New Line Magnetic 508ia Integrated Amp

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

  1. Ontheone

    Ontheone Poorly Understood Member

    Location:
    Indianapolis
    Perhaps we've identified the weak link. So my VAC appears to use an ALPS RK-27 potentiometer. See photo below. I know the LM805ia uses an ALPS as well but I'm not sure which one....definitely not the same one from the photos I've seen. I didn't feel like opening my LM up to view.

    [​IMG]
     
    Chris Amott likes this.
  2. Strat-Mangler

    Strat-Mangler Personal Survival Daily Record-Breaker

    Location:
    Toronto
    What have you tried prior to the ECC35?

    The weak link has always been the volume but not the pot itself. Its integration into the circuit is what is the weak link. The pot itself should only be about smoothness, quality, and reliability.
     
    Ontheone likes this.
  3. Ontheone

    Ontheone Poorly Understood Member

    Location:
    Indianapolis
    This makes sense and obviously I'm not an electrical engineer so don't fully understand the design basis and comparisons. I do know that Kevin Hayes at VAC is quite fastidious about integrating volume control correctly as not to degrade the music.
     
  4. Strat-Mangler

    Strat-Mangler Personal Survival Daily Record-Breaker

    Location:
    Toronto
    I'm unsure if the 805 addressed this as it supposedly has a true preamp out as opposed to the apparently half-assed version on the 508. I'm unclear in that.
     
  5. Chris Amott

    Chris Amott Forum Resident

    Location:
    PNW
    The 805 has the same input/outputs as the 508. There is no pre-amp out on either, and the pre-in seems to operate in the same fashion. i.e. it’s just a volume control bypass with a fixed 10db attenuators built in.
     
  6. AP1

    AP1 Forum Resident

    Location:
    TX
    There is always an option to replace 6SL7 tube with 6SN7. That will reduce gain by approximately 6dB. To compensate for loss of loop gain, you will also need to use feedback setting of 3 or 4. The positive side is that hiss through speakers will be significantly lower.
     
    Last edited: Aug 1, 2021
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  7. tlowe

    tlowe Life Explorer

    Location:
    somewhere
    Damn...sorry, is damn a bad word in this forum?:D
    One of my two months old KR 300B has developed a dancing blue glow, just under the top mica, causing a very disturbing crackling noise on one channel. Sending them back to Hong Kong's distributor for replacement. What a luck!

    [​IMG]

    Have read someone commented on the original 300B after sending his upgraded 300B for replacement, he is so right. After putting back the original, the soundstage is much narrower, overall lack of weight, thin sounding...
     
    Last edited: Aug 6, 2021
  8. Devg

    Devg Member

    Location:
    US
    The LM seems to be more prone to ground loop than any electronics I have had for some reason. I had to install a ground lift switch for the Lampizator DAC. I had then tried a Supratek DHT preamp but also landed up in nasty hum and ground loops. Tried a HumX on the preamp - though the soundstage was larger, with more depth then the line-in, the sound also became harsher. Right now I use line-in, till I can find a quality preamp that doesn't create ground loop issues. There is definitely more to be had from the LM with the right matching preamp.
     
    Ontheone likes this.
  9. Ontheone

    Ontheone Poorly Understood Member

    Location:
    Indianapolis
    I've had the same ground loop issues with the LM805ia. Had to use a HumX on my preamp.
     
    Devg likes this.
  10. tlowe

    tlowe Life Explorer

    Location:
    somewhere
    Those stock PSVANE 300Bs are really getting on my nerves after I sent my KR 300Bs for replacement. Regardless of which 6SN7s (KEN RAD VT-231/SYL 6SN7W/NU 6SN7/RCA VT-231...etc) I used, my setup sounds really too bright to me...:( I have even pulled out the DIY Canare 4S11 jumper cable and put back the stock jumper plates.
    In conclusion, yes, upgrading those stock 300Bs is really mandatory to get a warmer sound.
     
  11. Devg

    Devg Member

    Location:
    US
    @Ontheone I think it was you who advised to get the HumX. They truly worked as expected in eliminating the hum in my system.
     
    Last edited: Aug 11, 2021
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  12. Devg

    Devg Member

    Location:
    US
    @Strat-Mangler after repeated endorsement of the ECC35 in the 6SL7 position, I am inspired and bold enough to try one at higher cost, off-coarse still keeping within my budget :) Can you please point me to any listing or what should I be looking for when getting the ECC35 ?
     
  13. Strat-Mangler

    Strat-Mangler Personal Survival Daily Record-Breaker

    Location:
    Toronto
    All depends on what you're after. "NOS" is a designation that means New Old Stock. Unfortunately, it's also used by most sellers to mean "old tubes" regardless of how they are. That's why you'll see plenty of NOS tubes with burn marks confirming they've been used in the past.

    Since NOS tubes typically have a much longer life than modern production tubes, in most cases, that isn't cause for concern as long as the test results show the tube is testing as NOS (in which case they should be labeled ANOS - Almost NOS) or at least very strong. You'll typically pay through the nose for true NOS tubes so it comes down to budget. If you're looking for a true "virgin" NOS tube, be prepared to pay a premium for it. If you're OK with a tube that's been used in the past and has burn marks though it tests very strong or as NOS, that will bring down the price.

    So I guess the question is how much are you willing to spend and how important is NOS to you?
     
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  14. tlowe

    tlowe Life Explorer

    Location:
    somewhere
    You might want to read my post for a brief idea on the different versions and codes of ECC35
    Mullard ECC35 & ECC33

    This is a good place for pictures on ECC35
    6SL7 ECC35 CV1985 CV569 VT229 5691 | tubemongerlib
     
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  15. Devg

    Devg Member

    Location:
    US
    Yes, I am quiet OK with tubes that's being used but test strong. I have no experience buying ECC33/35 and hence don't want to overpay at the same time. How much do you think they typically cost in today's market ?
     
  16. tlowe

    tlowe Life Explorer

    Location:
    somewhere
    PM sent
     
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  17. Strat-Mangler

    Strat-Mangler Personal Survival Daily Record-Breaker

    Location:
    Toronto
    Since @tlowe responded, no need for me to add to the discussion. :)

    Let us know what your thoughts are once you try this tube out.
     
    Devg likes this.
  18. Devg

    Devg Member

    Location:
    US
  19. Strat-Mangler

    Strat-Mangler Personal Survival Daily Record-Breaker

    Location:
    Toronto
    Last edited: Aug 13, 2021
    Ontheone likes this.
  20. AP1

    AP1 Forum Resident

    Location:
    TX
    Ok @Strat-Mangler, you convinced me to try ECC35 in my LM-508ia. My regular tube to use here is 1579 of 1955 vintage made in Soviet Union for their nuclear energy industry.

    I got ECC35 with etched date code RU4 B8K, which likely means that it was made in 1958. This one is branded "Amperex", but it was made by Mullard at Blackburn factory. I tested that tube using spectrum analyzed and found that gain is on par with my other 6SL7 specimen. It means that it is NOS or close to it. I also compared distortion spectrum in test circuit which simulates operation conditions in LM amplifier. I found that though second harmonic is a bit higher than with other tubes I have, high order harmonics are almost non-existing. That gave me confidence that tube is in good shape and I can safely try it in amplifier.

    I installed it in my LM-508ia and ran it for several days of casual listening for burn in before trying any critical assessment. Finally I found enough spare time and started comparing Soviet and British tubes in service. It was clear that the sound is indeed different. The difference was smaller than when I compared 1579 with other tubes new and vintage, but it was there. I would say that 1579 gives a bit brighter sound, especially on string instruments. ECC35 was smoothing the sound. That can be compared with difference between sound in music hall vs. over damped studio. That may be useful if record is excessively bright on its own, but not for well made and balanced mixes. That effect of smoothing also affected perception of sound stage depth. 1579 had deeper sound stage with proper layering of cello and piano. On some records ECC35 made piano closer to the front than cello, which is wrong. Though ECC35 can make sound of vocal softer, which can be beneficial for some records. 1579 will make them feel like singer is closer to the microphone.

    To verify my observation, I invited my wife who supposedly have perfect sense of pitch. Her comments about sound of 1579 and ECC35 tubes, when we played same tracks through both tubes one immediately after another, were close to what I heard. That way I can be sure that all of the above is not simply my imagination.

    So for now I will keep 1579 in my amplifier and try to sell ECC35 to recoup at least some cost of my excersise.

    For reference - I use LM-508ia with B&W 802D speakers. Surely, those who have different speakers may have different opinion.
     
    Last edited: Aug 14, 2021
  21. Strat-Mangler

    Strat-Mangler Personal Survival Daily Record-Breaker

    Location:
    Toronto
    Appreciate your comments. It's all about synergy and tastes. Your description of the ECC35 does not mirror my experience nor almost anyone else's in this thread but perhaps you enjoy a much brighter sound or perhaps the other tubes in your 508IA are of a warm nature and inserting the ECC35 is too much of a good thing in which case I'd likely agree with using something else unless you'd be willing to experiment with tube rolling other positions to compensate.

    You'll quickly and easily sell the ECC35. It's a coveted tube for a very good reason and enjoys a terrific reputation as echoed over the many pages of this thread. There are 2 members who recently posted wanting to buy one. Perhaps you could contact them and try to arrange a mutually beneficial transaction? :)
     
  22. Pedro Guillemain

    Pedro Guillemain PLGA

    Location:
    Argentina
    Wich 1579 do you have?

    I've just bought an ECC35 and I will compare it with my favourites 6SL7 when it gets here, in a month or so.

    I'm also bought a rare 6C8G Amerty (made by Mullard) wich I'm burning. First impressions, vs my today's favourite, the Sylvania 6SL7 Brown Base Golden Letters, is that the Amerty is a little bit drier, but with deeper and more precise soundstage. Very promising.
     
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  23. AP1

    AP1 Forum Resident

    Location:
    TX
    Made by MELZ (МЭЛЗ) factory in 1955. It has stamps from regular QC (ОТК), military QC (ВП) and also nuclear/space grade QC (9). I bought 5 of them and selected one which had lowest noise and distortions in test circuit.
     
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  24. Pedro Guillemain

    Pedro Guillemain PLGA

    Location:
    Argentina
    I've been spending some hours with this very rare Amerty (made by Mullard) 6C8G in the 6SL7 spot on my LM-508.

    Compared to my latest favourite, the Sylvania 6SL7 Brown Base Golden Letters, it's a "little bit" drier, but better on many other aspects like deeper soundstage, pinpoint imaging, detail and PRaT. Summarizing, considerably more engaging.

    I will get a Mullard ECC35 in the next weeks and I will see how they both compare to each other. If they are clore, the Amerty is a pretty good deal as it costed me less than 20 bucks plus adaptor, wich I already had. A very very good tube wich is incredible for the price. I've tried several well rewarded 6SL7 (Melz, Brimar, Sylvania VT-231, etc) and this one is a step above for sure, although is very difficult to find one.

    There are many people that find the 6F8G tubes cheaper and better in general than their 6SN7 similar counterparts. Maybe it's also true with the 6C8G vs 6SL7 tubes. I have a couple of Sylvanias VT-99/6F8G in the 6SN7 slots and they are (as other member here also said) very very good for the price. The good news is that 6C8F tubes are pretty cheap to try. May be is because these tubes were made before WWII and, as some people say, there were better quality standars back then.

    Has anyone tried other 6F8G or 6C8G tubes in the LM-508????
     
    tlowe likes this.
  25. Chris Amott

    Chris Amott Forum Resident

    Location:
    PNW
    Tung Sol round plate 6F8G's are a bit better than TS BGRP 6SN7's. Better imaging, soundstage, finesse. I had a pair briefly but sent them back as one had a loose anode wire. I am actually getting a pair of pristine true NOS TS 6F8G's next week and assuming they sound similar, I may be selling a very nice of pair of TS BGRP 6SN7's shortly thereafter.
     
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