Your speakers should be dead quiet with your system at idle. If you can hear any noise coming from a tweeter would indicate a component design or installation weakness somewhere in the signal path.
You would think so…
I’m really thinking it is the preamp. I’ve been running the DS straight into the 250 for the burn-in phase, and although the noise is intense at normal listening levels, when I engage the output pad and turn up the DS volume there is almost zero noise coming through the speakers. This means when noise from the DAC or preamp are mitigated there is very little coming from the amp. But dang, my BHK Preamp compared to DS with pad is significantly noisier. I know 12v tubes will help somewhat (the old set were a bit quieter), but how much I wonder?
Interesting, I never encountered this noise with my old amp. Maybe the 250 input is just more sensitive or detailed.
My comment was based on experience. My speakers are as dead quiet with the system off as they are with the system at idle. That was the end point I set out to achieve when I put it together. If you can hear your tweeters make any sound with the system at idle then you have room for improvement somewhere in the signal chain.
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I, too, experience a level of extraneous hissing noise on the left channel of my system. Not remotely as bad as you describe - I have to be standing up against the speaker to hear said hissing noise. The right channel is silent.
I own two DS-DACS, BHK preamp, two BHK250s and BHK300s. I’ve tried various permutations of different DS boxes, BHK amplifiers, swapped tubes, I’ve tried different tubes, interconnects, but all to no avail. The hissing noise prevails. I swapped the BHK preamp for a Dynavector L300 MK2 and both channels were dead silent. Dynavector preamp doesn’t sound as good in my system as the BHK preamp so I just have to forget about the hissing noise on the left channel!
Admittedly - the level of hissing noise I hear isn’t excessively loud but, that said, there shouldn’t be any hissing noise - it should be silent, the same as the right channel. It’s just one of the many foibles and issues I’ve had to put up with since owning P S Audio equipment. The only saving grace is PSA & BHK equipment do sound excellent so I’ve persisted with them !!
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That’s right. It should be silent. If one channel can be silent, so should the other one.
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Tubes make noise it is a fact of life. How much depends on the number of tube components in the chain, the quality of the tubes and the gain and input sensitivity levels of the respective pieces. That is compounded by the sensitivity of the speakers. Substituting a SS component in place of a tube component will reduce the noise as will as introducing a tube preamp with lower gain than the BHK or an amp with a higher input sensitivity than the 250. Substituting a speaker with 85 db efficiency in place of one with 92 db efficiency will have the same effect. So Brodric “claiming” his all SS rig with 85 db speakers is “dead silent” is irrelevant to this discussion. He as usual is just looking for another opening to take a backhanded shot. In the “real world” a tube system that you only hear with your ears to the speakers is quiet.
Just to reiterate - my speakers are medium sensitivity (90db/w/m) but I am in a small listening room and I need to turn the volume level up to my my maximum listening volume (with no music playing) and hold my ear right next to the drivers to hear any hiss.
From my listening position (10 feet away) I can’t hear anything even if I turn the volume up beyond where I would be comfortable listening.
I’m using my system with a BHK Preamp going into BHK300s too.
So to me this still sounds like a hardware issue. Yes tubes/valves produce hiss but not to the extreme levels that the OP is suggesting.
Also I’ve never fully understood this idea that more sensitive speakers will cause more hiss because if your speakers are more sensitive you set the volume on the amp lower to get the same volume.
In the end the hiss level should be the same assuming you are listening at similar SPLs to other people.
From my (albeit limited) understanding the only problem with more sensitive speakers would be difficulty achieving lower volumes but that is not the problem here.
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Most of his problem went away when he changed out the preamp tubes. He is now down to within a few inches of the speaker.
The hiss I was experiencing was not volume dependent. If hiss is louder from one speaker than it is from the other, you’ve got an issue.
It’s funny that people think expensive NOS tubes sound better than current production tubes, not my experience at all. Go try some current production tubes, I’m sure you’ll be pleasantly surprised.
Don’t you find it strange that the previous owner sold the unit that soon?
Call PS Audio, if any of their suggestions don’t solve the problem, pack it up and send it in for repair.
It’s ridiculous that you need to swap tubes on US$ 12.000 (Pre + power) in order to get rid of noise and hiss.
When warmed up tubes should be silent. I’ve listened to a US$ 2,000 integrated tube amp on a pair US$ 18,000 Sonus Faber Amati, very audiophile, no hiss no noise not even during switching on or warming up, just beautifully reproduced music, or silence!
How do you define dynamic range if silence is not reproduced silent? Isn’t dynamic range the reason you buy these amps?
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That’s what I’ve been trying to say. Since I have basically the same set up (except with BHK300s) and get no audible hiss (unless I put my ear right to the speakers) I don’t understand how anyone can think this is normal.
I did notice an increase in hiss on my BHK300 that had the faulty input board before it started making the banging noises and I had to have it repaired.
That hiss was independent of volume level (as was the banging). Yes tube amps produce more hiss than solid state amps (in many cases) but the hiss should not be as prominent as some people are suggesting.
You don’t pay extra money to get worse sound quality. If it was me I would send the amp(s) back to PS Audio to get properly checked out.
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Just to clarify, now when I use the Directstream DAC with 20db output pad directly into the 250 it is pretty close to silent. With the BHK Preamp I can also mitigate the noise floor of the DAC, but now I have to figure out how to get the preamp self-noise into the 250 to be quieter. Different tubes and possibly attenuators (if they don’t mess up the sound) should do it. A 10db attenuator would definitely do it in the same way as the output pad on the DS, but I would hope they would sound better.
Unfortunately, while they sound better than stock, the NOS Tungsram tubes in both Pre and 250 raise the noise floor. And yeah, I think NOS tubes sound better, provided they have the right sound character.
What is a 20db output pad? Also the BHK preamp should be quiet - I’m not sure what you mean by self noise.
The Directstream DAC has a feature called “DAC Level” that knocks the analog output down 20db so you can crank the DAC volume when going straight into an amp and avoid hearing the noise floor. Without you have to turn the system up to extremely loud levels to get above and away from the noise floor.
At no setting is the BHK Preamp perfectly silent, and at certain volume increments (24 and 51) the noise level gets pretty high before it dramatically drops off at the next interval (you can hear a click too).
Ian
The attenuators will do the job and the ones from Rothwell at least will not negatively impact the sound. And you are correct with 90 db+ speakers the BHK preamp will never be completely silent if you insist on putting your head up to the speakers. I suspect that as long as there is not a problem with the gear that if you get a good set of tubes in the preamp and the amp you will hear no noise until you do get right up to the speakers.
The Directstream DAC has a feature called “DAC Level” that knocks the analog output down 20db so you can crank the DAC volume when going straight into an amp and avoid hearing the noise floor.
Yes but that is for reducing gain. It is not there for reducing hiss. BTW I and some others have found that it reduces sound quality. I prefer using the manual DAC volume to give me more scope for volume adjustment.
At no setting is the BHK Preamp perfectly silent, and at certain volume increments (24 and 51) the noise level gets pretty high before it dramatically drops off at the next interval.
Again as I keep saying that is not how it should be. My preamp is silent from my listening position even at very high volume levels. Doesn’t matter how sensitive your speakers are, because obviously if you have more sensitive speakers you will use a lower volume setting so the hiss should be the same as for everyone else.
Anyway it is up to you if you get your amps checked out or not. I know I wouldn’t be happy paying so much money and not being 100% satisfied with the sound.
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The DAC Level function does reduce sound quality IMO, but it was specially made so you could use the DAC directly with an amp. Using the DAC volume straight into an amp my ears start to bleed around 30 and the noise floor is still very audible. With the pad I can set the volume to 45-65, maintain decent listening volume, and not hear the noise floor.
Some questions: Are you using the stock preamp tubes? Have you tried DAC straight into your amps?
Using the DAC volume straight into an amp my ears start to bleed around 30 and the noise floor is still very audible.
That suggests your speakers may be slightly less sensitive than mine. I don’t hear the noise floor even when it is painfully loud. Right now I have the DAC set at 70 and that lets me push in to the mid to upper 30s for max comfortable volume. Previously that level was in the lower 20s for me. Also I’m not using the built in attenuator and no external attenuation (why add something else into the signal path).
Some questions: Are you using the stock preamp tubes? Have you tried DAC straight into your amps?
Yes right now I am using the standard tubes but I’ve tried some other NOS just to test them out and have not had any hiss issues.
I have tried the DAC straight into the power amps and it was still too loud for me (as I detailed in one of the other threads about volume levels) but again no hiss problem. Also it didn’t sound anywhere near as good as having the DAC going into the BHK Pre and then into the BHK power amps.
10dB attenuators on the input to your amps will do the trick. I’m using Whirlwind, no change in SQ. The 20 dB attenuator on the dac will have no affect on the hiss coming from your preamp. I lived with the hiss for a while. I wish I’d tried the attenuators sooner, but, I was worried it would affect SQ. Again, if you ask the CEO of the company that makes your equipment, he will tell you, it’s normal to hear some hiss with highly efficient speakers. Still funny to hear people say NOS tubes are better than current production.
Computers were probably better back then too! Lol, oh that’s right, the technology available today, was not available then. Maybe sitting around for 50 years seasoned them.