New Line Magnetic 508ia Integrated Amp

Discussion in 'Audio Hardware' started by GoldprintAudio, May 20, 2016.

  1. adamaley

    adamaley Forum Resident

    I enjoyed a Coincident Statement Linestage MkI on loan for a few months and it was a huge improvement to the sound. My only concern with it was it's relatively high gain of 13db, which didn't play too nice with my high gain output from my DAC and the somewhat high gain traits of the LM 508ia with the preamp tubes staying in play. I must say having a DHT DAC, preamp, and amplifier was quite intoxicating but it was almost impossible to find a satisfying volume level since the pre had no remote and I was using the DAC for remote volume attenuation. Another minor niggle is that I didn't find the preamp to be as quiet as I would have loved. I've ordered an off the beaten path Misho Myronov Wooden Preamp, which is 6DB in gain, and supposed to be extremely quiet. Hopefully it does the business.
     
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  2. Strat-Mangler

    Strat-Mangler Personal Survival Daily Record-Breaker

    Location:
    Toronto
    Keep us posted!
     
  3. Strat-Mangler

    Strat-Mangler Personal Survival Daily Record-Breaker

    Location:
    Toronto
    Not affiliated but for those who are interested, there's a pair of used EML 300B-XLS tubes at a great price here.

    EML-XLS 300b Power Tubes
     
  4. adamaley

    adamaley Forum Resident

    Which Lampizator are you using and what tube complement?
     
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  5. RH67

    RH67 Forum Resident

    Location:
    Simi Valley Ca.
    I have a custom built Level 4 DSD DAC, i can switch between ECC81 or ECC88 tubes. It`s also not a strictly DSD DAC it can do any format.
     
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  6. Strat-Mangler

    Strat-Mangler Personal Survival Daily Record-Breaker

    Location:
    Toronto
    Had a huge POP and a 2nd mellower pop. Managed to identify the culprit which is the tube at the bottom-left corner of your pic. Did you encounter that same issue?

    [​IMG]

    It exploded and we can see burn marks on it. This appears to be the cap in question.

    LGU2W471MELC Nichicon | Mouser

    15$ or so which is fine but I'm wondering if there would be better caps to replace it with which would be more resistant to this problem ever happening again.

    Also, I have no idea if this cap has any effect on the tone whatsoever.
     
  7. dianos

    dianos Forum Resident

    Location:
    The North
    There was one 470uF cap replaced in my case and 2pcs 1k resistors. Not sure where they were placed in the amp though. I had the large pop followed by smaller ones too. Worked without issues since repair.
     
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  8. Strat-Mangler

    Strat-Mangler Personal Survival Daily Record-Breaker

    Location:
    Toronto
    Wonder if it's possible for you to reach out to your tech to confirm this? Only asking because if that's the one that exploded, it means that now 3 people I know (myself included) would have experienced the same issue. So either it's a bad batch of caps LM was using for this model or it's a flaw in their design.

    My amp is 2.5 years old. I'm the 2nd owner. This kind of stuff shouldn't happen but flukes can occur. But when 2 or possibly 3 people have the same part die, that's a pattern others should be made aware of, IMHO.
     
  9. thomaskong

    thomaskong Forum Resident

    Location:
    Washington State
    All Class A amplifiers including Krell or SET are prone to degradation of cap due to extended exposure to high temperature.

    I had recapped it two times before.

    Thus I make it a rule to have LM 508 on only up to 2 hours.

    Then I cool it down for at least half an hour to extend its cap life.
     
  10. J.D.80

    J.D.80 Forum Resident

    Location:
    New York City
    I thought that amp took a good two hours just to fully warm up and sound its very best. On weekends, I'd leave it on for the entire day, and not shut it down until I was going into bed. Tube amps only sound better and better as they hotter and hotter.
    If you can only leave an amp on for two hours at a time, it's not an amp worth owning.
    Also, turning an amp on and off works the caps even harder.
     
  11. thomaskong

    thomaskong Forum Resident

    Location:
    Washington State
    I think it sounds fine after 15 minutes of warm up

    Even considering tube life, it is not a good idea to leave it on.

    Recapping happened to Krell and Silvatone 300B SET(20k$).

    If you leave A class amp on for whole day, you will need to re cap it in two or three years.
     
  12. J.D.80

    J.D.80 Forum Resident

    Location:
    New York City
    Cycling power on and off through an amp works/stresses capacitors far more than leaving an amplifier on.
     
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  13. dianos

    dianos Forum Resident

    Location:
    The North
    It is not uncommon that I have mine on for 5-8h per day. That cap is located under the extremely hot transformer. The transformer that also made a hum before repair that was tighten down after repair and now is silent. Not sure what happened but for me it started with smaller pops and one channel went out. Started swapping tubes and then after some minutes BANG. Turned it off directly and I could smell burned components. For me I strongly suspect a faulty tube triggered the problem.
     
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  14. adamaley

    adamaley Forum Resident

    I joined the Acme 805 team a month and a half ago, and I must concur with all the impressions given on it by the members here. An outstanding improvement on a level more than any other tube in this amp. Definitely worth the upgrade over the 805-AT (Never tried the Cossors before).

    I am tempted to try it the Acme 300Bs in the amp simply because of how fanstastic the Acme 805s are. The bass articulation, increased transparency + details make it a definite must try in this amp. It does all this while remaining smooth and composed with an expanded soundstage.

    I also finally received my preamp, a Misho Myronov Wooden Preamp that definitely does everything better than the Coincident Statement Linestage, a preamp I actually liked but didn't love.

    [​IMG]

    [​IMG]
     
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  15. RH67

    RH67 Forum Resident

    Location:
    Simi Valley Ca.
    Beautiful pre amp!
     
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  16. RH67

    RH67 Forum Resident

    Location:
    Simi Valley Ca.
    Who is the NA dealer for the Misho Myronov Wooden Preamp?
     
  17. adamaley

    adamaley Forum Resident

    Sorry, no dealer. Ordered directly from Misho himself in Bulgaria, had to wait about two months for the batch to be made and mine delivered. I don't believe he'll be making anymore this year, but there may be some that haven't been paid for from this year's batch. Contact info [email protected].

    Audio-antiquary
     
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  18. Strat-Mangler

    Strat-Mangler Personal Survival Daily Record-Breaker

    Location:
    Toronto
    I'm absolutely *shocked* that the 805s would have that big of an impact on the sound and even more so than changing the preamp tubes. My unit came with upgraded 805s (Psvane 805A-T) and was thinking of changing them possibly for NOS RCAs. Your experience makes me cautiously optimistic that I might experience a similar change, although what I had read before your comment was the preamp tubes made the biggest difference by far.
     
  19. Strat-Mangler

    Strat-Mangler Personal Survival Daily Record-Breaker

    Location:
    Toronto
    Normally, I frown on cross-posting (the practice of posting the same thing in multiple threads), but in case, it's warranted.

    There is a design flaw on the Line Magnetic LM-508IA involving the cap under the right output transformer which can eventually implode. In my case, smoke even came out of the amp after a *very* loud POP! So far, I have been able to verify 3 people experienced this problem ; myself, @dianos and @J.D.80

    The Nichicon cap in question is rated for a mere 450V at 85 degrees Celcius (185 F) and low ripple current capacity. On an aired-out simple circuit, that might be OK, but with the heat inside the amp as it sits directly under a hot transformer, it can possibly blow. This implosion affects a couple of other caps directly connected to it so those also need to be changed. In my case, a resistor also died.

    [​IMG]

    We can see the burn marks and the bulging top of the cap. Fortunately, the X slits allow the cap to simply expand instead of explode.

    As a sidenote, this and the adjacent caps apparently do not affect the tone so feel free to buy any reputed brand as replacements as long as they're from an authorized dealer. There are fakes on eBay and elsewhere so it is not recommended to source them from such platforms.

    My replacement cap is also from Nichicon but rated at 500V and 105 degrees C (221 F). My tech added protection by soldering a diode across this new cap to prevent this problem from happening again. The diode also has no affect on the tone.

    [​IMG]

    According to my tech, "the problem originates for two reasons. Insufficient ripple current in the original cap and the polarized capacitor is seeing a small but significant reverse voltage until the high-voltage relay trips. At most times only around -25V, but it did spike up to about -70 at one point. The diode shunts that away without affecting anything else. Once the high voltage kicks in, the diode does nothing."

    Credit goes to Dan Santoni of DTS Electronics located in Hamilton, Ontario ; Audio Repairs

    =====================

    We now at least know the reason why this became an issue and how to prevent it. Due to my experience and after reading that of others, I highly recommend current and future owners of this amp proactively replace the aforementioned cap and add the diode to prevent this issue from occurring.
     
  20. adamaley

    adamaley Forum Resident

    It's always tricky determining which tube makes the most difference. Disregarding all the other variables, adding the Acme 805 to the amp brought about the biggest change of any other tube upgrade. The delta is so much more significant compared to going from stock 805s to 805-AT. Or stock 300B to EML XLS or Elrogs, stock preamp tubes to current upgraded tubes. It is worth noting that my system is completely different from when I bought the amp originally, so take this statement with a grain of salt as there is very little control in this experiment. Perhaps, upgrading the other tubes first allowed the 805 change's qualities to shine through better. I can only report what I experience. I am so impressed by the Acme 805s that I plan on trying out the Acme 300bs to compare to the Elrogs. @thomaskong dared me on another site that this will happen once I tried the Acme 805s.
     
  21. freesole

    freesole Forum Resident

    Location:
    Seattle, WA
    Hmm I wonder if this is a problem on the 805ia as well... thanks for the notes.
     
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  22. Strat-Mangler

    Strat-Mangler Personal Survival Daily Record-Breaker

    Location:
    Toronto
    That's why I mentioned the 805IA. Pretty easy to check.

    1. Remove the tubes.
    2. Put the amp on its back. Remember to lift with your legs. ;)
    3. Unscrew the bottom plate.
    4. When facing the amp, it's right under the right output transformer (furthest right big block).

    Note whether there is a cap in that spot and if so, what its values are. See if they match what I either had or now have.

    If you could take nice high-definition clear pictures of the layout, that would be even more helpful and certainly might assist in other matters as well since I haven't found *any* pics of the insides of that amp, yet.
     
    freesole likes this.
  23. freesole

    freesole Forum Resident

    Location:
    Seattle, WA
    Might have this be a project this weekend haha. I'm not saavy with this stuff by any means so I likely won't even know what I am looking at but will take some photos.
     
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  24. Strat-Mangler

    Strat-Mangler Personal Survival Daily Record-Breaker

    Location:
    Toronto
    Scroll up to post 1131. Looks at the pic in the quote and click on it to make it go big. Bottom-left corner is where the cap is. My pics are of the cap itself.
     
  25. J.D.80

    J.D.80 Forum Resident

    Location:
    New York City
    I
    I would add that a soft cloth diaper or something that won't scratch the beautiful lacquer finish should be placed down before the amp is flipped over. Even a cotton t shirt could scuff it.
     
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