Blackstar Artist 15 power tube question

Discussion in 'Amp Central Station' started by virge0110, Apr 17, 2019.

  1. virge0110

    virge0110 TDPRI Member

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    Hi!

    A few months back, I picked up a Blackstar Artist 15 for a great price. I really enjoy channel 2 of the amp, but I was thinking about trying out some different tubes to see if I can get more/earlier saturation from the amp.

    I was wondering if anyone knows if it is possible to use other tubes besides 6l6's in the power amp. For example, I have heard that 5881's can be swapped with no issues.
    I was wondering if it is possible to use those or 6v6, el34 (not very likely) or other tubes as well?

    I am thinking about trying out some higher rated 12ax7 tubes in the preamp as well.
    The amp is cathode bias and I assume is running each tube in class A or it may just be the transformer that allows it to be 15 watts and use 6l6 tubes.


    Any advice or insight is appreciated!
     
  2. VintageSG

    VintageSG Friend of Leo's Ad Free Member

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    You may get away with JJ 6V6. EL34?, nah. Haunt Ebay to find a matched NOS pair of the Russian 6p3s ( their take on the 6L6 ) from the cold war era. The JJ 6V6 has a fairly well established reputation for coping in such swaps. Note that if you did go down that route, you may need to alter the impedance selector/speaker jack to accommodate the change. For the life of me I can't remember which way to go though!.

    In my ( limited ) experience, the Russian valves begin to saturate earlier, then go to a lovely zone of compression with quite smooth break-up. It isn't a major change, but it's there.
    Other things to consider are a speaker with lower efficiency or an attenuator so you get to turn the amp up more. An attenuator is one of those things you scoff at owning, until you own one, then you wonder why you didn't buy one earlier. Crank the amp, keep the neighbours happy, unplug the attenuator when playing out.

    Can you safely measure the applied voltages?.

    As to 'higher rated', in terms of gain, all correctly functioning 12AX7 valves are pretty much of a muchness. Sonically, there can be a world of difference. V1 is usually the money valve. Personal preference plays a huge role. In terms of new production, my personal ( and it's just that ) is for Soviet ( Sovtek/EHX et al ) --> JJ --> Ruby 12AX7HG5 ---------------------> anything else made by Shuguang. I have some old Brimar, Mullard, Mazda and Toshiba valves and just at the point of crispiness, they all have a slight edge.
     
  3. beninma

    beninma Friend of Leo's Silver Supporter

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    I think you might be happy just trying out different tubes of the model that the amp is designed with.

    Check out some of these link they have some examples of variance between different 12ax7 tubes:

    https://www.amplifiedparts.com/tech-articles/12ax7-comparison-current-made-tubes

    https://www.tubedepot.com/tube-comparison-tool

    https://www.thetubestore.com/12ax7-tube-reviews

    I replaced my JJ 12ax7s in my Orange Rocker 15 recently with EHX ones and there is an audible difference that is consistent with some of the test data on this page. I wasn't necessarily looking for more or less gain, that might be harder to come by, but the test data implies some of the tubes would add or subtract some small amount of gain.
     
  4. virge0110

    virge0110 TDPRI Member

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    I do not really want to try to measure the voltages, as I have no idea what I am doing.

    I'm mainly wondering if I can put something like a 5881 directly in without any issues. The 6v6 was mostly out of curiosity, since I like a lot of amps that use those power tubes.

    As for the gain/volume.. its not so much that I can't get drive tones at lower vs higher volumes. The amp itself is by design not made to have a lot of gain in it.
    I was thinking I could get a little more gain out of with hotter preamp tubes and maybe some sooner/more compression with lower output power tubes.
     
  5. beninma

    beninma Friend of Leo's Silver Supporter

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    You would need to check with Blackstar to find out if your amp requires rebiasing when replacing tubes.

    I fiddled with my Orange because it's Cathode biased and there's nothing to adjust.
     
  6. virge0110

    virge0110 TDPRI Member

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    Mine is also cathode bias. Blackstar is also not easy to contact, but I am trying haha
     
  7. corliss1

    corliss1 Friend of Leo's Platinum Supporter

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    Most modern 5881s would likely work in that amp buuuuuuuuuut any time you change the power tubes it's best to check the bias.

    Just because something is cathode biased doesn't mean that resistor value is correct for the power tubes you're working with.
     
    DaveTone likes this.
  8. beninma

    beninma Friend of Leo's Silver Supporter

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    That's too bad. My experiences with guitar businesses has been stellar.

    Too bad my experiences with local Techs have all been a bit sour! (Guitar stuff, not amp stuff)
     
  9. Rick330man

    Rick330man Tele-Afflicted

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    I heard one where a gentleman stuck a JAN Philips 6L6WGB in there. It sounded pretty good.
     
  10. virge0110

    virge0110 TDPRI Member

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    I got a reply back from Backstar:


    “The artist amps were not designed to accommodate a variety of different output tubes. Attempting to use different types of output tubes would require some modifications by a qualified repair-level amplifier technician, and would void its warranty.”
     
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