Custom 50 combo. Lead channel cut out.

Discussion in 'Amplifiers' started by jmp22684, Nov 13, 2017 at 8:09 PM.

  1. jmp22684

    jmp22684 New Member

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    Howdy!!

    Well I had a wonderful experience this weekend!! I play out regularly and just started gigging with the Custom 50, leaving my mesa road king at home. Half way through set one I went into a solo.... the quietest solo ever! packed house of dancers and boom.... blank stares, pissed of stares from the band mates. Luckily I run a Helix into a gizmo for channel switching and used to run only the Helix direct and still had that preset list handy. Had to stumble through the rest of the night which SERIOUSLY ticked off the drummer. I believe the exact words were, "Why doesn't he just get an amp that works." (not quite exact.... add some vulgarity to that) I understand, I should stop goofing around with these cheapo mesa's and prs amps... maybe I should get a peavey.

    Anyways!!

    I went to the box of tubes i keep handy in the car, but couldn't get to it in enough time between sets.

    Thing is.... if I tapped, or smacked, the top of the amp the Lead channel would cut in and out. At one point it seemed to be fine.... but come next song it was out again. This was all still during the first set before running an xlr to the helix. I figured loose preamp tube. But those seemed to be pretty tight.

    I've got it on my bench right now and all solder joints look solid.

    I'd consider it being a bad preamp tube, but that wouldn't cut in and out, it would just be dead.

    Trying to replicate the issue right now.

    Its pretty new, but out of warranty as I bought it as a returned open box item and PRS doesn't have a transferable warranty. She's new enough that I had to break in the speaker before the frequencies weren't ripping my head off.

    Being I play out regularly as a pretty good portion of the income I use to support my family... What I need is reliability, and right now the PRS just turned into the dog I don't trust because it bit me.
     
  2. DreamTheaterRules

    DreamTheaterRules Archon owning member

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    This is one of those "I understand, but I don't" moments. Any amp can have an issue. If it's a tube, it's not even related to PRS. IF it's something else, then it's one of the rare ones that have any issue. Get it fixed.

    Saying you don't trust it is like buying a new car that you know is a good one and a reliable brand, and something goes wrong 6 months in and you saying you don't trust it anymore. Fix the issue at hand and it will probably last you 50 years before anything else but a tube goes out. I understand the disappointment. I even understand the stupid comments from the drummer. Don't understand the trust issue. These are good amps. If you buy some cheap crap and it does this, I could understand the fear and trust issues.

    This is the good stuff. You've nothing to fear, but fear itself. I just made that up.
     
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  3. bodia

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

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    I'm with DTR. I'm just tossing out a random thought, but I've had a similar issue with poor power, or too much on the circuit. Odd that it would only occur on the Lead channel, so probably not a power issue. That and banging on it wouldn't help, if it was power. Ah, forget I said anything except, I'm with DTR
     
  4. andy474x

    andy474x Knows the Drill

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    Have you tried changing the preamp tubes out, not just seeing if they're loose? IIRC, the V1 and V3 tubes service the lead channel. V1 being closest to the input jack. 1/2 of the V1 tube goes to the clean channel, 1/2 to the lead, and all of V3 to the lead. So try swapping those out with a known good tube, and the phase inverter and effects loop tubes, just for good measure.

    Also, have you tried switching with the toggle on the amp, rather than the footswitch? Just a thought.

    Maybe others can chime in with possible tube related problems. Otherwise, yeah, I would say you've possibly got a loose solder joint somewhere. Don't give up on the amp. I love mine to pieces, it's a wonderful piece of equipment and I honestly don't know what I would replace it with if not another PRS amp.
     
  5. LSchefman

    LSchefman Hears Tones

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    I’ve used 2 PRS amps for my studio work that I make my living with for nearly 4 years. The only negative thing that ever happened was I once had a bad Russian tube that blew.

    The Allman brothers used PRS amps on several tours; Grissom uses them; Warren Haynes uses them; so does John Mayer. They’re extremely well built.

    Your band mates seem unusually dickish. Get the amp fixed and tell them to get over themselves.
     
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  6. DreamTheaterRules

    DreamTheaterRules Archon owning member

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    When I bought my Egnater Tweaker, it had a thing where when I'd turn it up a little it would just intermittently cut out. I called them, Bruce said to check tubes first. Of course, I visually already had. Took the back cover off for a closer look and was going to remove every tube, spray it with DeOxit and put it back in. Noticed one tube was not fully seated in the socket. First, I pushed it down where it should have been and played it for three days. Never had the problem again! After three days I took them all out like I intended, gave them all a shot and reseated them. Played those tubes for over a year before I replaced any of them, and never had an issue.

    Either during shipping it got knocked a bit loose, or it was just not properly seated at the factory. Thought I had a "problem" but it was just that one tube not being fully seated.
     
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  7. jmp22684

    jmp22684 New Member

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    Far warning: I ramble!! feel free to skip over the italics, lol. Bold = main point. That's my method of courtesy.

    I'll have to choose my wording a bit more carefully. Didn't intend the last sentence of the post to gain so much popularity.

    I know its a great amp. Both the Mesa and PRS are excellent amps.

    I haven't been able to replicate the problem. ANNNNNDDDD I don't know that I can go in with known good tubes anymore. I kept all my tubes in a shipping box, tubes in their old boxes some in worse shape than others. Mother in law, lives with us because she's not exactly the brightest crayon in the box.... as in its becoming an issue I need to find a solution for that our 4 year old is out smarting her. WELP!! She tossed that box of tubes, which was sitting in the entry way after the Saturday gig, into the trash can outside. Garbage pickup was Monday, luckily I caught it just in time. But the tubes were all over the place, some are rattling now, a couple were completely smashed. This box had 4 6L6's (2 of them I pulled from the custom 50 Saturday night), 4 5881's, 3 EL34s, 10 various preamp tubes.

    So guess who's buying more tubes!!


    I'll look around the forum but will ask here what your thoughts are on tubes.... I'm wanting to buy all new tubes for the amp being these are the ones that came with it, peace of mind. I'd also like to buy a new set of spares as well. So I don't want to go too high in price.

    Suggestions?

    Current tube that came with the amp: JJ Preamp, Ruby Power


    Want to avoid JJ, bad experience with JJs EL34s constantly blowing out in my Road King after only a week of use (Its new mesa tubes I decided to roll over and grab have been running strong under heavy use). I do have 4 JJ5881s in there, haven't blown up yet but one is definitely micro-phonic! Their preamp tubes gave me trouble in the boogie as well..... Low and behold I pull the chassis on the PRS after having the lead channel cut out.... JJ preamp tubes. LOL. It may only be bad luck but JJ tubes have consistently given me issues, eurotubes tech support said would need an amp tech, which have been permanently solved by switching to a different brand. So .... ya know... They just don't work for me.

    Want to avoid Groove Tube. In another thread here I read someone say they added too much harshness to the amp.

    So options may be:

    Power:
    Svetlana
    TungSol
    Mullard
    TAD


    Being a combo amp, I read that the TungSol and Mullard are "ideal" @ https://www.tubesforamps.com/best-6l6-tube-review

    Or stick with Ruby. But, and you all know this, it would be fun to try out some other guys in the PRS.

    As far as Preamp tubes I am open to suggestions as well!!! My biggest pet peeve has always been something sounding harsh, so that's something I'd like to avoid. To the point I couldn't stand my Mark V combo I owned for a short time. Sounded great when I bypassed the preamp and ran my own to the return, so I know it wasn't the box or speaker. Just a shrill, take your head off, frequency to the preamp.

    The basics: I play everything from Hendrix, Killers, STP, Foo Fighters, Clapton, Floyd.

    I'll keep doing some reading. Either way I'll plan on placing the order ASAP so I can get these in before this weekend's set of shows (I'd bring the mesa, but that a WHOLE other post of issues.... that definitely needs to see a tech. second hand old girl that was not taken care of at all, but I got for a killer price. Project amp. Last show the volume fluctuated so much with a bouncy stage it sounded like I had a tremolo pedal running.... REALLY bad, poor girl).
     
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  8. dmatthews

    dmatthews Dave's not here...

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    After a looooong time, the power tubes in my H (Custom 50 older brother) went. Recommendation from PTC was Ruby so I went with that. Tried some Groove tubes but didn't like them. Ruby gave me that tone back.
    I have a Custom 50 as well and it is killer. Got a lot of hours on it, and I got it used.
    Sorry to hear of your trouble though. I'm sure it'll be short lived.
    Oh... and tell your drummer to STFU. :D:p
     
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  9. LSchefman

    LSchefman Hears Tones

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    All of the new reissue tubes labeled Tung Sol and Mullard, etc., are simply labels slapped onto Russian and Chinese tubes. Nothing wrong with that, but they don’t have the reliability of the original tubes, and they’re actually poorly made. For example, the mica spacers don’t fit the glass interiors as well, causing tube rattle; the welding of the plates isn’t clean, and sometimes they’re simply folded and crimped into place; the getters are junk, etc.

    In the old days, when items like airplanes and medical equipment had to rely on tubes, they were simply made better.

    So for a few years I’ve been buying NOS tubes - New Old Stock, unused older tubes that were stored (the time of storage doesn’t change the tubes, there’s a vacuum inside, so no deterioration).

    NOS 6L6 WGB military tubes by Phillips aren’t all that expensive. They’re upgraded 5881s that break up a little sooner than the 6L6GBs, they’re a bit smaller, but they’re less likely to rattle, they last longer, and they sound better (to me, anyway). If memory serves, they were actually US-made for Phillips back in the late 70s or early 80s, when tubes were still being made here on quality equipment with quality parts.

    In new tubes, I had a set of Tung-Sol reissues come with a Two-Rock a few years back. They sounded pretty good and the ones I had didn’t rattle, but it was a head, not a combo.

    Tube rattle bugs me in combos; I have a Mesa Lone Star whose tubes rattle like crazy, and I really need to replace those 6L6s with the Phillips NOS. The Mesa blew its rectifier tube after only a short time, and the set of tubes it came with had three go microphonic in the first couple of months. Mesa’s service tech repeated what I knew, that new tubes basically aren’t very good, and have been getting worse over the past few years. I made the mistake of replacing the tubes with new Mesa tubes, and I’m sorry I did. The amp really can’t be used for recording at anything like normal volume unless I hook up an extension cab.
     
  10. jmp22684

    jmp22684 New Member

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    meh, no trouble. **** happens. I like projects, but I also like reliability. The mesa is my project and the PRS is supposed to be my reliable girl. Gotta do a tube roll and see what happens. In the meantime I'll be keeping an xlr run to the helix ready to switch to the modelling just in case I have another incident after replacing the tubes.
     
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  11. dmatthews

    dmatthews Dave's not here...

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    Ten bucks says you won't need the XLR, but I don't blame you for running it... Murphy's law...:cool:
     
  12. jmp22684

    jmp22684 New Member

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    Now I always assumed that if an amp called for 6L6GC's that it wasn't a good idea to put in GB's?

    Never purchased NOS tubes... but I would LOVE one that doesn't rattle in my amp so quickly after putting them in.

    Any suggestions on reliable resources?

    currently browsing www.nosvacuumtubes.net.... Though not sure what to make of what they have listed in their cheaper tubes.... especially because they list JJ tubes, which as far as I know are not NOS.
     
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  13. jmp22684

    jmp22684 New Member

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    With ya!!

    Thank god I still had the helix though.... Plan was to sell towards full midi controlled analog rack rig, in fact the size of the custom 50 chassis was a selling point to me as I plan on racking it with the pedals.

    slowly making my purchases towards that. So far I have: RJM RG16 loop switcher, and a ProStage Analog midi Wah as well as their volume (I always keep an end of chain Volume run @ 50% incase I need to go up or down in a hurry for those "UH OH!" moments.

    I was going to make all the final purchases last month, put it together and sell the helix.... had I done that I would have been up the creek this past weekend as I don't really intend on getting any distortion pedals.
     
  14. andy474x

    andy474x Knows the Drill

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    If memory serves, my first PRS amp came with Tung Sol power tubes (5881) and they were great. But, TBH, I've had just as good of luck with JJ tubes as anything else. I also ran JJ 6L6's in that amp for quite a while with no problems, along with other amps. I had a Tung Sol 12ax7 in the preamp of my Custom 50, V3 for the lead channel, I suspect it was defective because the lead channel opened way up with a new JJ. Both of my PRS amps, as well as some of my other amps, have had JJ preamp tubes in them for a long time with no problems, including gigs, moving trucks, etc. So, I guess steer clear of them if you want, but just thought I'd toss my 2 cents in.

    In regards to your EL34's crapping out, from what I can gather, no one makes good EL34's anymore, so don't take it as a brand issue. The Groove Tubes 6L6's in my brand new Vibrolux rattled for a while. It stopped recently and I'm going to let a sleeping dog lie, but I'm not super impressed with them far, especially because I think most GT's are just relabeled tubes. I may get another set for the Vibrolux down the road, but only because Fender/GT grades them now so you can replace with a like rating and not have to have the amp biased.

    In my experience, if a preamp tube is going to crap out on me, it's going to be rather early on. So just make sure you get some hours on your amp after changing them. Unfortunately, tubes are tubes and you can have duds. Best thing you can do is find the tone you like and keep spares on hand, unless you're having an abnormally high fail rate with a certain brand.
     
  15. jmp22684

    jmp22684 New Member

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    considering trying out:
    Preferred Series 6L6GC - something new I haven't seen
    or
    Tung-Sol 7581A - Looked interesting and had good reviews. One from an Archon Owner: http://www.thetubestore.com/Tubes/6L6-5881-Tube-Types/Tung-Sol-7581A

    Now I'm not entirely sure on preamp tubes. Seems to be discrepancy between manuals, and the PRS site as well. Nor do their manuals match my fuse layout of 3 accessible: 2x 10A/250V, 1x 1A/250V

    Also any preamp tube suggestions welcome. I've wasted too much time today reading and searching, I must get ready for other things now.

    According to the PRS website this amp has two PI tubes, no effect loop tube, takes a 12DW7 but has no position for it: :p

    Preamp Tubes (3) 12AX7, (2) 12AT7, (1) 12DW7
    PREAMP TUBE POSITIONS & FUNCTIONS
    V1 12AX7, Common Input Stage
    V2 12AX7, Lead Channel
    V3 12AX7, Clean Channel
    V4 12AT7, Reverb
    V5 12AT7, Phase Inverter
    V6 12AT7, Phase Inverter
     
  16. LSchefman

    LSchefman Hears Tones

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    Sorry, that was a typo on my part. I meant GCs.

    I believe the PRS HXDA can take 5881s, if memory serves. I have it loaded with NOS Siemens EL34s, though, and like the way it sounds with them. You might want to check with PRS re: your own amp.

    Both of my PRS amps are loaded with NOS preamp tubes; the DG30 has NOS Brimar 12AX7s (CV4004 military box plates) and the HXDA has NOS Mullards.

    I’m kinda fussy, I guess. The PRS amps are my main thing, the Mesa, not so much, though I do occasionally find a need for it.
     
  17. jmp22684

    jmp22684 New Member

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    Okay!! I do want to grab some NOS tubes, but I decided that I would wait to spend the money on that until after I build new boxes for the amp and ditch the combo setup. Don't want to add the stress to an investment.

    I grabbed the Tung-Sol 7581A Power Tubes and thought I'd give the Preferred series 7025 a shot in v1, v2 and v3.

    I have her biased pretty close to 30, they're within 1-2 of each other, so pretty close.

    However, with these tubes having a plate dissipation of 35 I was wondering if I should recalculate my bias setting. Pulling the chassis right now to grab the plate voltage.
     
  18. jmp22684

    jmp22684 New Member

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    Plate voltage = 460~464v
    Tung-Sol 7581A Plate Dissipation = 35w

    35w / 462v *.50 = 37.9 mA
    35w / 462v *.60 = 45.5 mA
    35w / 462v *.70 = 53 mA

    I still have her set around the 30 mark.... just wondering if I should adjust this a bit?
    have you guys ever strayed too far from the 30 +-5 spoken of on most prs amps?
     
  19. Boogie

    Boogie SuperD

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    The amp has to be designed for that swap. If it will take 5881s, you should be golden. I have old stock (as in, my dad bought them in 1953) USA Tung Sol WGBs and I would never drop them into my Twin or Bassman in fear of burning up those tubes. GCs are generally higher voltage and those amps supply the needed juice. I might be paranoid, but these tubes are destined for something special and I haven’t yet found the right amp. No sense wasting them on an experiment because there maybe another 50 years of service in them.
     
  20. jmp22684

    jmp22684 New Member

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    Got them all in and biased pretty close to 34.

    Ran her for 3 sets last night without issue!

    Wow do they sound nice!! I was blown away. They have a LOT of beef to them.

    The clean channel sounds fantastic, thick and not harsh at all.

    On the lead channel.... holy cow. They are heavy. It's the 1x12 combo. I usually ran with the mid shift pulled and the presence pulled for .... I can't remember. Amp is still up at the gig for tonight. But anyways... I had to push those back in, dial the bass back to almost 9 o'clock and kick on the bright switch.

    I did a palm mute, modest eq, gain (volume) around 12:30. It blew me back. Thick heavy thump on a palm mute. It was amazing. The kind you can normally only get out of a large cabinet, this little 1x12 was roaring!

    Almost..... Too much.... I like the boomy bottom end, but it was all in the bass frequency. I need to play with it more at home, but it was a little muddy, even with the bass dialed back and the mid and treble up a bit. This is where I really came to like mesa's eq (wasn't a fan until I learned how they gain stage it). But with that I feel like I could use treble to effect which frequency the mid was adjusting, etc... once learned I felt like I had a lot of control over the preamp, before learned.... pain in the butt to get a sound I liked on my Road King.

    I am going to try out some different preamp tubes in v2. I really liked what these tubes did, and at the moment it's too soon to say if it's the power tubes, preamp or a combination of both.

    So I liked what they did over all to the amp, going to play a little... but some how I would REALLY like to keep the thickness I got from the lead channel, but add a little more definition to it.

    At any rate, after I sit at home with her for a little longer, and get more hours on the tubes, I may very well find exactly what I'm looking for.

    Review at the moment and being I didn't have time to work out any negativities: I feel like it's a completely different amp. These blow the ruby power and JJ preamp tubes out of the water. Absolutely no contest. These are fantastic.


    Ohhhhh..... yes.... one thing I noticed: I always run a volume pedal at the end of the chain. When the pedal was low, and even adjusting the mast on the amp, the clean channel was REALLY thin and sterile. I didn't really notice this much with the previous tubes.

    I have a boss fv500L hooked up to my helix, which is run in 4 cable method: guitar into helix, send run to front of amp, amp send to return on helix, 1/4 out of helix back to the return on the amp. Seems return and send levels on custom 50 need to be all the way up to keep unity. As in with the helix not plugged in at all I measured output, then I plugged in only the send from the helix to the front of the amp bypassing the amps loop completely, adjusted to same level, then plugged into the effects loop and to get the same level keeping all things equal with and without the loop, they gotta be pegged. I know PRS says 2 oclock is the sweet spot. But there is a real output loss at 2 and I want everything unity beginning to end so that I get the same output with everything hooked up that I would as though I just plugged straight into the front with nothing else on the amp.

    If I could get away with zero pedals I would. I don't like what the helix and other pedals do to the amp, but I try to get it as transparent as humanly possible. Again, working on an analog rack setup at the moment. But the helix also serves as a good back up in case of emergency, as it did last weekend.
     

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