Vandersteen Quatro crossover

[awedio]

I suggested that audible diferences are harder to quantify. I wouldn't expect big changes, but that's because the XO is already of high quiality.

But I would certainly expect to hear changes, while you state:
>(different)/expensive components won't make any audible difference.

This is where we are not on the same page. Perhaps your avatar, Beethoven would agree with your take on caps.

 

[sreten]

Hmmm........

Waffling on about component differences which may be audible or not
but certainly will not give significant improvements seems pointless.

Especially when there seems to be far bigger fish to fry .....

/sreten.

 

[wigginjs]

Wow, I think I'm with sreten on this one.

So, let me get this straight . This speaker manufacturer included a box to place in between your preamp and your amp that is a 100Hz high pass, passive, batter-biased filter? I'm not a super-hifi expert, but I've never heard of anything like this. Why didn't they just accomplish this filter in their speaker xo? Component cost? Why is it biased with a battery? Why isn't this done more often? What happens when the battery dies? What happens when the battery gets weak? Why wouldn't they make it active w/ a power supply? Expense? I'm really intrigued...

 

[wheezer]

The dip switches are used to match the input impedance of the amp for a -3db from 1K to 100Hz tones from a CD or a sig gen and oscope.
The stereophile link gives some details.

 

[jam]

I have worked with this speaker. Sreten is right on this one leave it alone..............on second thoughts there is one way you could better this, with a good active buffer after the filter...........but then again you are introducing more electronics in the signal chain.

Jam

 

[wheezer]

Thanks Jam

 

[analog_sa]

What happens when the battery dies? What happens when the battery gets weak?

The battery will eventually get weak once it's over its shelf life. 5-10 years? Nothing much will happen once it's dead - just the caps won't have the polarising voltage and the dielectic will be a bit more non-linear. JBL and others also use it. Also some cable manufacturers. It's a lot cheaper to use a battery than more expensive caps. Laziness has so far prevented me from testing this idea. Maybe wheezer can take out the battery and give it a listen?

 

[fteixeira]

Circuit Diagram?

Wheezer,

I just found his thread. Do you (or anyone else) have the circuit diagram for the crossover?

I know the dip switches are used to sent the crossover frequency. However, I'm not totally clear how the caps are connected.

Thanks in advance.

fteixeira

 

[wheezer]

Neither do I.
I do have some Vit Q's and Gudeman to replace the infini and/or wima.
But have not done it yet.

 

[sreten]

Hi,

The dip switches adjust impedance (basically in parrallel with
the variable between models amplifer input impedance) such
that the capacitors values are correct for 100Hz 1st order.

There are far simpler / cheaper ways of doing it at the amplifier input.

/sreten.

 

[wheezer]

We know what it's for, thanks.
The question was if the schematic exists?
Do you have it?
Tx,
Mitch

 

[sreten]

We know what it's for, thanks.
The question was if the schematic exists?
Do you have it?
Tx,
Mitch

Hmmm........

Some sarcasm ?

You want a schematic for a series capacitor
with switchable parallel resistors on the output ?

You cannot work out the wiring or the values ?

/sreten.

 

[wheezer]

Indeed.
You didn't answer the guys question and
added to what we already know.

 

[sreten]

Indeed.
You didn't answer the guys question
and added to what we already know.

Well I'll let you work the bit you do not already know, it is simple.

/sreten.

 

[wheezer]

You got it... and sorry for the misunderstanding.

 

[fteixeira]

Agreed: The concept for a 1st order crossover is as simple as it gets. What Vandersteen is doing here with the parallel resistors to adjust the impedance to maintain the proper crossover frequency is also clear.

However, wheezer's pictures shows a bunch of capacitors (2 infinicaps and a few wimas?) with the biasing battery.

Call me a dummy, but how does the the biasing battery connect to the capacitors?
Why have the extra wimas? Is it to provide a greater capacitance range? If so why not use all infinicaps?
Is the battey just biasing the infinicaps or all the caps?
How would one go about calculating the proper biasing voltage?

Let me apologize right off the bat for my inexperience. I am interested in this 1st order crossover, but my electronic/audio skills are basic as best.

Thanks in advance,
fteixeira

 

[fteixeira]

Possible schematic found

After some searching, I found this link. A schematic is given which looks very much like the circuit in the M5-HP. Look at the circuit shown in item 5.

See http://www.thlaudio.com/wondrInfinCapmnl.htm

wheezer: can you confirm that this is the circuit used? Hopefully, you can pull the PCB out and trace the circuit. Obviously, there are the addition dip switches to set the cross-over frequency.

Happy holidays and a prosperous New Year!

 

[wheezer]

Sorry :-(
It's not the HP5 Vandy x-over.

 

[jeffreybehr]

wheezer, did you ever get an answer here? Or replace the caps with better ones?

I have the 5As now but without the inline filters*. If you prefer to keep the inline filters instead of adding a correct-value coupling cap at the input of your poweramps, I suggest you replace all the WIMAs and InfiniCaps with like values of better caps. Probably I'd use MultiCap RTXs ('styrenes) for the WIMAs and SoniCap Platinums for the InfiniCaps.



* I had already replaced the coupling caps in my poweramps to achieve an 85Hz filterpoint, and that works well with the 5As.

 

[wheezer]

Howdy Jeffrey,

M5-HP Oh, I gotcha. No, I've not found any info, nor searched any further.
Yea, I've seen the pic's of the 5A's. Beauty's Jeff.
You've strayed from home?

Changing the amp's coupling caps changes the corner frequency of the amp AND at the OPT. This can do the nasty on the OPT.
I schlep my Tek. function gen. to the media room when auditioning an amp or changing front end tubes. I've got the process down pretty good. Using the CD's tone of 100Hz and 1KHz is a PITA.
Every time I think about changing the caps in the M5-HP, I get cold feet. I have no experience w/speaker caps (AC only). Then the real estate issue.
I do love the RTX though. They serve as couplers in my phono stage and RTE in the RIAA. I'm sure someday I'll get around to it.

Regards,
W.