Query about Nighthawk

[mahiruha]

Hi Guys,
I recently acquired a nighthawk phono stage. I must say it is a very good phono stage but there is a problem. I am getting a increasing hissing sound if I rotate the volume knob in my SL amp beyond 9'o clock position when no vinyl is being played . I have tried it two tone arms and the issue is same. I know there are quite a few Nighthawk users in this forum. If they can kindly share their experience regarding the same that will be useful.

Thanks.

 

[myriad]

Hi Guys,
I recently acquired a nighthawk phono stage. I must say it is a very good phono stage but there is a problem. I am getting a increasing hissing sound if I rotate the volume knob in my SL amp beyond 9'o clock position when no vinyl is being played . I have tried it two tone arms and the issue is same. I know there are quite a few Nighthawk users in this forum. If they can kindly share their experience regarding the same that will be useful.

Thanks.

What are the carts and what gain and load they require?

 

[mahiruha]

What are the carts and what gain and load they require?

Hi Vasu,
I tried with both ortofon 2m red and Dynavector dv 20 X cartridge. First is a standard MM cart with 47 Kohm load and second is a MC cart. I put the Gain to MC and load to 1 Kohm . The thing is without cart touching the record If I increase the volume pot there should not be any sound from the speaker while keeping the phono stage turned on. At least my SL in built phono and creek obh 15 phono does that.

Thanks.

 

[sachu888]

I think it is Opamp oscillation.It is expected with some Opamps.You should not worry if it is not there during record playback.

Regards,
Sachin

 

[mahiruha]

I think it is Opamp oscillation.It is expected with some Opamps.You should not worry if it is not there during record playback.

Regards,
Sachin

It has to be there during playback but it is masked by the music. Since my speakers are highly sensitive so I never have to go beyond 9'o clock but my point is it shouldn't be there. So just wondering.Do you experience similar things with your battery operated DIY phnostage ?

Thanks.

 

[prem]

Hi Mahiruha

I had used Nighthawk for a very short while. I did not experience the problem you are facing.

 

[mahiruha]

Hi Prem,
thanks for your feedback. I just did an experiment and I think I found out what is going on. Actually in my present set up I am using two phonostages in one amplifier. One phonostage is inbuilt in my SL amp and other is external nighthawk. If i keep the nighthawk switched on and increase volume pot with the selector at the inbuilt phono I get a hissing sound. If I switch off night nighthawk the sl phono performs fine. When I use the nighthawk I can't really turn off the in built phono that's why some hissing sound is transmitted to the nighthawk. I must say if I keep the nighthwak turned on and use the sl phono the hissing sound is much pronounced than in the other configuration. Which means the noise floor in Nighthawk is much lower.

Thanks.

 

[HypnoToad]

Are you connecting the night hawk to the phono inputs of the amp or the aux inputs?

 

[mahiruha]

Are you connecting the night hawk to the phono inputs of the amp or the aux inputs?

To the aux inputs.

 

[sachu888]

It has to be there during playback but it is masked by the music. Since my speakers are highly sensitive so I never have to go beyond 9'o clock but my point is it shouldn't be there. So just wondering.Do you experience similar things with your battery operated DIY phnostage ?

Thanks.

I have not faced this problem,but some of the opamps in some circuit may have this problem.It could also be a RF issue.Try to place your phonostage in different position and see if noise gets reduced.
Phonostages are high gain circuit and may pick up some unwanted noise when record is not playing.You may not experience this noise during playback as it may be well below surface noise of record.

Regards,
Sachin

 

[jls001]

@mahiruha: when you tried different arms, did you ground the turntable chassis to the ground wire (usually black coloured) that comes out from the tonearm? And further, is the ground wire earthed to ground terminal of your Nighhawk phonostage?

Your Nighthawk runs on battery so there is no electrical earth. So the grounding wire that comes from your arm tube, forked to the turntable chassis, then to phono pre, must get its electrical earthing from the next device, namely, your line pre amp or integrated amp via the shield of the interconnect cable from the phono pre to line preamp (or integrated). So your line pre (or integrated amp) must be properly grounded. The power cord must have a ground pin.

Or am I sounding too complicated?:lol:

The above is one scenario. Another scenario is where something in your TT is picking up electrical hum. A symptom of this problem is audible hum at higher amp volume settings even when the turntable is not switched on (the phono being selected as source).

 

[mahiruha]

@mahiruha: when you tried different arms, did you ground the turntable chassis to the ground wire (usually black coloured) that comes out from the tonearm? And further, is the ground wire earthed to ground terminal of your Nighhawk phonostage?

Your Nighthawk runs on battery so there is no electrical earth. So the grounding wire that comes from your arm tube, forked to the turntable chassis, then to phono pre, must get its electrical earthing from the next device, namely, your line pre amp or integrated amp via the shield of the interconnect cable from the phono pre to line preamp (or integrated). So your line pre (or integrated amp) must be properly grounded. The power cord must have a ground pin.

Or am I sounding too complicated?:lol:

The above is one scenario. Another scenario is where something in your TT is picking up electrical hum. A symptom of this problem is audible hum at higher amp volume settings even when the turntable is not switched on (the phono being selected as source).

Hi Jls,
I see your point what you are saying. I think first part is taken care of otherwise with the presence of any second phonostage the inbuilt phono of the SL amp should have produced hum at higher volumes but it is silent. You are right in your assumption that Nighthawk is a battery powered phono so it has to be grounded via a complicated route otherwise its interference is bound to be picked up by the stylus of the other arm even if the TT is not playing. Anyway problem is solved now as the little hissing sound from the Nighthawk isn't too much of a problem. Having two arms in the same table connected to different phono stages can be a bit problematic.
Thanks.

 

[jls001]

Hi Jls,
I see your point what you are saying. I think first part is taken care of otherwise with the presence of any second phonostage the inbuilt phono of the SL amp should have produced hum at higher volumes but it is silent. You are right in your assumption that Nighthawk is a battery powered phono so it has to be grounded via a complicated route otherwise its interference is bound to be picked up by the stylus of the other arm even if the TT is not playing. Anyway problem is solved now as the little hissing sound from the Nighthawk isn't too much of a problem. Having two arms in the same table connected to different phono stages can be a bit problematic.
Thanks.

Oh, it's nice to know that you have resolved it.

I had, and still have, some amount of hum on my main 'table when using low output MCs like the DL-103 which requires one to turn up the volume by quite a bit in the line stage (typically 6 to 10 dB more than CD playback), the hum becomes audible between tracks, when one goes close to the speakers. It is not audible at regular listening distance. During normal playback, the sound of music drowns the hum, but I'm bothered by the fact that the overall noise floor is raised, which leads to reduced detailing.

 

[pratimbayal]

Hi Mahiruha

I use nighthwak , and I also get hissing sound. The hissing sound is there when tt is selected as source , whether the same is switched off or on but the phono is on . This hissing sound is only audible after 12 o clock and becomes quite large at full volume. However I listen at 9 or 10 o clock position and at that level there is no hissing unless I keep my ear on the speaker driver.

 

[mahiruha]

Oh, it's nice to know that you have resolved it.

I had, and still have, some amount of hum on my main 'table when using low output MCs like the DL-103 which requires one to turn up the volume by quite a bit in the line stage (typically 6 to 10 dB more than CD playback), the hum becomes audible between tracks, when one goes close to the speakers. It is not audible at regular listening distance. During normal playback, the sound of music drowns the hum, but I'm bothered by the fact that the overall noise floor is raised, which leads to reduced detailing.

Hi Jls,
from my experience I can say a good solid state phono stage shouldn't have any hum at all otherwise it becomes quite difficult for it to tackle low output moving coils. Actually the way this ground stuff works is quite different in my case. My transfi tonearm is isolated from the table and the ground wire comes from the tone arm itself and it goes into the ground of the nighthawk which in turn is battery operated. In a way there is no ground in its true spirit. In this case hiss is more. When I use my Vpi tone arm it has ground wire coming from the junction box (which I don think has any connection to the chasis) and ground wire gets attached to the Nighthawk so in this case also there is no ground in its true spirit.

I am confused now. What is going on. May be there is another way of explaining this. When I attach nighthawk to transfi I get more hiss and when I attach nighthawk to vpi I get less hiss. Now in the first case the other arm has a medium output MC so the SL phono circuit is set to high gain to play music from that moving coil so it is more prone to pickup static from air so more hiss.

When I attach nighthawk to vpi the transfi tone arm has a ortofon 2m red so the sl phono set to operate in a low gain mode resulting in less hum from the nighthawk.

In a way it is combination of type of cartridge on the second arm and grounding problem. But what I don't understand is Why Pratim has any hiss at all where there is no second phono stage. May be he has some other high gain circuit operating in the vicinity.

I again re iterate a good quality solid state phonostage at any price point particularly which has functionality of playing LOMC should be dead silent.

Looks like the hum or hiss is a common problem with nighthawk.
http://www.audiocircle.com/index.php?topic=78981.140
Thanks.

 

[prem]

Hi Mahiruha

Is it possible that the phono cables are creating the problem? Sometimes some phono cables pick up the power noise and create a hum

 

[jls001]

I again re iterate a good quality solid state phonostage at any price point particularly which has functionality of playing LOMC should be dead silent.

Looks like the hum or hiss is a common problem with nighthawk.
New Ray Samuels Phono Stage/ Nighthawk
Thanks.

I agree with the fact that a properly designed and made phono stage must be silent even at its (phono stage's) highest gain setting. In my case, I have proven this by moving the DL103 cartridge to a different, recently acquired turntable. It is silent at a gain setting (on the line level preamp) which is 10 dB more than normal CD listening. I haven't bothered to try higher gain, but I guess I must do it. BUT, when a light switch is turned on-off in the same room while this new 'table is playing, there is still a popping pickup. Phono preamp remains the same.

Regarding Pratim's Nighthawk, I had a word with him on Sunday. What I understood from our conversation is that his humming problem seems to be due to the absence of a dedicated grounding wire from his TT. I could be wrong here as it is my diagnosis from his description. Do give the Nighthawk the benefit of your doubt. Malvai is another happy Nighthawk camper and he swears that it is dead silent.

 

[malvai]

Mahiruha,
I have been using my Nighthawk for close to 3 years.... never have I encountered this problem, even with the dial turned to the max......

 

[pratimbayal]

I somewhat agree with Josua. Earlier I had a different tt - project RPM 4 , there was no such issue as such- as far as I can remember. I recenlty acquired a Micro Seiki idler drive Turn table from Mr. Kuruvila . The sound quality is excellent. However this hiss is there. What I heard from other members also , there is hiss problem with some of them . So it might be due to particular combination , grounding etc.. Though in my case the hissing sound is not an issue for normal audiotion . What is my problem is humm.. that is quite audible , ( may be electrical grounding issue or magnetic feedback ) what I discussed with Josua yesterday. I am trying to trouble shoot that.

Thanks

 

[mahiruha]

Hi,
thanks everybody for your feedback regarding Nighthawk phono. Looks like it needs an ideal environment for silent operation but it can be achieved.

@Pratim: I think to solve your hum issue. You must do two things. You must place the nighthawk as much away from the TT as possible. You must locate a place in your TT where you can solder a ground wire and that wire should be connected to the Nighthawk. I am not sure about magnetic feedback but you should check the manual if your TT can accept moving coil cartridges. I know some TTs cannot accept mc cartridges due to some reason.

Thanks.