HXDA tubes

Discussion in 'Amplifiers' started by myoldfriend, Jul 7, 2020.

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  1. myoldfriend

    myoldfriend New Member

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    Hey All,

    N00b only to this forum...

    While in the process of changing up my amp lineup, I noticed that there were big bottles (6L6GC) in my HXDA. Seems to be a dearth of info on this model at prsguitars.com and the interwebs in general. What I'm gathering from the chart I found is that the factory std is EL34 in the power section. I haven't gigged the head or playing for any long stretches. Yet. Thinking I should check the bias before pushing my luck any further.

    So while I know enough about tube amps to be dangerous ;) I'm wondering if anyone would care to chime in with tube choice, existence of a manual for the HXDA or anything (links, etc.) of general interest...

    Thanks!

    RK
     
    #1 myoldfriend, Jul 7, 2020
    Last edited: Jul 7, 2020
  2. Tahlee

    Tahlee Tollywood Rhode Island

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    Hello and welcome to the forum.

    My HXDA came stock with EL34s. Top of the line Winged C tubes.
     
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  3. WeFixFlats

    WeFixFlats Respect The Clave

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    As a previous owner of a HXDA, I can tell you that there's never been and will never be any manual for the HXDA. Before Flickr decided to charge for photo support, there were many photographs of bias adjustments, and the internal chassis layout, mine included. But they are gone now. In any case, whoever put 6L6GC's in this amp was looking and asking for trouble. It was designed for a high quality, matched set of EL34 power tubes. There are still many comment streams about tonal adjustments, bias settings(use the setting that's printed on the backpanel), tube manufacturers, etc...you just need to search for them, they are there in abundance going back several years on this site...Good Luck~!
     
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  4. myoldfriend

    myoldfriend New Member

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    Thanks for the confirmation folks.. Going to get a nice matched set of EL34s before powering up again.

    (EDIT: although, see further down in the thread for an update...)
     
    #4 myoldfriend, Jul 7, 2020
    Last edited: Jul 7, 2020
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  5. Boogie

    Boogie Zombie Two, DFZ

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    Read under the bias jacks on the back of the amp. Does it mention guidelines for rebiasing after changing to EL34, 6L6, KT77, or 6CA7? Yep...there ya go. ;) Now, does it absolutely rock with a great set of EL34s because it’s a clone of an iconic Marshall Plexi? Hell yeah brutha!

    Oh, and welcome!
     
  6. Tahlee

    Tahlee Tollywood Rhode Island

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    My head is a 25th Anniversary, which I believe is almost the same thing as the HXDA. I think the HXDA is based on the 25th Anniversary. I have a one page user manual. I hope this helps.

    [​IMG]

    If you zoom in on the Rear Panel Controls diagram, it says to re-bias if you switch to 6L6GC, EL34, C6A7, and KT77. So, it’s possible that your amp wasn’t damaged by the tubes that are in it now.

    [​IMG]
     
    #6 Tahlee, Jul 7, 2020
    Last edited: Jul 7, 2020
  7. Serious Poo

    Serious Poo Shoegazing Member

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    Doug built mine with 6L6’s. I suspect there’s a few things with these circuits that you might not be aware of.
     
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  8. WeFixFlats

    WeFixFlats Respect The Clave

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    The public facing, tube diagram on the PRS customer site says EL34s.. Same with the tube decal inside the amp. Now if someone wants to spend the money and do something different, have at it...Glad I sold mine, years ago, never bonded with it...
     
  9. Tahlee

    Tahlee Tollywood Rhode Island

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    I love mine, but I run it into a Rivera power attenuator to make it sound it’s best. I like to really push the amp hard. Pretty much dimed. I dial in my Van Halen brown sound and I am in heaven. That is how I prefer to use this amp.

    But, that’s when I’m at home and I can sound how I want to sound. When playing out in a cover band, I set it for clean for the songs that call for clean, and then I use pedals to get my creamy distorted tones.

    [​IMG]
     
    #9 Tahlee, Jul 7, 2020
    Last edited: Jul 7, 2020
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  10. myoldfriend

    myoldfriend New Member

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    Appreciate the feedback All, thank you; looks like everyone was right on.. I'm just relieved that I wasn't cooking the circuit! I've got a pair of KT77s off to the side that are going for a test drive after a re-bias... :D

    Seems my head left the factory with EL34s:

    [​IMG]
     
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  11. myoldfriend

    myoldfriend New Member

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    Thanks mang!
     
  12. Tahlee

    Tahlee Tollywood Rhode Island

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    This amp will not let you down. I have soooo many hours of play time on mine. Four hour band practices and four hour gigs week after week for years, and countless hours at home.

    I just got some new tubes for mine, but I stuck with the Winged C EL34s. I thought long and hard and almost got some KT77s, so I am looking forward to hearing how you like them.
     
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  13. Tucson Thump

    Tucson Thump Mint Heavy Relic

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    What a nice amp/cab setup!
     
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  14. bodia

    bodia Authorities said.....best leave it.....unsolved

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    Love the Hot Pink Axis. I had one in the same color, but the first year of the EBMM Van Halen partnership. I loved the neck on that guitar. Wish I would've kept it.
     
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  15. Tahlee

    Tahlee Tollywood Rhode Island

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    Thanks! I love the Axis. Pinks are super rare. I had that video game button killswitch installed. That’s a keeper.
     
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  16. bodia

    bodia Authorities said.....best leave it.....unsolved

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    This was my EBMM EVH....a 1991. I traded it in for a McCarty in '96 or '97

    [​IMG]
     
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  17. Tahlee

    Tahlee Tollywood Rhode Island

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    The pink and the green EVHs command TOP dollar. Even getting your hands on a pink Axis can be expensive. But worth it. I’ve owned mine for about ten years.

    Mine has black hardware now, including a Floyd Upgrades tremolo with a huge titanium block.
     
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  18. myoldfriend

    myoldfriend New Member

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    No surprises with initial results when compared with the 6L6GCs using a Heritage H535 with ThroBak Pre-T 301s thru a Morgan open-back 1x12 with a vintage JBL D120F. According to my tin ears, I'm hearing:
    • Less pronounced mids.
    • Tighter bottom end.
    • Slightly enhanced upper mids.
    • More creamy breakup.
    • More pronounced delta between the HX and DA toggles with the HX side giving up more bass.
    YMMV...

    [​IMG]
     
    #18 myoldfriend, Jul 8, 2020
    Last edited: Jul 9, 2020
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  19. Alnus Rubra

    Alnus Rubra Loving nature’s wonders

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    I heard the riff from “Panama” in my head as I was reading this post!

    Just love the wealth of knowledge on here and how great you guys are!
     
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  20. Tahlee

    Tahlee Tollywood Rhode Island

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    hahaha, funny that you mention Panama, because that is one of the songs that my band plays, so that is indeed a song you would hear me practice in Tollywood (my music room).
     
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