Down & Dirty 800v/a Dreadnaught

MrBuhl

Picked up a used and slightly abused (in shipping and not to me, previous incident to be clear) "Larry case" from @GlennDog & ordered the correct Avel/Lindberg toroid quite a while back. Finally got around to construction about two weeks ago.

Once again, I copied @westmassguy's excellent and very fine design for mounting, (at least in the very Joe homeowner way I'm capable of) and I was off to the races. This one doesn't make use of the copper foil of Dave's full-on designs because it already was coated with Dynamat when I received it. Also, it was drilled for RCA's and not Speak-On's on the box.





The incredibly helpful and resourceful @helipilotdoug hooked me up with Canare 4s11 for SDA cable, Speak-On connections for the 2b speaker cups, some very nice gold coated copper RCA binding posts at the Dreadnaught end, and some copper Furez spades to make up new Canare speaker wires as well.





While I was at it, I installed the "Larry Rings" I've been sitting on since the last run were produced, BH5 behind the woofs, sealed the magnets and cabinets with LocTite Powergrab, Dynamated the baskets, and upgraded the binding posts in the cups when I added the Speak-On connections. I also removed the false bases. The only thing left is to upgrade the crossovers on the 2b's now!






1.rackcdn.com/polkaudio.vanillaforums.com/editor/9w/gy4iu1b63yig.jpg

Burn in has begun, but man they still sound so sweet on the new Dodd with the Treasures!

agfrost

Cool!

How'd you decide to cut/install the BlackHole 5? One of a couple things I'm dragging my feet on for my 2BTLs.

westmassguy

Looking good Ed

MrBuhl

Thanks Dave - the crossovers next I think! It's a two-piece though - is that what you'd expect? I don't think I'd had them apart yet when we discussed them.

MrBuhl

agfrost wrote: »

Cool!

How'd you decide to cut/install the BlackHole 5? One of a couple things I'm dragging my feet on for my 2BTLs.

Thanks! I followed the recommended for my 1c's honestly, I just assumed it would be the same. Size was somewhat dictated by the BH5 I had on hand as well.

I cut out rectangles that fit between the brace and sidewalls to go just behind the mid-woofers as you would with the bigger brothers. Hope I was correct - they sound great anyway!

westmassguy

MrBuhl wrote: »

Thanks Dave - the crossovers next I think! It's a two-piece though - is that what you'd expect? I don't think I'd had them apart yet when we discussed them.

Split/two piece? Doesn't sound right Ed. Can you send me a photo of the crossovers?

MrBuhl

I thought that seemed wonky Dave!

westmassguy

Ed, those are 2A crossovers, not 2bs. The Dreadnaught should not be used with them.
It will not allow you to use a non-common ground amp.

MrBuhl

BTW I assigned +1 to blue/black and -1 to white on the sda cable connections, nothing blew up so I assume I got it right! (based on same +1 / -1 at the Speak-On i used on the 1cs.)

MrBuhl

Crap! So all this time they've been 2a's and not 2b's! I don't suppose it's possible to switch them to a 2b crossover if I purchased a pair?

Would also maybe explain the Dodd 50w popping the occasional fuse I imagine?

westmassguy

MrBuhl wrote: »

Crap! So all this time they've been 2a's and not 2b's! I don't suppose it's possible to switch them to a 2b crossover if I purchased a pair?

Would also maybe explain the Dodd 50w popping the occasional fuse I imagine?

You can convert them to 2Bs, with a new crossover, and 2 new MW6511 woofers.
Do not use that amp with them.

heiney9

What was so special about the Avel Lindberg for this application? Parts Connexion has Pilitron's on sale @ 60% off.

I wonder if they have a comparable unit to the 800VA A/L?

http://partsconnexion.com/plitron_transformer.html

MrBuhl

My understanding is selection is based on specs provided to @DarqueKnight from MP hisself, that this was the preferred choice. So that's what I went with!

http://forum.polkaudio.com/discussion/74472/the-ai-1-dreadnought-project-pt-1/p1

Other than being a sheep and following what I was told, I honestly can't say why the Avel 800 is the right one for this application LOL!

heiney9

I can look through the lengthy archives I suppose. Thought maybe someone could give a quick answer.

They have a 2000VA Pilitron, but I can't remember what specs are important.

H9

MrBuhl

It's on page 1 if you want to look, right under Fig 8.1 picture.

drumminman

Somone a while back sent DarqueKnight a plitron which he compared to the A-L in listening tests. He thought the A-L sounded better. This is all from memory - perhaps he'll chime in.

heiney9

MrBuhl wrote: »

It's on page 1 if you want to look, right under Fig 8.1 picture.

Yes, that's helpful. The spec sheet for Pilitron doesn't have any of that info.

I was just looking at saving a buck. 60% off is a decent discount, but if nothing fits the spec then I'll move on.

H9

heiney9

I should have just pulled the trigger on Mr. Buhl's.....lol.

Actually, I had one at one time (just the transformer) and sold it because it was sitting in a drawer not being used. I think that was before many decided even with a common ground amp the isolation transformer sounded better.

H9

DarqueKnight

drumminman wrote: »

Somone a while back sent DarqueKnight a plitron which he compared to the A-L in listening tests. He thought the A-L sounded better. This is all from memory - perhaps he'll chime in.

Here is the thread:

http://forum.polkaudio.com/discussion/131537/plitron-1000va-transformer-evaluation