Line Magnetic 518IA Integrated Amp and 502CA DAC

Discussion in 'Audio Hardware' started by IanL, Dec 25, 2015.

  1. IanL

    IanL Forum Resident Thread Starter

    Location:
    Oneonta, NY USA
    Those are the 12AX7's that I have never tried in the 518. I am extremely happy with the Mullard 10M's (and wasn't a big fan of the tele smooth plates), but I still wouldn't mind hearing what the Bugle Boys bring to the table. Please let us know what you think. And congrats on your new 518. You are going to love it!
     
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  2. Snoflo1998

    Snoflo1998 Active Member

    Location:
    UK
    How long would you say the amp takes to break-in from new, Ian? Have you ever clipped the amp into your Harbeths? I have a LM SET, and on the 8 ohm tap (86dB/W/m speakers like your Harbeth in a small room) there can be some alarming swings on the power level meter with bass. The volume setting is just above 9 o'clock and it is pretty loud with it there. I was wondering if the power level meter isn't entirely accurate? As far as I am aware, I have not clipped the amp. Thanks on your thoughts.
     
  3. This this thread does include the Line Magnetic 502CA DAC, does anyone know if a new version will be available this year? Thanks
     
  4. Snoflo1998

    Snoflo1998 Active Member

    Location:
    UK
    I don't know, but the current one is a very good DAC. I haven't rolled tubes yet but the 502 put my nfb 3 Audio-gd DAC out to pasture. The 502 doesn't have stygian bass but it is very musical. It sounds better to my ears than the Schiit Gungnir DAC, which I sold on pretty quickly. The Gungnir had a detailed, forward sound I didn't like.
     
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  5. IanL

    IanL Forum Resident Thread Starter

    Location:
    Oneonta, NY USA
    It seemed like most of the tubes, the WE845's in particular, took a lot longer to come on line than the amp itself. In fact, I can remember the huge change just from the first to the second song I ever played on it. As I recall, the amp sounded fully broken-in while I was still using the stock 845's. Then when I put in the WE845's, it was sort of like starting over. Those things took a long time to open up. If you skim this thread from the beginning until I received my full working set of WE845's (which took a while since one of my original pair was DOA) I would say at that point the amp was settled in.

    As far as the Harbeths go, no, I have never heard clipping. What I do see is that the sweet spot on the volume knob is not a huge range with these rather inefficient speakers. When the volume is low, you want to turn it up. When the amp was new, there was also an upper limit on that sweet spot. Things could get a little edgy if you turned it up too loud. However, with time, that upper limit essentially went away, and if it is still there, it is at far too loud a volume for me to ever know about it. I usually listen between 9 and 10 o'clock on the volume knob. Digital and vinyl are very close in volume, with digital perhaps a hair louder at the same spot on the dial.
     
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  6. IanL

    IanL Forum Resident Thread Starter

    Location:
    Oneonta, NY USA
    I agree with you on the quality of the DAC. I love it. I get crazy amazing bass with my tube combo. For the rectifier I use a Sylvania 6X4WA that Brent Jessee picked out for me, from 1967. I think it was $20. And when I had my Mullard 12AU7's in there, it was a monster! I eventually swapped in some CBS 7318's for the Mullards, and the bass lightened up slightly while everything else turned into pure magic.
     
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  7. Snoflo1998

    Snoflo1998 Active Member

    Location:
    UK
    That seems spot-on with how things are with me too, thank you, Ian. I have all the stock tubes in place (the amp only arrived 2 weeks ago). I'll wait a bit before rolling. Yes! I had the same experience with the first to second song sound transition on the new amp. Those WE845s are expensive. Psvane? *sigh*

    Oh wow, thanks for that 6x4 recommendation! The last recommendation I got was for GEC 6x4 for a not-so-paltry sum of $400 :sigh:. I'll get to rolling some day, it is just that everything sounds fine as is. When I had my Conrad Johnson system I was tube rolling like crazy until the point came when I just had to admit to myself that the CJ sound wasn't for me.

    Rory
     
  8. Encore

    Encore Well-Known Member

    Location:
    Denmark
    I notice that you're using expensive NOS tubes and a directly heated rectifier? Does the LM 518a need a directly heated rectifier? My understanding is that directly heated rectifiers don't provide the soft start of indirectly heated rectifiers, and that they are a lot harder on the other tubes in an amp.
     
  9. IanL

    IanL Forum Resident Thread Starter

    Location:
    Oneonta, NY USA
    I'm afraid this particular topic is a little over my head. Maybe someone else can chime in...
     
  10. IanL

    IanL Forum Resident Thread Starter

    Location:
    Oneonta, NY USA
    If I were buying a new pair now, I think I would try the Psvane 845-TII 845-TII (pair) for about half the price. To tell you the truth, the stock 845's are a more colorful tube than the WE845's. Perhaps a little faster too. They are a lighter approach. The WE's bring a lot of weight and texture. They fully flesh out the mids and dig deeper in the bass. But both are nice approaches. If I were still using my stock 845's, I would switch back to the RCA black plates (6L6GC) to add some bass grip, and either stick with the Philips rectifier to further establish that bass foundation, or maybe the Gold Lion for it's ability to pull even more beautiful tonal colors out of those stock 845's. That colorful presentation is extremely addicting.
     
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  11. Encore

    Encore Well-Known Member

    Location:
    Denmark
    The 5R4GYS, like 5U4G, are tube types where the cathode and the heater are combined, whereas in e.g. the GZ37, the cathode and the heater element are separate structures. That means that it takes a little while for a GZ37, i.e. an indirectly heated tube, to deliver the full power to the rest of the amp, and thus this tube type in effect has a soft start built in. A directly heated tube OTOH delivers full power almost instantaneously, and that there is no soft start for the other tubes in the amp. This is harder on the tubes, but I have to admit that I don't know how much harder. I mean, there a plenty of amps out there with directly heated rectifiers, so it can't be completely hopeless. But from what I gleaned from the web, it is advised not to use directly heated rectifiers if it can be avoided, so I haven't tried the Philips 5R4GYS I bought before I learned about the difference.
     
  12. IanL

    IanL Forum Resident Thread Starter

    Location:
    Oneonta, NY USA
    Thanks for that info. As you noted, I have definitely invested some money in my tube collection, and I would hate to be shortening their lives with the wrong choice of rectifier. I think I will do a little research. I have other options, like a Mullard GZ34/5AR4 metal base from 1957, but it is so damn smooth and creamy that I would need to make some other tube changes to get the whole combo into the right balance again.
     
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  13. Snoflo1998

    Snoflo1998 Active Member

    Location:
    UK
    Thanks! I will probably try the cheaper 845s later in the year. So nice not to have to worry about tube rolling too much anymore.
     
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  14. Encore

    Encore Well-Known Member

    Location:
    Denmark
    Check out 8:00-10:30 in this video:

    The video is from a series of instructional videos that this guy has put up, and although I'm not a technician, it seems to me that he knows what he's talking about. He doesn't attempt to quantify the problem, though. Just how big of a problem is it? The fact that directly heated rectifiers were produced in such numbers in the first place may seem to indicate that they aren't that hopeless. Maybe somebody with more knowledge than me can chime in?
     
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  15. wwright

    wwright Forum Resident

    Location:
    San Francisco, CA.
    I have never explored the individual architectures of NOS tubes. Your comment on the GZ37 helps explain the mystery of warm-up timeframes, at least in some cases. Another clue in the puzzle - and another reason why I love this crazy hobby.

    Does the 6L6GC carry any unique considerations or behavior when replacing the 63P3s, or is it a straightforward swap? As mentioned, the more desirable NOS 845s are almost half the price of the amp itself, so I may take the RCA route suggested by our kind host.
     
  16. IanL

    IanL Forum Resident Thread Starter

    Location:
    Oneonta, NY USA
    Thank you for posting this video. After watching that, I immediately pulled the Philips rectifier and replaced it with my Mullard GZ34 metal base. I do miss that extra bit of bass slam, but the Mullard is more articulate and nimble through the midrange in addition to having the sweeter tone. So it's not necessarily a backwards move. I just feel better about the longevity of my other tubes. Luckily the Genalex is also a GZ34 so I can keep that one in the mix as I revisit the overall balance of the all the tubes.
     
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  17. IanL

    IanL Forum Resident Thread Starter

    Location:
    Oneonta, NY USA
    6L6GC is a direct replacement for the 63P3 in this amp. Roll away!

    RCA 845's are the most expensive route you can take. I bet they sound phenomenal though. Luckily the current production Chinese 845's sound pretty great, and there are several choices at various price points.
     
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  18. Encore

    Encore Well-Known Member

    Location:
    Denmark
    Glad to help. But credit belongs to Uncle Doug--you might want to give his youtube channel a like :)
     
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  19. Encore

    Encore Well-Known Member

    Location:
    Denmark
    I feel that I should add that Audio Note use almost exclusively directly heated rectifiers in their gear, so there may be a sonic reason for it. However, if you feel that the Philips is only giving you marginally more bass slam, and that the Mullard GZ34 is better in the rest of the range, then it's probably the right decision to stick with indirectly heated.
     
  20. suntzu

    suntzu New Member

    Hi Guys,

    I love my Line Magnetic 502CA DAC as well. It doesn't have the most advanced specs. But there's something beguiling about the sound.

    Please let me know. What are your recommendations for the rectifier tube in there?
     
  21. IanL

    IanL Forum Resident Thread Starter

    Location:
    Oneonta, NY USA
    I use a Sylvania 6X4WA. I haven't tried a lot of tubes in this spot, but I am very happy with the Sylvania.
     
  22. suntzu

    suntzu New Member

    Thanks for your reply IanL. So I can just insert the Sylvania 6X4WA in place of the stock Line Magnetic rectifier? I don't need to change the jumper settings? Thats the part which I'm unsure about. Not even sure where they are.
     
  23. IanL

    IanL Forum Resident Thread Starter

    Location:
    Oneonta, NY USA
    There are two jumpers right next to the tube socket. You need to change them both to "6X4". Once you are looking at it, it is obvious what to do.
     
  24. suntzu

    suntzu New Member

    Great. Thanks a lot!

    Hope you're enjoying your setup. I play the LM502 DAC with my LM 219IA. Loving the combo.

    I have been tweaking my LM502DAC though. Have changed the 12AU7 tubes to Brimar. I've also swapped in Burson Audio V5 op amps. I enjoyed having the Burson V4 op amps for a while. So I'm running in the trio of V5s now to see if there are incremental improvements in sound.
     
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  25. Bboterham

    Bboterham Member

    Location:
    Holland
    I've been using CBS 12bBZ7 tubes for the inputs and they did improve dynamics compared to most of the 12ax7's I've tried. With these, GE 6L6G coke bottles (I think they're Canadian made, they look similar to the Marconi 6V6G) and the PSVANE 845 TII are a great match. The latter brought more speed and focus compared to the stock tubes, which is a good balance for my wide taste of music styles.

    I do have a question though: do the input tubes have to be matched? Am I right to think that the triodes are being used in series, one tube for each channel?
     

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