Heybrook Heylo crossover re-build (or not?)

[keiths]

Hi all,

A few months ago I bought a pair of Heybrook Heylos off ebay. When asking here about them, Dave (DSJR) said something like "they have very thin solid core wiring and very low wattage resistors in the crossover. The crossover should be brought up to hi-fi standards before any serious listening".

I've finally taken a look at the crossover. Here's a photo:

http://www.simister.com/public/xover1.jpg

I can't see the value of C2 due to C3 being glued over the writing - I don't want to try and cut the glue away until I've decided what - if anything - I'm going to do, but it's the same physical size as C1.

Also I didn't look too closely at R1 but I think from the photo it's Red, Orange, Black, Silver, Brown - which would make it 2R3 1%. It's physically very small, so I guess it's 0.25W I'll check again before I do anything.

Please bear in mind that I don't know what I'm doing, but I think the schematic is this:

http://www.simister.com/public/xover_sch.jpg

So what is worth changing? I don't want to spend too much, or swap componants for the sake of it with no sonic reward. I guess rewireing would be the first step (I would probably use the same Ortofon speaker cable that I'm using to connect the speakers to the amp). Maybe change R1 for a bigger wattage and change the non-polarised 10uF electrolytic (C3) for a film cap?
Is it worth changing the other film caps and resistor? What about the inductor?

Thanks chaps - all advice gratefully received.

[Reid Malenfant]

Hi Keith, you have the 18 ohm power resistor in the wrong place fella, it needs to be in series with at least one of the capacitors that are accross the woofer voicecoil, not in series with the woofer. I can't see to be 100% precise if the capacitors are in parallel...

Looks like it could benefit from some work, but there isn't a lot to modify unless changing caps :lolsign:

[keiths]

Thanks Mark. Told you I didn't know what I was doing :lol:

The caps are definately in parallel and both caps are in series with R2.

Try again:

http://www.simister.com/public/xover_sch2.jpg

As you say, not much to change, but was still wondering if I should leave the existing film caps alone and only change the non-polarised electrolytic?

[Reid Malenfant]

That's better :)


As you say, not much to change, but was still wondering if I should leave the existing film caps alone and only change the non-polarised electrolytic?
In all honesty i'm not that sure i'd bother ;) You see it's simply shunting any higher frequencies to ground that get past the LF choke & as such it's not in series with any driver so shouldn't affect the sound.

Doesn't leave a lot does it :lolsign: Unless you fit much better quality film caps of course :scratch:

[keiths]

In all honesty i'm not that sure i'd bother ;) You see it's simply shunting any higher frequencies to ground that get past the LF choke & as such it's not in series with any driver so shouldn't affect the sound.

Is that true of C2 as well? In which case I could leave the LF side of the crossover alone (other than changing the wire) and just replace C1 with a much better film cap and replace R1 with a higher power/better quality resistor?

[Reid Malenfant]

Yes, the only other thing you might consider is replacing the choke feeding the bass driver with an air cored choke. The thing is though it'd have to match the DC resistance of the choke that is already fitted. As long as you have an accurate ohm meter it might be worth considering ;)

[keiths]

Cheers Mark. I think I'll leave the choke alone as I can't measure it's inductance and I don't think my cheapo meter is going to be accurate enough to determine the DC resistance.

Any suggestions of brands and suppliers for the film cap and resistor?

[Reid Malenfant]

I'm being driven mad by the way i have to keep pressing buttons to get anywhere on here :steam:

You could try Solen, they aren't too expensive & they should be a cinch to find ;)

Again no post preview & had to copy the post, go to the main forum page, back to the thread & try again :steam: I can't take much more of this :rolleyes:

[Marco]

Move yer ISP then from 'Bullshite Telecon' (no, that last letter wasn't a typo!) to something better.... ;)

Marco.

[Reid Malenfant]

Move yer ISP then from 'Bullshite Telecon' (no, that last letter wasn't a typo!) to something better.... ;)

Marco.
:lolsign: Things are ok now chap ;) It really was getting so bad i was going to sod off for the night but things are now at least as good as the best of the old server :eyebrows:

You have a PM by the way :cool:

[keiths]

Back to normal here too :eek:

[keiths]

Move yer ISP then from 'Bullshite Telecon' (no, that last letter wasn't a typo!) to something better.... ;)

Marco.

To be fair to BT, I've suffered no major issues from them as an ISP in over 12 years (ISDN2e originally, then broadband).