[Marantz Imperial 6 sound and crossovers]

Hi Dean,

You replaced the original tweeters bij New Large  Advent tweeters. 

Can you give me the type and specifications. You said no coil, only 7uF capacitor, if I understatement it well. And what about the resistors in the tweeter circuit?

Regards, Libertus 

 

[Marantz Imperial 6 sound and crossovers]

15 hours ago, Dchristie said:

Libertus, in the model 5, the woofer has a natural acoustic rolloff at 2000 hz( no additional crossover components are needed) . The woofer rolls off by itself at the crossover point and is wired directly to the amp. The tweeter crossover is very similar to the model 6.   A 1.0 mh mh coil is shunted across the positive (+) and ground (-) inputs and a 4.0 uf cap is in series with the positive input which provides a 2nd order cutoff for the tweeter at all times. There is also a 10 ohm, 5 watt resistor shunted across the tweeter terminals. These components are always active in the crossover circuit. A 3 ohm, 5 watt resistor in series with the positive input and A 10 ohm, 5 watt resistor shunted across the + and - inputs of the tweeter,  are switch operated to provide an increase and decrease in the tweeter output, respectively. 

Thank you,

It is as you described. I noticed only the coil is 0,6mH in both Marantz 5 (without Imperial) woofer with paper cones and rubber. Tweeter the same model as in  the Marantz 6, only smaller and smaller magnet.

I measered all component from Marantz 6 Imperial also, in one I replaced the resistors (1%,10W) and Capacitor 7uF. I did not hear any differance with the one not modified. So I replace the original components back again.

When you have heared a Marantz 6, the Marantz 5 is disapointing. But overall I like more the AR3a.

Thank you for all information,

Libertus 

 

 

[Marantz Imperial 6 sound and crossovers]

On 1/31/2023 at 7:53 PM, Dchristie said:

Could possibly have different versions of the Marantz Imperial 6 speaker. But the version I am familiar with here in the USA is as described in the above forum discussion. The schematic from the Marantz 6 service manual is attached for your information.

 

Imperial6_crossover_schematic.pdf 559.64 kB · 7 downloads

Hi, I managed to open your pdf. I noticed 1 speaker is as in the pdf diagram, in the other one, the wires are wrong. So I re-wired them.

Do you have also a pdf diagram from Marantz 5 model. I checked the wires and noticed the woofer has no crossover frequentie and is directly connected to the input terminals. 

Regards, Libertus 

[Marantz Imperial 6 sound and crossovers]

Thanks, I had to download a pdf app

 

[Marantz Imperial 6 sound and crossovers]

I can not open the Imperial  6 schematic.pdf. Can you post this attachment again.

 

[Marantz Imperial 6 sound and crossovers]

Hi thanks,

According crossover board Marantz Imperial 6 I have (seriële nr's 27807 and 27819) the woofer is in serie with a 4 ohm resistor, this resistor is in parallel with coil 1.0mH.

If the switch is in normal position, 7uF is in serie with 3 ohm resistor and tweeter. The tweeter is in parallel with 8ohm resistor. 

The 0.6mH coil is only used in the decrease position in parallel wit a 6 ohm resistor 

Regards, from the Netherlands

PS: I have also a Marantz 5

Very strange the woofer is not connected to the 1.0mH coil, but direct at the plus and minus connectors.

[Marantz Imperial 6 sound and crossovers]

On 12/17/2012 at 7:07 PM, Dchristie said:

Hi, I just finished upgrading a pair of Marantz Imperial 6 speakers. The original Imperial 6 as well as the later 6B and 6G models all used the same crossover which was essentially a 1st order 1.0 mH inductor with a 4 ohm resistor bipass shunt on the coil for the 10 inch bass/mid driver and 2nd order

(7.0 uf cap in series and a 0.6 mH inductor shunt) plus a 3 ohm resistor in series for the phenolic tweeter which also has an 8 ohm resistor shunt across it's + and - terminals. The crossover also had additional resistors via the 3 position switch to add or decrease resistance to the L-Pad to adjust the level of the tweeter. I personally did not need the felxibility of the L-pad so I left the additional resistors out of the circuit when I rebuilt the crossover. I also added another set of binding posts on the back of the speaker to allow bi-amping.

As to your question, yes the "cardboard" cap in the clasp is the 7.0 uf cap. The easiest fix would be to just purchase any high quality metallized polypropylene cap ( a 6.8 uf is OK since a 7.0 may be hard to find) . (You can also combine several values in paralel as the values add up if you want to get more precise) but Parts Express has Dayton Audio Precision 1% metallized caps which sound very good and are not very expensive ( around $10 for two 7.0 uf caps). This would be the most simple update you can do for the speakers and you could most likely use the original clasp on the crossover board to hold the new cap ( depending on the size of the new cap).

Now if you really want ot hear your speakers at their best, then I would suggest an all- out update and replace the caps, resistors, and even inductors and also the wire. The Imperial was a very good ( and also underated) speaker for its time and can sound incredibly good. I also replaced the phenolic tweeter with a New Large Advent tweeter as the phenolic ( while good for the cost) just did not measure up to the better tweeters. The 7.0 uf cap worked just fine with the Advent tweeter with no L- pad. I also bi-amped the speakers with 2 Marantz 170 DC amps and this allowed me to adjust the woofer with the tweeter levels which is essential. Running out of space but feel free to call me at 509-443-7196 if you want to visit about any of this.

Dean

Hi, according the imperial 6 I have, is the coil over the tweeter only active in switch position decrease. Plus the 6ohm resistor parallel to this coil.