[etc6849]

Are you sure it's not clipping? I drive mine with a Benchmark DAC3 B with pro level XLR outputs, and send the DAC3 an AES 0dBFS signal from my PC. If I move my BHSE volume up to the 2 o'clock position, I definitely get clipping. I verified this using a HV differential probe and my oscilloscope.

I'd assume I'd have much more volume room on the BHSE dial if I drive it using consumer level inputs. BTW, it sounds outstanding on my SR-009's I also bought from the original owner. I kind of wish it had a little more headroom when using the X9000's though (hence why I got my oscilloscope out). It definitely will do very close to the advertised 1600V peak to peak. I tested this all the way down to 20Hz.

Seeking some advice - my BHSE started to have distortion on the left channel whenever the volume goes past the 2 o'clock position. Swapped the tubes too and the problem persists. Any ideas?

 

[VandyMan]

Are you sure it's not clipping? I drive mine with a Benchmark DAC3 B with pro level XLR outputs, and send the DAC3 an AES 0dBFS signal from my PC.

I recommend setting the DAC3's jumpers to -10dB, if you are connected directly from the DAC3 B to the BHSE.

 

[etc6849]

This is not really needed as the BHSE handles a pro level signal just fine. The clipping I see is exactly at the limits of the BHSE per its specs and has nothing to do with the higher pro level signal from the DAC3.

The one reason I would want to make that change is if I heard hiss or knew that the overall distortion of the entire system could be improved... so you certainly could be right in some situations. I'm not sure what this would gain me here though. Just finer volume control, but still the BHSE is going to clip a little before 1600V peak to peak?

I recommend setting the DAC3's jumpers to -10dB, if you are connected directly from the DAC3 B to the BHSE.

 

[VandyMan]

This is not really needed as the BHSE handles a pro level signal just fine. The clipping I see is exactly at the limits of the BHSE per its specs and has nothing to do with the higher pro level signal from the DAC3.

The one reason I would want to make that change is if I heard hiss or knew that the overall distortion of the entire system could be improved... so you certainly could be right in some situations. I'm not sure what this would gain me here though. Just finer volume control, but still the BHSE is going to clip a little before 1600V peak to peak?

BHSE clipping at 2 o'clock means you are overloading the input, most likely. I've never had my BHSE clip. I would check with HeadAmp.

 

[etc6849]

I am definitely NOT overloading the input. If I was, it would show up in my measurements as I could never display a sine wave at full voltage output like I am in the measurements below.

You will never get more than ~1500V peak to peak out of the BHSE. Sadly, sending it a consumer voltage level signal can't make the tubes operate at higher voltage. It's just not how things work electrically. Once the total gain is at a certain level, it will clip... Think of total gain as volume dial of your DAC + volume dial of the BHSE.

https://headwizememorial.wordpress....tatic-amplifier-for-stax-omega-ii-headphones/

"The amp can output 1500 V p-p measured stator to stator..." Stator to stator means L+ to L- or R+ to R-:

If you want to use more of the volume range of the BHSE volume knob, by all means use consumer level voltage inputs. Heck, you can turn the volume knob up all the way and just use your DAC to control volume. But no matter what, when what the headphone sees is always going to clip after ~1500V peak to peak as shown in my measurements below.

I'm attaching a non-clipped measurement, and a second one where the measurement is clipped. Note the volume dial is slightly higher in the clipped picture.

This is just how the amp operates. It is clearly speced and designed to clip after ~1500V peak to peak. You can measure this too by using a voltmeter (ONLY IF YOUR METER CAN HANDLE ~600Vrms or higher or ~1600Vmax). Just remember, the volt meter is going to show Vrms which would be 530Vrms, not peak to peak. How to convert convert volts rms (Vrms) to volts peak to peak (Vpp): https://www.allaboutcircuits.com/tools/rms-voltage-calculator/

If someone wants even more voltage than what the BHSE can provide, there are options like the KGSSHV Carbon at ~2000V peak to peak, but I don't own one so can't measure it to verify. I also love the sound of the BHSE so much I could never part with it

I was just responding to the poster here saying they hear distortion when the volume dial is high. They really could be hearing the amp clip if they have hard to drive headphones and like to listen to the really loud.
@dstubked

BHSE clipping at 2 o'clock means you are overloading the input, most likely. I've never had my BHSE clip. I would check with HeadAmp.

 

[VandyMan]

I am definitely NOT overloading the input. If I was, it would show up in my measurements as I could never display a sine wave at full voltage output like I am in the measurements below.

I have no interest in debating you on this. You reported a problem and I offered a solution that works for me. My BHSE never clips. I get the full range of the volume control by setting -10dB on the Benchmark DAC as I decribed. If you don't want to do that, no problem.

 

[Beachfloyd]

I heard an audible hum (almost a buzz) coming from my BHSE’s psu when I turned it on after not using it for a couple of days. The hum/buzz got a bit louder as soon as the amp’s second light came on after warming up, and continues until I switch it off. My x9000’s have no extra noise coming from them, regardless of whether music is playing or not, and everything sounds just fine. The noise from the psu isn’t loud enough to disrupt my listening, but this is a change from my experience up to this point, as I’ve otherwise enjoyed a lack of audible noise coming from the psu.

…Or maybe there’s always been a hum/buzz and I’m just now noticing? Either way, it caught my attention tonight, especially the jump in volume once the amp turned on.

Is this sound from the psu normal? Should this be any cause for concern? The amp itself sounds the same as always, so I’m not too worried, but you never know!

 

[SolarCetacean]

I heard an audible hum (almost a buzz) coming from my BHSE’s psu when I turned it on after not using it for a couple of days. The hum/buzz got a bit louder as soon as the amp’s second light came on after warming up, and continues until I switch it off. My x9000’s have no extra noise coming from them, regardless of whether music is playing or not, and everything sounds just fine. The noise from the psu isn’t loud enough to disrupt my listening, but this is a change from my experience up to this point, as I’ve otherwise enjoyed a lack of audible noise coming from the psu.

…Or maybe there’s always been a hum/buzz and I’m just now noticing? Either way, it caught my attention tonight, especially the jump in volume once the amp turned on.

Is this sound from the psu normal? Should this be any cause for concern? The amp itself sounds the same as always, so I’m not too worried, but you never know!

That sounds like a transformer buzz. My Stax tube amps also produce a buzz from the transformer after the warm-up process. I've tried a bunch of DC blocker and power conditioner products to try to eliminate the buzzing and none have worked. The amp works fine though and has been for over a year since I got it; it's just a bit annoying for desktop use.

 

[LouisArmstrong]

Any last word on whether the T8000 or BHSE suits the X9000 more?

 

[Chefguru]

Any last word on whether the T8000 or BHSE suits the X9000 more?

Bhse for sure.

 

[Sko0byDoo]

Unobtainable T2?

 

[vrockz]

Hi,

Are there any benefits in upgrading the power cable on BHSE.