Vandersteen 5A's Internal crossovers/batteries

Thanks again for all the information regarding my post.

MoFi,

Don't know why its not more widely used, one explanation could be that you'd need twice the capacitance otherwise required. For an example if your crossover design for the high-pass filter for the tweeter calls for a 5uF capacitor followed by a 15uF capacitor with a .3mH coil to ground from their midpoint (typical values).

To convert this to a actively biased crossover you would need two 10uF (replacing the 5uF) capacitors in series with their midpoint being the bias point followed by two 30uF (replacing the 15uF) capacitors in series with the bias point being their midpoint, so you can see the bill of materials stack up pretty quickly.

Good Listening

Peter

Peter...thanks for the very incisive explanation. I wonder why more manufacturers don't use this method? That's what threw me, I have never really heard of this being done in a crossover before.

Active biasing of capacitors in a loudspeaker crossover was invented by Gregg Timbers of JBL/Harman. It is used in the Everest D66000 for an example, applying batteries as mentioned above. In the newer Everest D67000 the bias voltage is achieved via diodes rectifying the incoming voltage from the amplifier which charges an electrolytic capacitor. The advantage to this approach is that the bias voltage always will be higher than the incoming voltage, and there no need to replace batteries.

JBL Everest D66000 XO schematic

Active biasing of capacitors places a bias voltage to a midpoint between two capacitors relative to ground. The voltage can be applied with a battery, or a series connection of batteries to achieve a higer bias voltage or as described above. Th sonic benefit form active biasing is only achieved as long as the bias voltage is higher than the incoming AC voltage from the amplifier, that being said 27VDC (3 ea 9V batteries in series) is certainly high enough for even very loud playback.

Good Listening

Peter

(((Hey guys, just a curious question, why are there batteries in the crossover?)))
There are three 9 volt batteries in the main inside crossover board of 5s,5A,5A carbons and Sevens that put 27 volts on the capacitors
that are in the signal path this allows the music to sound more transparent and clear.
When you haven't listened to your system in 2 weeks
and turn it on it sounds as good as you were playing yesterday without the half a day plus run in.
As Zd542 pointed out this is part of the same concept as Vandersteens/WEL DBS Syetem patent.
Best, JohnnyR

"01-31-15: Mofimadness
Hey guys, just a curious question, why are there batteries in the crossover? "

The batteries are used in the same way AQ uses them in their DBS system.

Hey guys, just a curious question, why are there batteries in the crossover?

Do the crossovers have some sort of a software program in them that requires a battery to maintain memory?

I do agree that you send them into Vandersteen for replacement.

Yes you're right. Thanks for advice.

Alan
Why not do it right send to Vandersteen.
for 60 bucks or so its worth having a perfect Job done and if anything is wrong fixed in house.
When part time armchair soldering folks get into things and burn up the sides of expensive parts it like letting a 3rd grader make the soup, Tasted good until he asks how much Ajax should go in next time.
JohnnyR

How much did Vandersteen charge to replace the batteries
for the pair?

Thanks for your help

I just took the crossover and amps out and sent them to Vandersteen for him to repair them. It was done right with no chance of screw up. The speaker is too valuable for error.

Thanks for all your help. Yes I agree that the soldergun tip might be too big. So to be on the safe side. I will buy a new 35 watt iron from Radio Shack and Silver solder from Music Direct.

Thanks again,

Alan

I recall the classic Infinity IRS Epsilon used two 9V batteries per loudspeaker to bias the joining point of a series/parallel set of capacitors in the tweeter network which is said to noticeably improve the top end.

I used Energizer Advanced Lithium 10 Year backup battery and mailed my crossovers to Vandersteen and they did the soldering for me. I don't think they charged much. I don't need to change batteries for another 10 Years . I suggest you use the same batteries.

I don't think it matters what kind of soldier you use because no signal runs through what you're working on. But to be honest, we're all audiophiles here, and you'll buy the silver soldier anyway (As would we all. Just make sure you cryo it first.) lol. The reason they tell you to use an iron, is because you probably don't have much room to work, and a full size gun may not allow you the access you need. Before you buy anything, look everything over really well. You need good lighting, so you might as well set something up now, before you start. Check to see if you can get an iron in below the connection you will be soldering. The tip of the iron will need to be under, and in contact with the metal you are going to apply soldier too. If, for some reason it looks like access will not be optimal, you may be better off getting a gas powered soldering iron or torch. None of this stuff is expensive, it is just a matter of what will fit where you are working. If you go into Lowes or Home Depot, all of these types of soldering tools are right in the same place, next to each other. Just pick the one that you think will work best.

Make sure you put something under what you are soldering to catch any drips. Also, before you soldier the battery, test everything first on a couple pieces of old wire first, just to get a feel for the equipment you bought. Even if you have soldiered things before, not all irons have the same feel, and heating time.

I forgot to ask that Richard in the manual says to use a soldering iron not a soldering gun. What do you suggest? I own a weller soldering gun.
Radio Shack has a 35 watt iron. Also should I use silver solder?

Thanks Alan

I think the Advanced Lithium 9V Battery is the only one they make. Are you sure you're not looking at the rechargeable 9V battery? Also, if I remember correctly, you have to soldier the batteries. They don't just plug in.

I use Ultimate Lithium by Energizer. Supposedly they are the longest lasting. I also use Duracell Quantum Battys which may or may not be lithium.