New Rig Infant Pics - Any Guesses what it will be?

[K1JJ]

Hola!

Just gave birth to a new baby. Brand new custom homebrew chassis and canvas to paint.

The tubes will be displayed broadside and in full view with a large 23" X 25" Plexiglass window.


Any guesses to what kind of configuration it will be when it grows up? 

Hint: The solid state board is part of the system.

Also looking for a name. (Fabio is already taken.)

Isn't she a beautiful baby?   

Tom, K1JJ

[K1JJ]

Close up of the DNA

Running out of room - but just gotta build another rig.  (pant-pant)

[KL7OF]

Love those low rider tube sockets.....Lowered and blown....Yeah

[N3DRB The Derb]

I'm in a similar situation re running out of room.The entire shack has to be rethought because the gear is ready to plop down into place and used instead of every other day being " worked on the rig day" with the resulting kaos and running bench junkpiles all over.

Tom, I'd call the new rig Quadzilla if it were me. 

[KL7OF]

4x 4-1000s in class A ...driven by sand state class A ...the ultimate Low distortion, Low Harmonic, Low tube socket rig........enclose in glass,..... mirror the  fenderwells,  add a chromed chain link steering wheel...some Von Dutch.....

[WD8BIL]

Looks like a PDM modulated quad of 4-400s.

[Joe Long]

Looks like a quad of 4x1's

[Steve - WB3HUZ]

VFO?

[W2VW]

I'd call it The Diathermy Machine.

[W3RSW]

Thomas, you need to practice what you preach OM, 
   I see real 4x1 glass, not Coleman chimney glass !

Say, a piece of 8" PVC around that fan and across the heat sink would give better cooling;

          See: The Great JJ Wind Tunnel & Sink Farm


Steve,... JJ don't need no stinkin' VFO, he are one.  Man, what a rig; wish I had his talents and energy.

[W1AEX]

Ahhhh Mr. Vu. You have such wonderful toys. I'm guessing that the tubes on top are just for illumination. Underneath is a single MPF-102 series modulating another MPF-102 with full bandswitching capabilities from 160 meters - 6 meters.

[K1JJ]

4x 4-1000s in class A ...driven by sand state class A ...the ultimate Low distortion, Low Harmonic, Low tube socket rig........enclose in glass,..... mirror the  fenderwells,  add a chromed chain link steering wheel...some Von Dutch.....

BINGO!

Steve, KL7OF gets the stuffed bear.

Yep, lowered and blown - I like it!  The sockets WERE lowered to get more air past the glass in addition to the holes in the tube's base.

Yes, this will be a quad of 4X1's running in ultra-linear Grounded-Grid with RF negative feedback to the MosFet driver. 

For the MRF-150's  MosFet amp, the big copper/aluminum/aluminum heatsink fins (and large fan) will give a class A drive of couple hundred watts pep. The 4X1's will be in idled up and use  negative RF feedback to the earlier MosFet driver.  I will be driving the MosFets with about 10w pep from an FT-1000D that is running class A also. 

I fired up the air system for the 4X1's and find the FIRST tube is getting a little less air than the last three. I am experimenting with round Plexiglass stops at the top of the last two tubes to balance off the air flow to equalize it all. That blower gives good air at 120VAC. It is a 240VAC blower, so I'll have it on a 220V Variac and see where the peak air vs: lowest noise works out.  A better method of air distribution wuda been with four tubes in a square, with the blower in the middle center. But then, I couldn't display them as well as in a line.

Rick - Good idea on the 8" PVC pipe for the MosFet rig. Right now it runs very cool doing OB transmissions at 100w carrier and 600 pep in class B. The limitation appears to be how fast I can take heat away from the device junctions themselves. The heatsinks and fans cool the copper quickly, but the pill metal and white tabs have a certain transfer time for the heat - like a bottleneck. But all in all, it will work FB as is.  Maybe a small 2" pvc pipe that tunnels air DIRECTLY to the Fets devices wud be a good idea too.

One important reason for the project is because I need some more heat in the shack. Some of my other rigs have the air sucked outside with external blowers, for less noise and less heat in the summer. I'm too lazy to go out and reverse the connections to push air in. But that causes the WX and mositure to come into the shack.  So, quad 4X1's with an inside blower will be real good for that.

Last month, I found the need to build up a (12) 813 linear, but that proved to be too difficult to bother with for technical reasons. With the 4X1's displayed broadside, this line up will be just as pretty. I have all the parts already, so why not?

It will be interesting to drive it with the modified FT-102 that uses an impecibly clean NE-602 balanced modulator. I'm already impressed with the way it sounds just driving the MosFets alone.

The FT-102 is capable of huge positive peaks since it uses a balanced modulator, so the quad 4X1's will certainly be used to accomodate this dynamic range... :-)

Derb, the name, "Quadzilla" tells me your Kung Fu is strong! That will be the current name so far.  Maybe some day you can say to me in Japanese broken Engrish, " You as slong as Quadilla!"   


Later -

T

[WBear2GCR]

I know exactly what it will be...


            LOUD !!

[K1JJ]

Ahhhh Mr. Vu. You have such wonderful toys. I'm guessing that the tubes on top are just for illumination. Underneath is a single MPF-102 series modulating another MPF-102 with full bandswitching capabilities from 160 meters - 6 meters.

heheheheh -  Yep, just a PW fake-out rig for tough economic times.

It reminds me of back in the 70's when they had the "gas shortage"  -  the street racers got inventive. There was a kit out that simulated a big Roots 6-71 super charger sticking out of the car's hood. It looked exactly like the real thing. Guys bolted these on and rode around town using recorded tapes (probably 8-tracks) of a dragster revving its blower - to scare the competion... :-)

Just like the natives who wear those long bamboo poles on their BA's with guy ropes holding them up?   

T

[w8khk]

Tom,

In order to reduce the air intake noise, and get double duty from the single blower, why not duct the intake air past the mosfet heatsink.  A little creative plumbing past the irregular surface could really quiet things down, and allow more air to flow before it is heard at the mic.

just my random thoughts...

73, Rick

[Ed/KB1HYS]

If'n ya can, mount the blower in the center beween the two middle tubes. Less airflow balancing issues then.  Although I don't know how that will effect your layout plans.

Looks nice!  Are all your rigs "Under Glass"

[w3jn]

It ain't a REAL xmitter unless you need to use 872As as the biass rectumfriers.

[K1JJ]

If'n ya can, mount the blower in the center beween the two middle tubes. Less airflow balancing issues then.  Although I don't know how that will effect your layout plans.

Looks nice!  Are all your rigs "Under Glass"

 Rick:  Yes, I've been experimenting with air flow. Some guys model it first by building it on a cardboard box of similar dimensions.  I shud be able to get it right.

Ed:  Only my glass power tube rigs for AM are under Plexiglass. The external anode tubes are in standard metal 19" racks.


** BTW, based on an old idea I got from Bill/HG, I used three large toroid cores to run the two filament wires through for the filament choke. No turns, just a straight run thru of #2 wire. After putting 10 ohms in series with it (simulating the input impedance of 4 tubes) and adding a signal gen signal, the inductance dropped the majority of RF voltage across the "choke" on 160M. It will work FB as a very simple, high current fil choke for GG.  Winding a bifilar choke has always been a big job when the fil currents are high, This method solves it.  Thanks to Frank/GFZ for the test suggestion.


T

[KL7OF]

TOM ..You can control the airflow for each tube by controlling the outflow at the top of each chimney....restrict the high flow chimneys to direct the flow to the lower flow units...the RCA BT1-S had 4 approx 2 in dia x 3 ft fiberglass tubing stacks with little balance dampers in them to the outside of the cabinet......You could maybe have chrome curved exhaust tips or ...Lake pipes with cutouts...

[WA1GFZ]

Sorry om I would mount them 2 by 2. Consult with the smart man of quads and see what he says..Remember he didn't need late suppressors with his layout.
Long plate leads is going to make it unstable. It would look nice though.
Imagine connecting all those tubes to the plate choke and then to the plate tuning..looong leads

[N3DRB The Derb]

Nichrome ribbon and suppressors along with some NFB in the input shud do it. + Nichrome 80 ribbon is shiny all to hell, lotsa bling bling to it.

[K1JJ]

Sorry om I would mount them 2 by 2. Consult with the smart man of quads and see what he says..Remember he didn't need late suppressors with his layout.
Long plate leads is going to make it unstable. It would look nice though.
Imagine connecting all those tubes to the plate choke and then to the plate tuning..looong leads

Yep, I agree.   I did think about that before laying it out. But I figured it was gonna be used only on 160M and 75M. I have other amps designed specifically for 40-10M.  So maybe it will be OK.  I can't say you didn't warn me... :-)

I just wired the bottom sockets. Actually there's no wire down there except for the fil leads coming in. The screens/grids and fils are all wired with 1/2" thick copper strap. Looks more like a solid state rig for high current.

For the plate circuit, I'll mount the plate choke above the tubes and try to keep the RF tank leads as short as possible to the pi network using thick strap..

Though, if ya look at a standard broadcash transmitter, the leads are pretty long and they are grid driven to boot.
We'll have to see how it works out.

Derb - Yes, I will use the nichrome wire if I need to. GG is usually pretty stable, but with four tubes, ya never know.. :-)

I'll post a pic of the underside wiring probably tomorrow.

T

[Opcom]

If it's going to be class A, you could put a little inductor from plate to plate along the top and make it a distributed amp. Have to do something along the bottom as well for the filaments where the drive goes in, and from the opposite side if I recall. might not be practical.

the poor airflow at the first tube is possibly due to too much velocity and turbulence right there. If you could get much of the air blast to go partway down the sides of the enclosure instead of hitting that first socket so hard it may help.

Anyway you're going to make the CBers whine when they see all that dissipation and realize it is class A and does not splatter. Good job!

[K1JJ]

the poor airflow at the first tube is possibly due to too much velocity and turbulence right there. If you could get much of the air blast to go partway down the sides of the enclosure instead of hitting that first socket so hard it may help.

Hi Patrick,

Yes, the last tube gets the highest pressure cuz that where the air stops and compresses I suppose.  I made up some tube hole reducers to try too.

Here's the latest progress. Maybe all the "infrastructure" will slow down the air so it will get more thru the first tube now.

I used copper strap for all grid and screen connections for lowest inductance.   Even the filaments use copper strap, but mainly to handle the 75 amps of current before it splits down the line.  I plan to mount the input tuning (T network to match 12 ohms of four tubes) outboard on a very short coax at the rear.

I've always liked this small final tube "sub-chassis" technique of building to get the most efficient air flow possible.

Notice the filament choke. It's just three large ferrite cores with #6 wire going thru. I checked it and it works FB down to 160M.

It may be hard to see, but every individual screen and grid has it's own connection strap to its own local socket ground in addition to the copper bus having periodic straps to ground. Yes, a true "grounded grid" amp.  I ain't taking any chances.

Still need to add the three 0.01 uf filament bypass caps.

Notice most of the copper strap is facing edge-on to the blower, for minimum air resistance.

T

[KL7OF]

That filament choke is very cool...So simple....Are those ferrites any special mixture?   How did you test it?...Thanks for the pics..