Troubleshooting my Laney Ironheart Studio

Discussion in 'Pickups, Electronics & General Tech' started by neurosis, Jul 19, 2019.

  1. neurosis

    neurosis SS.org Regular

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    I have a problem with my Laney and want to see what you guys think.

    I have had amps serviced before but always thought I should learn and try to do it myself eventually. I think that time has come. I have no experience fixing tube amps but have been reading on it and feel confident attempting a diagnosis with a little help and from what I've read and seen changing tubes, which I think is what I need in this situation won't be too hard.

    The lead channel is working perfectly fine but the clean and Rhythm are not. Since the issue is focused on one channel only but everything else works perfectly fine it must be some tubes.

    How would you test what tubes need to be changed? Is there any visual cue I could take or do I have to open up the head and get my multimeter in there?

    Thanks a lot for any advice.
     
  2. Descent

    Descent SS.org Regular

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    What's the problem really? You don't describe the issue.

    I think generally the 1st channel is the first preamp tube, but see if you can find a schematic on your amp and post it here. Depends on the design but you'd be tweaking preamp tubes afaik.
     
  3. mnemonic

    mnemonic Custom User Title

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    You can get a new 12ax7 and try swapping it into each slot to see if anything changes. It only has three preamp tubes so it shouldn’t take long.

    You’ll need to open it to access the tubes. Don’t touch anything else in there when changing them, especially if the amp is on and plugged into the wall (high voltages). Most amps have bleeder resistors to drain the voltage off slowly after the amp is turned off, but I wouldn’t make any assumptions.

    I looked online and I couldn’t find a tube layout for the IRT studio. I would assume two preamp tubes and one is the phase inverter (V3, if they are labelled on the pcb), unless the power amp is some sort of dual single-ended design or something (doubt).

    If my assumption is correct, V3 is in the power amp and a problem there would mean no channels would work. So I’d focus on V1 and V2. But I’m skeptical they’re the problem as the gain channel would probably use both. So if one was blown, the gain channel shouldn’t work.

    First thing I would do is clean out all the jacks with contact cleaner (deoxit or similar) before messing with tubes.

    How are you changing channels? Footswitch or with a switch on the front of the amp? Both don’t work?

    Check the silly stuff, make sure you don’t have a channel volume on zero.

    Plug your guitar into the FX return and cycle though the channels. If you get sound on all channels you’ve isolated the problem to before the FX loop.

    Do those do audio over USB? I’d plug that in also and see if the problem persists using usb audio.

    After that you can try swapping preamp tubes. If there is no change after all of that, you might have a problem with the switching system. Dead relay, broken switch, or a loose solder joint.
     
  4. diagrammatiks

    diagrammatiks SS.org Regular

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    Have fun taking this thing apart.

    3 preamp tubes. Last one is the phase inverter.

    Although all the tubes are shared between both stages. So if only the lead channel works it still might not be a tube issue.
     
  5. lewis

    lewis SS.org Regular

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    Probably sounds silly to some - but my mentality was to also do a full retube once even one tube appeared to have gone. Kept the amp always sounding fresh and sweet.

    I moved on from tube amps quite quickly anyhow once the Kemper was released.
     
  6. neurosis

    neurosis SS.org Regular

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    Sorry for the confusion. This amp has a Clean, Rhythm and Lead channel. Clean and Rhythm share the same EQ. I hardly ever use the lead channels which is still working perfectly fine. When I switch to the Clean or Rhythm I get no sound.

    Thanks a lot for the advice.

    I couldn't find a schematic either but there's a youtube video with a person taking the amp apart and demonstrating how to bias. I also checked other videos that showed how to safely discharge the amp in case it had some current still on it. I'll read and learn some more before I attempt anything, though and as you recommend try not to touch anything other than those tubes.

    Going to follow your advice and test the FX loop next. I tried switching both with the foot switch and the front panel switches but the issue remained the same. Only the Lead channel works.

    Interesting!!!! I thought the preamp and power were separate and tubes were engaged based on channel selection. I actually thought this is how every amp works. I have a lot to learn, obviously.

    Yeah I am mostly using the Axe Fx these days and was considering selling this head many times but it's a great amp to do a quick plug and play and not have to go through my computer into the monitors and I love how it takes pedals. So want to fix the issue. That way if I don't keep it at least I'll have something worth selling.
     
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  7. neurosis

    neurosis SS.org Regular

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    So I got to run through all of your test and here are the results:

    Over USB only the lead channel works. The dry/direct also works but with less volume (to be expected I think).
    Plugging directly into the FX loop bypasses all the EQ controls but I switched through all the channels and all of the worked!
    I tired the 1W and 15W input for all configurations and it gave the same results.

    So what do you think this is? only thing I have left to try is a tube swap I guess. Going to see if I can get ahold of some new preamp tubes and see fi that helps.

    What is your opinion based on these results?

    I cleaned all the inputs and outputs but it seems to be an issue with the Clean and Rhythm which seem to share some circuitry.
     
  8. mnemonic

    mnemonic Custom User Title

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    Sounds like the problem is isolated to something specific to the preamp, on just those two channels.

    I doubt it’s a tube since the lead channel is working (and should be using all tube stages available) but if you can get a new 12ax7 you can try swapping it into each slot to see if there are any changes.

    It’s hard to say from a distance, I think it may still be a problem with the switching system (bad relay or broken switch, maybe a loose solder connection somewhere).

    The amp is probably using using ribbon connectors or other small molex plugs to connect the various boards inside it together, you can try wiggling those around and making sure they’re seated firmly. I had a problem with the cab sim of my Fryette GPDI not working, it was just a loose plug.

    You could try emailing Laney, there may be some known issues or they may be able to point you in the right direction.

    Otherwise a visit to a tech may be in order.
     
  9. neurosis

    neurosis SS.org Regular

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    Thanks a lot for sharing your knowledge. It's helpful. Lately I have been in full DIY mode but you may be right with the recommendation to see a tech.

    I think I am going to email Laney about it and in the meantime open it up and see what's going on. I bought it new in 2013 if I remember correctly. In all of that time it was mildly used (as I favored my fractal and VSTs) but when I moved it proved itself to be a great pedal platform so I was mainly using it on the clean. Therefore it's a bummer that it's no longer working.

    if you are right and it's just a few ribbon connectors I should be able to set those back in place. I haven't smelled anything so doubt it overheated and affected a bad joint or something like that.

    I am wondering if it may have been an issue with one of the potentiometers. The gain was scratchy on the clean channel for a while. Maybe the interior mechanism bent out of shape and broke? The temperature changes where are crazy and it can get really humid so maybe it's affected some kind of mechanical failure like you suspect.

    I'll see you posted. Thanks again!
     
  10. mnemonic

    mnemonic Custom User Title

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    You could try cleaning out the pots. If you can see the back of them you may be able to spray some contact cleaner in, then turn them back and fourth. When it’s off, of course.

    I’ve had scratchy pots before and I have had a busted one in a pedal I made before (tone knob in a tubescreamer clone), and while they can be scratchy and annoying, I’ve never had one 100% kill the signal. Even on the broken one, there were dead spots but it made noise as I turned it.

    In fact you could try that, with the amp on, on the Crunch or rhythm channel, try moving all the knobs back and forth to see if you can get any sound out of it.

    If you hear the same scratchiness as you move the knobs then you’ll know the problem is before the tonestack.
     
  11. Hogie34

    Hogie34 SS.org Regular

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    Even though the lead channel is still working, it could still be a preamp tube. The 12ax7 has two sides / stages per tube. Depending how it’s wired , the half of the tube that is bad, may be your clean channel stage. Buy a set of known , tested , good tubes. If it’s still having the same issue, it could be an issue with your switching relays. Tubes are the cheapest self diagnosing method. After that, you’re best taking it to a tech. Learning on a single channel amp is one thing. Learning how to repair a modern channel switching circuit is a whole new can of worms with no experience.
     
  12. neurosis

    neurosis SS.org Regular

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    Alright! Tonight I had a little time to troubleshoot this thing. I adjusted and replugged all the different connectors and replaced all the preamp tubes for Tung Sols. On closer inspection I am pretty sure the v1 one was shot. I removed all the dust, put contact cleaner on all the switches and pots and now it works. Thank you all so much for the advice. I learned a bunch of new stuff and it was fun. What wasn't fun is the spider I found in the thing, LOL.
     
  13. diagrammatiks

    diagrammatiks SS.org Regular

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    I just wish this amp wasn't such a bitch to take apart.
     
  14. Hogie34

    Hogie34 SS.org Regular

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    Awesome! Glad to hear you got her working.
     
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  15. neurosis

    neurosis SS.org Regular

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    I am no expert but it looked overall clean and easy to understand for an electronics noob like me. I didn't mess with more than the connectors and the tubes, which went ok but going under the PCBs to touch any of the components can't be that easy. What I didn't like is how the front panels has that lip that goes over the pots. It made accessing the parts to add dioxit a little annoying. The tubes are also really close to this lip. But otherwise it's a really nice amp TBH. I dig it.
     
  16. neurosis

    neurosis SS.org Regular

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    Thing sounds a lot more clear now, too. Really happy with it.
     
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  17. diagrammatiks

    diagrammatiks SS.org Regular

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    I mean most traditional amps are 4 screws on the bottom and 4 screws for the back plate.

    This thing has like million screws. Although this reminds me my tubes need changing as well
     
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