SRS 1.2 plus Dreadnaught Project

westmassguy

This was a little more demanding than a typical recap. Sonicap and Mills were chosen for the Crossover. All Inductors were retained. All the original wire ties were replaced, since everyone of them was loose. Resistors were relocated to the bottom of the circuit board to create more real estate on the top side. Sonicraft came through as usual, with the exact values I needed for the Caps, and Mills Resistors. Clarity doesn't make a 5.8uf or a 4.4uf. I would have had to settle for a 5.6uf, and two 2.2ufs to make up the other Caps. The Polyswitches were replaced with three 1.5 ohm Mills MRA-12s wired in parallel. All Caps were secured using 3M VHB Tape, Nylon Wire Ties, and brush-on cyanoacrylate for the stacked Caps. The 40uf was made up from two 20uf caps in an over under configuration, with double belly-band wire ties. The circuit trace was extended out from the board, and both ends soldered. The large spool Inductors were kept only as mounts for the Crossovers. New, low resistance, Erse SuperQ, 16 gauge Laminated Steel Inductors were hand tuned to the required 16.8mh value. The Resistance for the existing Spool Inductor was 2.6 ohms, while the Erse measured .5 ohms after unwinding. The deep bass for these puppies will increase dramatically. The Binding Post Cups were reworked. New, Imported, Heavy Duty, Gold Plated Copper Posts were installed, and the Pin/Blade connectors replaced with SpeakONs. Clear acrylic sealant was used on the back. As a side note, someone had swapped the original red and black nuts. They must have assumed these were the original SRSs, which did have the poles reversed.

westmassguy

The Dreadnaught was a bit of a challenge. I want to thank Jesse for putting up with my PITA PMs, and DarqueKnight for his work, and lengthy, informative thread on the Dreadnaught. Since I had a budget, I wanted to use an off-the-shelf enclosure. The custom enclosures I've seen are beautiful, but come at a price. After some digging, I was able to find an enclosure from one of my regular suppliers, Digikey. It's 10" X 10" X 4" approximate, cast aluminum, and available unfinished, or with a factory applied, black textured finish. I chose the black. When I received it, the fit and finish were exceptional, and very professional looking. The casting is about 3/16" thick, which should provide excellent RF Shielding. I wanted to take it a bit further, and decided to add Copper Foil for additional EMI Shielding. To prevent any galvanic activity in the future, the interior was given two coats of aluminum primer, followed by two top coats. To reduce resonance, Dynamat Extreme was applied everywhere possible. The 800va Avel Toroid was ordered and received the next day. They're 100 miles from me. I wasn't happy with steel the hold-down hardware supplied with the Toroid.
The method I chose for mounting the Transformer was rather simple. I cut a 6" round disk from some leftover 1/2" MDF. Eight concentric holes were drilled, for use with heavy nylon wire ties. I used one of the supplied sponge gaskets that came with the transformer, underneath. I was well aware of the warning regarding over-tightening mounting hardware. All the wire ties were cinched snug, but not too tight. A 1/4-20 SS Flat Head Machine Screw, painted flat black was used to mount the assembly. The mounting hole was drilled and countersunk in the enclosure, and is flush with the back. The 1/2" MDF has two advantages. Since the enclosure will be used in the vertical position, the MDF brought the transformer out, and closer to the center of gravity, which will make it more stable, and MDF is of course non-metallic. Black Chrome SpeakONs were chosen for the connectors. Since this will be used with Hardwood Floors, heavy duty, through-hole rubber feet were installed. The casting procedure for the enclosure results in a slight taper on the 4" side or bottom. To make the assembly sit upright and plumb, small fender washers were installed under the rear rubber feet. The Dreadnaught ended up surprisingly stable and balanced in the upright position, due to shimming the rear feet, and how the Toroid was internally mounted. For additional protection from slippage, I added ridged foam blocks at the top, bottom and sides of the transformer, and another block on top of the transformer which is compressed once the cover is installed. All in all, I'm very pleased with the end result.

zane77

Nice job, I used epoxy and micro balloon filler to fill the center hole of the toroid and drilled a through hole and used a brass bolt to mount it to the case. Holds it very firmly in place.

westmassguy

zane77 wrote: »

Nice job, I used epoxy and micro balloon filler to fill the center hole of the toroid and drilled a through hole and used a brass bolt to mount it to the case. Holds it very firmly in place.

Thanks. I saw your method and it looked good. I think there's a plethora of mounting methods that will hold it securely, and not damage the windings.

ZLTFUL

Aside from the copper foil, your Dreadnaught looks eerily similar to mine. :cheesygrin:

Same enclosure and everything.
Where did you get your hands on the copper foil because now I want to do the same. I was planning on horizontal instead of vertical though as I will have a shelf set aside for the Dreadnaught...

Good looking project!

westmassguy

ZLTFUL wrote: »

Aside from the copper foil, your Dreadnaught looks eerily similar to mine. :cheesygrin:

Same enclosure and everything.
Where did you get your hands on the copper foil because now I want to do the same. I was planning on horizontal instead of vertical though as I will have a shelf set aside for the Dreadnaught...

Good looking project!

Thanks ZLTFUL. The Copper Foil I get off eBay. I use a ton of it for other projects. It's normally advertised as shielding for Guitar pick-ups. I use the 2" wide roll. It's also available in sheets, but the 2" is hard enough to work with, can't imagine the difficulty smoothing out a 10" x 10" piece of it. Jesse advised me that vertical mounting resulted in better SQ, plus it will be tucked away behind a cabinet. You must apply a barrier between the copper and aluminum, otherwise corrosion will follow eventually.

ZLTFUL

Gotcha. Thanks for that. Jesse never shares that kind of good information with ME. :cheesygrin:

westmassguy

You have to tickle his cockles

pitdogg2

westmassguy wrote: »

You have to tickle his cockles

Kinky:eek:

westmassguy

Nah it refers to the chambers of the heart, get your mind out of the gutter Pit

Moose68Bash

Great job, and thank you for such thorough documentation of the project.

It is always fun to see how these projects take on new refinements as time progresses!

westmassguy

Thanks Moose

Toolfan66

Are these 1.2's or 1.2tl's? if 1.2's why not the TL mod? Also using gimpods boards would have given you more real estate..

Looks great non the less, and I know you had fun doing it, I loved doing mine..

westmassguy

Thanks Toolfan. They're 1.2s, and I had budget to work with, which did not include new boards, and several new inductors.

F1nut

Nice work, Dave. The enclosure looks great. Is the copper glued in place?

westmassguy

F1nut wrote: »

Nice work, Dave. The enclosure looks great. Is the copper glued in place?

Thanks Jesse. It comes in a roll, and is self adhesive.

Mike Reeter

Nice work as usual Dave, I need to get my hands on a Dreadnaught one of these days.

westmassguy

Thanks Mike. Shoot me an email, and we can work something out

deafbykhorns

Toolfan66 wrote: »

Are these 1.2's or 1.2tl's? if 1.2's why not the TL mod? Also using gimpods boards would have given you more real estate..

Looks great non the less, and I know you had fun doing it, I loved doing mine..

I was thinking the same thing, the schematics dont differ all that much.
I would be curious if the upgrade is worth the effort, if your already changing parts it seems like a no brainer

westmassguy

deafbykhorns wrote: »

I was thinking the same thing, the schematics dont differ all that much.
I would be curious if the upgrade is worth the effort, if your already changing parts it seems like a no brainer

No they don't, but the price would have, and as I've already said, it wasn't in the budget. The owner had already purchased the RDO-194-1s as well

Toolfan66

Yeah, I can see where the tweeters kill it, the inductors are not that expensive.

Maybe some time down the road you can sell the 194's put that toward the 198's..

headrott

Both projects look great. Thanks for sharing the projects.

westmassguy

Thanks headrott

deafbykhorns

From what some are telling me, the tweeter replacement seems like the most dramatic change.
I'm sure next tax infusion might bring on some future upgrades...