CurtPalme.com Home Theater Forum

apple156 · Joined: 02 Oct 2006 Posts: 8 Location: The Netherlands

Ile · Posted: Tue Feb 06, 2007 3:02 pm Post subject:

apple156 · Joined: 02 Oct 2006 Posts: 8 Location: The Netherlands

That is a cool looking hushbox, did you made it yourself?

**kal** · Posted: Tue Feb 06, 2007 4:53 pm Post subject:

Ile · Posted: Tue Feb 06, 2007 5:30 pm Post subject:

Person99 · Joined: 09 Mar 2006 Posts: 4899 Location: Flower Mound, TX

I've actually been giving some thought to Ile's hushbox (the best looking one I've ever seen and the only one that works well in a dropped PJ set up). Ile used to have the hushbox open at the top. What if we just put a plate with side skirts on the back of the PJ that angled up at 33-45 degrees. Put some sound insulation in it. So basically, you have essentially the back of ile's hushbox attached to the back of the stock 808 case.

I may try some experiments to see how much that lowers the noise.

Dave

Alaric · Posted: Wed Feb 07, 2007 3:29 pm Post subject:

Hi Guys,

Watching this thread and reading some of the links (avs) there seems so merit to swapping the NMB fans out when they get older and seeing that my BG808s has quite a few hrs on the chasis, i started searching.

I came across an ebay add :

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&sspagename=ADME%3AL%3ARTQ%3AUK%3A1&viewitem=&item=130076999667&rd=1

Which is for the faster model, however the PDF's have some useful data.

and so I asked about the B30's and here is the response :

---

Only B10 B30 B50 are in production in E00 (Reference). Reference is fully sealed, closed, shielded. Similarly B10 B30 are only in production in V00 (Valueline). Valueline has "balls whizzing" as open ball, unshielded.

What I can suggest is use the B50 fan with a simple fan controller, then reduce the speed to about 9-9.5V.

The B50 at 7V is almost exactly a B10.
So a B50 at 9-9.5V would be a good equivalent of a B30.

Usefully you could vary it either-side-of-that so achieving exactly the airflow & noise you require.
---

What do you recon ???

I guess you'd have to put some form of extra resistor in thier to bring down the speed to the B30 spec, then it should perform better having better & quieter bearings ???

Cya,
Lee

Ile · Posted: Wed Feb 07, 2007 4:58 pm Post subject:

picree · Joined: 31 Mar 2006 Posts: 351 Location: Johnson City, TN

Person99 · Joined: 09 Mar 2006 Posts: 4899 Location: Flower Mound, TX

WTS · Joined: 08 Mar 2006 Posts: 1276 Location: Calgary

I pretty much did the same thing on the back of my 1200x and it does deflect the sound away. I sit right under it too and I do notice a difference.

Also I put furniture stuffing material(it's sort like rock wool) in the lid and that helps alot, I can notice the difference when it's not in there thats for sure. When is it not in there, when I'm in between board tests because it's a bit of a hassle putting it back in everytime I close the lid(cealing mounted pj).

Person99 · Joined: 09 Mar 2006 Posts: 4899 Location: Flower Mound, TX

WTS · Joined: 08 Mar 2006 Posts: 1276 Location: Calgary

For the back piece I just used a heavy piece of cardboard (maybe 20" or solong and about the same width as the pj) with an old pillow cover, one of the ones with padding in it and a zipper style. Then I used a solid copper wire about 20awg and tied it to the pj and then to the far edge of the cardboard. Hi-tech don't you know, course it's not permanent, well at least until I can come up with something better.

The pillow cover sits on top of the cardboard and absorbs some of the noise but doesn't interfere with the air flow.

No pics but it's not too hard to imagine

picree · Joined: 31 Mar 2006 Posts: 351 Location: Johnson City, TN

I would say it cut down on the directional-ness by about 1/2. Noticeable. I mean the noise is still there but it more diffused...especially if you sit right under it.

I used some pre-painted aluminum flashing material that came in brown. 14" width I think. I then lined it with some fiberglass board. Since the board isn't rated to go on the inside of a duct and is friable I sprayed the surface of it liberally with 3M contact adhesive until it created a skin on it (you can't see it in the photo but it's there). I also tapered the insulating board down on the edges so as to not obstruct the airflow.

REMEMBER: If you do this, make sure you spray the insulation with some sort of glue to keep it from frying. You don't want to be breathing fiberglass!

Curt

Person99 · Joined: 09 Mar 2006 Posts: 4899 Location: Flower Mound, TX

Very cool picree. So, are the fans working harder, or is the airflow enough? I would have thought it might need a more open area around the fans.

Dave

picree · Joined: 31 Mar 2006 Posts: 351 Location: Johnson City, TN

I haven't noticed a difference in fan speed. The vents aren't as blocked as much as it looks in the pictures. I don't have a thermostat or anything. If I can judge by the amount of convergence drift I see over an afternoon of football, I would have to say it's running pretty cool. After having the proj on for even six hours I check the dot-hatch and there isn't any drift. FWIW...

Curt

BTW-the projector cover is off because I'm continuing my quest to mount HD144s! Soon, very soon......we have a prototype! I hope to post photos of yet ANOTHER way to mount HD144's on an 808.............a lot of lathe work. It is tricky to do it right!

WTS · Joined: 08 Mar 2006 Posts: 1276 Location: Calgary

Hi Kal,

I remember reading somewhere that you were having heat problems after you changed the fans to the silenx. I ran my 1200x yesterday for about a total of 7hrs and at the end of the evening I opened up the case and checked all the heat sinks with my finger tips. The neck boards weren't even warm really, actually there was only one heatsink which I could only hold my finger tips on for about 10secs(offhand I don't recall what the board is). All the heatsinks were no were near what I would consider hot by any means and if you can hold your finger tips on them then they're not hot in the electronics world.

I run my pj at 1080i. I would say I'm happy with the cooling my pj gets and the noise is alot better than with stock fans. I should mention that I didn't replace the angled fan in the rear.

**kal** · Posted: Mon Feb 12, 2007 3:46 pm Post subject:

Hi Walter,

Good timing! Below are my findings after a week of testing with a couple of temp probes.

I measured the temperature directly on a variety of the heat sinks at the same scanrate each time. This took me all week because (a) it somtimes takes up to 2 hours for each temp to stabilize, (b) I did 2 whole sets of tests from start to finish to make sure that temp probe placement didn't change too much based on positioning (it didn't), and (c) I had to put the all 3 old NMB stock fans back into the projector and redo all temp tests.

H-Shift/Focus board (middle): 46.0C (NMB) -> 54.5C (SilenX)
H-Shift/Focus board (bottom): 46.2C (NMB) -> 53.3C (SilenX)
Horiz board (on top): 28.0C (NMB) -> 42.5C (SilenX)
Vertical board (on top): 39.6C (NMB) -> 50.2C (SilenX)
SMPS (underneath): 36.8C (NMB) -> 41.1C (SilenX)

All tests done with a 1080i/60Hz signal as input.

Remember that I replaced the fans as follows:

Angled 80CFM NMB fan -> 72CFM SilenX fan (this one only cools the H-Shift/Focus board)
2 other NMB 80CFM fans -> 90 CFM SilenX fans (these cool everything else)

Some of these temp jumps are huge! For example, the horiz board which is basically cooled by one of the 80CFM NMB or 90CFM SilenX fans jumps 14.5C even though the new fan is 'supposed' to be 10CFM larger!

Same with the SMPS. The "Larger" 90CFM SilenX fan cools worse than the 80CFM NMB fan.

The NMB fans are staying in place. Anyone want to buy $120CAD worth of SilenX fans?

Kal

**AnalogRocks** · Posted: Mon Feb 12, 2007 4:54 pm Post subject:

Damn. Guess their CFM ratings are overly optomistic after all.

Alaric · Posted: Mon Feb 12, 2007 5:08 pm Post subject:

Hi Kal,

Interesting Info.

However did you take any external temp measurement at the same time, ie the general air arround the PJ, as this may affect the internal results ???

So where do we find some better fans now Sad

cya,
Lee