65W/channel into 8 Ohms, 100W/channel into 4 Ohms, protection system with no sound quality degrading active circuitry added into the signal path, THD <0.005% @ 1kHz, upgraded power supply, SNR 96dB ‘A’ weighted, Class ‘A’ follower driver stage, polypropylene bypass capacitors, second set of speaker outputs, optional MM phono, headphone output, standby function, bypassable tone controls, low-resonance and acoustically damped chassis, all-metal casework with a solid aluminium front panel, slim-line Azur remote control with aluminium top panel
This review is based on pairing the amp with DB Dynamics Polaris 488F floorstanding loudspeakers and a Yamaha CDC-575 CD player. The 640A is a potential replacement for a NAD 712 integrated amp, so there will be many comparisons with the NAD. Musical styles included rock, funk and acoustic guitar with vocals.
The 640A was purchased second hand, upon unboxing the first thing I checked was that the amp does not go into Protection Mode when the volume is cranked (a problem mentioned in a few reviews here). Phew!
Now for the subjective comparison with the NAD. Keep in mind these observations are based on the DB Dynamics loudspeakers and my living area's (untreated) room acoustics. The 640A is significantly brighter in the vocals. There is also more punch to the mid-bass, the low frequency range doesn't go as deep as the NAD.
The observations about bass were confirmed by some measurements of playing pink noise through the system. The 640A dropped more than 8dB at 25 Hz (compared to 32 Hz), while the NAD only dropped 2dB. The measurements were less conclusive regarding the bright vocals- I was expecting to see more response around 2kHz for the 640A, but this was not the case. However, there was a 4dB dip for the 640A from 800-1600 Hz, perhaps this makes the vocals sound brighter than the NAD (which was pretty flat from 800 to 4k).
Stereo imaging is less clear on the 640A. Extremes of left and right are well defined, but the centred sounds seem to be smeared between the speakers without any definite location.
Although the NAD is the "winner" here, of course it depends on the rest of the system. I suspect that my speakers are quite bright, therefore the darker sound of the NAD works well to "tame" them. The brighter 640A took things too far in this case.
But with different speakers, the brightness of the 640A could be an asset. For the price they're available for second-hand these days, it's a good amp.
I don’t even remember when I both mine together with Azure CD. Never managed to push it up over the half. Protection kicks in and sound is OFF. If you have a party assume you will be kneeling trying to unplug and plug the amp while holding the power button. So if you need excuse to say Sorry for looking under you skirt but I was only trying to bring the music back on, this amp is for you . For me I am tired of unplugging and plugging it back on. The problem got worse I can not even go above say 1/3 and it will shut off for no reason.
I thought this protection is good it will protect my amp. I did have to repair it once by replacing the . Power transistors at the certified repair shop which BTW did not look much better than any other store. They charged me arm and leg and amp is still doing the same protection cut off.
If you think that is the only problem you are wrong. After a year remote stopped controlling the volume. One needs to get up press the remote and ‘help the value button a bit till it starts working again. Very fancy British design.. Pity I did not go for some consumer level cheapo piece of equipment. It would work today. Anything to declare? Yes, don’t buy it.. It is garbage.
This amplifier is shockingly bad, when I bought it I did not like the sound, gave it a good break in, and nothing happened. I eventually lent it to my cousin, and got it back a few days ago. I clearly understand why I lent it, it is veiled to a great degree, no detail in the music, something is wrong with the volume as it starts clipping just over half power. I decided to open it up, and no wonder it is full of cheap chinese parts, cheap Xunda caps, the power supply is worthy of a phono stage, not an amplifier, it should be beefy and up to the requirements of a decently powered (on specs) amplifier, but it´s very substandard. It is dull, it sounds as if there was a curtain covering the speakers. I have a pair of sonus faber grand piano, which I run using a unison research s6 30W tube amp, and use an accupahse CD player, the combination is superb. When I connect the CA Azur, everything just degrades completely, admittedly it is a cheap amplifier, but it also sounds very cheap too. I have a very old Marantz SR-2385 which simply wipes the floor with the CA, there is no comparison whatsoever. It is much better to buy an old, higher quality amplifier than one of these cheap new amps. Do not buy, there are better options out there. I am very disappointed by CA, I also bought a 640P Phono Stage and it is equally bad. I will never buy CA equipment again.
I have the Cambridge Audio 640A v2 75-watt amp, coupled with the 640C CD player and a pair of Monitor Audio GS10 speakers. When it works it sounds fine but it rarely works. There is a protection mechanism in the amp that turnsthe unit off when I have the volume above half (i.e. 12 o'clock). The clowns at the shop where I bought it have had it in for testing twice and declared it to be OK. Now they are trying to tell me that running the amp louder than half is pushing it too hard and the problem is all of my making. I would be interested in hearing if anyone else out there has had a similar experience with this brand of equipment.
The short version: Good neutral sound with probably the worst build quality ever.
The longer version:
I bought this unit back in 2005 together witj the 640C CD player and combined it with a pair of tannoy R2 speakers. The sound it produced is very neutral and laid back but involving at the same time. Later I replaced the Tannoy with the Audiovector K3 speakers and that was a perfect match. Clear, vivid sound. However it does lack a bit of commanding presence. The sound stage is a bit small and the depth too is a bit small. My current Marantz puts up a more realistic sound stage.
Sound is well balanced with an ever so slight tendency to the higher tones and a bit lacking in bass punch.
No other issues there. The only thing they should have done, is lower the output of the CD player or decrease the amplification of the amp. You cannot put the volume control pass the 9 o'clock position without playing too loud. A pair of attenuators took care of that problem.
The biggest problem is its build quailty. The build quality of the unit (and also CD player) is very poor. The CD player failed after just 1 year. After having it repaired a couple of months later the control buttons on the unit failed.
The amplifier damaged its left channel twice over the period I owned it. I never play loud (I live in an appartment) and the speakers a very amplifier friendly.
So I purchased the Cambridge Azur 640a integrated amp and the Athena F2.2 floorstanders and within 2.5 days I hae received both since I live in a close state to the audioadvisor.com headquarters (they're in MI, I am IN). But on to the important stuff....
Yesterday when I got the amp (speakers to ... Read More »
Ok im still trying to decide on my amp, Im down to the Nad C352 and the Azur 640A, from what I read is they both seem to be fine amps, the Azur is about a $100.00 less than nad and I like the looks better.
Whats the bigest Pro's and Con's?
I have the Axiom Mti 60's
ThanksRead More »
So as many of you probably know i managed to score a great deal on the 540a a few days ago, including a 15 day try at home period.
Now i am completely satisfied with the performance of this amp, but i could return it and get the 640a from the same place for only 30€ more.
Now my question is, is th ... Read More »