jc
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Post by jc on Mar 17, 2014 23:02:06 GMT
Just to prove there is the feint flicker of DIY activity at CJ towers, I've had a first bash at layout for super dooper passive cross overs to breathe life into my 'speakers (ye olde integrated will run them when done, until the Aclass finally gets built). The original xover uses very basic components so shouldn't be hard to improve upon, as below. As the upgraded components are substantially larger I'm intending to make back to back boards carrying high pass on one and low pass on the other, in an attempt to reduce the footprint of each complete xover. Each of these should work out roughly the same board dimensions as the original full xover. Obviously a VERY rough idea, hopefully you can see the intention without the circuit drawn out. To be continued...
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Post by Deleted on Mar 17, 2014 23:18:25 GMT
Just to prove there is the feint flicker of DIY activity at CJ towers, I've had a first bash at layout for super dooper passive cross overs to breathe life into my 'speakers (ye olde integrated will run them when done, until the Aclass finally gets built). The original xover uses very basic components so shouldn't be hard to improve upon, as below. As the upgraded components are substantially larger I'm intending to make back to back boards carrying high pass on one and low pass on the other, in an attempt to reduce the footprint of each complete xover. Each of these should work out roughly the same board dimensions as the original full xover. Obviously a VERY rough idea, hopefully you can see the intention without the circuit drawn out. To be continued... Hi Chris Looks interesting. I wish I could find a way to open my old DCM QED 1As to upgrade the XOvers, especially replacing the electros, without damaging them. They have glued the damn woofers in, and I have read that it is a real P.I.T.A. to get them out to gain access.
Kind Regards Alex
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Post by drymdrum on Mar 18, 2014 0:22:39 GMT
Yes Chris/Alex,
something I've had in mind for my old but faithful DIY TLs from way back must be about forty years but still in great working order. Probably a testament to how I built them. I don't have a problem with opening them up well don't think so until I try. Just the total weight puts me off even trying to move them. Now that you've come forward Chris I might just be encouraged to have a look inside. Regards, Alan
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Post by PinkFloyd on Mar 18, 2014 11:48:27 GMT
Hi Chris, What is the pitch for the 20uF electrolytic because I have some lovely EVOX film capacitors that I am more than happy to send you to fit in those positions.... they are 22uF so pretty much spot on and will "sound" a lot nicer than the 20uF 'lytics. Mike. Whoops, sorry.... I thought you were using the original PCB..... ignore my previous comment
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jc
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Post by jc on Mar 18, 2014 19:19:23 GMT
Hi Mike, Thanks for the thought Alex, that sounds a bit frustrating! Mine are outboard, so no hassle there. I had a first tidy up today, looking better but not there yet. Mulling over P2P vs stripboard at the mo... (I know diagonal tracks are a no no, what about diagonal components?)
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Crispy
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Post by Crispy on Mar 23, 2014 19:38:12 GMT
Just to prove there is the feint flicker of DIY activity at CJ towers, I've had a first bash at layout for super dooper passive cross overs to breathe life into my 'speakers (ye olde integrated will run them when done, until the Aclass finally gets built). The original xover uses very basic components so shouldn't be hard to improve upon, as below. As the upgraded components are substantially larger I'm intending to make back to back boards carrying high pass on one and low pass on the other, in an attempt to reduce the footprint of each complete xover. Each of these should work out roughly the same board dimensions as the original full xover. Obviously a VERY rough idea, hopefully you can see the intention without the circuit drawn out. To be continued... Chris, I presume these are out of your Naim SBL speakers - I have a couple of photo's from my mate's SBL speakers and I am sure they look the same and I am pretty sure he would be very interested in upgrading his crossovers, keep me posted on what components you decide on and what the total cost ends up being.
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Post by PinkFloyd on Mar 24, 2014 10:13:01 GMT
Hi Chris,
Have you contemplated potting the entire crossover?
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jc
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Post by jc on Mar 24, 2014 15:07:32 GMT
Hi Chris, Yes, you are correct and yes, will do! Mike, I've tried that before but despite putting them in good natural sunlight and watering them, the damn things just wouldn't grow
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Post by PinkFloyd on Mar 24, 2014 21:28:55 GMT
Hi Chris, Yes, you are correct and yes, will do! Mike, I've tried that before but despite putting them in good natural sunlight and watering them, the damn things just wouldn't grow Not potting in earth mate Potting in wax
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jc
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Post by jc on Mar 24, 2014 21:55:12 GMT
Oh right, silly me So, would you pass the wick through the inductors or wrap it around the caps? Would the resistors prevent the wick from keeping a flame? What happens when the wax burns away and it all falls apart on the floor. Blimey mate, that's a fire hazard! I still don't see how that will help them grow...
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Post by PinkFloyd on Mar 24, 2014 22:09:59 GMT
hehe....... I think you know what I mean you "pot" the entire crossover in wax which, in turn, ensures the internal cabinet resonance (vibration) does not interfere with the components on the crossover..... you essentially make a mould, drop the X-over into it and pot with melted wax.... nowadays (if you're lucky) you'll see the odd blob of hot melt glue applied "randomly".... a decent, properly potted, X-Over will reap sonic benefits. Never as good as an external X-Over is going to be but certainly better than running the X-over "naked" inside the cabinet. Mike.
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Post by PinkFloyd on Mar 24, 2014 22:17:55 GMT
Copied from: www.hilberink.nl/codehans/tannoy52.htm"The previous 15" Monitor Black had an integral crossover network and line-matching transformer built into a square aluminum box mounted on the side of the chassis. All components were 'potted' in wax to prevent resonance and to protect the wax paper capacitors used at the time from moisture." A bit more about potting: www.audiocircle.com/index.php?topic=52104.0I'm starting to feel REALLY old now...... not a lot of info on potting X-Overs on the net
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Post by Deleted on Mar 24, 2014 22:24:06 GMT
Hi Chris, Yes, you are correct and yes, will do! Mike, I've tried that before but despite putting them in good natural sunlight and watering them, the damn things just wouldn't grow Not potting in earth mate Potting in wax I managed to resist the temptation with this lot ! I think someone tried to clone Poms that way ?
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Post by PinkFloyd on Mar 24, 2014 22:25:59 GMT
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Post by PinkFloyd on Mar 24, 2014 22:27:20 GMT
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Post by PinkFloyd on Mar 24, 2014 22:36:53 GMT
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jc
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Post by jc on Mar 24, 2014 22:41:18 GMT
I must admit I had heard of it being done to entire xovers but couldn't remember an actual instance of it in a production model. An external unit is probably a cheaper option too. Plus, if using ally caps, alley cats, "The Aristocats"! Ahhhh, they don't make 'em that any more...... Anyway, if using aluminium capacitors you'd have to junk the whole xover when their life expired.
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jc
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Post by jc on Apr 1, 2014 20:18:33 GMT
Another mm of progress, I've progressed the boards to 90% done. (excuse the dodgy pic quality) LF HF Idea of stacking them... Obviously I'll use standoffs in place of the way-over-budget fabric coaster! The boards are opposite-handed, so when stacked as shown the +ve's and -ve's line up on the input side.
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Post by PinkFloyd on Apr 1, 2014 20:53:52 GMT
Another mm of progress, I've progressed the boards to 90% done. (excuse the dodgy pic quality) LF HF Idea of stacking them... Obviously I'll use standoffs in place of the way-over-budget fabric coaster! The boards are opposite-handed, so when stacked as shown the +ve's and -ve's line up on the input side. Hi Chris, Very nice work so far, there's nothing quite as satisfying than modding a pair of loudspeakers. I would tend (if it were me) to look at the two boards as two pieces of bread and stuff something in-between them to make a damping "sandwich".. something that will absorb the resonance. You could supplement with the stand-offs but make sure and use nylon stand-offs and nylon bolts, applying some thread lock before nipping them up. You could even fit the two boards together with about 8 stand-offs (the more the merrier) and then pump in some silicon sealant into the sandwich, that would make it pretty "dead" between the boards. Same with both top surfaces of the boards, you could pump silicon in and around all of the components. Obviously test the X-overs first
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Post by PinkFloyd on Apr 1, 2014 21:11:05 GMT
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jc
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Post by jc on Apr 2, 2014 21:54:55 GMT
I did think about Mike but as the paxos are "outboard" and temporary I gave it a miss. I could glob on some hot melt glue if I felt the need, like the manufacturers used to do. We get a kind of bitumen tape on a roll here, again very handy stuff with loads of uses. I'm half way through a 50m roll!
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Crispy
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Post by Crispy on Apr 4, 2014 20:26:50 GMT
Another mm of progress, I've progressed the boards to 90% done. (excuse the dodgy pic quality) LF HF Idea of stacking them... Obviously I'll use standoffs in place of the way-over-budget fabric coaster! The boards are opposite-handed, so when stacked as shown the +ve's and -ve's line up on the input side. Looking good Chris, have you got to a stage where you can listen to them?
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jc
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Post by jc on Apr 6, 2014 19:24:51 GMT
Hi Chris, no testing stage yet I'm afraid. Progress, due to time, is painfully slow. I'll also need to set the "sybils" up first. No ordinary 'speaker in this respect and takes quite some time to do it right. The rough costing for all the parts is £120 plus whatever enclosures are used. Being in the UK you can obtain them cheaper because of post savings and also a different inductor provider is a tad cheaper, details to follow...
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Post by smokeycigar on Apr 9, 2014 6:27:22 GMT
Nice work. I also have a large crossover including zobel/ imp comp. I need to "tidy them up". They started and stayed as a blob of soldered components with speaker wires wrapped around the leads.
The components you are using, should easily increase the SQ.
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jc
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Post by jc on Apr 9, 2014 22:39:04 GMT
Nice work. I also have a large crossover including zobel/ imp comp. I need to "tidy them up". They started and stayed as a blob of soldered components with speaker wires wrapped around the leads. The components you are using, should easily increase the SQ. Yes, have a go and post your findings with pictures.
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