Monitor 7C - advice on next step

3rdrockblue

I have completed the crossover mod on my 7c pair with a Claritycap 12 uf, two Jantzen cps in parallel (33uf and 1uf) for the 35 uf. To replace the polyswitch and the resistor which are in series, I uses a 2.5 Ohm Mills wire wound resistor.

The change is astounding.

• The speakers are more efficient, lower levels need from the amp.
• Imaging is excellent. Some instruments seem like they are between the speakers and my listening position.
• Mid bass is vastly improved.

On the other hand, I now understand what many say about SL2000. Even though my hearing is on the edge of the infamous resonance, the tweeters do seem brighter. For now I am EQing down at 13k to make the sound mellower. I called Polk but the RDO-194 is back-ordered. They asked me to call in a few weeks.

Meanwhile, I found out about the TL mod for use with the RDO-198. I understand how its implemented and that it needs a 5.8 uf cap in parallel with the 2 Ohm resistor. Since I replaced the 2 Ohm with a 2.5 Ohm resistor, will the mod still work, or should I not bother and be content with an RDO-194?

Thanks.

pitdogg2

Well usually we use a 1/2 ohm resistor for the polyswitch which you included in the 2.5 ohm resistor, so Adding the 5.8 cap as long as there's no inductor change in the speakers that used the sl2500 tweeter you should be fine.

3rdrockblue

Just want to be clear on this. In the TL-mod, the 5.8 uF cap goes parallel to the 2 Ohm resistor . Can I parallel it with the combined 2.5 Ohm?

Also the TL mod includes swapping the 0.23 mH inductor across the SL2000 with a 0.27 mH inductor. This inductor swap, I can do.

I am using the schematic from @westmassguy in this post for reference:
https://forum.polkaudio.com/discussion/192120/monitor-7-with-tl-upgrade

westmassguy

3rdrockblue wrote: »

Just want to be clear on this. In the TL-mod, the 5.8 uF cap goes parallel to the 2 Ohm resistor . Can I parallel it with the combined 2.5 Ohm?

You should be fine

pitdogg2

👍

Gardenstater

If you want to be sure I'd do a 0.5 ohm Mills and a 2.0 ohm Mills and parallel the 5.8uF with the 2.0 only. The properties of the contour network will be altered if it is paralleled to 2.5 ohms. If you wanted, you could try it both ways and listen for any difference.

3rdrockblue

Thanks all, for the suggestions.