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AUDIO FORUMS >> General Discussion and Support >> Tannoy Monitor Red crossover question
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Message started by litefootdan on 02/20/18 at 14:05:22

Title: Tannoy Monitor Red crossover question
Post by litefootdan on 02/20/18 at 14:05:22

Hello Decwarians!!!

I'm going to try to build a pair of crossovers for my 15" reds and I've come across a schematic that I love to bounce off you all. here is a link..

http://www.44bx.com/tannoy/images/MonitorRedSilver15xO1.gif

Could anyone shed light on whether this crossover is a good roadmap to follow? Also, what is the Low Frequency coil with the three lines running through it. Is that an inductor?

Thanks anyone and everyone who can help me get going with this thing.

Dan

Title: Re: Tannoy Monitor Red crossover question
Post by litefootdan on 02/21/18 at 04:44:32

Well...... I think I've already made a mistake. I didn't study my schematic and I've purchased some Goertz air-core inductors for the crossovers. The Un-official HF modification calls for a .5mH inductor, so far so good. But I've just found out the LF calls for an Iron-core inductor. I didn't take note of the 3 lines denoting Iron-core. My mistake. I guess this is going to be an interesting project.

Title: Re: Tannoy Monitor Red crossover question
Post by deucekazoo on 02/21/18 at 14:29:35

I think you will be fine. The reason they use iron core inductors is because of size and cost. The down side of iron core inductors is saturation at very high currents which you don't have to worry about with air core. Just make sure to keep the mH the same and DCR as close as possible to the original.

Title: Re: Tannoy Monitor Red crossover question
Post by litefootdan on 02/22/18 at 02:39:01

Thank you so much Mr Kazoo :)

Its funny. I just had a look at my replacement inductor (Goertz 3.9mH 14awg) and it doesn't spec the its DCR. Also I cant seem to find any DCR specs on the web regarding the original crossover's LF coil. Tannoy's site says they provide no repair parts for discontinued drivers and cannot/will not share specs for their previous crossover components. I'm starting to think I should have done more research instead of buying stuff.... Oh well, eventually I'll get it right. I've got some pretty sweet capacitors in the crosshairs.

Title: Re: Tannoy Monitor Red crossover question
Post by deucekazoo on 02/22/18 at 14:29:11

You would have to measure DC resistance yourself if you have access to the original parts. I think you will be OK with the 14 awg you have. It comes down to they use less wire on the iron core inductors then the air inductors. More wire more resistance so you have to go up in gauge to offset. New x-over parts should make those speakers sound good. Make sure you take some pics of the x-over then you get done.

Title: Re: Tannoy Monitor Red crossover question
Post by litefootdan on 02/22/18 at 18:25:42

Thanks a ton for your insight. I do have the original crossovers but they are in a sealed tin box which feels potted, and I don't want to ruin them. They sound pretty nice with originals but I'm hoping for better with my build. I've spoken with Chris at Jupiter about using his caps and it looks like that is the way I'm going. Then I need to look into resistors/variable resistors. This will be my first foray into layout so we'll see how that goes. Hope I don't muck it up too much. I'll document but I'm very slow at things.

Again, thank you so much for your input