OK. I'm trying to figure out posting photos
An externally hosted image should be here but it was not working when we last tested it.
Ok. Let's see if I was able to post a photo. It's of the MS25Ti crossover from one of my pair. It looks a bit different than the one you posted, Galu. So, I need to figure out which are the electrolytic capacitors, to replace, and which are part of the overload protection circuit, to bypass. It seems the two blue ones are the caps to replace, unless they're part of the protection circuit.
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The large blue cylinders are the non-polar (bipolar) electrolytic capacitors.
The small blue discs are the Positec protection devices.
Apart from the above, there are three inductors (coils) and one resistor, which you may leave untouched.
The small blue discs are the Positec protection devices.
Apart from the above, there are three inductors (coils) and one resistor, which you may leave untouched.
I've put the two crossover versions side by side for comparison.
The main difference in Version 2 compared to your crossover (Version 1) appears to be the inclusion of a 3.3 ohm resistor in series with the tweeter capacitor.
Adding a small value resistor in series with your tweeter capacitor (the 3.3uF) will change the response of the tweeter, and that's something worth experimenting with when replacing the capacitors.
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Galu, thanks. Very good information for me as I'm starting. Yeah, I could try to add a resistor.
I've just found 2 local electronics shops, I'm going to buy a basic soldering station. I'm making a list of the bits. Banana plugs, too.
I bought these MS25Ti new in 1986. Crackin' that one open last night was like opening a time capsule. It has thick, white damping, it was in there so tidy.
Yes, the perspective in the photo is deceiving, the MS10 is quite compact. The dimensions H x W x D
MS25Ti 15.75 x 10.25 x 8.75 inches (40 x 26 x 22cm)
MS10 11.75 x 7.75 x 6.75 inches (285 x 195 x 170mm)
I've just found 2 local electronics shops, I'm going to buy a basic soldering station. I'm making a list of the bits. Banana plugs, too.
I bought these MS25Ti new in 1986. Crackin' that one open last night was like opening a time capsule. It has thick, white damping, it was in there so tidy.
Yes, the perspective in the photo is deceiving, the MS10 is quite compact. The dimensions H x W x D
MS25Ti 15.75 x 10.25 x 8.75 inches (40 x 26 x 22cm)
MS10 11.75 x 7.75 x 6.75 inches (285 x 195 x 170mm)
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Yes, I've had the 25s forever and then I just got the MS10 in a sweet 3.1 surround system from craigslist. Which made me think of freshing up the MS25Ti. But I was a bit hesitant to open them. Around the same time, I got another craigslist deal, with scant info I went and picked up a freebie set of speakers and a stereo receiver, needing repair. The speakers are Paradigm 7se, like this photo but mine are more used. I thought I would have a go at the Paradigms, sort of a warm up for the MS25Ti. But since I'm making a parts list, I'm doing the Paradigms and Shorts at the same time. Perhaps I should start a new thread.
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The MS25Ti has a simple crossover which makes it an ideal basis for experimentation.
You may like to try the effect of replacing the bipolar electrolytics with MKP polypropylene film capacitors. This may help brighten up your muddy midrange sound.
The Paradigm 7se crossover is also simple. Post a photo of yours to see how it compares with the ones I have attached.
You may like to try the effect of replacing the bipolar electrolytics with MKP polypropylene film capacitors. This may help brighten up your muddy midrange sound.
The Paradigm 7se crossover is also simple. Post a photo of yours to see how it compares with the ones I have attached.
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Galu, right on it, as ever. I had a photo of my 7se crossover to post, here it is.
I was going to ask, I've identified the big yellow film one, and there's the chiclet gum piece down there, and the resistors. But no electrolytics that I'm obliged to replace? I don't want to pull it unless I have to, it's glued and screwed, somewhat less elegantly than the Mordaunt circuit board and gasket.
And you say that film type capacitor may open up the sound on the MS25Ti?
Ok, the 7se. They were quite larger than what had been my main speaker, the MS25Ti. I was questioning what I had got myself into. I didn't even take off the grills, I just swapped them out with the 25s. There was a scratchy noise. I looked, the glue had dried on one of the dust covers, it was bouncing in the cone. The glue on the surround was looking quite suspect, too. The other speaker was the same: the dome was still on but dry, brittle glue, and the barely adhering gooey mess under the surround.
I've only just started poking around with cones, a novelty, like opening my speaker for the first time in 34 years. At first, poking cones is like touching your eyeball, it's something one just doesn't do.
So, I was thinking of how to repair the 7se cones, researching that mysterious rubber glue that nobody but Jeff seems to sell. Well, I got tired of looking at it so I carefully scraped the dry glue residue and unceremoniously stuck the dome with some wood glue. The next day I swapped 'em out again, plugged them in. I was happily surprised, I thought they sounded quite good, gooey mess or not. Rather clear and open, they may want to be a bit more convincing or emphatic down through the mids and lows: louder. What I heard is consistent with the mixed reviews I read.
Part of why I liked the sound of the Paradigms was how they performed in my main surround system, on either side of a 55" screen. I have speaker stands for the Mordaunts, I made them all those years ago. They were too tall beside the screen, I cut new stems to lower them. Better but now too low. I'm talking about the sound here, where it seems to come from. But when I put the Paradigms on those stands, perfect! Sound was coming directly from peoples mouths, panning was smooth. Something about the two-way and the reflex port below. It just seemed to be coming from the right place. The speakers disappeared.
So now I need to tidy up the Paradigms and get the MS25s singing
I was going to ask, I've identified the big yellow film one, and there's the chiclet gum piece down there, and the resistors. But no electrolytics that I'm obliged to replace? I don't want to pull it unless I have to, it's glued and screwed, somewhat less elegantly than the Mordaunt circuit board and gasket.
And you say that film type capacitor may open up the sound on the MS25Ti?
Ok, the 7se. They were quite larger than what had been my main speaker, the MS25Ti. I was questioning what I had got myself into. I didn't even take off the grills, I just swapped them out with the 25s. There was a scratchy noise. I looked, the glue had dried on one of the dust covers, it was bouncing in the cone. The glue on the surround was looking quite suspect, too. The other speaker was the same: the dome was still on but dry, brittle glue, and the barely adhering gooey mess under the surround.
I've only just started poking around with cones, a novelty, like opening my speaker for the first time in 34 years. At first, poking cones is like touching your eyeball, it's something one just doesn't do.
So, I was thinking of how to repair the 7se cones, researching that mysterious rubber glue that nobody but Jeff seems to sell. Well, I got tired of looking at it so I carefully scraped the dry glue residue and unceremoniously stuck the dome with some wood glue. The next day I swapped 'em out again, plugged them in. I was happily surprised, I thought they sounded quite good, gooey mess or not. Rather clear and open, they may want to be a bit more convincing or emphatic down through the mids and lows: louder. What I heard is consistent with the mixed reviews I read.
Part of why I liked the sound of the Paradigms was how they performed in my main surround system, on either side of a 55" screen. I have speaker stands for the Mordaunts, I made them all those years ago. They were too tall beside the screen, I cut new stems to lower them. Better but now too low. I'm talking about the sound here, where it seems to come from. But when I put the Paradigms on those stands, perfect! Sound was coming directly from peoples mouths, panning was smooth. Something about the two-way and the reflex port below. It just seemed to be coming from the right place. The speakers disappeared.
So now I need to tidy up the Paradigms and get the MS25s singing
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The small 'chiclet' is a a film capacitor, so there are no electrolytics in your 7se crossover needing to be changed. Film capacitors do not deteriorate with age, so I would leave well enough alone.
In the case of your 25Ti, you have a choice of replacing the electrolytics with new, high quality ones or with MKP ones. The latter are likely to make the most sonic difference, but only you will be able to judge if it is a difference that you like.
By replacing the caps in one speaker and comparing it with its untouched companion, you can monitor the result of your renovation. Capacitors are not expensive, so you may want to experiment with both types. As I say, the crossover is so simple that experimentation is the order of the day, so have fun!
In the case of your 25Ti, you have a choice of replacing the electrolytics with new, high quality ones or with MKP ones. The latter are likely to make the most sonic difference, but only you will be able to judge if it is a difference that you like.
By replacing the caps in one speaker and comparing it with its untouched companion, you can monitor the result of your renovation. Capacitors are not expensive, so you may want to experiment with both types. As I say, the crossover is so simple that experimentation is the order of the day, so have fun!
Here are the MS10s doing passable duty while the larger units are on the bench.
I've started filling the online shopping cart from my nearest electronics store. Just a quick call to chat about soldering tips and I'll confirm. Woo hoo. Goodies.
Ok, from the two photos, the MS25Ti crossover, tweeter section. The coil and capacitor are reversed, I assume that makes no difference. Your capacitor is 4uF to my 3.3uF, my store has an electrolytic in the 3.3 value, I'm thinking of going with that. My store also has a 5w resistor at 3.3ohm, as in your photo, I'll try that in mine, too. Does that sound good?
Ok, the woofer part. My store doesn't have electrolytic at 7uF, I was going to have to double up. But they have the big yellow (taxi) film one at a tolerable 6.8uF. It's 160v, though, to the stock 50v unit. I've read that's it's ok to go higher, but that much? I'm bypassing the positec, some sneaky voltage isn't going to rush in and take my MS25 girl away, I hope.
The other photos. It's my new audio work station. Those Koss M85 Plusses would have been joined to my main system if not for the sweet MS10s. Once the dust has settled, the work station is where the 10s may live. The MS25 on the bench is the one that always got knocked, it's why I opened it first. I'm gonna tidy it right up, clean that duct tape residue, glue the grill frame together, maybe cut a new one.
You can see peripherally some half-broken plastic on the Paradigms: the grill badge, and one of the binding posts on the other. But for a couple small scrapes, they're in great shape. A very good freebie set for just gluing on a dome.
Last thing. I found a youtube channel, Steve coincidentally. He showcases different components with the same (quality) companion pieces, quite interesting. Among the speakers he tested the Paradigm 7se, which is how I found him. Yes, interesting
Paradigm 7se - YouTube
I've started filling the online shopping cart from my nearest electronics store. Just a quick call to chat about soldering tips and I'll confirm. Woo hoo. Goodies.
Ok, from the two photos, the MS25Ti crossover, tweeter section. The coil and capacitor are reversed, I assume that makes no difference. Your capacitor is 4uF to my 3.3uF, my store has an electrolytic in the 3.3 value, I'm thinking of going with that. My store also has a 5w resistor at 3.3ohm, as in your photo, I'll try that in mine, too. Does that sound good?
Ok, the woofer part. My store doesn't have electrolytic at 7uF, I was going to have to double up. But they have the big yellow (taxi) film one at a tolerable 6.8uF. It's 160v, though, to the stock 50v unit. I've read that's it's ok to go higher, but that much? I'm bypassing the positec, some sneaky voltage isn't going to rush in and take my MS25 girl away, I hope.
The other photos. It's my new audio work station. Those Koss M85 Plusses would have been joined to my main system if not for the sweet MS10s. Once the dust has settled, the work station is where the 10s may live. The MS25 on the bench is the one that always got knocked, it's why I opened it first. I'm gonna tidy it right up, clean that duct tape residue, glue the grill frame together, maybe cut a new one.
You can see peripherally some half-broken plastic on the Paradigms: the grill badge, and one of the binding posts on the other. But for a couple small scrapes, they're in great shape. A very good freebie set for just gluing on a dome.
Last thing. I found a youtube channel, Steve coincidentally. He showcases different components with the same (quality) companion pieces, quite interesting. Among the speakers he tested the Paradigm 7se, which is how I found him. Yes, interesting
Paradigm 7se - YouTube
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Does your store have a 3.3uF film capacitor? That would be preferable in order to match the quite acceptable 6.8uF film capacitor. If not, make sure the electrolytic one is a bipolar (non-polar) version suitable for loudspeaker crossovers. Voltage is not a problem except that the higher voltage film capacitors are physically larger, and hence more difficult to fit on an existing crossover board.
Regarding the tweeter resistor, buy the 3.3 ohm 5W, but also buy a smaller value (or two), if possible, so you can experiment to find the most suitable value for your purposes.
There's no need to bypass the Positecs if they are reading a resistance of under 1.0 ohm (remember to subtract the resistance of your multimeter leads). Any higher than 1.0 ohm and they need replaced (problematical) or bypassed (easy).
Regarding the tweeter resistor, buy the 3.3 ohm 5W, but also buy a smaller value (or two), if possible, so you can experiment to find the most suitable value for your purposes.
There's no need to bypass the Positecs if they are reading a resistance of under 1.0 ohm (remember to subtract the resistance of your multimeter leads). Any higher than 1.0 ohm and they need replaced (problematical) or bypassed (easy).
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Disregard my photo (Version 2) of the MS crossover (I suspect it actually comes from a 35Ti).
On further consideration of the component layout, I now suggest NOT adding a resistor in series with the tweeter.
Let's see how you go with the capacitor upgrades first.
P.S. Mordaunt Short claimed that the resistance of the Positecs was taken into account when designing the crossover network. So, maybe bypass them only if they've gone high resistance.
The resistance of the smaller Positec is in series with the tweeter filter by the way, but I can't predict the audible effect of adding more resistance at this position.
The resistance of the smaller Positec is in series with the tweeter filter by the way, but I can't predict the audible effect of adding more resistance at this position.
Yes, my store has the 3.3uF film cap, also at 160v. I was shying away from it because of the higher voltage rating, and it's more than 3 times the price of the electrolytics. But if I forego the electrolytics, I will avoid having the other 3 caps from the package floating around my work area, which is good. So the 3.3 film cap is a go.
Ok, editing. I just read your comment about the duelling crossovers. Ah ha! Resistance is futile. No resistors this time.
Thanks also for the tip on ohmeter leads. I may bypass bypassing the positec. I'm reading maybe .5ohms across there.
Yes, I'll do one speaker first and compare to the original. And, again, I have those sweet MS10 as a sort of reference. It was those little buggers that got me on this train in the first place.
Yes, I've noticed that the small Positec lives on the tweeter side of power. That's where our larger resistor lives in the 35 crossover. Cool
Ok, editing. I just read your comment about the duelling crossovers. Ah ha! Resistance is futile. No resistors this time.
Thanks also for the tip on ohmeter leads. I may bypass bypassing the positec. I'm reading maybe .5ohms across there.
Yes, I'll do one speaker first and compare to the original. And, again, I have those sweet MS10 as a sort of reference. It was those little buggers that got me on this train in the first place.
Yes, I've noticed that the small Positec lives on the tweeter side of power. That's where our larger resistor lives in the 35 crossover. Cool
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I think our postings crossed! 🙂
Go ahead and buy the selection of resistors you suggest - they may come in useful in future.
Go ahead and buy the selection of resistors you suggest - they may come in useful in future.
