[Marvin55]

Hello All,

I have owned and enjoyed a set of original VR4s (serial # below 200) for some time.
Here in Australia imported speakers are mostly very expensive and I can't forsee any way I'll be replacing them!

However I have decided to rebuild the crossover with current high quality parts, and I hope someone can advise me on the size of the largest coil in the bass crossover, as well as a few other things.

A principle I am keeping firmly in mind is that the crossover is correct as it is, and I can only hope to achieve marginal improvements with new parts.

The big coil, an iron core item, is unmarked and measures on my cheap-o meter at 38 mH which seems about right. Can anyone give me a more exact size?

I am hoping to use Jantzen C-Core (toroidal) coils in the bass crossover, is there a superior cored coil? Does anyone list a coil so big as a standard part? Much as I'd like to use air-core coils they will be outrageously large and expensive to achieve a decent DC resistance and are therefore unsuitable.

Any other comment/advice is welcome.

Marvin55

Sydney
Australia

[douglesc]

If you replace those inductors (coils) I just don't think you would gain enough to make it worth while, it would be small, because what you are talking about are part changes and not circuit changes.
Your biggest gains will be replacing those solen caps with better ones, I would leave the bass cross over alone and focus on the mid range tweeter by replacing those caps. Even the resistors are at least 25w resistors and he did parallel most of them. Even back then Albert's cross overs were way above most of the competition in quality.
What I mean by circuit changes is that Albert has just about ALL of the mid removed from those bass drivers. While it is true that air core is cleaner than metal core, there is a sliding scale there, in other word at what power level.
just my opinion and you could call Albert and see what He thinks.
just trying to save you some grief

[es347]

I agree with Doug...call the man himself before tearing into one of his x-overs 

[Marvin55]

Hi all,

I'm the original poster of this thread. Years ago, I had someone replace the crossover parts with higher quality parts, mainly Jantzen caps and modern resistors.

I emphasize that the components were refreshed but the circuit remained exactly standard.

The crossovers were outboarded due to the Jantzen caps only being available in smaller values, leading to large numbers of parallel caps.

Last week the cat, a qualified agent of chaos, leaped onto the crossovers and broke a few solder joints... words were said!

Does anyone have a circuit diagram for the original VR4s? Or perhaps a photograph of the top crossovers? I made a diagram at the time of the rebuild but I would like a confirmation of the diagram I made.

On a related note, is anyone aware of suitable replacements for the woofers?

Cheers

Marvin 55

Australia