Monitor 7 "TL" Project

westmassguy

This was a fun project. Started with nice, clean, late model, Monitor 7 crossovers. The 5B SL3000 schematic was used as a reference. All caps, resistors, and Hi-Pass inductors were removed. Sonicaps and Mills MRA-12s were used throughout. As usual, a 5.8uf shunt cap was installed, and the Polyswitch was replaced with a .5 ohm Mills Resistor. The existing .22mh Hi-Pass shunt Inductor had to be changed to a .27mh @ .5 ohms. A 22 gauge would have been close, but that gauge is not a stock item from my regular suppliers. A .3mh, 20 gauge Jantzen was chosen. The Inductor was unwound to .27mh, and a .2 ohm resistor added in series to equal the required .5 ohm DCR for the shunt. All resistors were mounted to the underside of the circuit board to keep the top side clean, and provide room for the new shunt cap. New standoffs, and new riser boards for the large Lo-Pass shunt Caps were installed. Cardas Binding Posts topped off the project. Lastly, some wire management was done, and the Tweeter's ground leads had 3/16" female spade/quick-connects installed for the new RDO-198-1 Tweeters.

zane77

Nice work, very clean, all the work you post looks great!

westmassguy

Thank

gmjungbluth

Very Cool!!! I'm looking forward to your evaluation of how they sound once everything is put back together. I see you're putting in new tweeters -are you thinking about rings or anything else?

G

Faustin

Very nice Dave. Will the cabinets get some new veneer??

westmassguy

gmjungbluth wrote: »

Very Cool!!! I'm looking forward to your evaluation of how they sound once everything is put back together. I see you're putting in new tweeters -are you thinking about rings or anything else?

G

The person I did them for is giving them the full treatment, Hurricane Nuts and Machine Screws, Dynamat Extreme, Blackhole 5, and the RDO-198-1s.

westmassguy

Faustin wrote: »

Very nice Dave. Will the cabinets get some new veneer??

Thanks Bruce. Cabinet work is up to the owner.

xjghost

IDK what all that means but it looks nice.

BKphoto

as always, nice work...

westmassguy

xjghost wrote: »

IDK what all that means but it looks nice.

Thanks. Get your learn on and you'll know what it all means

westmassguy

BKphoto wrote: »

as always, nice work...

Thanks BK

westmassguy

nbrowser wrote: »

Very nice work, and here I thought I was on the sauce for wanting to do my little 5's...no TL mod mind you but upgrade the stuff inside...must make for a decent upgrade in the sound quality department.

Thanks nbrowser. The 7s are great to start with. The upgrades make what was good, better, by a wide margin.

mhardy6647

This is a serious question :-P

Does adding the additional volume (i.e., the huge caps and additional layer of stuff, if I am interpreting the photos correctly) to the XOs have any substantial (audible) impact on the enclosure volume (i.e., more to the point, tuning)?

westmassguy

mhardy6647 wrote: »

This is a serious question :-P

Does adding the additional volume (i.e., the huge caps and additional layer of stuff, if I am interpreting the photos correctly) to the XOs have any substantial (audible) impact on the enclosure volume (i.e., more to the point, tuning)?

The internal volume of the 7C is 2,285 cubic inches. The new larger caps are about 5 cubic inches total. Blackhole 5 is 1.375" thick, but only displaces .25" according to the manufacturer. A 4" X 12" X 1.375" section will displace 12 cubic inches. 5" for the cap, plus 12" for the Blackhole 5, equals 17 cubic inches displaced. 2,285 less 17 is 2,268. That's equivalent to a reduction of internal volume of .0077%.

mhardy6647

Thanks - just wondering how much that impacts the calculated resonant frequency and other parameters of the cabinet -- presumably not much, but then again, most aren't linearly related to volume (as I recall).

westmassguy

I would imagine that a .0077% decrease in the internal volume would be negligible. The smaller Monitor 4s and 5jrs could possible be affected, but they usually have less components in their crossovers anyway, so it's probably a wash there too.

westmassguy

Thanks

biernutz1

Just like to say David does fantastic work and the Monitor 7's sound better than new, any one out there thinking of upgrading there crossovers I would highly recommend David. I will be upgrading the crossovers in my SDA SRS 1.2TL in the near future and David will be contracted for that build also.

westmassguy

biernutz1 wrote: »

Just like to say David does fantastic work and the Monitor 7's sound better than new, any one out there thinking of upgrading there crossovers I would highly recommend David. I will be upgrading the crossovers in my SDA SRS 1.2TL in the near future and David will be contracted for that build also.

Thank You Sir.