Q&A - Audio Connections

How to connect your Brennan B2


To connect B2 to loudspeakers you will need speaker leads with 4mm plugs to plug into the B2. We sell 3 metre leads but you can buy or make your own. 4mm plugs are often called banana plugs. The loudspeaker connectors on the B2 are spaced 10mm apart so don’t buy plugs that are wider/fatter than that.

Loudspeakers should ideally be eight ohms but B2 is OK down to four ohms if you keep the volume below the max. The loudspeakers should be rated to handle at least 15 watts RMS continuously. Our BSP50 loudspeakers are rated at 50 watts.

The power amplifier is a bridge amplifier - red and black outputs are both driven - so you cannot connect the two black terminals together and you cannot use the loudspeaker outputs as an input to another amplifier.

The power amplifier is short circuit and thermally protected - if it does shut down just press stop - remove the fault or let it cool and press play again.


You can plug headphones with a small 3.5mm jack into the combined spdif/line out connector. The headphone volume is adjusted by the knob on the front.

Plugging in the headphone will normally disable the loudspeakers (but see the section on Jack Sense below).

The line out connector has shared uses so it doesn’t have a dedicated headphone amplifier or a true line level output for that matter. If you need audiophile quality or have “difficult” headphones then I suggest using an optically coupled headphone amp like this.

Connecting to an amplifier or AV equipment - optical

The best way to connect to an amplifier is optically - but you need an amplifier with an optical input. There are two advantages to optical.

1) The digital “signal” delivered to the amp is exactly what left the Brennan.
2) The equipment is electrically isolated so there is less likelihood of ground loops and other kinds of interference upsetting the amp.

Conversely a traditional analogue electrical connection suffers from - attenuation, frequency response, cross talk, interference and ground loops - but may be adequate especially for short hops.

The optical cable should have a Toslink connector at one end (for you amp) and a 3.5mm plug on the other like this.

Connecting to an amplifier or AV equipment - electrical

Brennan B2 uses a 3.5mm stereo jack and your amplifier probably has twin phono (or RCA) sockets so you will need a cable like the one on the left to connect them.

Important - because of the shared use of the output you need to turn up the volume almost on the B2 to max - say level 60 - and leave it there. Use the volume control on the final amplifier to get the right listening volume.

Some audio equipment may need a higher signal level up to 3.4V pk-pk or a lower impedance say 600 ohms. I recommend using an inexpensive external optical DAC for this.

Splitting the output

Some owners ask about sharing or switching the B2 output between different amplifiers. The simplest way may be to use a phono splitter (search for “phono splitter” or “rca splitter”). That will be prone to the interference issues I mentioned above but may be adequate for your needs.

I recently discovered an optical splitter (search for “optical splitter”) that should allow you to drive several amplifiers without any degradation and without any interference - although you will need amplifiers with optical inputs or external optical DACs.

Jack Sense

The normal behaviour of the B2 is to disable the loudspeakers/power amplifier if something is plugged into the SPDIF/Line out. It doesn’t matter whether it's optical or electrical.

If you would like the B2 to continue to drive the loudspeakers - because you want the B2 speakers in parallel - then you can disable this behaviour with

Settings -> Jack Sense -> Jack Sense Off

HDMI Audio

B2 can optionally send the sound to the HDMI output. This is a digital signal so has many of the advantages of optical. You can hear the sound on an attached TV and HDMI is being used increasingly by audio equipment.

You must enable the HDMI output using the settings panel - the cog icon - on the web UI.



Questions and Answers

4 ohm Speakers

Q: How will B2 perform with my 4 Ohm 10 watt speakers or will it destroy them?

I haven't tested this extensively - but B2 is was fine driving BSP50's in parallel to simulate a 4ohm speaker. The power amplifier has a thermal shutdown and this will kick if too much power is drawn because of the reduced load - but it will be fine for normal listening levels.

Beware though B2 is capable of destroying your 10 watt loudspeakers - so keep the volume down.



Q: Does the B2 take Headphones?

Yes - plug them into the Line Out at the back - that will mute the main speakers.


Q: I'm not getting anything out of line out / SPDIF - is it digital or do I have to set something up in a menu?

The B2 line out is a hybrid connector that has an electrical analogue signal for driving headphones and other audio equipment plus an optical digital signal for driving amplifiers with optical inputs (or high end DACs again with optical inpts). Optical and electrical signals don't interfere so they are both output at the same time. You will need a special optical cable - you can buy from us - if you want to use the optical signal.

If you are having problems make sure the volume is turned up and check the line output with some headphones. If there is sound the problem is the cable or amplifier. If there is no sound there may be a problem with your B2.

Unused Speaker Ouputs

"Hi Martin , if I connect the B2 to a separate amplifier ( Icon Audio valve amp ) via the aux out to drive speakers and do not connect any speakers directly to the B2 is there any danger that the B2 amplifier will ' get cooked' over time ?
David G"

Hi David - No problem the B2 amplifier is happy to be left unconnected indefinitely - Martin

Analogue Line Out

Q: Does the B2 have an analogue line out as my HIFI does not have a digital line in?

Yes - B2 has analogue line out. Because B2 is so small there isn't a lot of room for connectors so we used a special combo connector for SPDIF/Line Out. You can plug in a standard 3.5mm stereo jack for analogue or plug in our optical cable that has a standard Toslink connector on the other end for digital. Optical is not susceptible to ground noise so is better - if you have kit that has it. 

Non Brennan Speakers

Q: Can I purchase my own speakers for the B2?

B2 was designed for 8 ohm loudspeakers - like our BSP50s. The BSP50s are matched to the power and physical size of the B2. If you are looking for higher quality loudspeakers then you need to think about spending more than £200.


External High End DAC

hi, good luck with this new product. Question. If i load CD discs and connect the device to an external high quality CD player which can be used as a DAC (Simaudio Moon CD 3.3) in my high end hi fi system, are the files compressed or will it sound the same as playing the CD? Thank you.

On B2 CDs are normally compressed to FLAC and FLAC files are reconstituted to exactly the same samples - so it will sound the same as the original CD - because it is the same.

Does B2 drive speakers? 

Q: Can you hook up speakers to the B2,,as did the JB7.I did not see any speaker wire connections on the back of the B2..Thanks

Yes - there's a small picture showing speaker wires on the Features page at the left.


Q: Can I use B2 in conjunction with my wireless Sonos Speaker system?

Yes - you can connect the B2 line output to Line In on the Sonos base station - sorry I'm not familiar with the Sonos model numbers - you will need a 3.5mm to twin phono lead.

You can't connect the B2 to the Sonos wirelessly though - they have a proprietary system I believe.

Aux In

Q: I cannot seem to play the line out from a VideoLogic DAB tuner through the Aux Input of the B2 without to sounding as if though it's being overdriven because the speaker output is distorted. This morning I swopped the JB7 and the B2 around and tried again - the DAB tuner plays through the JB7 without any distortion and yet it distorts through the B2. Any ideas what's causing this please?


Sounds like you have run into one of the limitations of the Raspberry Pi - you need to restrict the USB speed to get crackle free Aux In. Use Settings->USB Speed->Low Speed.

Update: Selecting Aux In now automatically switches to low speed USB though the Pi needs to reboot - takes a few seconds.

SPDIF /Line Out

Q: I'm not getting anything out of line out / SPDIF - is it digital or do I have to set something up in a menu?

The B2 line out is a hybrid connector that has an electrical analogue signal for driving headphones and other audio equipment plus an optical digital signal for driving amplifiers with optical inputs (or high end DACs again with optical inpts). Optical and electrical signals don't interfere so they are both output at the same time. You will need a special optical cable - you can buy from us - if you want to use the optical signal.

If you are having problems make sure the volume is turned up and check the line output with some headphones. If there is sound the problem is the cable or amplifier. If there is no sound there may be a problem with your B2.

Line Out Level 

Q: What is the audio level out of the line socket?

Its not a true line out - this output doubles up as headphone output so the level changes with the volume control - unlike a classical line out. The level goes up to about 1V pk-pk or 350mV RMS.

Speaker Switch 

Going through the Q&As it seems my 6 ohm 100 watt speakers will work with the B2

However I presently use them with an Radio/CD/cassette player. Is there some way I can switch between the B2 and the Radio e.g. a changeover switch in the speaker cables?

Yes the speakers will be OK on B2. Yes you can buy a speaker switch that will switch your speakers between B2 and your Radio I found this at Amazon for example. But just search for "speaker switch".

Weak Line Out

Q: I have 10 speakers in my workshop where I was hoping to use the b2 at the moment they are driven by three amps. I was intending to integrate the b2 by connecting via the 3.5 mm line out to TVs phono leads. The Brennan is producing a poor quality sound and also the output is controlled with the b2's volume button. I'm sure this apart from the poor sound quality is not good for the b2 's amp. Do I need to buy a separate dac and connect my system with that or is there a cheaper solution?

I just tested this inexpensive DAC with optical input - £12.99 from Amazon. This DAC will produce a signal that does not go up and down with the B2 volume control. It may also have a lower impedance which may help with your setup. The optical coupling will help combat any ground loops. You will need to buy the optical cable from us or equivalent elsewhere.


Connect to my Rotel Amp

Q: I have a rotel rmb1075 amp linked to a rotel rsp 1068 processor how do I connect a b2 to this set up and what cabling would I need?

In general there are two ways to connect B2 to a Hifi Amp. 
1) Electrically using a copper cable. This sends an analogue signal and is ok but is prone to interfence and ground loops.
2) Optically using an optical fibre. This sends digital values so there is no noise or distortion and no ground loops - but you need an amplifier with a optical input or an audio DAC (usually they have optical inputs).
If you connect electrically you will need a cable like this from Amazon (search for 3.5mm to phono)

If you connect optically you need one of these which you can buy from our shop page or search for "toslink to 3.5mm cable" 

Eight Mono Speakers

Hi Martin, I have been tasked with replacing a clunky multichanger CD unit in an independent shop for something better and smaller. It currently runs 8 speakers (which they want to keep). When providing all over music I think it might be better to have 8 mono feeds. Since the size and the ruggedness of the B2 is impressive, can you suggest how I would achieve the mono feeds to the speakers please?

This depends on the power and impedance of the eight speakers. Are they driven by a PA amplifier already? The "right way" would be to feed the B2 line out into a mixing PA amp using a 3.5mm splitter so that left and right were fed as two inputs of the amp. But you might get away with feeding the B2 left loudspeaker to four and right to four. I will add a mono switch to the software wish list though.

Four Speakers


Hi Martin
Firstly many thanks for all your recent help in getting my B2 working with an open network; everything is working brilliantly.

I am still considering whether to send you my JB7 for repair. However, is it possible to connect my JB7 speakers to the B2 in addition to the B2 speakers which I bought with it? In other words, can I drive 4 Brennan speakers from the B2? If so, what do I need to buy to allow me to do so please and can you supply? Look forward to hearing from you.

Many thanks. And again, my sincere thanks for all your help and a fantastic piece of kit.

Best wishes Bill

Hi Bill

Glad to help with the network thing. There are two ways you could wire the speakers. 1) In series - this will reduce the amount of power you get 2) In parallel - technically this overloads the amplifier and it will shut down - but only if you play at high volumes - its not serious just press stop and let it cool for a second or two.

I did a sketch of what I mean by series and parallel - hope that makes sense. If you order some speaker leads from us that will allow you to just plug things together so you get a good connection that you can quickly attach and detach.



Two Volume Controls - Whats Right?

I have just bought the B2,upgrading from my JB7 and must say it is a magic little box. Using the Line Out and a QED mini jack & phonos cable, I am connecting the B2 to my Arcam Mini Solo. It all works fine, I just have a couple of questions (I am a hi-fi novice):

The volume controls have to be used on both the Arcam and the B2. I thought I would only be using the amp from the Arcam? can the B2 control its volume? I have Jack Sense set to On (have tried with it off with same result).

To get the level of sound I like, I have to have the B2 around 55 and the volume on the Arcam at 55. If I don't have the volume up on the Brennan as well I cannot get the level of sound. The Arcam goes up to 72 and even at this level, without setting the B2 volume high the sound is quite low. Playing a cd direct on the Arcam I would set it around 40 to get the same level. Is there a reason why I have to use both volume controls?

The Arcam amp handles 25 watts per channel. The Arcam Muso speakers are rated up to 8 ohms.

The sound is great (CD's ripped using FLAC) and there is no issue with having to use both volume controls. I just want to check whether they should work this way and if I need to change anything.


Hi Chris - easy one this. Just crank up the volume on the B2 as high as you can without getting distortion on the loudest passages - then drop it down one or two and leave it at that setting. There is nothing wrong - and in fact everything right - about setting the B2 volume to max (64) in this configuration - Martin

Wireless Speakers


Hi Martin

I am considering the B2 to consolidate all of my CDs and MP3 music in one device but I would need to be able to stream the output via WiFi so that I can listen in multiple rooms.

One solution appears to be the audioengine W3 (http://audioengineusa.com/Store/Wireless/W3-Wireless-Audio-Adapter) but I can't figure out if the B2 will provide 16bit music output via the USB C to a W3 instead of a a Bluetooth dongle.

Can you advise please?

Many thanks.


P.S. I don't want to use Bluetooth as it will not do multi-room and I have found it to be very unreliable.

Hi Simon

B2 cannot currently drive wireless speakers or the USB device you mention - both are technically possible - but using Sonos speakers with B2 is probably your best bet. One B2 owner suggested turning B2 into a local internet radio station and that way the Sonos speakers would play whatever you play on the B2 - so there is more to come and Sonos is the market leader .



Aux In Attenuator


Hello Martin,
Having ripped all of my CDs onto the B2, I have started to think about transferring my cassette tapes.
I played a tape through my Denon DN-790R deck and listened to the sound through the B2. It was clearly very distorted.
The software on the B2 is 27th. Jan 17.
Some years ago I made a 20dB passive attenuator to use with the Denon, so I put this in the signal path.
This time the sound was not distorted but far too faint even when the B2's volume control was at 64.

The Denon output spec is 775mV (0dBm) with a 47k ohms load.
Could you tell me please the impedance and sensitivity of the Aux In circuit on the B2? (or what chip you are using if that is simpler). I can then construct a suitable attenuator unless you have another suggestion perhaps.

Thanks for your help,

Hi Adrian - here is a snippet of the Aux In circuit. Your 20db attenuator is obviously a bit too drastic. You just need a pair of resistors in each of left and right or a dual gang potentiometer. The right answer will depend on your electronics skills and what you have to hand. Martin



Speaker Wire

Hi, I urgently need B2 speaker
Wires. Can you tell me when they are
likely to be back in stock again, or
perhaps where I can purchase them elsewhere.
Kindest regards


Hi Anthony
If you can manage a screwdriver then you can probably buy some 4mm plugs on Amazon and get some speaker flex from Homebase etc.
4mm plugs are also known as banana plus – don’t go for very expensive there is no advantage and they might be too wide to fit
I bought some made up speaker leads this week from here  - the wire is a bit thick for my liking but you can probably phone then get them made up exactly the length you need if not comfortable with wiring.

Volume 64 steps?

Curious: Why does the volume go to 64? Thanks. JR


Hi JR - good question - the superficial answer is to give you best control over the volume. The detail is that the DAC we use has 64 steps. I could translate this to say 100 steps on the knob and display but all that happens is that some adjustments - say 51 to 52 - would have no effect on the actual volume and 52 to 53 would give you the increase you get now. I could reduce the steps to 32 and go up two at once but of course you would lose fine control - Hope that makes sense - Martin

Yamaha Receiver

Q: What lead do I need to connect B2 to my Yamaha RX3040 Receiver?

Hi - I just looked at a picture of the RX3040 - what a monster - its bigger than my first car! Seriously though - your amp has optical inputs which is ideal - uncompromised audio quality - so you should buy the SPDIF lead from our shop page - or similar elsewhere.

If your amplifier does not have optical you generally need a 3.5mm to RCA (aka Phono) lead. Like this from Amazon. 


Headphone Level & Quality

I have a problem with using headphones on my B2 in that music (the bass in particular) sounds fuzzy as if the headphone speaker membrane is broken or the volume is too high. I get this effect with two different brands of headphone. The sound through speakers is fine.
I note that I like to use a volume setting of about 35 with speakers but with the headphone I need to use a setting of 60 to get equivalent loudness. Is this normal? Would a headphone amplifier help?

Hi Colin the higher volume setting for headphones is normal. If you want the best quality headphone experience then consider using an external optical DAC and headphone amp - like this from Amazon - though you can pay a lot more for High End kit.

Optical to Coaxial

Hello Martin
I wanted to connect my B2 to my dac but it only has the 75 ohm bnc digital electrical input. Can you suggest a way of doing this thanks Allan

Hi Allan. I Googled "optical to coaxial converter" and got this from Amazon. Martin

High End Power Supply

Hello Martin
Can the power supply be upgraded. Have seen advert for Longdog audio from MCRU but not cheap.

Hi. If you are using the B2 to drive speakers then you may get a benefit in using a specialist low noise power supply - you will need a 24V supply. The benefit will be limited however because some electrical noise is generated by the motors and digital electronics within the B2 itself. 

If you are looking for the ultimate quality then couple a B2 with a high end DAC using an optical cable.

Then use a specialist low noise power supply on the DAC. 


Recommended Digital Amp

B2 owner Chris D bought and recommends this digital amplifier for use with B2.

Moving Coil Cartridge

I know that you can play a vinyl turntable through the B2, but will it support a moving coil cartridge, or does it require some kind of converter?

Hi Chris - you need something called a phono pre-amplifier. You can buy them as standalone units or if you are using B2 with an amp - feed the turntable into the phono input of the amp and feed the amp line out into the B2 - Martin


Hi, I'm a recent owner of a B2 and I'm absolutely delighted with it. I'd describe the elegance of design as "Jobsian".

I like to use headphones for the quality of sound but when I use my usual headphones (audio-technica) the sound is very poor, low vol and screechy. Maybe their impedances don't match or some electrical thing. Are there any h'phones you might recommend as compatible with the B2? Thanks.

Hi R - Jobsian eh? Thanks - Are we related?

I think this is another case where you might want to consider a dedicated headphone amp - above.  Martin

Headphones and Speakers Together

"Very pleased with my B2  - it replaces my JB7; however on the JB7 I had speakers attached and Sony wireless headphones running from the Aux out AT THE SAME TIME. Can't seem to do this with the B2?

Paul Hampshire"

Hi Paul. Use Settings->Jack Sense->Jack Sense Off. Martin


Five pin connector

Hi - my amplifier has a five pin line connector - how do I connect B2 to it?

I guess your amp has a five pin DIN connector and you want to play B2 through the amplifier. I suggest you buy two leads. 1) a 3.5mm jack to phono lead 2) a 5 pin DIN to four phono sockets like this.

You may have to check the amplifier manual or just experiment to get the sound to come through - Martin

Graphic EQ on Speakers

Hi Love the B2. I'm remembering why I bought some of those CD's that were gathering dust on the shelf (ok, shelves...cellar, in cupboards etc). Trouble is I then want to listen to them all at once.

I have a dunce question - so please keep any answer simple enough for even my limited understanding. Is it possible to put a graphic equaliser or something similar between the output and the speakers to allow altering the bass/treble depending on the nature of the tracks. If so is there any spec / model I should look for?
Cheers jim

Hi Jim - sorry I don't think there is likely to be such a product - its possible theoretically but because of the power levels it would be expensive. You need a tone control in B2 - its on the wish list and your question has raised the priority Martin

Mono Jack?

Hi. Just bought your b2 and filling it now. I also bought the speakers to use in the kitchen and wonder if I can connect a Yamaha subwoofer via its system connector which looks like a mono jack which would fit your line out socket. I don't want to just try it though, in case I short the output. Will you advise please?

Not a good idea - it would short left and right. Search for stereo to mono 3.5mm splitter - you can find cables to avoid this. Strictly speaking you will only drive the subwoofer with left or right but low frequencies tend to be mono.

Bi-Wired Speakers

Hi, can the Brennan 2 connect to bi-wired speakers, such as high quality Kefs?

Hi Duncan - yes you just need to connect the top speaker terminals to the lower speaker terminals at the back of the speakers - then connect to B2. You could run two sets of speaker cables back to the B2 but its probabaly going to look unsightly having eight speaker wires at the back of B2. Martin