D&A TRIPLE STAGE PHANTOM ISSUE

[Sonar]

The 1 6jg6 is just a dud to complete the filiment circuit.
You should PM nomadradio and get the heads up.
You can google the "twin peaks" thing too, you may not be tuned up properly.

http://www.worldwidedx.com/threads/d-a-pdx-400.23121/page-2#post-65771

I don't like tunning up an amp without reason but since i have new tubes for it I thought I'd see if my phantom passed the twin peaks test.
It passed. I decided to retune it using the second peak on both the driver and the driver tune.
Even though the second peaks on those knobs peaked at the same place output wise (on my wm 1) I found that when leaving the amp tuned in the alternate peak position I get about 300 more watts. Although it basically dead keys about the same as when the amp was tuned in the peak position that I've been using for the longest time, the pep is now 800 as opposed to 500.
I'm debating on whether or not to remove the old tubes and replace them.
I think 800 on this gem of a phantom is about right.
Even if I get 1000 out of the new tubes so what.
I know there's not going to be any difference on the other end between 500 and 800. I'm thinking this amp was incorrectly tuned all this time. Thanks for sharing the nomad post. And thanks to nomad for posting that twin peaks information. I'm still wondering if I should tune the final screwdriver dodad on the back of the amp for max smoke as suggested by d&a or lowest swr as suggested by mostly everyone else? Thanks again.

 

[ExitThirteen]

Interesting, didn't know that the 6JG6A was a "dud" tube... in one of the (many) Phantoms I had, the tube was actually functional, it was the first of three stages.

But, mine also said it was a "Triple Stage", so that may be the difference between the "Triple Stage" Phantom and the "PDX-400" Phantom.

~Cheers~

 

[357]

Nomad would be the Elmer here...300W more...I'd be rollin a celebratory
not to mention the tubes running way cooler and in-tune

 

[Sonar]

Nomad would be the Elmer here...300W more...I'd be rollin a celebratory
not to mention the tubes running way cooler and in-tune

I never looked at the tubes while running the amp but it actually runs very cool.
On the other hand if it wasn't correctly tuned as, I suspect it wasn't, like you say the tubes were most likely taking a beating.
There's on more thing I'm going to do and that's turn the driver output up a bit from under 11/2 to 2 watts dead key.
I always wondered what if any difference a 2 watt dk will make if any at all.
Now I've 10 replacement 6lq6's and doubt I need them.
I guess It'll be a long time before I worry about having to purchase any more.
I paid about $10ea. for them. It's amazing that the Sylvania's in there are stamped with the d&a mark. If there not original they were probably purchased from d&a early on and replaced by original owner of the amp. I'm not sure if one could purchase replacements from d&a but if so they were probably no more than$7 ea. At 800 watts pep with about 11/2 dk and 20 pep I'm guessing the Tubes are good. 800 seems to be the consensus as far as output for the phantom.
I would definitely suggest anyone owning a phantom no matter which one check the twin peak situation. Re tuning the amp sure made a difference and the other good thing to come out of it was it's most likely tuned properly for the first time since I've owned it. Thanks.73 p.s. I'm still very tempted to drop the replacements i bought in. Good damn!! I really am a chicken bander. I'm getting 800 out of it and even though I know a couple of hundred more isn't going to make a difference on the other end I wanna see the wm 1 hit a 1000. I jest!!

 

[2RT307]

I'm happy to see so many people really enjoy the old tube gear. My tec is fairly sure the phantom has a weak tube. Considering the one's that are currently in there are original to the amp it might need a few. Mike of Mike's radio repair who does the work on my equipment is making it easy on me. I'm just going to send him the tubes and he's going to test them. I'll take it from there. 73View attachment 19144

You've got a really nice setup there! Glad you got it working right.

73,
Brett

 

[Sonar]

You've got a really nice setup there! Glad you got it working right.

73,
Brett

Thanks Brett. I finally got a couple of HF's (ft950 ts450) but haven't had the heart to disconnect the madison. I also had every intention to sell off some of the pieces i don't use and some I won't be using but, just couldn't do it. Their like old friends. I'm even sending loosecannon a d104 for a modification. It's wired for the madison even though that rig will be retired I'm sill using it and enjoy it tremendously. I really enjoy the old equipment. It's often problematic but the nastagia of using oldies but goodies out weighs any potential problems that might and usually do arise. Thanks. 73