Monitor 7 with TL Upgrade

westmassguy · September 2020

Clarity CSAs, Mills MRA12 Resistors, Hand Tuned Salvaged Bobbin Inductors, New Imported Insulating Binding Posts:

dromunds · September 2020

Sweet!

Faustin · September 2020

Purdy

Gardenstater · September 2020

Thanks for sharing. Did this go from a SL2000 to a RD098?

xschop · September 2020

Nice. It's like the caps take up the same volume as the terminal plate/pcb boards.

westmassguy · September 2020

Gardenstater wrote: »

Thanks for sharing. Did this go from a SL2000 to a RD098?

Correct

westmassguy · September 2020

xschop wrote: »

Nice. It's like the caps take up the same volume as the terminal plate/pcb boards.

You have to get creative with the limited real estate.

Gardenstater · September 2020

You saved that customer something like $70 over using Sonicaps, I think.

Gardenstater · September 2020

Dave have you ever attempted a Peerless to RD0198 mod, or would you advise the customer against that?

westmassguy · September 2020

Gardenstater wrote: »

Dave have you ever attempted a Peerless to RD0198 mod, or would you advise the customer against that?

No I haven't and I wouldn't. There's no need. The Peerless is a fine tweeter in its own right.

Gardenstater · September 2020

So, just to reassure me, even a Peerless tweeter that has been played for 40 years is still most likely just as good sounding (with appropriate XO) as a newly manufactured RD0198? In other words they don't really wear out like a MW does?

westmassguy · September 2020

Gardenstater wrote: »

So, just to reassure me, even a Peerless tweeter that has been played for 40 years is still most likely just as good sounding (with appropriate XO) as a newly manufactured RD0198? In other words they don't really wear out like a MW does?

I've rebuilt dozens of Peerless Crossovers for happy customers. Let your own ears decide.

Gardenstater · September 2020

I have myself as a happy customer on my 7B crossover rebuild (with Danish Peerless) but unfortunately I have no way to compare. I guess I'd have to get a 7C and do the mod you did and then A/B the two pairs of speakers.

dromunds · September 2020

What has to be altered in the crossover to go with the RD-0198?

westmassguy · September 2020

dromunds wrote: »

What has to be altered in the crossover to go with the RD-0198?

Same as the Monitor 5 SL3000 Modification:
5.8uf shunt capacitor across the 2 ohm resistor, and replace the .23mH inductor with a .27mH @ .5 ohms
Change the .110 quick connect on the tweeter negative lead to .205

xschop · September 2020

So the only difference between a 5B and 7B is the cabinet volume and passive?

Gardenstater · September 2020

xschop wrote: »

So the only difference between a 5B and 7B is the cabinet volume and passive?

Well not exactly. That XO above is the similar to my 7B's with Danish Peerless and MW6500s, except I have a 1A fast blow fuse instead of the polyswitch and the tweeter resistor is 4.5 Ohms and there is also a 2.7 Ohm resistor in series with the .23mH inductor and in parallel with the tweeter. Close to this except 4.5 Ohm instead of 4.7 Ohm. The fuse only has 190mOhm resistance as opposed to 500mOhm (?) for the polyswitch.

I believe the 5B and 7C XO'ers may be the same because they both had the SL2000 and MW6502?

westmassguy · September 2020

xschop wrote: »

So the only difference between a 5B and 7B is the cabinet volume and passive?

Correct. The larger cabinet and tuned passive give the 7 deeper bass, but everything else is essentially the same.

westmassguy · September 2020

Gardenstater wrote: »

xschop wrote: »

So the only difference between a 5B and 7B is the cabinet volume and passive?

Well not exactly. That XO above is the similar to my 7B's with Danish Peerless and MW6500s, except I have a 1A fast blow fuse instead of the polyswitch and the tweeter resistor is 4.5 Ohms and there is also a 2.7 Ohm resistor in series with the .23mH inductor and in parallel with the tweeter. Close to this except 4.5 Ohm instead of 4.7 Ohm. The fuse only has 190mOhm resistance as opposed to 500mOhm (?) for the polyswitch.

Your 7 is a different generation/revision. The 5 from that generation (time period) also had the 8 ohm MW6500, and Peerless. Different animals.

Gardenstater · September 2020

Yes I edited my post to say that I believe 5B and 7C were comparable XO'ers, apparently. I get that the PR's were different sizes and tunings. I am ASSuming that the Model 5 and 7A and 7B had identical or nearly identical XO'ers as long as they had the Peerless and MW6500, which are 8 Ohms. The 5B and 7C have the SL2000 and MW6502, which is 6 Ohms.

Correction: MW6502 is 4 Ohms.

westmassguy · September 2020

The MW6502 is 4 ohm.

Gardenstater · September 2020

Thanks. I corrected it. I guess I was remembering that the 7C with the SL2000 and MW6502 was 6 Ohms. SL2000 appears to be around 8 Ohms avg. impedance.

https://us.v-cdn.net/5021930/uploads/editor/0r/k60tgrjai18r.jpg

Thiele Small Parameters of misc. MW's:

https://forum.polkaudio.com/discussion/133992/thiele-small-parameters-for-mw6500-drivers

xschop · September 2020

Last question, is the Passive radiator found in 7B the same as CRS+?

westmassguy · September 2020

xschop wrote: »

Last question, is the Passive radiator found in 7B the same as CRS+?

No idea. There were two different passives used for the CRS/CRS+ depending on the generation. The 2nd generation used the SW102, the 3rd generation used an SW100, and the 4th generation used the SW102.

todmarsden · September 2020

Hey! Those are mine! I finished assembling them last night and now in the burn-in process. They sound great to far. Thanks for the top notch work David! I'll get back on this thread once I've hit 100-200 hrs.

westmassguy · September 2020

todmarsden wrote: »

Hey! Those are mine! I finished assembling them last night and now in the burn-in process. They sound great to far. Thanks for the top notch work David! I'll get back on this thread once I've hit 100-200 hrs.

My pleasure

skrol · September 2020

I have a pair of 5B that I'd like to do the SL3000 conversion.

In the schematics, I see the 5B original, 5B Rev with SL2000 and the 5B SL3000 (though the schematic says SL-2000. Those are shown in the previous posts. The one lacking is the Monitor 5 Series 2 (last version used SL2500). I'm wondering how the 5 series 2 differs from the others. One difference would be the elimination of the polyswitch. It is likely similar to the Monitor 7 series 2.

westmassguy · September 2020

skrol wrote: »

I have a pair of 5B that I'd like to do the SL3000 conversion.

In the schematics, I see the 5B original, 5B Rev with SL2000 and the 5B SL3000 (though the schematic says SL-2000. Those are shown in the previous posts. The one lacking is the Monitor 5 Series 2 (last version used SL2500). I'm wondering how the 5 series 2 differs from the others. One difference would be the elimination of the polyswitch. It is likely similar to the Monitor 7 series 2.

I've yet to see the Mon 5 rev2 crossovers. On the 7s and 10s the crossover point was changed, so the capacitor and inductor values differ quite a bit. The Mon 5 SL3000 mod was a way to shoehorn the trilaminate into the older design with as few changes as possible.

Monitor 7 with TL Upgrade

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