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Kronos AV
Kronos AV
In the complicated landscape of audio, many companies put stratospheric price tags on great performance. Our mission couldn't be more different. Simply put, we offer the most performance for the money by finding the sweetest spot between price and diminishing returns. We've all been on the consumer side: music lovers, musicians, and audio enthusiasts looking for top-tier sound without breaking the bank.
Everything we do at Parasound is customer-centric because that's how we define value. Most of our customers don't have trust funds and have to work for their money — so we give them their money's worth and then some. Every time another expert compares our product to equipment that costs three times as much, we have succeeded.

Parasound Halo A21 Power Amplifier
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  • £2,399.00
  • Regular price £2,899.00
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The Parasound Halo A21 two amplifier is a power amplifier that draws directly from the hefty lineage of the 5 channel A51 and also obviously the A31 additionally.

Like it's bigger brothers - it's also a THX Ultra 2 certified product, and it can be used in tandem with the A51 to bolster a 7 or 9 channel home cinema system, or be a stand-alone high end two channel amplifier also - or a combination of both. On this last point - the A21 can be used to stunning effect with the Parasound range of pre-amplifiers such as the JC3+, P5 or the larger and flexible P7. So the A21 is a real all rounder for want of a better phrase, but don't let this deftness fool you in any way shape or form.

As the A21 is based on exactly the same topology as the John Curl A51 and A31 design, as an the amplifier it can of be sublimely subtle when required, and unflinchingly 'brutal' (in a terribly good way!) when raw power is needed. Remember - again the A21 has the same high bias class A/AB operation of the A31 and A51, and also has the benefit of the directly coupled design  which means that there are no capacitors or inductors in signal path, which gives the utmost accuracy for the amplifier to work with. This balance of clarity and 'clout' means that the power output to draw upon (with both channels drive) is 250 watts @ 8 ohm's and 400 watts @ 4 ohm's, meaning that it has real dynamic headroom for the best depth of field and aural texture.

It can of course be used effectively as a 'mono-block' in bridged mono mode as well meaning that you can drive up to 750 watts into an 8ohm load for those of you requiring huge power into larger more challenging loads, or for those of you whom are hard of hearing!

As you would expect the build quality and components used in the A21 are pretty much second to none. The A21 features both balanced and unbalanced inputs (RCA's are gold plated) with a designated ground lift switch, and these high quality inputs are matched with heavy-duty 24k gold-plated 5-way speaker terminals on the output stage. For those also wanting to tweak their THX certified installations the A21 features adjustable gain pots for up to +6db over THX Reference level.

Despite it's impeccable 'HiFi' credentials - the A21 also features included rack ears and has a choice of power activation (front panel, auto sensing and 12v) to ensure that for those wanting the best sound in the custom installation scenarios it is a mandatory option.

The Parasound Halo A21 is available in black and silver finishes - please specify on order.

Circuitry designed by legendary John Curl
THX Ultra2 certified
High bias Class A/AB operation
Balanced inputs with discrete circuits and XLR connectors
Direct Coupled - no capacitors or inductors in signal path
Complementary MOSFET driver stage and JFET input stage
16 beta-matched 15 amp, 60 MHz bipolar output transistors
1.2 kVA encapsulated toroid power transformer with independent secondary windings for each channel
100,000 µF power supply filter capacitance
DC Servo and relay protection circuits
AC present, channel status, high temperature indicators
Heavy-duty 24k gold-plated 5-way speaker terminals
Gold-plated RCA input jacks; ground lift switch
Auto turn-on by 12v trigger or audio signal, 12v trigger out
4u Chassis, carry handles, rack mounting adapter included
Continuous power output (all channels driven):
 250 watts RMS x 2, 20 Hz - 20 kHz @ 8 Ω 
 400 watts RMS x 2, 20 Hz - 20 kHz @ 4 Ω
 750 watts RMS x 1, 20 Hz - 20 kHz @ 8 Ω
Current capacity: 60 amperes peak per channel
Power bandwidth: 5 Hz - 100 kHz, +0/-3 dB at 1 watt
Total harmonic distortion: < 0.2 % at full power
IM distortion: balanced 16 V rms < 0.04 %
Slew rate: > 130 V/µsecond
Dynamic headroom: > 1.5 dB
Interchannel crosstalk: > 80 dB at 1 kHz; > 63 dB at 20 kHz
Input sensitivity: 1 V for 28.28 V, THX Reference Level
Input impedance: 33 k Ω unbalanced; 66 k Ω balanced
S/N ratio: 112 dB, input shorted, IHF A-weighted
Damping factor: > 1100 at 20 Hz
Width: 17-1/2” (445 mm)
Panel height: 7” (178 mm)
Height with feet: 7-5/8” (194 mm)
Depth: 19-1/8” (485 mm)
Power Requirement
 Standby: 25 Watts
 Full Power into 4 Ω: 1500 Watts
Net Weight: 60 lb. (27.3 kg)

Stereo&Video (May, 2014) 
"This amazing group of equipment best demonstrates the audio industry's present state of the art.", October 2005
"Out of the box the A 21 sounds wonderful. I sampled several Red Book CD's of different recording quality and musical genera's and quickly came to the realization that the A 21 was indeed a very special amplifier, and I could not wait to begin the serious evaluation after burn-in." - Shane Mattson

Audioholics, December 2004
Product of the Year Award 2004 - Two-Channel Power Amplifier 
"For those who desire the power of a Mack truck with the finesse of a Mercedes Benz in a two-channel amplifier, look no further than Parasound." "With the assortment of unbalanced and balanced inputs, triggered output, and ground lift option no stones were left unturned with this well built, attractive design."

Audioholics, October 2004
"The A 21 and A 51 amplifiers are both loaded with usable features above and beyond most other amplifiers in today's market." "I cranked the volume way up and found myself free of that inhibiting audio alarm in my head that nags at me to turn it back down. Using the Parasound amp allowed my speakers to portray every aspect that I had come to expect without adding any noticeable sign of distortion or flaw." "The Parasound Halo A 21 and A 51 are top rate amplifiers at a great value. Parasound seems to have attended to every aspect of their design including the excellent build quality internally and externally matched with great looks." Overall Rating: 5/5 Stars - Ken Stein and Steve Dellasala

Luister (Netherlands), November 2003 (Norway), July 2003

We have several deomonstation areas in both of our branches. Please give us a call on 03435236169 or email to enquire about hearing products at your local branch. 

Please always contact us before to make sure the product(s) are available

Express Deliveries

Express Delivery is FREE on all orders over £50. Express Delivery offers delivery in 24-72 hours from time of purchase. We use premium couriers for this service, mainly DPD & Royal Mail. DPD will offer you a one hour window for delivery to make sure someone is at home, or you can reschedule the delivery if no one is around. 

Standard Deliveries

Here at Kronos AV, we have vast experience with e-commerce sales. Making sure that your parcel arrives undamaged is a huge priority for us. That’s why at Kronos AV, we only use premium couriers for all our orders. All our parcels are shipped with DPD or Royal Mail and are always sent Signed For to make sure it gets to the right person. 

If for any reason your parcel does arrived damaged, please get in touch, and we will be happy to get everything resolved for you. We are always on hand to help!


Delivery is FREE on all orders over £50. In order to offer FREE delivery to UK customers, we use several premium couriers to ensure your delivery arrives safe.

Most large orders (over 2kg) ship using DPD or DHL courier and smaller orders (under 2kg) by Royal Mail signed for services.

The most appropriate courier will be chosen for the items ordered to ensure the quickest possible delivery.

We can offer very generous trade in offers across the majority of our product range. 

Why not ask and see how much you HiFi is worth!

To find out how much your HiFi is worth... Click Here

If you have any question, please feel free to call us on 03435236169 or email