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PF-20T tube rolling strategy

Discussion in 'Amps and Cabs [BG]' started by Seth Miller, Sep 10, 2016.


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  1. Seth Miller

    Seth Miller

    Jul 10, 2014
    Colorado
    image. So, I finally bought one. Love it. I'm completely new to the tube rolling game. I've attached a pic of the tubes I ordered to experiment with.

    What is the best way to go about this? I'm thinking: leave the ruby in v2 and start swapping out v1 to start. Or would changing out v2 make a bigger difference.

    Also, what combination of the new ones would work well together? I suppose if I had more money and was more clever it have bought pairs of each of these.
     
  2. JimmyM

    JimmyM

    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    In my PF-50T, the only one that makes any difference to my ears is V1. And I did a little tube swapping myself, with a new Tung Sol and a couple of NOS tubes, and I thought the Tung Sol and NOS tubes made it too bright and tight. But it's fun and doesn't cost much, and it's certainly less expensive than a crack bender, so have at it :D
     
    mbelue, Microbass, AstroSonic and 2 others like this.
  3. Seth Miller

    Seth Miller

    Jul 10, 2014
    Colorado
    Thanks!
     
  4. Muckaluck

    Muckaluck

    Oct 11, 2005
    Whitby, Ontario
    I would be interested to hear how that gold lion sounds compared to the others. Please keep us updated.
     
  5. Seth Miller

    Seth Miller

    Jul 10, 2014
    Colorado
    I haven't really had a chance to turn it up enough to get a really good feel. It seems like it's not lacking in the warmth dept from what I can tell. It's in v1 now as a matter of fact.
     
  6. Mikeee71

    Mikeee71 Supporting Member

    Sep 6, 2013
    Tung sol's will brighten the tone up a bit but I always felt they were thin sounding in the lows and mids! I would go JJ's
    Be careful with the long plates some are very sensitive to vibration.
     
  7. Seth Miller

    Seth Miller

    Jul 10, 2014
    Colorado
    Right now I have tube amp doctor power tubes in. Preamp tubes are gold lion v1 and a tube amp doctor. I'm really liking the way it sounds. One thing I noticed with the stock tubes is that I was hearing a sort of vibrato effect that wasn't pleasing on the lower notes. Too much of a good thing maybe. Now it's still appreciable but tightened up quite a lot. Very musical. Idk if I'm explaining it well.
     
  8. PianoOfDoom

    PianoOfDoom

    May 30, 2011
    NYC
    Bumping this oldie, as I have a PF-20t and 210av on the way.

    I've been impressed with the Russian Gold Lions in my mic pre, so I'm wondering if it's worth it to try them out in the Ampeg. I also love the TungSol pre/JJ power combo in my Vox AC15, but in both cases here, I'm not sure the previous success will translate into a great bass amp tone.

    Any updates from tube rollers on the effect of swapping the preamp (or power amp) tubes in the PF-20t? I'm going for a very metallic (as in the substance, not the musical genre) roundwound/TBird tone, like the Birthday Party or late-career EN/Alex Hacke. This is strictly for recording, probably with either a tube mic or Beyer M88. I may pop for an RE-20 if warranted.
     
  9. Wasnex

    Wasnex

    Dec 25, 2011
    I don't have any experience with the PF-20t, but maybe some of my experience with tube rolling will help anyway.

    Regarding current production Genalex Gold Lions...I have rolled these tubes in several amps and generally preferred the standard Chinese version over the Russian B759 premium version. Both Gold Lions tend to have fairly strong and well defined/articulate mids.

    The brightest, nastiest 12AX7 I have rolled is the EHX 12AX7. IMHO this tube might be good for high gain guitar, but I wouldn't use it for anything else. But some people like it in their bass amps. The EHX is one of the less expensive 12AX7s so at least your not risking much.

    My experience is the EHX 12AX7 is very high gain, has weak bass and lots of treble. Perhaps it would useful in a dark bass amp with too much low end. In my experience this tube breaks up fairly easily, but does not transition into distortion smoothly or evenly across the frequency spectrum. So if you want a tube that is touch sensitive to ride on the verge of breakup, not a good choice. If you want bright, always on, heavy distortion, it might work for you.

    The best touch sensitivity I have achieved in a bass OD channel has been with the Chinese Gold Lion. This tube produced the smoothest, darkest, creamiest, and most controllable distortion out of about 7 current production tubes I tried. With this tube, the fundamental remains focused without the low end washing out at higher gain settings than the other tubes I tried. Sino 12AX7B was almost identical, and I wouldn't be surprised if it is the same tube...just not screened to the Genalex standard. It's likely Shuguang makes both.
     
  10. PianoOfDoom

    PianoOfDoom

    May 30, 2011
    NYC
    Wow! Thanks for the long and thoughtful post. I am happy to hear that the cheaper Gold Lions may actually sound better! I guess that's a good place to start then. I may also take the TungSols out of my Vox temporarily to compare.
     
    Wasnex likes this.
  11. JimmyM

    JimmyM

    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    Why not do that with the Gold Lions, too?
     
    Wasnex likes this.
  12. PianoOfDoom

    PianoOfDoom

    May 30, 2011
    NYC
    Only one of my Lions is a 12ax7, and the PF needs two. Plus, I moved it into an La2a comp clone, which is a pain to take apart :)
     
  13. Wasnex

    Wasnex

    Dec 25, 2011

    If you decide to crack open the La2a to get to the tube, try the Gold Lion in V1. Usually V1 makes the most difference. Also, you don't necessarily want an amp full of only one type of 12AX7. Sometimes using a combination of tubes in a specific order creates a very nice synergy. One of my favorite combinations for bass amps is a Russian Mullard ECC83 in V1 and JJ ECC803S everywhere else.

    When I am rolling tubes, I roll the contenders through one tube socket and select my favorite tube. Often I start in reverse order, so if the amp has two 12AX7s in the preamp, I start with V2.

    After I select the best tube, I roll the contenders through the next tube socket. You should do a least two rounds. I.E. Go back and confirm the tube you initially selected for V2 is still your favorite after you select your favorite for V1. If you have only one of a particular tube model, roll it through all positions so you can see where it works best...I would do this last

    Sometimes you wind up choosing a specific compromise based upon what the tubes do and what your goals are. Maybe one combination of tubes gives you the tight lows and articulate mids you like, but another gives you incredible distortion. Since you can't have both, you must choose.

    I recommend taking it it slow and writing down your impressions. Tubes do behave a bit different from one circuit to the next, but in many circuits the exhibit recognizable similarities.
     
  14. JimmyM

    JimmyM

    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    I've found that only V1 in the PF-50T gives you any sort of change to speak of, and I can't imagine it would be any different for the PF-20T. But taking apart stuff that's a pain...that's a darn good excuse not to try it. It's certainly kept me out of trouble more than once :D
     
    Wasnex likes this.
  15. PianoOfDoom

    PianoOfDoom

    May 30, 2011
    NYC
    That sounds like a good strategy. Thanks again! I've got some extra JJs already, TungSol in my AC15, and I guess I can dig out the Gold Lion from the comp. I'll order up one of the Chinese Lions and maybe a Sovtek, as I read some nice reviews of those as well.

    Still cheaper than when I tried to find a set of roundwound strings that I like.
     
    Wasnex likes this.
  16. PianoOfDoom

    PianoOfDoom

    May 30, 2011
    NYC
    I completely botched my Thunderbird pickup wiring and had to take it to a shop. Years of easy PBass surgery made my overconfident in my tech skills. So yeah, I should definitely think before I crack things open :). The comp isn't THAT bad, but it's 500 series, so lots of tiny screws and tight compartments. I'll probably do it anyway.
     
    JimmyM likes this.

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