Negatron ii HT

[NBPK402]

I am assuming the screw terminals are for the speakers and for power (for the VU Meter)... the there is a single cable that plugs into one of the white terminals in the 3rd picture, no idea where the other end goes

 

[NBPK402]

New horn stands...right channel in place, just needs to be wired up tomorrow we will do the left channel. Sometime in the near future the rears will be completed, center made, and to finish off the setup...horns will either be wrapped with carbon fiber or painted. This fall I will be putting the Denafrips Athena up and the Lujin U1 mini. The Marantz av8805a is doing a pretty good job, and the front channels go through the Pontus and then active crossovers. All lower base channels will be room tuned with Dirac. Sorry for the blurry pictures. I will retake some after we get the left side done in better lighting.

Plate amp is on top of the f20...still need to wire up the VU Meters, and fab a support brace for them.

Below the horn in the amp stand is the temporary amp for the mids and compression driver. A new dual channel amp with meters ids currently being made of Mesquite, and carbon fiber.

 

[NBPK402]

Better pics...

 

[NBPK402]

Question...does it make a difference what color a speaker is behind a acoustically transparent projection screen?
Is it better to paint a speaker with a satin or matt finish or is a gloss finish ok (behind a AT screen)?

I am asking this as I plan to get a projection setup down the road and it is about time to paint the k402 horns.

 

[NBPK402]

I am asking this to find out if the color will affect the image seen on the screen. I know theaters use flat black, and in the past I did the same, but I would like a nice colorful speaker when the screen gets up...without affecting the image on the scrreen.

 

[NBPK402]

Update: I decide to try out the Fosi v3 monoblocks in my setup...what the heck they are so inexpensive and raved about everywhere.

They arrived very well packed and shipped fast from Amazon. I also ordered a 2nd 48v power brick since they are about 10' apart. I hooked them up to my Celestion axi2050s (replaced the Icepower 50asx2BTLs), and gave them a nice listening too. First thing I noticed was there was zero hiss from the compression drivers...even with my ear at the horn mouth! Now this was something I def wanted...as the Icepower does have hiss although you had to put your ear at the horn mouth to even detect it. Next I notice a brighter, clearer mids and HFs. When I purchased these...I figured if they were not good for the horns...they would go to the atmos channels, but it looks like they will stay on the compression drivers.
.

Now the only downside to these bad boys is they run hot. I have searched and this is normal, mine are actually cooler than when the posted tests were posted. I still would like these to be cooler and found one guy who added a silicone pad to each amp and then put a large heatsink on each amp. The guy claims luke warm now, so that is my next mod! I have copper heatsinks for the bottom of each amp and a 50mm high fan style aluminum fan for the top of each amp coming.

I also purchased a Teradak Linear Power Supply from Aliexpress for my Roon. I am still burning it in, and it is a little improvement to my ears on my system over the stock brick. So far I am hearing a little bit clearer and tighter sound. I also am hearing low level cymbals and brushes that I have not heard before on certain tracks.

I am waiting on a few new allenhead bolts (the ones I ordered were to short for the wood inserts as the threads are not flush with the top of the inserts), which should be here soon. Then I will be assembling the 2 amps. Each amp will have 2 125asx2btl amps in it connected to its own VU meter. One amp will be for the heights,, and the other for the 15" mids. The cabinets were not made the way I specified, but look good...so I am still going to be using them. Once I get them assembled..I will post some pics and explain what is not as I requested. The cabinets have carbon fiber front and rear panels and a Mesquite cabinet stained to match the subs, rack, and horn stands.

On the MEHs, and my acoustic panels...my wife said the look was to dark, so I ordered some off white speaker grill material (the color I think looks better now as it lightens up the room...my wife was right). I am waiting on some small pieces of aluminum to guide and hold the grills on the top and sides, and the magnets will be used for the bottoms of the grills.


I am using what was left of my off white duck cloth material (acoustic panels), for recovering the acoustic panels and have ordered some more to finish the rest of the panels..

The rack is now fully assembled, and the next item will be making doors with white grills (same as the horns). I hope to have these done sometime soon.

 

[NBPK402]

Today I finished the 2nd acoustic panel stands. I have a bunch of parts arriving this next week, so I should have more pics next weekend. The curtains on the left side will be coming down and one of the upper acoustic panels will be placed there. In addition my height channel speakers will be mounted just below the acoustic panels hanging on the front wall.

 

[Sonnie Parker]

Love the new amp cases... Lol... Your the only guy I know that will have horns for surrounds... That is just so cool... Hey, if Sonnie can have ML ESLs for surrounds you can certainly have horns...

Uh... I have all horns now with my JTR speakers. I'll be posting a new video as soon as I can get our painter over here to repaint our entranceway, where I've patched the walls.

Question...does it make a difference what color a speaker is behind a acoustically transparent projection screen?
Is it better to paint a speaker with a satin or matt finish or is a gloss finish ok (behind a AT screen)?

I am asking this as I plan to get a projection setup down the road and it is about time to paint the k402 horns.

I don't think you can see through the acoustic screens, although I could be wrong.

You know, with horns, being they are more directional, you shouldn't get too many reflections off the side walls. I'd really only be concerned with reflections for two-channel music, as it probably won't make too much difference for movies. Of course, that's just my opinion.

 

[NBPK402]

Uh... I have all horns now with my JTR speakers. I'll be posting a new video as soon as I can get our painter over here to repaint our entranceway, where I've patched the walls.


I don't think you can see through the acoustic screens, although I could be wrong.

You know, with horns, being they are more directional, you shouldn't get too many reflections off the side walls. I'd really only be concerned with reflections for two-channel music, as it probably won't make too much difference for movies. Of course, that's just my opinion.

Congrats on your new horns! I Have had horns several times and MLs once. At tines I wish I had a simpler setup and electrostatic again. There was a magic with my Classe Audio, Mitchell, MLs. So very different from all my previous and current horns.

On being able to see the speakers behind the screen...I have seen others with lighting behind a AT screen, and you could se the speakers (Not like without a screen though). I am really just curious if the speakers were sayna gloss red, yellow or other color that pops...would the projector cause a reflection toward the screen.

 

[NBPK402]

I removed one horn from its cabinet today...it will be going cabinetless to match the fronts. The 2nd cabinet I am going to pay someone to remove the horn...as I have been unable to figure out what is still holding it in the cabinet, besides silicone, and I have been unable to get the silicone removed..

First cabinet took me 4 hours to remove the horn, and this was after the drivers and wiring were already removed! On this horn I used silicone caulk adheasive plus dual layers of a dynamat type substance. This I think is the cabinet that dialed in the easiest and best...I think the dynamat was the reason. Now the pain with dynamat is the removal...way harder than installing...as it really sticks to mdf!

 

[Sonnie Parker]

Four hours... wow... I bet that was tedious, to say the least. I believe I'd hire someone to do it too.

 

[ddude003]

I have found, IMHO, that horns sound best with a tubed preamp and/or tubed amp... And the mids and bass sound best with solid state amps... Which complicates things with bi or tri amping... Where electrostatic usually handle the highs and mids with one panel, tubes sound great here, and then manage the lows with an solid state amp... I guess this may be just my preference... Stats just seem faster to me... Creating great leading edge transitions... Yea, tubes are harmonic generators for more air and sparkle...

 

[JStewart]

On being able to see the speakers behind the screen...I have seen others with lighting behind a AT screen, and you could se the speakers (Not like without a screen though). I am really just curious if the speakers were sayna gloss red, yellow or other color that pops...would the projector cause a reflection toward the screen.

Seymour AV has a black AT backing available for their AT screens. They might be good folks to ask.
Contact info on this page:

Seymour AV | About Seymour AV

Seymour AV is the premier manufacturer of acoustically transparent home theater projection screens in the world, maintaining the highest standards in projection screen innovation, design and craftsmanship

seymourav.com

 

[NBPK402]

Seymour AV has a black AT backing available for their AT screens. They might be good folks to ask.
Contact info on this page:

Seymour AV | About Seymour AV

Seymour AV is the premier manufacturer of acoustically transparent home theater projection screens in the world, maintaining the highest standards in projection screen innovation, design and craftsmanship

seymourav.com

That might be the solution, thanks!

 

[NBPK402]

I have found, IMHO, that horns sound best with a tubed preamp and/or tubed amp... And the mids and bass sound best with solid state amps... Which complicates things with bi or tri amping... Where electrostatic usually handle the highs and mids with one panel, tubes sound great here, and then manage the lows with an solid state amp... I guess this may be just my preference... Stats just seem faster to me... Creating great leading edge transitions... Yea, tubes are harmonic generators for more air and sparkle...

It has crossed my mind to try and find the old Classe dr6 preamp that I used to have...or the Audible Illusions Modulus 6 tube preamp (except the modulus is not balanced)....both were while I had Martin Logans.

Currently I am in awe of the Fosi v3 on the Celestion axi2051s.

 

[NBPK402]

Today I worked on my system a bit...I finally am almost completely happy with my new grill attachments...the reason I say almost is I messed up when mounting the new grill brackets and screwed rith into the grill material. Now I need to make another grill. The next thing I am going to do is attach some pieces of rubber to the brackets to possibly prevent rattles, but listening tonight Inheard none.The new grills have J channel style brackets. I use 2 on the top that capture the horn, and 1 on eachnside to keep it aligned properly. To remove I just lift the grill up until the side brackets are cleared. I did it thisnway because magnets just would not cut it as the I think the weight if the grills made the grills just slide down. I have been using clamps to hold them in place, so getting this done today, I think it looks much nicer. I was going to just use the J channel on the top and the magnets on the side, but this was easier (except for messing up on one hole, and also pushing 2 magnets partially out toward the grill (I could notmsee the magnets with the fabric over them.At least all the goofs were on the same grill!

I also hooked up A XLR switcher that I purchased from Sonnie, and it works great. This allows me to presetmthe levels on boot for my Marantz av8805a and also on the Athena preamp. No more having to max one level, and always worried that if anyone accidentally switched the other one on the volume might blow a driver. Now all I needed was a HT bypass, and now what I havenis essentially a external HT Bypass. The Athena is by default selected (it has no 12v out, and the Marantz has 2), and with power from the Marantz avp via 12v it switches to it. Now I do not need to upgrade to solve the problem!
Attached are a few pics that show the new mounts for the grills.

 

[Sonnie Parker]

Looks like professional work on those grills - nice job!

I'm glad that switch worked out for you. It did the job for me while I used it.

 

[NBPK402]

Today I made another grill...with no visible errors. It has been about 10 years since I did this (the original Negatron HT), and I did a whole room with panels...some with acoustic treatments, and the rest without.

 

[NBPK402]

Thanks Sonnie it works perfectly. The f20 grills are as tight as a drum...the horn grills are good, but I just could not pull them as tight as the f20 grills.

Today I installed one pair of copper heatsinks on the bottom of the Fosi v3 monblocks. I should have the other pair of copper heatsinks soon for the other amp. I installed these on the bottom due to Fosi using the paste on the bottom of the amps (for using the case as a heatsink). I have another heatsink that is being cut in half (so it will be almost the size of the top of the amps. I hope to have that back from my neighbor soon...it is a wild looking heatsink for this small amp, but itmshould keep these babies cool. I also used some little 3m adheasive circles to attach the feet to the heatsinks...the feet are aluminum, with a steel ball and a o-ring inside (the o-ring is to provide friction for adjusting the height if needed. I am using these feet on almost everything in the rack and my amps too. Dom they make a difference in the sound...no idea, but I liked the look and they are functional. The old rubber bumper feet were just relocated to random spots on the case, in case I ever want to return to stock.

 

[NBPK402]

Both amps now finished, and run so cool...that I have to switch from auto to off, to see if they are even on! Now this is how cool they should be running.

 

[ddude003]

The last time I saw heat sinks like that was on a supercomputer somewhere...

I suppose your next revision will be liquid immersion in Fluorinert or cryogenics...

 

[NBPK402]

Sneak pic...1st amp almost ready for wiring. Next amp is almost ready too.These amps for the time being will have Icepower 125asx2 btl mono amps...one for the mids and the other for the heights (down the road the 2nd channel will be for more woofers).

 

[NBPK402]

Just ordered a 2nd pair of the Fosi V3 monoblocks...gonna try them on the compression drivers and the dual 15" woofers. Power is similar to the Icepower 125asx2BTL amp modules, but the Fosi V3s are much better in the mids and highs and supposedly in the bass too. We will see.

If they are much better....we might install them inside of the new cases...since they turn on by signal, we just run the cables out the back and mount the amps on heatsinks.

 

[NBPK402]

Just got in my 2nd pair of Fosi v3 monoblocks (this pair is 5amp and the other pair is 10amp). I switched the old pair over to my mids since they can use the 10amp power supply more than the compression drivers, and the new pair went to the compression drivers.
Initial listening is that 500hz to the horn subs at 80hz is cleaner, tighter, crystal clear (which now matches the 500hz to 20k). Def a upgrade from the old icepower 50asx2btl and 125asx2btl amps.

Highly recommended! Total cost for 4 shipped to Mexico (including shipping and duty), heatsinks and feet will be under $1k for 4 amps. Hopefully next week we will have them sitting (temporarily in my new amp cases with working VU meters (no lighting for now, but might have in the future...if I decide they need lighting).

 

[NBPK402]

It has been awhile since I did a tune...so today I decided to do a new one. The beige trace is my left channel which is 3' from the side window wall, and the purple trace is mupy right channel which is 20' from the other side wall. Changes since the last tune are the new rack and the new Fosi v3 monoblock amps. Response is +- 5db 20hz to 20khz now.

Initial listening is much clearer in the vocals and high end. Below the vocals the bass is more full than it has been since going cabinetless.
Attached are the pics of my REW screen and also my Xilica settings. (I am sure if I knew what I wss doing, I could get this even flatter and more consistent channel to channel, but I do not know enough to be able to do a low phase tune). Plus my room is so live.

Usually I use all the FIR and PEQs for the left channel and the right uses less...this time I used 6 or less for each driver.