D&A phantom rework

[ElectronTubesRule]

Be quite about the GI7B if you let too many people in this the price will go up!!!!


If you have 800V at .500-.800 ma on those transformer's your in the money. 2 GI7B tubes reguire 2500V @ .800ma to put out 1000 watt's cleanly on SSB and about 650-700 clean watts on AM with absolutely beautiful output on a scope. You do need some serious air flow at the very least a Mircowave type fan on the tubes ceramic portion and heat sink area and a muffin fan blowing directly on the bottom pin. According to some Russian Friends that where radio tech's in one in the Army one in the Navy both said you are better off not using the offical socket for the GI7b and all of it's variants if you decide to build in the UHF/VHF spectrum. Harmonic issues with the OEM socket for this tube family.

Plenty of people make ready to use power doubler's for old obsolete Ham Linear that can be used for the above. If you have .400-.500 and 800V you can use a doubler/tripler to get you to 2500-2700V but no way to make up for a shortage of current. So find out how much voltage and current you have then we can help direct you to products to make life easier. You could build one your self all they are caps and diodes some toss in bleeder/balance resistors but you do not need to have them.

If you have enough identical transformers you can also think about parallel and series wiring schemes to get you where you want to be.

I should say that you can use a Gu-31 or GS-31???? It use's the same amount of power and current as the GI7B but will easily do 1000Watts cleanly all day long with the same amount of power consumption for the most part. I have seen them do 2200-2400 on AM cleanly but I doubt one tube would last long at that levelof output. At 1000watts it is designed for 1000 hours of keydown time. So one tube versus 2 for more power output. You will pay more for it but it is still far cheaper then what you will spend on sweep tubes. $65-$149 for one of them + $35-$50 for shipping. Get two and you will have a spare.

 

[liquidh8]

I have to get a bit of time to check out the xformers. I can build and solder and fab the amp, but the actual circuit design is where I would need to get some help.

 

[SmackDown]

subscribed

 

[liquidh8]

Well, no load, on the driver stage which is one xformer, and the finals, which is the other 2, is 850 volts, no tubes in the sockets. I would have to wire my meter in series in the to check the current. I have 3 xformers, all the same part number.

 

[ElectronTubesRule]

Remind me and I will find the email address and web site for a D&A replacement power board. You need at least 800 no load volts but it will easily allow you to do 2000-2500-2700 volts of out put depending on how you set it up. Current output is critical though because you will have the same current out of the power multiplier board as went in it only increases voltage. Since they are identical transformer's you can easily do them parallel to get the current you need. It is also easier to wire then in series if they are electrically identical but from what I have read you would still want to toss a current limiter in the line to make sure you did not draw more then the transformer's in series can handle.

You have a lot of choices depending on the current output and voltage output you have to play with. So once you know you can decided what you want to do.

You might want to google Triode Board as well. It is a one stop solution for electronically controlling your triodes it is a very solid design!!! I am considering it myself because I hate to reinvent the wheel. I know where is the fun in that though.....LOL

 

[liquidh8]

Thank you. I was thinking of going with 5 811a tubes, kinda like the ameritron. Unless I can run 7 with all three transformers, lol. I need a driver stage. I have a few schemtics, i'll be trying to mesh them together, but would need to post them to make sure all the parts and values are correct.

I would appreciate the addy for the d&a replacement board, that would be nice.

 

[liquidh8]

I should say they are currently, all 3, wired in parallel. The schematic calls for 900v, so I went out and have about that, give or take. Just not sure how to go and measure the current, since I can't toss the tubes in the there for a load. One or more have a short in them I think.

I was looking into the GI7B, That would be awesome, but I am not up to speed enough to design the circuit around one.

I have a schematic for the triple stage phantom, to see what I had already, but mine is a dual stage, bi linear, and cbtricks doesn't have a schematic for it. Though I would add the 250 switch since i looks easy.

 

[liquidh8]

The one option I have, that is looking good, is to recap it, about 120 bucks, and use 10 EL509's. I can make the sockets work, even buy new ones. 10 tubes and sockets on fleabay, about 120 bucks. so 24 would give me all the caps and tube with sockets. My buddies KLV1000 will do 700 SSB on my DOSY all day long, and a 75 more on the built in meter, lol. It uses the EL 519's, 1 driving 4.

I wonder why D&A used 4 driving 6? Why not 2 Driving 8? Anyway, the 811's are in the budget, but that is a rework of the amp a bit, $110 for 4 matched tubes, and I need a fifth for a driver, or a small 1 pill to drive it ($75). A few other parts, voltage doubler, different chokes, (+/- 100). I am close to $300 for 800 watts. Or do I use the original scheme, and get 1K?

 

[liquidh8]

here is a question. The KLV550 is a 5 tube, 1 driving 4, EL519/509. Why couldn't you take the phantom, re-tube it to the EL509, and make it 2 driving 8? Does it need to be 4 driving 6?

 

[liquidh8]

Ok guys/ I received 10 EL509's to convert the phantom, 1 broke during shipping. My question now is, can I use 4 6lq6's for the drivers, and use 6 EL509's in the final stage? I have 5 good 6lq6's, and 9 good EL509's. After the holidays and in the new year I'll get some other tubes.

 

[ballydoctor]

Help please I bought a new XFORCE Base amp and when I plug it in I have a AC hum. I am getting all kinds of answer bridge Rectifier, Transformer. Could it be a Brdge rectifier and or is it the transformer, This is brand out of the box and XFORCE will not even anser the phone or my email. PLEASE HELP


CMPEPPENELLI@CFL.RR.COM


Christine

 

[liquidh8]

Help please I bought a new XFORCE Base amp and when I plug it in I have a AC hum. I am getting all kinds of answer bridge Rectifier, Transformer. Could it be a Brdge rectifier and or is it the transformer, This is brand out of the box and XFORCE will not even anser the phone or my email. PLEASE HELP


CMPEPPENELLI@CFL.RR.COM


Christine

?????? Wrong thread

 

[liquidh8]

OK, I found something on kens electronics that says to use the el509's, to move pin 3 to pin 9, then tie pins 2 and 3 together on the tubes sockets, anyone know if this is right? Will it work with the way the phantom is layed out?

Thanks guys

 

[Mudfoot]

Is Ken's store still open for business?

 

[wavrider]

If you do not know what you are doing then please STOP.

There are voltages in that chassis that could be lethal. For safety sake's take it to a tech that can do the conversion.

Yes the wires do need to be moved, the input tune does need to be reworked as well as the output PIL network.

The Russian tubes are not a drop in replacement for 6LQ6, look at the spec sheets and this is easy to see.

OK, I found something on kens electronics that says to use the el509's, to move pin 3 to pin 9, then tie pins 2 and 3 together on the tubes sockets, anyone know if this is right? Will it work with the way the phantom is layed out?

Thanks guys