Helm Audio Bolt Review (Portable DAC & Amp)

[ahofer]

This would be an interesting candidate for baseline blind tests of hi-fi DACS. Could you tell your kilobuck DAC from this one? Most of the time, no.

 

[TheTalbotHound]

Amir, are you going to measure the Hidizs S9? If it is anywhere near as good as the S8 it would be interesting.

 

[PeteL]

This would be an interesting candidate for baseline blind tests of hi-fi DACS. Could you tell your kilobuck DAC from this one? Most of the time, no.

It would be a bit difficult to do a fair comparison, because the 0DBFS on this when unloaded would be at 2V where most desktop standalone are at 4V+ so to maintain consistant levels, some preamplification, or attenuation would be necessary and that alone may have more impact than the DAC.

 

[Mulder]

Amir, are you going to measure the Hidizs S9? If it is anywhere near as good as the S8 it would be interesting.

I have the Hidizs 9 and have had the Hidizs 8. To my ear Hidizs 9 is at least as good as the Hidizs 8, but it drains my smartphone battery very fast. I would not recommend Hidizs 9 for a smartphone.

 

[Sprint]

I am using iOS. Which of the issues did you experience? The battery drain or the Hidizs 8 poor quality?

The Hidizs8 did not function at all when I connected my iOS to Hidizs8 using the supplied lightning <-> mini usb cable. The first few days it worked and some update on iOS came and it did not work anymore. But the same Hidizs8 unit worked very well over a USB C mini usb connection to my MacBook Pro.

 

[TheTalbotHound]

I have the Hidizs 9 and have had the Hidizs 8. To my ear Hidizs 9 is at least as good as the Hidizs 8, but it drains my smartphone battery very fast. I would not recommend Hidizs 9 for a smartphone.

yeah my preference is usually to go for stuff with an external battery.

Would also be nice if amir could review some bluetooth portable DAC amps like he did with the Qudelix 5k and earstudio ES100. I know sony make the SBH24 and SBH56, and fiio make the BTR5. Other than those i dont know any others but im sure there are some more out there.

 

[Palex]

It to be pleasant to me - Highscreen TrueSound Pro. (60$)

 

[Veri]

Now I am curious about the ibasso DC03 and DC04. Dual CS43131, SE resp. balanced headphone out.

I believe WolfX measured them, check out l7audiolabs.

 

[Billy Budapest]

Yes, better than the Apple adapter, but for 11x the price. I wonder what Apple could do for $20-25 if they could be bothered?

You have to be a little more specific! The US-spec Apple dongle is decent, and when the price is taken into account, very good. On the other hand, the EU-spec Apple dongle is mediocre no matter which way you cut it.

 

[Soniclife]

I really liked to hear the statement in the video at 8:10. "Subjective testing is important for these things, The measurments we have are for continuous power, but some of them can do better for momentary peaks(...) I find that subjectively some of them sound better than others(...) Measurments is the baseline but listening is important"
-Amir

Does that mean we need to use a more meaningful test, which would illustrate it's real music power better?

 

[Billy Budapest]

@amirm THX explains what its certification for the Helm Bolt is . . . sort of:

“The BOLT DAC/AMP has passed many rigorous THX Certification audio quality tests ensuring a flat frequency response, low distortion, low noise and a stable, high output suitable for a wide range of headphones delivering a superior audio experience.”

https://www.thx.com/blog/helm-launches-bolt-dac-amp/

 

[PeteL]

Does that mean we need to use a more meaningful test, which would illustrate it's real music power better?

Good question, I don't have the specific answer for these specific class of device, to me as I also mentioned elsewhere differently, the power supply is always an important part of how a product perform. The fact that these products don't have one but rely on an other device supply, that in itself leaves questions unanswered but I can't go much deeper on this.

 

[Jimbob54]

It would be a bit difficult to do a fair comparison, because the 0DBFS on this when unloaded would be at 2V where most desktop standalone are at 4V+ so to maintain consistant levels, some preamplification, or attenuation would be necessary and that alone may have more impact than the DAC.

2v single ended is the standard, no?

 

[PeteL]

2v single ended is the standard, no?

You're right. I think I just seen to many balanced dac review lately

 

[Jimbob54]

You're right. I think I just seen to many balanced dac review lately

Now the real question ,that others have referred to in this and other dongle reviews, is does one get (up to) 2v and this level of performance from phones (which are probably the main use case)? If so, all phones or does it depend on each model? If not, do reviews of dongles need to include a phone element as well as connected to a PC? Personally I wouldnt get a $100 dongle for desktop DAC duties when the Topping D10/E30 and the like exist, but I want the dongle that has the best power to performance ratio for my mobile needs.

 

[amirm]

@amirm THX explains what its certification for the Helm Bolt is . . . sort of:

“The BOLT DAC/AMP has passed many rigorous THX Certification audio quality tests ensuring a flat frequency response, low distortion, low noise and a stable, high output suitable for a wide range of headphones delivering a superior audio experience.”

https://www.thx.com/blog/helm-launches-bolt-dac-amp/

Thanks. With no detail of such criteria, it is hard to judge what it really means.

 

[PeteL]

Now the real question ,that others have referred to in this and other dongle reviews, is does one get (up to) 2v and this level of performance from phones (which are probably the main use case)? If so, all phones or does it depend on each model? If not, do reviews of dongles need to include a phone element as well as connected to a PC? Personally I wouldnt get a $100 dongle for desktop DAC duties when the Topping D10/E30 and the like exist, but I want the dongle that has the best power to performance ratio for my mobile needs.

Well on this review it already only reach 2V on easy loads, that wouln't change, my curiosity was about under load performance, if it's consistent regardless of the source, but maybe I'm putting too much tought into it and it's fine. 1.4V in 32 ohms is to me close to the lower acceptable limit, if consistent.

 

[Billy Budapest]

Thanks. With no detail of such criteria, it is hard to judge what it really means.

This is about as detailed as they get. I guess you have to register as a “partner” to gain access about their particular testing regime:

“WHAT WE TEST
THX engineers complete hundreds of different scientifically-formulated tests to ensure the highest audio-visual standards possible.
. . .

AUDIO SIGNAL PATH
Frequency response, distortion, signal-to-noise, and crosstalk are tested to ensure audiophile-quality performance with flat frequency response and low noise.
HEADPHONE AMPLIFIER OUTPUT
Our engineers test for an undistorted audio output capable of driving high-performance headphones and producing top-notch sound.

PERFORMANCE BENEFITS
A comprehensive set of over 150 performance tests verify that the video and audio hardware is capable of delivering an optimal entertainment experience. Specifically:
. . .

OPTIMAL AUDIO
Optimized audio output professionally verified to provide clarity and full bandwidth, from movies to music.”

https://www.thx.com/thx-mobile-devices

 

[PeteL]

This is about as detailed as they get. I guess you have to register as a “partner” to gain access about their particular testing regime:

“WHAT WE TEST
THX engineers complete hundreds of different scientifically-formulated tests to ensure the highest audio-visual standards possible.
. . .

AUDIO SIGNAL PATH
Frequency response, distortion, signal-to-noise, and crosstalk are tested to ensure audiophile-quality performance with flat frequency response and low noise.
HEADPHONE AMPLIFIER OUTPUT
Our engineers test for an undistorted audio output capable of driving high-performance headphones and producing top-notch sound.

PERFORMANCE BENEFITS
A comprehensive set of over 150 performance tests verify that the video and audio hardware is capable of delivering an optimal entertainment experience. Specifically:
. . .

OPTIMAL AUDIO
Optimized audio output professionally verified to provide clarity and full bandwidth, from movies to music.”

https://www.thx.com/thx-mobile-devices

I frankly question the Value for a manufacturer, to go and obtain these certifications. THX trying to get back in the game, OK, 20 years ago it may have meant something, but we, that are quite interested in these subjects, and understand what these words mean, to me, I would much rather see on a manufacturer website a Audio Precision measurment report, than being told that THX approve, and for the rest of the crowd that could want a portable dac dongle amp, I don’t think they even know what THX is... So who is it for really? Maybe some business deal, THX willing to get their brand out there, and Helm willing to try a AAA amp module on future products, and trying to get some « partnership, one stop, we not only provide amplification circuitry, but also stamp and measure your other products, or something like that. The THX new business model is hard to follow. I don’t know if it’s evolving, but before the first THX head amps where out, I know their licences and royalties where out of control expensive. I see it now on relatively inexpensive gear so it may have changed.

 

[Tatteredmidnight]

Amir, did you measure the output impedance?