**Hifiman HE-400 Impressions and Discussion Thread** - Page 130

OK so I found a very decently priced amplifier that works well with my setup. It's called the Sense G5 hybrid amplifier. It really helps to roll off the treble that most complain about. I got it for ~$150 from this seller:

http://www.aliexpress.com/item/Wholesale-Free-Shipping-Sense-G5-Hybrid-Vacuum-Tube-Headphone-Amplifier-Brand-New/537708912.html

"12AU7 tube + VMOS transistor class A output

Power output: >1000mW
Frequency response: 10Hz-50KHz
Headphone impedance: 32Ω-600Ω
Signal-to-Noise ratio: >90dB
Line input: RCA 
Headphone output: 6.35 mm stereo jack
ALPS volume control
WIMA MKP10 ELNA AV BC capacitors
Dimensions: 163 x 252 x 68 mm
Weight: 2.5 Kg
Input voltage: AC110V-120V 220V-240V 60/50Hz (110V version will be takes 5-10 working days to order)"

It took over a week to get it to me with EMS shipping. It sounds better with the Hot Audio Dac Extasy than the F17, E09K, and O2. The only problem I'm having is that after about an hour I hear this constant high pitched whine sound come through the headphones, even when the volume is turned all the way down. (Ground Loop maybe?). So after I turn off the unit, take out the tubes and wait 30 minutes or so and put the tubes back in. Annoying sound disappears. 

Quote:

Originally Posted by richierich 

OK so I found a very decently priced amplifier that works well with my setup. It's called the Sense G5 hybrid amplifier. It really helps to roll off the treble that most complain about. I got it for ~$150 from this seller:

http://www.aliexpress.com/item/Wholesale-Free-Shipping-Sense-G5-Hybrid-Vacuum-Tube-Headphone-Amplifier-Brand-New/537708912.html

 Why does that amp look so familiar?

Another solid amp that rolls off the top end a bit would be the Emotiva a-100. Yes, it's a speaker amp, but think of it this way: it only outputs 2W more than the venerable Lyr everyone pairs these with, and arguably sounds completely comparable at half the price. Runs pretty cool as well. 

Yeah the Sense G5 actually sounds amazing powering the HE-400s. It's just hit or miss coming from an unknown Chinese vendor .

Quote:

Originally Posted by richierich 

OK so I found a very decently priced amplifier that works well with my setup. It's called the Sense G5 hybrid amplifier. It really helps to roll off the treble that most complain about. I got it for ~$150 from this seller:

http://www.aliexpress.com/item/Wholesale-Free-Shipping-Sense-G5-Hybrid-Vacuum-Tube-Headphone-Amplifier-Brand-New/537708912.html

Aliexpress?  Don't think I'll be an early adopter of chinese-knock-off-market hi-fi :P

That said, if you manage to sort the fault, you might have found yourself a sweet deal.  Do you have any known-good tubes that you can swap in once the fault occurs?  I can't imagine the tubes being great, given the vendor, and it'd be a cheap, non-intrusive attempt at a fix.

Well I just ordered some 3S4 NOS tubes off eBay. Hopefully it's the tubes that are at fault *cross fingers*.

Most companies offer restocking fees for returns within warranty. Usually it is not 20% however but a bit lower.

Quote:

Originally Posted by yokken 

Head-Direct is still jerking me around saying the return period is 30 days from when you purchase it. So let me get this straight, I didn't have my HE400s for 2 weeks and that counted against my return period? You've got to be kidding me.
Ms. T called me to talk about it. She wasn't aware they were the defective ones so she is talking with someone about it. Hopefully I won't have any more problems.
She emailed me back saying the "President" said I can return them for a 20% restocking fee. What a joke. I can sell them for more than that. Great company.

While there is usually a restocking fee with a return at most places, that seems little outrageous to me!

Quote:

Originally Posted by yokken 

I'm familiar with restocking fees, but I'm not going to pay $80 to send it back to a bunch of asses. I'd rather give a nice guy on these forums a good deal.

Definitely a nice gesture on your part. 

Quote:

Originally Posted by Mad Lust Envy 

I had the power. The NFB5 had about 3.5watts to the HE400 (I preferred the NFB5 to the Lyr which I also owned). The HE400 just doesn't have the emphasis on bass I wanted. I KNOW it's there. I just want it more prominent than it was. No amount of power is gonna transform the bass anyways. Even my SA-31 that puts out almost 2x the power of the Lyr at 40ohm wasn't gonna make a big difference). The difference is there, but not a huge one in terms of emphasis. Even unamped, the HE400 had really good bass. Just not emphasized to my desired level.
You can call it loose or uncontrolled, but I prefer it that way.

Have you tried boosting the frequencies with an equalizer? 

Sorry if I'm repeating previously asked questions, this forum moves to darn fast.

I guess Hifiman/HeadDirect is not used to their products being refunded