I have worked on many of these over the years.
You can remove the can on the midrange by taking out the screw in the center.
If it fits your new midrange, good. If not, oh well.(if it does, glue it on and seal the hole you don't use(there's another for the wires)
The original woofers and mids were pretty good CTS units.
There were a few different crossovers over the years, some of the cabinets are just lovely(not a great fan of the grill cloth patterns/colors,though).
I have put EPI type 10" and 8" into these, the RS225 loved it(I'm thinking it's about 24l, don't recall exactly)
You can remove the can on the midrange by taking out the screw in the center.
If it fits your new midrange, good. If not, oh well.(if it does, glue it on and seal the hole you don't use(there's another for the wires)
The original woofers and mids were pretty good CTS units.
There were a few different crossovers over the years, some of the cabinets are just lovely(not a great fan of the grill cloth patterns/colors,though).
I have put EPI type 10" and 8" into these, the RS225 loved it(I'm thinking it's about 24l, don't recall exactly)
The Monacor midrange has a dcr of 3.2 ohm.
Surely any decent hi-fi amplifier won't be thrown by an impedance which, over the frequency range of the mid, is likely be comfortably in excess of that figure?
That midrange is not "alone"The Monacor midrange has a dcr of 3.2 ohm.
Surely any decent hi-fi amplifier won't be thrown by an impedance which, over the frequency range of the mid, is likely be comfortably in excess of that figure?
I am worried by parallel woofer + midrange + tweeter impedances in a simplistic "caps only" crossover.
And since it´s a small light speaker (hint: "midrange") it will not (yet) have the higher impedance a large heavy woofer would show at midrange frequencies.
As an analogy, imagine a typical woofer impedance curve, but shifted up 2 octaves (being conservative).
Woofers typically show minimum impedance between 200 and 400 Hz, I can easily imagine that poor midrange will show about 4 ohm around 800-1000 Hz .... lots of Music there.
I bet it will take a punishment.
Besides that, being 4 ohm instead of 8 means it will pull higher power from amp.
Couple that to small light voicecoil (compared to woofer) and abundance of midrange program in standard music (Drum´n Bass excluded
) and I can see a short life line in its future.And I´m not even a Gipsy
But that information pertains to entirely different drivers, not the replacements, so surely we are guessing regardless?
We have the parameters of all three replacement drivers, so couldn't the crossover design experts suggest an appropriate crossover circuit?
You know I am not one of the crossover design experts.
Old school - make it work by means fair or foul -that's me!
Depending on the amount of attention that is to be paid to a job like this, if the drivers are the same size and type, and there are no significant resonance issues then the main thing that needs to be done is to adjust the sensitivity. In other words change the resistance values in the existing crossover while maintaining its function. This is an easier option and it is quite educational IMO and is something that's achievable. Starting a new crossover is always possible, it can be harder to do, it can give as good a result as you like.
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I have no argument with that.
However, Eli has done something when replacing the capacitors that has prevented the midrange from working, and that would need to be remedied first.
We would have to refer to the original crossover photos, taken before the capacitor upgrade, in order to deduce a schematic. As I said earlier, such an endeavour would only make my old head spin!
Any takers?
P.S. Plus changing component values to suit a 4 ohm midrange when the original was 8 ohm.
However, Eli has done something when replacing the capacitors that has prevented the midrange from working, and that would need to be remedied first.
We would have to refer to the original crossover photos, taken before the capacitor upgrade, in order to deduce a schematic. As I said earlier, such an endeavour would only make my old head spin!
Any takers?
P.S. Plus changing component values to suit a 4 ohm midrange when the original was 8 ohm.
The photos are not at good angles, and it would be easier for someone who had it in their hand to identify the area hidden near the input plate, the area around T- including the ground connections, a discrepancy between the two channels near the A+ connection and to identify the switch.
True enough, I am just considering the original circuit lost
What´s left, clearly does not work
A couple sharp well illuminated pictures taken from different angles, allowing for component values reading would certainly help, but I fear we are already too late or that.
I suggested somebody experienced looking at what´s left and sort of "backtrack" on what it could have been.
Fwiw I can do that on an amplifier hand drawn schematic, can detect and correct errors and reasonably guess missing values; sadly not even close on the crossover design area but am certain many can.
There´s a "cheat" out of this , are same era Scott crossover/cabinet schematics available? For other models of course.
Or same era 3 way crossovers, including the then popular 3-level tweeter attenuator?
Designers tend to have their own "pet ideas" or their "signature" preferences and tend to repeat them, more or less, in different models, those might provide a clue.
Plan C would be to buy or clone a crossover proper for the new components, of course.
Dear all, thank you so much for taking interest into this. I did take down most of the old cross-over now, so I'm reluctant to go back to it.
So, I'd like to ask again Galu's question, as I fear it got lost in the series of answers: does it make sense now to add a 3-4 ohm series resistance to the mid? I don't want to replace this new driver that I just bought (just for the story's sake, I did notice that the mid was of 4 ohm when I bought it, I even pointed out to the store that sold me the drivers as replacement for the Scott's original ones, and they told me that it was fine).
Anyway, now I've started playing around with this VituixCAD program, here is how the current crossover looks like...what do you think?
Thanks again everybody!
So, I'd like to ask again Galu's question, as I fear it got lost in the series of answers: does it make sense now to add a 3-4 ohm series resistance to the mid? I don't want to replace this new driver that I just bought (just for the story's sake, I did notice that the mid was of 4 ohm when I bought it, I even pointed out to the store that sold me the drivers as replacement for the Scott's original ones, and they told me that it was fine).
Anyway, now I've started playing around with this VituixCAD program, here is how the current crossover looks like...what do you think?
Thanks again everybody!
I suggest you don´t take a screen picture with a cellphone but straight "capture" the screen, which is way sharper and cleaner, does not have room lighting reflections, etc.
It literally shows what´s in your screen and nothing else.
1) show on your screen what you want to post
2) press the keys [Left shift] and [Print screen] simultaneously.
That "captures" what´son screen
3) you need to have some Graphics program open, I use oldstyee IrfanView simply because it´s very simple and always works, but there are many.
Click inside its screen and paste the image you just captured, you will see it there
4) save it somewhere, easiest is on Desktop, as a .jpg You will need to give it a name.
5) now you can upload that .jpg here, in a sharp clean way:
Voila, straight from my desktop:
much better, huh?