Bakoon Amp-13R Review and Impressions - Under Pressure

Some measurements below for high-efficiency speaker use cases. Using an 8-ohm resistor block since this is what would be expected for most high-efficiency speakers (windbanders). Both channels are driven with a load, but only one is measured.

Bakoon Amp-13R
1W (slightly more at 2.884Vrms) into 8-ohms 1kHz (THD+N using 90kHz bandwidth)
2Vrms input (volume knob adjusted to get output)



Note the above is worse than well implemented flea powered tube amps, e.g. SET DHTs.

--

The amp is marketed as a 25W amp. 25W should be able to power moderate efficiency speakers. Let's try 3W and 5W, which are 4.9Vrms and and 6.32Vrms (into 8-ohm loads) respectively. I'm sort of picking numbers that I will usually see why listening to music.

Bakoon Amp-13R
~3W into 8-ohms 1kHz (THD+N using 90kHz bandwidth)
2Vrms input (volume knob adjusted to get output)


Bakoon Amp-13R
~6W into 8-ohms 1kHz (THD+N using 90kHz bandwidth)
2Vrms input (volume knob adjusted to get output)


I guess the good thing is that the amp doesn't get that much worse going to 3W or 5W from 1W.


For what it's worth, the amp does feel more comfortable just under 0dBU (levels are where we normally test headphones). The difference here is that we are using a demanding load for headphones at 8-ohms. But with sub 16-ohm impedance headphones (some planars), we can get an idea of what to expect.

Bakoon Amp-13R
~< 0dBU into 8-ohms 1kHz (THD+N using 90kHz bandwidth)
2Vrms input (volume knob adjusted to get output)

This looks good - at headphone output levels.

Quick conclusions:

• Pretty shitty performance (distortion) at low speaker power levels (1W), which explains why I felt the Bakoon sounded soft and underpowered on the Frugalhorns.
• At expected headphone levels, distortion level similar in level and pattern to SET amps. No issues with the 8-ohm load. Probably why this is one of those amps heralded as being good for planars (low-impedance). FWIW, I didn't feel that the Bakoon Amp-13R sounded subjectively like tube amps at all. It's a bit drier and thin sounding.

 

Let's look at distortion across the audio band. It's very consistent.

~1W 37Hz


~1W 8.2kHz


THD vs Frequency
1W, 8-ohms

Yeah, the distortion is super consistent across frequencies.

 

Level sweeps with distortion next. The Bakoon Amp-13R does roughly meet its 25W spec (8-ohms). (-40db is 1%)

Bakoon Amp-13R
THD (no N) vs Output (W)


Bakoon Amp-13R
THD+N vs Output (W)


What's a little bit disappointing is the high-ish distortion plateau. Not only that, but the distortion pattern isn't clean nor pretty (SET like).

 

Measurements Conclusions:

The Amp-13R performs admirably with headphones, even handling demanding orthodynamic types well, with commendable measurements in distortion levels and patterns akin to single-ended triode (SET) amplifiers. However, its performance with speaker loads is less satisfactory. It struggled notably with speakers like efficient Frugalhorns with Fostex drivers, resulting in a soft sound characteristic of underpowered amplifiers.

Despite claiming a technical output of nearly 25W, its actual effective output, considering its THD compared to its performance at higher outputs, might align more closely with that of a 0.2W amplifier. This implies that its effective power delivery for reasonable low distortion might not match its nominal power rating when it comes to driving certain types of speakers.

Perhaps more efficient speakers such as super-efficient (98db) horns like Voxativs or Lowthers would allow the Amp-13R to perform better in real-world applications.

The Bakoon Amp-13R is a nice cute compact package. But the fact is, you cannot violate the laws of physics with Class AB. Too much style over substance for a six thousand dollar amp.

 

It's about typical THD+N -vs- measured output level curves.

Let's take a look at the Bakoon graph and compare it to say the Crown CDi1000. The THDN of the Crown isn't great, merely good enough for speakers it is supposed to power, hence why I chose this as an example. Sure the Crown is made for totally difference purpose - massive power, but there should be some expectation that the curves would be somewhat optimized for the wattage output (for the speakers). HINT: look for the "sweet spot".



With the CDi1000, distortion keeps going down with increasing output until it reaches a sweet spot between 5W and 500W output, the target of the speakers (Cinema systems) it would likely be used for.


Now let's take a look at Magni 3 which has a slightly different curve. Like the CDi1000, distortion starts to go down with increasing output. The difference is that after a large sweet spot from -5dBu to 10dBu output, distortion starts to rise slowly until clipping (the clipping is not shown).



Finally, here is the Bakoon. The sweet spot is 5mW to 75mW which is just too low to power moderately high-efficiency speakers (93-94db) such as the Frugalhorns. After this sweet spot, the distortion rises to a highish -47db THD and stays at this high plateau - an area that I do not consider "usable" to have good sound. As I said, this is curve is really unexpected for a "25W" amp and reflects more like a 1/2 to 1W amp.

NOTE: how the sweet spot is so far far away from max 25W power rating.

 

Given that the performance from 20Hz and 20kHz is the same as 1kHz, this would not be difficult (we can just interpolate it). What we would need is to establish criteria for Y-axis. In the case of the Bakoon Amp-13R being marketed as 25W amp and ideal for high-efficiency speakers, a max Y-axis of 8W would be reasonable, with coverage of 1/2W to 8W being of interest. I'd say 1mW to 8mW would be reasonable based on the stated purpose of the amp.

From a headphone perspective, it would be different. The Bakoon would fare better.