Monitor 7 Mods / RDO-198 Question.
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Toolfan66
Posts: 16,945
Looking at the schematics for Monitor 7’s with the SL2500 I have a couple questions.
One there is no polyswitch shown in the schematics so is it necessary to still incorporate the .5 ohm resistor?
Two what about the 5.8 shunt cap to use the RDO-198, should that still be used?
I had or misplaced some notes I kept from posts that westmasguy had posted but I can not find them, as I knew I would be doing this someday..
Thanks..
One there is no polyswitch shown in the schematics so is it necessary to still incorporate the .5 ohm resistor?
Two what about the 5.8 shunt cap to use the RDO-198, should that still be used?
I had or misplaced some notes I kept from posts that westmasguy had posted but I can not find them, as I knew I would be doing this someday..
Thanks..
Comments
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I think the 7C has the same crossover and active drivers as the 5B, so the TL mod for the 5B works. This is westmassguy's thread:
https://forum.polkaudio.com/discussion/192120/monitor-7-with-tl-upgradeGeorge / NJ
Polk 7B main speakers, std. mods+ (1979, orig owner)
Martin Logan Dynamo sub w/6ft 14awg Power Cord
Crown D150 amp
Logitech Squeezebox Touch Streamer w/EDO applet
iFi nano iDSD DAC
iPurifier3
iDefender w/ iPower PS
Custom Steve Wilson 1m UPOCC Interconnect
iFi Mercury 0.5m OFHC continuous cast copper USB cable
Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
Custom Vibration Isolation Speaker Stands and Sub Platform -
Looking at the schematics for Monitor 7’s with the SL2500 I have a couple questions.
One there is no polyswitch shown in the schematics so is it necessary to still incorporate the .5 ohm resistor?
Two what about the 5.8 shunt cap to use the RDO-198, should that still be used?
I had or misplaced some notes I kept from posts that westmasguy had posted but I can not find them, as I knew I would be doing this someday..
Thanks..
The RD0198 is supposed to drop in to replace the SL2500 so personally I wouldn't do any modifications to the crossovers as it's already 'TL modded'. No need for an extra cap or resistor.
Definitely rebuild them with some better quality parts though -
Larry,
If your monitor 7's came with the SL2500 I would follow the "schematic_m7s_rev2.pdf"
If they did not I would follow the "schematic_m5b_sl3000mod.pdf" and the link George provided. -
Gardenstater wrote: »I think the 7C has the same crossover and active drivers as the 5B, so the TL mod for the 5B works. This is westmassguy's thread:
https://forum.polkaudio.com/discussion/192120/monitor-7-with-tl-upgrade
Perfect, thank you!! There was another post he did as well I had, but this helps.. -
Larry,
If your monitor 7's came with the SL2500 I would follow the "schematic_m7s_rev2.pdf"
If I use this schematic, I pretty much have everything here, it won't cost me much for the project.
And they are all Sonicaps. But my question is still, do I use the 5.8 shunt cap? (and I do have 2 here) I am surprised there is no fuse block or polyswitch in the schematic for this model.If they did not I would follow the "schematic_m5b_sl3000mod.pdf" and the link George provided.
If I do this, and use Sonicaps the 34uf alone is a little over $100.00ea.
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Larry,
If your monitor 7's came with the SL2500 I would follow the "schematic_m7s_rev2.pdf"
If I use this schematic, I pretty much have everything here, it won't cost me much for the project.
And they are all Sonicaps. But my question is still, do I use the 5.8 shunt cap? (and I do have 2 here) I am surprised there is no fuse block or polyswitch in the schematic for this model.
The 5.8 is a contouring cap from my understanding. I'm also thinking they took care of that with the 8uf over the resistor and subtle changes in the series 2 schematic.
It doesn't appear there is any need for the 5.8uf cap in the series 2 schematic. The last SDA 3.1 they didn't use a polyswitch in that model either. So at some point Polk was not using fuses or polyswitches in the XO designs.
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Larry,
If your monitor 7's came with the SL2500 I would follow the "schematic_m7s_rev2.pdf"
If I use this schematic, I pretty much have everything here, it won't cost me much for the project.
And they are all Sonicaps. But my question is still, do I use the 5.8 shunt cap? (and I do have 2 here) I am surprised there is no fuse block or polyswitch in the schematic for this model.
The 5.8 is a contouring cap from my understanding. I'm also thinking they took care of that with the 8uf over the resistor and subtle changes in the series 2 schematic.
It doesn't appear there is any need for the 5.8uf cap in the series 2 schematic. The last SDA 3.1 they didn't use a polyswitch in that model either. So at some point Polk was not using fuses or polyswitches in the XO designs.
My thoughts exactly on the 8uf.
I am just going to build with that schematic, as I have the following in my closet, it only makes sense, and I am actually just doing this for fun..
2 12uf Sonicap
2 27uf Sonicap
2 2.7ohm Mills resistors
2 RDO98 Tweeters
2 Sets of Cardas Binding Posts
Plenty of Super Rondo internal wiring
BH5
Rings
Robs Tweeter Billet Face Plates
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Larry,
If your monitor 7's came with the SL2500 I would follow the "schematic_m7s_rev2.pdf"
If they did not I would follow the "schematic_m5b_sl3000mod.pdf" and the link George provided.
^^^^This^^^^Home Theater/2 Channel:
Front: SDA-2ATL forum.polkaudio.com/discussion/143984/my-2as-finally-finished-almost/p1
Center: Custom Built forum.polkaudio.com/discussion/150760/my-center-channel-project/p1
Surrounds & Rears: Custom Built forum.polkaudio.com/discussion/151647/my-surround-project/p1
Sonicaps, Mills, RDO-194s-198s, Dynamat, Hurricane Nuts, Blackhole5
Pioneer Elite VSX-72TXV, Carver PM-600, SVS PB2-Plus Subwoofer
dhsspeakerservice.com/ -
So it looks like the later monitor 7’s the cabinets are a little different with the grill pegs being on the grills themselves, the binding post cup is lower as well.
So is the grill still made of MDF or plastic I wonder..
