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Modify Tukan cross-over

bighead1707

bighead1707

pfm Member
Heard that internal cross-over is the weakest link. Other than going to Active, do anyone have idea to modify its internal passive crossover? e.g. replace better component, re-wiring...

Thanks

Morris
 
Well, the Tukan crossover does have a Bennic electrolytic capacitor that could conceivably be swapped for something better and there are a couple of resistors that could be swapped for better ones.

The other capacitors are solen foils and are actually pretty good.

The inductors are ferrite cores (0.9 and 0.1 mH from memory).

You could conceivably bypass the the internal crossover (same way as for active) and build an external passive crossover. I think that getting the crossover out from the enclosure yields bigger benefits than swapping the components for exotics.
 
Hi Morris,

I am currently upgrading the crossover in My Proacs and have been advised to go for Mcaps and Caddock resistors. I will let you know how it sounds. I will be doing the upgrade in the next few days.

Cheers, Neil
 
You could conceivably bypass the the internal crossover (same way as for active) and build an external passive crossover. I think that getting the crossover out from the enclosure yields bigger benefits than swapping the components for exotics
Click to expand...

That was one of the things I was considering doing. I'll put the high spec stuff in first and see what the improvements are
 
I think that you need to look at why Linn use a 3uF bennic in parallel with a 5.1uF solen. There is another 5.1uF used in this crossover, so it could be an excercise in reducing part values stocked.

For resistors, Caddock are supposed to be very good, but I'm not sure if they are available in the values required.
 
Changing original filter components for higher quality ones in the quest for a better sonic result assumes that the crossover network is optimised for their particular set of drivers.

I can't imagine mid-market manufaturers with a wide product range would invest a lot of time measuring each set of driver configuration and putting together a set of filters to yield an optimal response. Certainly not for those 'speakers manufactured before the advent of CAD-systems.

I wonder how many people would pay to have their mass-produced loudspeakers revoiced with a new crossover. Could be a specialist niche market with reasonably fast turnaround given that sawdust does not need to be created. My copy of LspCAD and calibrated mic is gathering dust ...

James
 
Well, I upgraded the crossover of my ProAc Response 1SCs today.

I replaced the 3 solen polypropylenes in the tweeter and bass networks with MCap supremes and MCap Zn's, replaced the expotus resistors with Caddock resistors and rewired with silver/PTFE wire. Was it worth it? yes.

Even without the components being fully burned in I am getting masses more detail throughout the entire frequency range, deeper more controlled bass, a generally faster and more dynamic sound with a massively increased soundstage. Bloody good actually.

Well worth the money and effort. It should get even better over the next few weeks too.

Cheers, Neil
 
I think that you need to look at why Linn use a 3uF bennic in parallel with a 5.1uF solen. There is another 5.1uF used in this crossover, so it could be an excercise in reducing part values stocked.
Click to expand...

I think the design called for a 8uF capacitor and the cost of one of this particular value sourced from Solen was much much higher than using the 5.1 Solen cap in conjunction with a far cheaper 3 uF one. Even the DBL passive crossovers which cost several times a pair more than the Tukans did use (extremely) cheap electrolytics piggybacked on better polypropylene ones in an effort to contain cost. I am doing some experimenting in this particular arena and will have more to say about it within the next few weeks.
 
From http://www.falcon-acoustics.co.uk the price for a 5uF Solen is £1.89 inc. VAT. The price for an 8.2uF Solen is £2.45 inc VAT.

A 3uF Alcap electrolytic costs £0.38 inc VAT, so the differential between the costs is £0.18. I'd say that the cost of soldering in an extra component (and measuring the extra component, if you believe that Linn do this...) will be higher than just sourcing the correct value.

So either (a) it sounds better, or (b) Linn had millions of the 5.1uF caps and they used a cheap electrolytic to get the correct value.

The situation with the DBL might be that some of the caps have pretty big values... Once you get to 15uF, foil capacitors start getting big (and expensive). In the context of a crossover that costs over £1000, I wouldn't be happy to see 3uF electrolytics...
 
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