View Full Version : Tannoy crossover build
I am in the process of building new crossovers for my Tannoy 15 red monitors. I received the components a while ago but still contemplating how to lay them out. Any pointers will be appreciated.
Here is picture:
http://132.205.220.170/audio/misc/red-crossover-1.jpg
The Black Adder
31-10-2013, 08:53
Righto... :)
Keep the signal path as short as you can.
Make sure you position the coils properly
Don't skimp on the speaker posts
Hard wire to the drivers if possible
Hard wire from the amp if possible
Make them external
I can see you have some very nice bits there so once they are made you will need to take some time with them and let them bed in. MR's take a while and so do the Duelunds. I use both makes in my 'Uber' MG crossovers. :eyebrows:
With the reds I can't stress enough that one of the biggest things to take in to consideration (above new crossovers) are the cabinets. The reds are not renound for deep bass, they are more a midrange driver, but a beauty :).
New crossovers will make both aspects better but please don't expect a huge difference in sound over the original crossovers. You will get a more focused sound and better resolution but the cabinets are the main things that bring these olde Tannoy DC's to life. Same with the MG's but the MG's have a more balanced sound.
BTW.. What make of foil coil is that?
Hi Kudret
I'd echo what Joe said but add the following specific advice:
Inductors should be placed at the corners if possible to maximise distance between them. Their axis should all be at right angles to one another to prevent electromagnetic interference between them. Caps can be microphonic, so mount on a blob or two of clear silicone (can easily be removed) to help damp them. External boxes are best as Joe says but I'd not entirely agree RE changes. Good crossovers (design and components) CAN transform these DC drivers, but I'd agree with Joe that the cabinets matter most. If you take it as read that good cabinets are used and compare a decent crossover with an older tired crossover, the difference in response is immediate and usually positive. The Reds do midrange best as has been said.
Thank you both Black Adder and Reffc.
My Tannoys are in 50 year old DIY corner York cabinets. Workmanship was not perfect but I like
their vintage looks. I'll post a picture of them later on. They must have seen little use and in
retrospect I am not sure if it was necessary to build these crossovers. I do get nice mid range
and sufficient bass out of them. If I can refine the bass a little then I will achieve my objective
with these new crossovers.
The crossovers will be external and I am looking for Mogami W2972 wire to use all the way from the
amp to the drivers. I will be using the four-pin connector to connect them to the drivers as I do not
want to harm the rivers. I was also planning to use banana plugs on the speaker end but direct
wiring to the amps is also possible.
I must admit I skimped on the inductors. The big one is 14AWG Erse (which was on sale) and the smaller
one is Solen. I bought some epoxy and I will cast them in epoxy (copying Duelun's idea :$) after I
finalize the design. I'll follow your suggestion for securing the caps and positioning the inductors. Any
other suggestions are welcome.
The Black Adder
31-10-2013, 13:13
Thank you both Black Adder and Reffc.
My Tannoys are in 50 year old DIY corner York cabinets. Workmanship was not perfect but I like
their vintage looks. I'll post a picture of them later on. They must have seen little use and in
retrospect I am not sure if it was necessary to build these crossovers. I do get nice mid range
and sufficient bass out of them. If I can refine the bass a little then I will achieve my objective
with these new crossovers.
The crossovers will be external and I am looking for Mogami W2972 wire to use all the way from the
amp to the drivers. I will be using the four-pin connector to connect them to the drivers as I do not
want to harm the rivers. I was also planning to use banana plugs on the speaker end but direct
wiring to the amps is also possible.
I must admit I skimped on the inductors. The big one is 14AWG Erse (which was on sale) and the smaller
one is Solen. I bought some epoxy and I will cast them in epoxy (copying Duelun's idea :$) after I
finalize the design. I'll follow your suggestion for securing the caps and positioning the inductors. Any
other suggestions are welcome.
Hi Kudret.
If you like the response from your current cabs then that's fine. If they are good cabs then your half way there. If they were Lancasters I'd have had to slap your wrists, lol...
Great, keeping them external is a good idea and not just because of sonics but to be able to tweak them once made in the future. LOL, although your parts are pretty future proof already.
I've never tried Mogami cables so I can't really comment on those but what I've found is that Van Den Hul The Wind MKII Hybrid for external use and Van Den Hul CS-14 Hybrid are superb choices for the Tannoys. Marco here pointed me in the direction of those and I'm very happy indeed.
Ah.. Erse. I got some of those for my other crossovers. Great coils indeed. The 14AWG is perfect so I wouldn't worry about that. That is really quite enough for the LF. To cast the Solen in epoxy sounds like a great idea but I've never tried that so that's a new one to me. Should work out fine.
Keep us updated on the progress and if you want any more help, we are here so just ask. Paul has some great experience with crossovers as well as cabinet design too.. Take a look at his cabinets - http://referencefidelitycomponents.co.uk/products/loudspeakers/
I tried finding Van Den Hul CS-14 Hybrid or Inspiration Hybrid but I was not successful.
Mogami is a quad core speaker wire and 14 AWG version was available locally which is
too thick for the 4-pin connector. Mogami W2972 is the 15 AWG version and might just
fit. If I can find Van Den Hul CS-16 Hybrid that would be even better but VDH is not easy
to find.
Here is one of my Tannoys:
http://132.205.220.170/audio/misc/Tannoy2.jpg
I tried finding Van Den Hul CS-14 Hybrid or Inspiration Hybrid but I was not successful.
Origami is a quad core speaker wire and 14 AWG version was available locally which is
too thick for the 4-pin connector. Mogami W2972 is the 15 AWG version and might just
fit. If I can find Van Den Hul CS-16 Hybrid that would be even better but VDH is not easy
to find.
Hi Kudret,
If you find out who the main VDH importer/stockist is in Canada, they should be able to obtain it for you as a special order. Lovely Yorks, btw! :)
Marco.
I tried finding Van Den Hul CS-14 Hybrid or Inspiration Hybrid but I was not successful.
Origami is a quad core speaker wire and 14 AWG version was available locally which is
too thick for the 4-pin connector. Mogami W2972 is the 15 AWG version and might just
fit. If I can find Van Den Hul CS-16 Hybrid that would be even better but VDH is not easy
to find.
Here is one of my Tannoys:
http://132.205.220.170/audio/misc/Tannoy2.jpg
Lovely cabinets Kudret.
Don't worry too much about finding that particular cable. For the lengths/duties involved, ANY decent quality OFC of 1.5 to 2.5mm2 section multistrand is fine.
One of the reasons why I like CS-14 Hybrid is because, apart from its high quality, it is so thin and flexible to work with, resulting in one being able to solder very neatly, point-to-point, minus the use of any sonically degrading PCBs:
http://imageshack.us/a/img534/5278/tannoycrossovers2.jpg
http://imageshack.us/a/img803/2562/tannoycrossovers.jpg
(Pic shown of the crossovers inside my Lockwood Major/Tannoy 15 MGs).
However, I'm sure that the cable Paul mentions, if used correctly, will be just as good. As an aside, you guys should try the Duelund resistors (those little 'cigars'), as they are stunningly good and really open out the top end, as well as significantly increasing filigree detail retrieval :)
Marco.
I agree RE the cable Marco. Good quality flexible cable with large enough individual (multi) strands that hold their shape when twisted (not the ultra fine stuff) is always my preference. Those Duelands I understand have a graphite core (literally a pencil lead) so intrigued asto how they terminate them. Personally, I find Mills or Welwyn resistors perfectly adequate. I can't comment on sonics of resistors except to say that the Mills/Welwyn wire-wounds add no audible noise and do the job they're meant to. Only thing I would say is to always fit 12w minimum and go for the tightest tolerance possible. These things matter more than whose name is in the outside.
Wakefield Turntables
03-11-2013, 10:00
Yeah I'd be interested in that, I'm looking at speaker cab design of my MG's, as well as X-) designs (again) :eyebrows:
That's an interesting choice of components Marco; are those the standard inductors?
http://imageshack.us/a/img534/5278/tannoycrossovers2.jpg
Hi Mark,
I'm not sure - I'd have to ask the chap who built them. However, I do know that they came from Wilmslow Audio:
http://www.wilmslow-audio.co.uk/loudspeaker-crossovers-108-c.asp
I've always wondered whether there would be any improvement gained by changing them for equivalents of the Mundorf Foil M-Coils (air-core), shown on the Hi-fi Collective website: http://www.hificollective.co.uk/components/mundorf_foilcoils.html
One day, I'll try it. It's simply a question of being arsed, as the sound I'm getting at the moment is beyond awesome! :D
Marco.
Well,two of them are already air coils. I can't see one of them to be sure and the fourth is definitely ferrite cored. To be honest, they don't look anything special and are surprisingly small - I would expect their DCR to be quite high.
Indeed, which is why I was wondering about upgrading them all to Mundorfs. Thing is, although they may not be 'anything special' in isolation, the sonic synergy with the partnering components, and the speakers themselves, certainly is (which is why I haven't been arsed so far to fiddle any further with the crossovers) ;)
Marco.
Hi Paul,
I agree RE the cable Marco. Good quality flexible cable with large enough individual (multi) strands that hold their shape when twisted (not the ultra fine stuff) is always my preference.
Indeed. In that type of application, my priority with cable choice would always be the above, and thus whatever most aided the achievement of the best solder joint, than anything pertaining otherwise to 'cable quality'.
However, the silver plating on VDH CS-14 Hybrid (as per the matching 'Wind' external speaker cable), adds a little 'treble sparkle', which in my experience with vintage Tannoy DCs is rarely a bad thing :)
Marco.
Indeed, which is why I was wondering about upgrading them all to Mundorfs. Thing is, although they may not be 'anything special' in isolation, the sonic synergy with the partnering components, and the speakers themselves, certainly is (which is why I haven't been arsed so far to fiddle any further with the crossovers) ;)
Marco.
The LF inductor should be air core Marco as that's where most power is consumed (yours looks to be an air core here). The HF can be a ferrite or P-core without any sonic degradation providing that it's properly power rated so that it doesn't saturate. Cheaper too as there's less copper involved than for an air-core. The notch filter I believe should be a 0.68mH air core of 2.25 Ohm DC resistance. The resistance is very important to get spot on here as it affects how the notch filter operates (bandwidth and depth). You can use a lower resistance air core and add series resistance. Air cores here are fairly cheap as they're fairly small.
0.68mH air core of 2.25 Ohm DC resistance.
Hmm.. that's a lot of resistance for such a small coil. As you say, it will need a resistor adding (or to be wound with very thin wire).
Hi Mark,
I'm not sure - I'd have to ask the chap who built them. However, I do know that they came from Wilmslow Audio:
http://www.wilmslow-audio.co.uk/loudspeaker-crossovers-108-c.asp
I've always wondered whether there would be any improvement gained by changing them for equivalents of the Mundorf Foil M-Coils (air-core), shown on the Hi-fi Collective website: http://www.hificollective.co.uk/components/mundorf_foilcoils.html
One day, I'll try it. It's simply a question of being arsed, as the sound I'm getting at the moment is beyond awesome! :D
Marco.
I see that Wilmslow Audio don't even list the DCR of their inductors - which is a bit naughty as it is really very important.
Hmm.. that's a lot of resistance for such a small coil. As you say, it will need a resistor adding (or to be wound with very thin wire).
It is Mark. The values were measured values from the Tannoy originals. I cross-checked with my own original crossovers and they corresponded to the same value so when building mine, I used an air core (which had 1.25Ohms DCR ) and added 1R in series. I believe the MGs are the same as they share the same 3KHz horn resonance which the notch filter is there to compensate for.
Yep, I'm sure you are right - it's easy enough to measure. I was more thinking that a replacement coil of the same value is very unlikely to have that level of resistance and if the supplier doesn't even list the coils resistance (Wilmslow Audio) there s no way of knowing (unless you buy it and measure it yourself).
Hi Kudret,
If you find out who the main VDH importer/stockist is in Canada, they should be able to obtain it for you as a special order. Lovely Yorks, btw! :)
Marco.
Thanks Marco. I emailed the Canadian dealer again. He was not able to find any inspitation hybrid or CS-14. May be he can find some CS-16. If not, I'll use the 14AWG quad core Mogami that I already have. I'll just remove one of the cores.
Lovely cabinets Kudret.
Don't worry too much about finding that particular cable. For the lengths/duties involved, ANY decent quality OFC of 1.5 to 2.5mm2 section multistrand is fine.
Thanks again Paul. I know probably it won't make much difference but it's just that after all this effort I just wanted to have the piece of mind and not to worry about any future upgrades.
Very impressive line of products btw.
I agree RE the cable Marco. Good quality flexible cable with large enough individual (multi) strands that hold their shape when twisted (not the ultra fine stuff) is always my preference. Those Duelands I understand have a graphite core (literally a pencil lead) so intrigued asto how they terminate them. Personally, I find Mills or Welwyn resistors perfectly adequate. I can't comment on sonics of resistors except to say that the Mills/Welwyn wire-wounds add no audible noise and do the job they're meant to. Only thing I would say is to always fit 12w minimum and go for the tightest tolerance possible. These things matter more than whose name is in the outside.
Hi paul, 30 Ohms Duelund cast resistor in the HF section is rated 10 Watts. 50 Ohms one in the notch filter section is I believe 5w. Hificollective did not have the cast resistor for 50 Ohms so I got the regular one. Do you suggest I find the 50 Ohms in 10watts?
Hi paul, 30 Ohms Duelund cast resistor in the HF section is rated 10 Watts. 50 Ohms one in the notch filter section is I believe 5w. Hificollective did not have the cast resistor for 50 Ohms so I got the regular one. Do you suggest I find the 50 Ohms in 10watts?
Hi
the 30R in the HF is fine at 10 Watts. The 50 isn't (or shouldn't be) the notch filter...that should be 10R from memory. The 50 is the shunt resistor after the autoformer across the rails and ought to be rated more than 5W although even at that it shouldn't get too warm. By the way, it should only be 50R IF retaining the autoformer. If using fixed value inductors, you need to re-calculate that value otherwise you'll put way too much energy into the HF section.
Looking at the circuit diagram for your drivers, you simply take the electrical setting that you want to use (if electrically flat it's the green setting for the input for MG/HPDs) and that is connected across to the orange setting on the autoformer giving an impedance ratio of 2. You divide the 50R by 2 for an inductor fixed to the same inductance as the green setting (2.9mH) to give you 25R.
I'm assuming here that you've used the MG circuit for yours?
This is the crossover I am building for 15" Monitor Red:
http://www.44bx.com/tannoy/images/MonitorRedSilver15xO1.gif
Ah..that explains it Kudret...very different from MG/HPD x-overs. The notch filter uses different values to the MG/HPD...the diagram appears to show a variable 50R in the notch filter? You may have to experiment with the values a little there. Any change of resistance from optimal affects depth or breadth of the notch. For later MG/hpd's that cap value is 3u3F too, so it would be interesting to see why they've chosen different values for the Reds.
Ah..that explains it Kudret...very different from MG/HPD x-overs. The notch filter uses different values to the MG/HPD...the diagram appears to show a variable 50R in the notch filter? You may have to experiment with the values a little there. Any change of resistance from optimal affects depth or breadth of the notch. For later MG/hpd's that cap value is 3u3F too, so it would be interesting to see why they've chosen different values for the Reds.
That's a relief. For a moment I was worried that I ordered the wrong caps.
but 50R (or whatever value) should still be at least 10 Ohms right?
That's a relief. For a moment I was worried that I ordered the wrong caps.
but 50R (or whatever value) should still be at least 10 Ohms right?
The 50 Ohm in that position is for the notch filter so can be less as its not taking a huge amount of current. You can get away with pretty much what you have. My only concern there is the actual resistance value as the unofficial filter appears to use a variable resistor (ie it's not fixed at 50R but presumably is a potentiometer which can be varied to suit notch depth or breadth). If you go to the higher end (ie 50 ohms) I think that broadens the filter but reduces the overall attenuation. If you drop the value (say to 10 Ohms) then that increases attenuation but narrows the frequency width that it operates across so you may just want to do a little research on perhaps an optimalfixed value for that position. Later circuits for the MG/HPD has that as 3.3uF with 10 Ohms and a 0.68mH inductor (DCR - 2.25R)
The LF inductor should be air core Marco as that's where most power is consumed (yours looks to be an air core here).
Thanks, Paul. From the pic I posted, which one is the LF inductor? Also, to save me trying to find my original notes, what foil width and inductance value should it be (as if I'm upgrading I'd like to use the Mundorf Foil M-Coils, shown here: http://www.hificollective.co.uk/components/mundorf_foilcoils.html)
Cheers, dude! :cool:
Marco.
Thanks, Paul. From the pic I posted, which one is the LF inductor? Also, to save me trying to find my original notes, what foil width and inductance value should it be (as if I'm upgrading I'd like to use the Mundorf Foil M-Coils, shown here: http://www.hificollective.co.uk/components/mundorf_foilcoils.html)
Cheers, dude! :cool:
Marco.
Top right and bottom left in your photo appear to be air-cored inductors Marco. The LF one should be on the input positive terminal with positive direct out to the bass driver and a 16uF capacitor shunted to the negative terminal. The value for the LF on the MGs is I believe 1.2 mH (0.4R). Looking at the spec sheets for those Mundorf foil versions, the CFC16 or the CFC14 would be fine (1.2mH/0.4R or o.29R). Personally, I'd stick with the 17mm width to get closest electrical match to the originals.
The biggest one is probably the LF inductor.
Mundorf are far from being the only manufacturer of foil inductors though. Jantzen make copper, silver and wax ompregnated foil inductors.
Top right and bottom left in your photo appear to be air-cored inductors Marco.
So you mean the two 'black-coloured chaps', shown here, diagonally from each other:
http://imageshack.us/a/img803/2562/tannoycrossovers.jpg
The LF one should be on the input positive terminal with positive direct out to the bass driver and a 16uF capacitor shunted to the negative terminal. The value for the LF on the MGs is I believe 1.2 mH (0.4R). Looking at the spec sheets for those Mundorf foil versions, the CFC16 or the CFC14 would be fine (1.2mH/0.4R or o.29R). Personally, I'd stick with the 17mm width to get closest electrical match to the originals.
Thanks. I guess that upgrading both at the same time wouldn't do any harm? :)
So would both the air-cores in question be the same value (as you've stated above) or would the 'non-LF' one be different, and if so going by the spec sheets for the Mundorfs, which one should I use for the 'non-LF' air-core?
This will likely be a project for the new year.
Marco.
The biggest one is probably the LF inductor.
Mundorf are far from being the only manufacturer of foil inductors though. Jantzen make copper, silver and wax ompregnated foil inductors.
So the square-ish looking one on top right, you think, Mark? I know there are other manufacturers, but I've had very good results before with Mundorf products, particularly their capacitors, so I would probably go with those. I see Duelund also do wax ones, but at eye-watering prices, even for me!! :eek:
Marco.
The inductor values are all different in the circuit for the MGs Marco. LF is 1.2mH, Notch for the MG I think is a 0.82mH and the HF (without autoformer) I think is the same value as for the HPD (2.9mH). These need to be correct. What I don't understand from your picture is why you appear to have four inductors in circuit. I guess it's a question for the chap who built them as he will be able to confirm the circuit used.
The circuit used was this one, Paul, although some tweaks were applied (after listening to the results 'as is'), which may explain the use of extra inductors:
http://www.guitars-of-love.com/tannoy15goldcrossovermods.htm
Marco.
tbh Marco, you may get little if any benefit changing those inductors to foil ones. None that you're likely to hear anyway. If they were mine, I'd keep the air cored ones you have in circuit and change the ferrite cored ones for air cored equivalents but just ensure that DCR values aren't altered in-circuit. Spend the savings on your slush fund for the next cartridge or put it towards more music ;)
Marco, to be honest, I think you need to read up on the subject a little - it will pay dividends. After all, knowledge is power, as the saying goes.
tbh Marco, you may get little if any benefit changing those inductors to foil ones. None that you're likely to hear anyway. If they were mine, I'd keep the air cored ones you have in circuit and change the ferrite cored ones for air cored equivalents but just ensure that DCR values aren't altered in-circuit. Spend the savings on your slush fund for the next cartridge or put it towards more music ;)
No worries, Paul - all good advice. So, if I did that, studying the circuit I've used, which Mundorf Foil M-Coils should I buy from the HFC website, in order to replace the ferrite-cored inductors currently in circuit? :)
Marco.
Marco, to be honest, I think you need to read up on the subject a little - it will pay dividends. After all, knowledge is power, as the saying goes.
You're absolutely right, Mark. Trouble is, my mind just doesn't work that way. It's very hard to become interested in things that just don't interest you (and in fact bore you to tears). Basically, all that concerns me are the end (sonic) results, and how much better music sounds as a result! :)
Marco.
No worries, Paul - all good advice. So, if I did that, studying the circuit I've used, which Mundorf Foil M-Coils should I buy from the HFC website, in order to replace the ferrite-cored inductors currently in circuit? :)
Marco.
For the notch filter you just need one that matches the 0.82mH 12.2 Ohm needed in circuit (for the HPD this was a 0.68mH 2.25 Ohm with a 10 Ohm resistor in series). You're best contacting whoever built your crossovers and obtaining the values of the ferrite cored inductors so that you use a like for like replacement in mH and resistance. That way you need change or add nothing else in circuit. I can't speculate as to what those values are because you appear to have that extra inductor in circuit.
Ah - okey dokes... I think I might have the values in my original notes, given to me by the chap who built the crossovers.
Just to be clear, are the ferrite-cored inductors in question that big copper-coloured 'bobbin' thing, behind the two big Clarity Cap caps, and the one with the yellow and green stripes on top? :)
Marco.
That looks like it could be P or ferrite cored Marco. The central slim one with the ferrite centre to it is the other one.
Coolio, Paul. Thanks for your help. When I have the work carried out, I'll report the results and my findings on the forum :)
Marco.
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