to go ahead & replace them on AB's advice & wasn't expecting to hear much of a difference.

To my ears it was a night & day difference & for the better! I didn't think the 19's could sound this good. You can always put the old caps back in if you feel you need to.

If you have 2 pair of 19's you could do the complete upgrade in one pair & compare those to the original unmodded pair?

I can only say again that I was a bit sceptical about this but haven't regretted the changes at all, in fact, I'd never go back to stock.

FWIW I used ordinary copper stranded wire for the bypass, but a much heavier gauge.

Cheers,
John

[Altec Best]

Thanks a lot for the photos AB--now I can actually see that you have the ground lugs connected with three short wires, as I guessed. So for that part of the upgrade that's all that's involved is the three wires, right?

To answer your question, I'd like to do this upgrade in stages if at all possible. I've already cleaned the treble and midrange pots with contact cleaner (and I've experimented with bypassing the treble pots since I always leave the treble pots turned "all the way up" anyways). Next, I want to connect the four ground lugs in one Model 19 speaker to see what improvement that makes. Then I can do an A/B comparison and will probably notice the improvement everyone's talking about -- and in that case I'll immediately connect the four ground lugs in my other three Model 19's. After both pair of Model 19's have the ground lug upgrade, I'd like to listen for a while (to get used to the "new" sound) and eventually will probably try the caps upgrade in one of my Model 19's (but save the original caps just in case) and do an A/B comparison with a speaker with the original caps. If I notice another improvement, I'll put new caps in both pair of Model 19's (I'll use Solens--you recommended them and I talked to Bill at GPA a few months ago about it and he recommends Solens too....).

Do you think I'll be able to get to the ground lugs to (safely) solder the three wires to them without removing the original caps? Any advice on that?

Not to turn this into a "wire thread", but does anyone know (AB?) if I can use speaker wire to connect the four ground lugs or is there another kind of wire/guage that is better for this part of the upgrade?

John has a good idea do the upgrade in one pair and just A/B the 19's you won't beleive the difference,especially if they are still original.I suggest do it all at once because once you solder in the caps you won't be able to get to the resistors after that.Just do a reverse manufacture if you have to take lots of photos and just replace the old components with the new. I would not go any bigger than 14 awg you may want to use 16 awg stranded wire for your first it is easier to work with.Now to safely solder depends on your soldering iron/tip you are using.What do you have and is it a variable temp.soldering iron station ? Always try to keep the leads on the caps,resistors,etc... As long as possible it will help to keep the heat away from them when soldering.Also when removing the originals try to keep the leads in tact as well in case you ever want to reuse or replace them back into the XO.Just don't cut them short,and you should be fine,give yourself extra time if you are unsure.And be patient you will make less mistakes.

"Because I didn't feel I could do the ground lugs without removing the original caps, I decided to go ahead & replace them on AB's advice & wasn't expecting to hear much of a difference.

To my ears it was a night & day difference & for the better! I didn't think the 19's could sound this good. You can always put the old caps back in if you feel you need to.

If you have 2 pair of 19's you could do the complete upgrade in one pair & compare those to the original unmodded pair?

I can only say again that I was a bit sceptical about this but haven't regretted the changes at all, in fact, I'd never go back to stock.

Good points John ! IT was worth the effort, you have had sometime now with the upgrade, good move wasn't it ?

[SOOTSHE]

IT was worth the effort, you have had sometime now with the upgrade, good move wasn't it ?

Absolutely....you won't believe the difference.
You'll only need the old caps for sentimental value!!

[voice of the theater]

I pulled one of the Model 19 crossovers today and it looks like there's no way I'm going to be able to solder in the ground lug bypass wires with the existing caps in the way. There's just no room to work. So, I'm going to bite the bullet and replace all the original caps with Solens. Both of you guys swear by this upgrade and it makes sense to me that those old caps have probably shifted in value. Once I remove the old caps, I'll put in the three ground lug bypass wires and then I'll put in the new caps. I asked around a couple of places locally and I'm told that the solid core inductors and the resistors are not (as) prone to changes like the capacitors are so I'm going to keep the original inductors and resistors and just replace all the capacitors. I pulled up a Model 19 crossover schematic online--and it looks like I'll need a 6 uf, an 8 uf, a 16 uf, and a 21 uf capacitor for each speaker. Are those the right values? I know I'll need to combine caps to get some of these values--for example, I'll combine a 20 uf and a 1 uf to get the 21, right?

http://home.earthlink.net/~jmarkwart...1201-8aRev.pdf

[SOOTSHE]

I pulled one of the Model 19 crossovers today and it looks like there's no way I'm going to be able to solder in the ground lug bypass wires with the existing caps in the way. There's just no room to work. So, I'm going to bite the bullet and replace all the original caps with Solens. Both of you guys swear by this upgrade and it makes sense to me that those old caps have probably shifted in value. Once I remove the old caps, I'll put in the three ground lug bypass wires and then I'll put in the new caps. I asked around a couple of places locally and I'm told that the solid core inductors and the resistors are not (as) prone to changes like the capacitors are so I'm going to keep the original inductors and resistors and just replace all the capacitors. I pulled up a Model 19 crossover schematic online--and it looks like I'll need a 6 uf, an 8 uf, a 16 uf, and a 21 uf capacitor for each speaker. Are those the right values? I know I'll need to combine caps to get some of these values--for example, I'll combine a 20 uf and a 1 uf to get the 21, right?

http://home.earthlink.net/~jmarkwart...1201-8aRev.pdf

This is what you need to rebuild your Crossovers to original spec.

Capacitors
a) 21uF , so you will need a 12uFand a 9uf
b) 16 uF, so you will need 2 8uF's
c) 8 uF
d) 6 uF

I used Solen 400v DC

Resistors if out of spec.
a) 3.9 ohm 10 watt 2% audio grade 2 will be needed.
b) 3.0 ohm 10 watt 2% audio grade 1 will be needed.
c) 2.0 ohm 10 watt 2% audio grade 1 will be needed.

I'd strongly recommend you do the resistors as well, purely from the point of view that if you ever do want to make sure they're up to spec you'll have to pull all your new caps out to get to them. They are such an inexpensive item that it isn't really a cost issue, but it will be a real pain to have to do it later on. Just ask me....I know, because I didn't do mine either & then had to undo all my handywork to get to them!!

Definitely don't change the inductors, as that will alter the tonal characteristics quite dramatically & I'm told that they shouldn't have drifted too much in value.

I got a better sound by bypassing the L Pads......you'll need a 10 watt 10 ohm resistor for the mid pot (which duplicates the "optimum" setting). If you like the top end to run flat out just by-pass the pot. I found this a little too bright in my room so I just used a 3.3 ohm resistor.....sounds great.

No expert here, but I think you're better off with the similar values when you try to make the correct values. So the 16 cap will be 2 x 8 & the 21 cap will be a 12 & a 9.

Regards,
John

[voice of the theater]

OK, now I'm thinking about doing the resistors too -- as long as I'm going to be in there anyways with a soldering iron. What brand resistors did you guys use? I know 2 and 3 are common values but not sure what manufacturer makes 3.9.....