Thinking of converting this beast to 24LQ6's @ $12.59 each. Attached is a modified schematic showing how. Basically tying the heater of 5 tubes in series to get 24 VAC to the heaters. 120/5 = 24 Thought's???
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D&A phantom rework
- Thread starter bearcatfan78
- Start date
I'm considering doing a change of glass in my Phantom. I'm thinking of going the EL519 route though. I know the pins will need re-wiring (2 of them and jumping one) and I know the pins will stretch the sockets (but I'm definitely not going back to the original tubes so the socket stretch isn't a major concern. I looked at the 24LQ6's and the 31LQ6's too. It's my project for February.
3's
3's
Thinking of converting this beast to 24LQ6's @ $12.59 each. Attached is a modified schematic showing how. Basically tying the heater of 5 tubes in series to get 24 VAC to the heaters. 120/5 = 24 Thought's???
Excellent idea, be sure to wind some bifilar type chokes (one for each bank of 5 tubes) and place them in your 120 volt series filament supply line; this will keep RF out of your AC wiring at home.
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Well I don't know if your phantom is like mine, but pin 9 in my sockets has been removed completely. I had considered a el509/6kg6/6p45s rework until I discovered I had to change the damn sockets. Ugggggh!!! So it was back to the drawing board. That's when I decided to go with 24lq6's. Also what would you suggest the best way to make a decent bifilar type choke for this is????
A bifilar choke is two pieces of insulated wire wrapped on a ferrite core, the purpose is to block RF from getting into your house AC lines.
For your application, if you could fine a ferrite rod (like the kind you find in old AM broadcast radio sets) about 2 inches long and wrap the wire around it, it is not critical, just make sure that you have enough turns) that would work for you..
A second idea is this:
Cut a slot out of a ferrite donut and use that for your core .
.
For your application, if you could fine a ferrite rod (like the kind you find in old AM broadcast radio sets) about 2 inches long and wrap the wire around it, it is not critical, just make sure that you have enough turns) that would work for you..
A second idea is this:
Cut a slot out of a ferrite donut and use that for your core .
.
LOL. I kinda made that sound like I didnt know how to make a bifiliar choke. No I meant what would you sugest for this application, but I got it. I like the ferite donut design alot. Thanks for the advice. 
) 73 :headbang
) 73 :headbang
BJ radionut
Supporting Member and 6m addict
gla1000eng
This link should be of help...I have done a couple of MAV 250's...gutting the 4 tube driver stage...pairing up the 2 xformers on the final stage, bigger current diodes and extra filter caps...worked well.
The GLA-1000 to 519's a little tricky as the tubes are slightly taller... on the D&A's...when you rework the sockets just drop them down about an inch, open the socket holes a little so the tube fits through and gets air. I also added a small fan to move air under the chassis to keep the sockets and PS caps/diodes from getting warm...Worked well...
Next one that comes my way cheap will get a pair of GI7BT's...
http://www.ne.jp/asahi/evo/amp/device/el509.pdf I have used the 509's very similar mostly...both OK...509's fairly plentiful still about 20USD each +/_...last 4 I bought were 18USD...really a heavy glass version from Russia...Winged "C" brand (old Svetlana factory) http://ko4nr.tripod.com/upgrades_and_modifications_for_d.htm
Be Careful
GL
All the Best
BJ
This link should be of help...I have done a couple of MAV 250's...gutting the 4 tube driver stage...pairing up the 2 xformers on the final stage, bigger current diodes and extra filter caps...worked well.
The GLA-1000 to 519's a little tricky as the tubes are slightly taller... on the D&A's...when you rework the sockets just drop them down about an inch, open the socket holes a little so the tube fits through and gets air. I also added a small fan to move air under the chassis to keep the sockets and PS caps/diodes from getting warm...Worked well...
Next one that comes my way cheap will get a pair of GI7BT's...
http://www.ne.jp/asahi/evo/amp/device/el509.pdf I have used the 509's very similar mostly...both OK...509's fairly plentiful still about 20USD each +/_...last 4 I bought were 18USD...really a heavy glass version from Russia...Winged "C" brand (old Svetlana factory) http://ko4nr.tripod.com/upgrades_and_modifications_for_d.htm
Be Careful
GL
All the Best
BJ
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Well I am at a Bistro on campus so keep that in mind. Waiting on my better half. I did not see any resistors in the tube 120 feed line. Your first tube will pop more then likely then it will pop the next and the next in series etc......You need to stick a resistor and a diode in that line. If the ac is dirty then you will need a cap in their too to clean that ac up a bit. Also what is your local power like? Is it clean or full of ripples. If your power fluctuates much you will have issues.
Just my $.02 though.
You can actualy use doubler,tripplers and voltage divider's to power tube amp with no transformer at all. Some guys in Europe on 220/240 do this. It would not be my first choice but if a budget does not allow it is better then nothing.
Just my $.02 though.
You can actualy use doubler,tripplers and voltage divider's to power tube amp with no transformer at all. Some guys in Europe on 220/240 do this. It would not be my first choice but if a budget does not allow it is better then nothing.
I have to check the x-formers, since there are 3, and see if they are all good. I think they are supposed to be 800vdc at the sockets, but with all 11 tubes out (the little keying tube to) Will I read that 800vdc? I may have to just salvage different parts and make a different amp.
BJ radionut
Supporting Member and 6m addict
The el-509's are basically a drop in replacement for the 6lq6/6me6 or the 6mj6's all are 6.3v filament tubes...
You have to change the socket configuration wiring as the grid and heater pins do differ from the 6lq6 vs the el-509's. The existing sockets are the same pin count and el's will fit. I however preferred to change them as the ceramic replacements I found were a much stouter version than the Bakelite versions D&A used in most of their amps...
Now a little logic...11 tube sockets at $2.50 each +/- = say $28.00
11/ el-509's at best price $15.00 each (more like $20-$22 with shipping)....
11 x $20.00 = $220.00 + sockets $28.00 = $248.00 parts only
Add in 20 or more hours labor gutting the existing RF deck / installing new sockets and wiring...how much is your time worth?
Now you understand why you can buy or carry those "Things" away for a song!
The 4 tuber's like the Mav 250's much less of and investment and yield an amp project for less than parts cost of one of those monster autrosities...IMHO
Will you learn something....most certainly!....but the output difference maybe 1 S unit(6db)...IMHO...no not really....but your call to make
Even if you could find 6lq6's in a lot for $25 each....$300 just to re-tube her as she sits.
Now your question...yes you can read the B+ voltage with the tubes removed...but watch your butt...only with a GOOD meter and test leads rated at a 1000 volts or more...Be careful the power in that amp will kill you in an instant....if it does not...you may wish you did not wake up!
Please be careful
Adding tubes together like 5/24v to equal 120v filament, again IMHO is a death wish or a good reason to have the FDNY on stand-by when you throw the switch...I won't even touch a Firebird or the likes that does not contain a separate filament winding rated for the tubes (6.3/12v OK) and weird combinations like the old TV's used...nope not anymore!
There is many a story there by anyone who worked on those...
GL...Be careful
All the Best
BJ
You have to change the socket configuration wiring as the grid and heater pins do differ from the 6lq6 vs the el-509's. The existing sockets are the same pin count and el's will fit. I however preferred to change them as the ceramic replacements I found were a much stouter version than the Bakelite versions D&A used in most of their amps...
Now a little logic...11 tube sockets at $2.50 each +/- = say $28.00
11/ el-509's at best price $15.00 each (more like $20-$22 with shipping)....
11 x $20.00 = $220.00 + sockets $28.00 = $248.00 parts only
Add in 20 or more hours labor gutting the existing RF deck / installing new sockets and wiring...how much is your time worth?
Now you understand why you can buy or carry those "Things" away for a song!
The 4 tuber's like the Mav 250's much less of and investment and yield an amp project for less than parts cost of one of those monster autrosities...IMHO
Will you learn something....most certainly!....but the output difference maybe 1 S unit(6db)...IMHO...no not really....but your call to make
Even if you could find 6lq6's in a lot for $25 each....$300 just to re-tube her as she sits.
Now your question...yes you can read the B+ voltage with the tubes removed...but watch your butt...only with a GOOD meter and test leads rated at a 1000 volts or more...Be careful the power in that amp will kill you in an instant....if it does not...you may wish you did not wake up!
Please be careful
Adding tubes together like 5/24v to equal 120v filament, again IMHO is a death wish or a good reason to have the FDNY on stand-by when you throw the switch...I won't even touch a Firebird or the likes that does not contain a separate filament winding rated for the tubes (6.3/12v OK) and weird combinations like the old TV's used...nope not anymore!
There is many a story there by anyone who worked on those...
GL...Be careful
All the Best
BJ
I think you are right, I got the amp not working for almost nothing. If the xformers work, or 1 or 2, I could use the case, tank circuit, switches and other misc parts for a different build. I really just have to find something I can copy.
My labor is of no concern, I have been an A-10 Warthog electrician/avionics craftsman/supervisor for 13 years, I have the ability to build it. But the tube knowledge is a bit lacking I forgot pretty much everything from college about tube amps, lol. But the price of parts is definitely an concern.
My labor is of no concern, I have been an A-10 Warthog electrician/avionics craftsman/supervisor for 13 years, I have the ability to build it. But the tube knowledge is a bit lacking I forgot pretty much everything from college about tube amps, lol. But the price of parts is definitely an concern.