Nobsound NS02G aka JLH 1969 Class A amp

Discussion in 'The Doorway' started by TubeHiFiNut, Dec 3, 2018.

  1. TubeHiFiNut

    TubeHiFiNut Administrator Staff Member

    Rather than resurrect the now year+ old thread on this amp, I figured that I would post my listening impressions here.

    If you are interested in the background, the original thread is here:

    http://www.hifihaven.org/index.php?threads/class-a-ss-jlh-plh.2797/

    For those of you keeping score, the Nobsound NS02G is based on the JLH 1969 Class A amp - a two stage, SS amp designed by John Linsley-Hood in 1969.

    It needs to be acknowledged up front that I did not give this amp a fair shake a year ago. The B&W CDM1 (very high WAF ;) ) are a horrible match (86db inefficient, complex crossover, etc) for this amp (the TPA3250 with Astron Linear PS and Topping TP60 amps are much better matches for the B&Ws and actually sound good).

    My big rig is down while I get the Man Cave renovations completed. I brought the NS02G amp upstairs and hooked it up to my cheap test speakers to make sure the amp is still working - and it is! :)

    Tonight the Nobsound NS02G, Schiit Saga and JBL 4408 speakers are taking place of pride upstairs in the Living Room system. :)

    This will be a long term listening test. I will provide periodic listening impressions.

    If you have, or are getting, a Nobsound NS02G, please contribute to this thread with your listening impressions. :)

    More to follow, including pics when I get everything set up. :)
     
    StevenZ, opa1, Negatron and 3 others like this.
  2. TubeHiFiNut

    TubeHiFiNut Administrator Staff Member

    It should also be noted that the Nobsound NS02G showed promise driving the University 6201 12" coaxials in @je2a3 's JE Labs OBs - a much better match on all counts than the B&W CDM1 - until I lost the right channel.

    Here's hoping that we will not have a reoccurrance of that mishap.
     
  3. Can't wait to see what you think once you get a nice long listening session. I have used several little chi ese amps, and i have been verybsurprised as to how good they sound.
     
  4. TubeHiFiNut

    TubeHiFiNut Administrator Staff Member

    So far, I am very pleased with both the Topping TP60 and the TPA3250 amp (especially with the Astron LS10A linear power supply and custom @MikeyFresh Audio Astron LS10A to TPA3250 power cable).

    At ~$200, both are excellent The Doorway amps. For approximately the same price, I am hoping that the Nobsound NS02G will be a similar value.

    Come to think of it, perhaps this thread should be in The Doorway room. :)
     
    MikeyFresh, opa1 and Negatron like this.
  5. I have 5 Nobsound TPA 3116 stereo amps I am going to use for my Atmos channels. I listened to them on the JBL 4360s and they sounded pretty good. I have a friend that swears by these and he is either listening to them on his Danley SH50s or His Klipsch k402s.
     
  6. TubeHiFiNut

    TubeHiFiNut Administrator Staff Member

    I love my SE tube amps (SET 845, 300B and 2A3, SEP EL84). No other amps can connect me to the music like they do.

    For the money, though, the Topping TP60 and the TPA3250/Astron LS10A are tough to beat. For ~$200 brand new, they are both silly good.

    Just my opinion. :)
     
    Negatron likes this.
  7. I bet they are... mine were I think $40 each after power supplies...major bargain! I have about $200 in my DIY Pass ACAs already, and I still need to make the cases, and get the heat sinks. I cannot wait to hear those on my horns.
     
  8. TubeHiFiNut

    TubeHiFiNut Administrator Staff Member

    The TPA3250 was $80. The Astron LS10A was $125. Power supplies rock. ;)
     
    Negatron likes this.
  9. opa1

    opa1 Moderator Staff Member

    Glad you pulled the rabbit out of the hat. It was time for a update! :) I was thinking about that amp just the other day.

    BTW: I just checked these out again. It's no longer 159.00. :)
     
    Last edited: Dec 3, 2018
  10. TubeHiFiNut

    TubeHiFiNut Administrator Staff Member

    $231.99 with free shipping.

    I can't remember if I had to pay shipping at the $159.00 price?
     
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  11. TubeHiFiNut

    TubeHiFiNut Administrator Staff Member

    And here we go:

    20181205_183251.jpg

    Crappy cell phone pic - will try to get a better one tomorrow.

    Sonos Connect - Schiit Modi Uber - Schiit Saga - Nobsound NS02G - JBL 4408. Wire/cable is Canare and Tek-Line.

    Initial impression (not warmed up) is that the fun factor is definitely there. Hard not to start the toe tapping.

    The JBLs are a lot more my "cup of tea" than the B&Ws. There, I've said it and will undoubtedly be drummed out of polite Audiophile circles everywhere. ;)

    The little Nobsound NS02G is driving the JBL 4408s very well - louder than I normally listen - and without straining.

    The comparison of how badly this little amp died when trying to drive the B&Ws to how it is be-boping along driving the JBLs is quite a eye-opener.

    Now I can finally figure out just where the Nobsound NS02G fits in the (amplifier) scheme of things. :)

    More to follow. :)
     
    opa1 likes this.
  12. opa1

    opa1 Moderator Staff Member

    Hey I like the 4408's! Wonder how much the Saga is contributing to the sound?
     
  13. TubeHiFiNut

    TubeHiFiNut Administrator Staff Member

    I hold the Saga in very high regard. :)

    Plus the remote control is kind of nice. ;)
     
    opa1 likes this.
  14. TubeHiFiNut

    TubeHiFiNut Administrator Staff Member

    Additional listening impressions:

    The Nobsound NS02G and the JBL 4408 match up nicely. The JBLs are very involving. The NS02G has plenty of power to drive them.

    Nice to be able to finally hear this little amp with appropriate speakers.
     
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  15. TubeHiFiNut

    TubeHiFiNut Administrator Staff Member

    This combination wears well over time.

    I started this morning playing some of my bride's favorite music, at volume. Sure enough, she came in, sat down and started listening - toes tapping. :)

    That's what this combination seems to do the best - boogie factor, PRaT, whatever you want to call it.

    Not the last word in resolution - differences in the various streaming services were apparent but not as starkly so as on the Man Cave rig.

    This is a really fun (and has the "Bride Seal of Approval) combination. :)

    Now, does it still fit "The Doorway" parameters? Let's see:

    Sonos Connect: $350 (new)
    Schiit Modi Uber: $170 (discontinued - replaced by Modi Multibit at $249)
    Schiit Saga: $350 (new)
    Nobsound NS02G: $160 (new - now selling for $232)
    Cables: $200 (approximately)
    JBL 4408: ~$400 (Discontinued)

    Total approximate system price: $1,630.

    Not chump change but I think it would still fit the bill. :)

    And now, back to listening. :)
     
    MikeyFresh likes this.
  16. je2a3

    je2a3 Junior Member

    DSCF1263.jpg

    I've been listening to this amp driving Altec 755Cs in 618 cabs and also SK98s during the past week. I pretty much agree with @TubeHiFiNut assessment of this amplifier. It definitely needs efficient speakers since I measured only about 5W per channel before clipping on my test bench instead of the claimed 10 WPC. If I were to nit pick, I hear a slight glare in the upper midrange, most evident with brighter recordings of female vocals. But overall this amp succeeds in sounding like a good tube amplifier which was essentially why JLH designed it. I just ordered PIO caps to bypass the 2200uf electrolytic output coupling capacitor and also replace the 2.2uf film type input cap. It might take a while to get them from eastern Europe but I think that will take care of the upper midrange glare I noticed.
     
  17. TubeHiFiNut

    TubeHiFiNut Administrator Staff Member

    @je2a3 - I am pleased that our individual assessments pretty much line up and am very, very interested in how the PIO caps work.

    That should be a very nice upgrade. :)
     
  18. TubeHiFiNut

    TubeHiFiNut Administrator Staff Member

    Spent the evening listening to the NS02G and I must say that it continues to please.

    I am very eager to hear how the upgrades @je2a3 is making to his NS02G turn out.

    In the meantime, things are sounding pretty good in the Living Room system. :)

    Hmmmm.....wonder if I can sneak my SK98s upstairs. ;)
     
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  19. opa1

    opa1 Moderator Staff Member

    Following along. :)
     
  20. je2a3

    je2a3 Junior Member

    001.jpg

    I heard a buzz with the input level control at maximum which I traced to an unconnected AC ground. AC ground terminal is now connected to the chassis, no more buzz.

    002.jpg

    Since I already had the top cover off and found a pair of .47uf PIOs in my stash, I replaced the stock 2.2uf film type which reduced the upper midrange glare. This was not a simple task, I had to partially disassemble the chassis and unsolder the pair of green (left channel) and blue (right channel) transformer leads from the power transformer to gain access to the bottom of the PC boards. I also had to remove the Alps input pot when I worked on the right channel PC board.

    003.jpg

    I don't think I'll receive those compact 10uf PIO caps I ordered from EU before Christmas. So for the moment each channel's output electrolytic cap is bypassed by a 4uf mylar + smaller value PIO caps - glare is further reduced. These tweaks made the amp a lot more musical to my ears!

    What really drew me to this amp is its DIY roots. Just like DHT-SET amps, it is an ancient design, simple circuit with low parts count. It will never sound exactly like a nice tube amp because it is a very nice sounding solid state amp!:cool:
     
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