[dhaninugraha]

I'm currently listening to the Spotify Premium on rMBP > NS-08E (stock tubes + Burson V5i SS opamps) > Senn HD25-1 setup. Max volume on the rMBP, volume knob is set a couple clicks past the 9 o'clock mark on the NS-08E. Connecting them both is a 3.5-to-3.5 I made out of Mogami 2534 and a pair of gold-plated Oyaide clone 3.5mm plugs.

First thing that I can say for certain, is that the V5i SS sounds airier than the stock NE5532s that came with the NS-08E. It also gives a better sense of ambience and realism in live recordings -- when I close my eyes, it's as if I could imagine which instruments are where and how low and/or far the clapping audience sits relative to the artist, and if said audience is chanting faintly from afar, or somewhere closer to the stage. John Mayer's Where The Light Is: Live In Los Angeles is a good example of this.

More impressions to follow.

 

[edulov]

Thanks for sharing your experience.
I'd love to propose a small test, but for shure it happens in really good open cans.
Look for a losless Uriah Heep - The hanging tree. Best of all - some reissue/remaster, like the "It was 40 years ago" album. There in many places you must hear not just a good positioning and soundstage width, but be able to locate instruments in 3D.

 

[Tom Steed]

Thanks for sharing your experience.
I'd love to propose a small test, but for shure it happens in really good open cans.
Look for a losless Uriah Heep - The hanging tree. Best of all - some reissue/remaster, like the "It was 40 years ago" album. There in many places you must hear not just a good positioning and soundstage width, but be able to locate instruments in 3D.

Ok, I tried this track in flac format. There was a lot of left/right positioning and all the instruments were well defined. I could separate them and they didn't blur together. That said it wasn't my fav Heep song. I prefer the Salisbury album as i knew the recording studio well and heard the acoustics first hand.

At the moment i am using Russian 6j9's with the Vi5's. They are very bright and punchy in the midrange. I will be moving to the other tubes soon. Either way with a tube and op amp upgrade this little box punches well above it's weight. Depending on budget, you can go for the Vi5's at the top end and get a chip that is designed for audio presentation or at the lower end a normal audio op amp chip and as they say 'your mileage my vary'.

My setup is pc based:
Asus xonar essence stxII
Nosound with Russian 6jn, Mullard e180f and Amperex 6688. not matched valves but i found good deals on fleabay.
Sennheiser HD600

 

[sup27606]

Just put a pair of Burson V5i and now I hear all sorts of hissing sounds and low level hum. The noises do not change with volume. Also (weird), the hissing sound changes in intensity if I move around my headphone cable. The humming remains unaffected. The old opamps were dead silent. I guess, the opamps are defective. Anyone has any ideas? Thanks.

They sound phenomenal though.

Update: The hissing is completely gone now, but the low level hum remains. Its easily audible during quiet passages. I am sorry this turned out this way, because otherwise the opamps really make the amp shine, with clearly better imaging and treble details.

 

[edulov]

About opamp noise
1. Valve and opamp are connected in a very specific way in this amplifier
2. Opamp is not jaus a packaging. It has its internal scheme (a specific pin assignment) and electric parameters

When I made an opamp rollup, I looked for compatible devices with specific sound profile (neutral, wide, transparent & etc). But I made a note that they differ not only in amping current, but also have a slightly different specs. So when one of testees produced a notable backgound noise, I made a detailed comparision and found that being potentially soundwise better, its resistance and impedance numbers are different compared to others. Because forgetting about noise it sounded best from the bunch.

So, i'd recommend to try another tubes, even a stock ones to see, what happens with noise.

 

[sup27606]

I found the Burson ones both wide/deep and very detailed. That's why, despite the humming, I was just listening for hours yesterday. The sound is slightly warm which gives an almost speaker like feeling.

I will have to look for the factory tubes where I kept them, and once I find them, I will test with the new opamps.

Have you or anyone else face humming noise with the Burson, or is it just me? I am wondering whether this pair could be defective and whether to send them back (the window is short).

Assuming the amps are ok, and the noise is due to a mismatch in electrical parameters between them and the tubes, is it safe to continue using them? What can I do to mitigate the noise. Would changing the power supply help? Ha! I really like the sound.

 

[edulov]

Safe - yes. The difference is not that huge to damage, but keep listening noisy music?
There is a small possibility that power unit isn't OK, providing lesser or higher voltage. If you have a tester or can lend it - make a check. BTW, twice I had an issue with a bad contact in a wall power socket which were causing noises. Take a look also.

 

[sup27606]

The noise is not loud, and only audible during quiet passages. Even when there is low conversation in the room, it becomes almost inaudible. I have tried to remove the thought of the noise from my head, so that I can enjoy music, with the hope that some day this issue will be resolved

I have got a tester. I will check the power adapter tonight. There are big resources on the web for troubleshooting noise issues in amps, but many of those are for electronic experts, or even if I understand enough to follow them, I don't have the expertise to handle unexpected scenarios. If power turns out to be not the issue, I am not sure how to troubleshoot further though.

I already tried a different wall socket, and still had the issue. Thanks for the suggestions.

 

[edulov]

I hope we agreed that testing a completely different pair of bulbs may give a hint. It would be very rare that BOTH opamps came with the SAME ISSUE.

 

[sup27606]

Certainly. I will try to find the old tubes tonight. Also considering a battery pack to test for power issues.

 

[Tom Steed]

Certainly. I will try to find the old tubes tonight. Also considering a battery pack to test for power issues.

You can also try different cables, from your sound source to the nob amp and if your headphone cable can be changed try that as well.
Make sure the earth wire from the circuit board to the back panel is still attached.

Previously with different op amps I had hiss that changed when i moved the headphones, i reversed the cable and that cured it.#
With the Vi5's i have no noise, the only noise now is part of the recordings

 

[sup27606]

Previously with different op amps I had hiss that changed when i moved the headphones, i reversed the cable and that cured it.

I am also experiencing the same effect. when I move around the cable, the hiss reduces or becomes quiet. By reversing, did you mean, use a different cable? I am using the Sennheiser 6XX with the original cable it came with. I checked, the earth wire is securely connected to the chassis.

With the Vi5's i have no noise

Jealous!

About the hum, I notice when I twist the power connector while plugged into the amp socket, the hum reduces or goes off completely for very specific positions. Also, I tried a different set of tubes (factory ones) than the ones I am using (Amperex 6688) and the noise remained the same.

 

[Tom Steed]

I am also experiencing the same effect. when I move around the cable, the hiss reduces or becomes quiet. By reversing, did you mean, use a different cable? I am using the Sennheiser 6XX with the original cable it came with. I checked, the earth wire is securely connected to the chassis.


Jealous!

About the hum, I notice when I twist the power connector while plugged into the amp socket, the hum reduces or goes off completely for very specific positions. Also, I tried a different set of tubes (factory ones) than the ones I am using (Amperex 6688) and the noise remained the same.

I was using Sony headphones and the cable had a 3.5mm jack at each end, i reversed it and it worked. The 6xxx use their own cable, maybe a replacement will make a difference.

 

[edulov]

The plugs of some cables could be disassembled and you will find a really bad soldering quality. Talking about Nob, its In/Out connectors are "deepened", so some cables could not be completely inserted, causing different sound distortions - I had this issue.

 

[sup27606]

Ok, I checked again today evening and now it is dead silent. Not sure what was going on before. I will continue to monitor for the next few days to see if the humming comes back.