Full Disclosure: I was contacted by another member here with an opportunity to review the Burson Audio Fun and Bang. Initially it was an opportunity to keep a review unit after giving it a review. I wasn't looking for another desktop amp in this price range but for the price of free and an honest review I figured why not? In the end there was a miscommunication with Burson that did not allow both reviewers to keep both units. I decided to keep the Fun instead of the Bang since I listen primarily to headphones or my Dali Helicon 800's for two channel.
Here's a link to my original Burson Audio Fun review https://www.head-fi.org/showcase/burson-audio-fun.23238/reviews#review-20998
Also, I was unable to review the Bang in conjunction with the Fun as i'm sure the designer had intended since I did not have access to both at the same time. As a result I used my Schiit Ragnarok as a preamp.

Equipment Used:
Before I did this review I had planned on reviewing this unit with my Dali Helicon 800s. However, after the issues my review partner had with this unit in regards to pops and screeches I decided to pull out my Orb Audio Mod2 speakers rather than risk damaging my Dali speakers.

Speakers: Orb Audio Mod2 Satellites 4 ohms

Ampifiers: Schiit Ragnarok used as a preamp. Compared to Schiit Vidar

Source: Microsoft Surface Pro 4 with Roon connected to a Schiit Bifrost Dac with multibit

Song lists:
Paul Mc Gowan's dirty dozen from PS Audio
https://www.psaudio.com/pauls-posts/pauls-picks/

Zeos's song list for testing headphones that i compiled from his you tube videos
https://tidal.com/playlist/a0d3509b-d8c2-4116-b9f1-83909b34d105

Cecilia Bartoli St Petersburg
https://tidal.com/playlist/7c327507-dc9a-44de-8a58-d61ed71f3ff7

Pure-Maria Callas
https://tidal.com/playlist/c2fd08bc-9eee-4453-a4cf-9e98568608cf

and other songs from my playlists.

Review
Burson Audio's line of products are made with solid metal construction that feel solid and feel like quality. The Bang feels well made and I wouldn't hesitate to stack other components on top of this unit. This unit comes with two RCA cables, a tool to remove the top to Opamp roll and a power brick. Connection wise it has two RCA inputs and a set of stereo speaker inputs. It also comes with a 4-pin Molex connector which would allow you to use it inside an open bay in your desktop.
In my listening tests I used the Schiit Bifrost multibit and Schiit Ragnarok as a preamp. Upon first turning the unit on with my speakers attached I did hear the "pop" that my review partner warned me about but after that I heard no additional questionable sounds. The sound from my speakers were well controlled within the speakers reproducible range. I did not hear any distortions at low or reference levels. In comparison to the Schiit Vidar the transients weren't as quick and the sound wasn't as full. At lower listening volumes the Vidar was able to produce a wider range of sound than the Bang at volume adjusted levels. However, even though the price of the Vidar is comparable to the Bang, the Vidar is about 5 times the size of the Bang and has more power output. If the footprint of your amp is a concern then the Bang is definitely a great option. I also noted the unit got very warm during the review. I don't see how this would be good inside a PC case.
Overall, I would say this is a good unit if staying inside the Burson Audio line. If it wasn't for the quality control issues that have plagued the Fun and the Bang that I have reviewed, I would whole heartedly recommend this line.

Pros
1. Solid metal exterior construction.
2. Sound after the initial "pop" or "screech" is full and detailed.
3. Enough power to drive my 4ohm Orb Audio Mod 2.1 speakers without much effort
4. Option to insert into an open bay on your desktop with a 4-pin Molex connector. (not really practical due to heat issues though. See list of cons)

Cons
1. This is the second Burson Audio product I have reviewed and both units have had issues with odd pops or sounds when operating the unit. Also, based on my review partner's experience with the same unit I don't feel confident in their quality control and am hesitant to trust my expensive speakers with their products.
2. The unit gets very warm with prolonged use. This would be fine as a desktop solution but I don't see how this would work well inside a computer.
3. Dang that blue light is bright!
4. Not a fan of power bricks but since I don't see it after it's plugged in I can live with it

Full Disclosure: I was recently contacted by another member here with an opportunity to review the Burson Audio Fun. Initially it was an opportunity to keep a review unit after giving it a review. I wasn't looking for another desktop amp in this price range but for the price of free and an honest review I figured why not? In the end there was a miscommunication with Burson that did not allow both reviewers to keep the unit. As a result I decided to do the review anyway and ship the unit back to the original member as long as shipping was paid. So in the end this review is an honest unpaid for review.


Pros:
This is a powerful detailed pre/amp that was able to easily drive my power hungry Mr Speakers Ether C flows and Sennheiser 6xx. It is a solidly built unit. There was no play or looseness in any component. Although it is only a $100 more than the ifi nano black label it is a much better built and powerful unit that goes beyond what you would expect for the price difference. It is very detailed in the highs and has a lot of power to drive the lower frequencies.

Cons:
I noticed a higher noise floor when compared to the ifi nano black label, Schiit Lyr 3 and Schiit Ragnarok. It was most noticeable when listening with the Audeze isine20. The bass although substantial, can sound boomy. The highs although detailed can sound artificially enhanced, especially when compared to the smooth sound of the schiit amps. As a result I found it to be easily fatiguing. Like another reviewer noted there was an annoying buzzing sound the first time I turned it on.

Equipment Used:
Headphones: Isine20 with LCDi4 premium braided cable, Audeze LCD4z with wood cups with LCD4 premium braided cable, Mr Speakers Ether C Flows with Moon Audio blue dragon cable, Sennheiser HD6xxx mass drop edition with Venus Audio cable.

Ampifiers: Ifi nano black label, Schiit Lyr3, Schiit Ragnarok

Source: Microsoft Surface Pro 4 with Roon connected to a Schiit Bifrost Dac with multibit

Song lists:
Paul Mc Gowan's dirty dozen from PS Audio
https://www.psaudio.com/pauls-posts/pauls-picks/

Zeos's song list for testing headphones that i compiled from his you tube videos
https://tidal.com/playlist/a0d3509b-d8c2-4116-b9f1-83909b34d105

Cecilia Bartoli St Petersburg
https://tidal.com/playlist/7c327507-dc9a-44de-8a58-d61ed71f3ff7

Pure-Maria Callas
https://tidal.com/playlist/c2fd08bc-9eee-4453-a4cf-9e98568608cf

and other songs from my playlists.

Conclusion:
This is a well made, powerful preamp/amp combo that gives you a lot for the price. I would not hesitate to buy this if I was looking for a unit in this price range. Burson has done a great job with this unit.