Ive been living with the A&R Cambridge A60 integrated amplifier for a little while now and I thought I might give those who may be interested an update on how weve been getting along. Michael Hood offered to rebuild one of the classic British amplifiers for me several months ago... It took him some time because not only did he recap the amp with some very nice Nichicon 105 C grade caps, he also converted the power supply to run on 125 volts 60 Hz AC. Thanks again, Michael! The A60 uses European style DIN connectors for line level ins and outs. Mr. Hood was kind enough to send some high quality DIN to RCA pig tails so I didnt have to wait to get some. The amp has inputs for CD, Tuner and Phono (The phone jacks are standard RCAs accessible through a slot in the back panel. I imagine the designers did that to help shield the connections. It accepts MM cartridges only. Grounding is accomplished with a lug next to the access slot.) I used short RCA cables. Nothing special accept that the interconnect from the dedicated CD output from my AD-500 is a heavier than usual set of phono cables. The tape loop is being used to send audio out to my Technics EQ and I connected the cassette deck section of the AD-500 to the tape loop on the EQ. I had originally kept me Realistic STA-46 receiver in the rack and used the tape output to feed the tuner section into the A60. I had second thoughts, though. The rack was rather crowded and I just dont listen to the radio anymore. I took it out and put it in storage. I havent missed it at all. The front panel is sparse with only a row of push button selectors for iputs and tape loop insertion. There are buttons for mono and a high low pass scratch filter as well. Curiously, the mono switch not only effects the output of the amp but it switches the feed to the tape outs to mono too. Nice touch! The scratch filter is set very high and doesnt do a great deal to filter out noise in the upper mid range. The cutoff seems to be in the neighborhood of about 10 kHz. I havent found much use for it. Its interesting to note how the speakers are connected to this little amp. There are three binding posts for each channel. Two are hot positive and one is negative. Which positive post you use decides whether the speakers will be switched off when headphones are plugged in or not. There is no front panel switch so I opted to use the switched output. What really turned my head when I first powered up this amp is what I didnt hear... It is exceptionally quiet. As a matter fact, the only way one would know it was powered up is to look for the pilot lamp on the front panel. Even with my head right next to the speaker, I cannot hear any hiss or hum at all. Very impressive. Many modern amps have a great deal of hiss in the output stage and you can hear it plain as day no matter what position the volume control is at. The noise is not too bad if you have it cranked but at listening at low levels can frustrating as hell. So far, so good. I started playing some CDs to start with and I was immediately struck be the clarity and detail I was hearing. My CD player of choice is a TEAC AD-500 combination CD player and cassette deck. As near as I can tell, only two such models were ever built and sold, the TEAC and the Optimos SCT-50. I have both. The TEAC uses 4 x oversampling and analog filters. Very old school and accurate. The response is flat and the highs are clean and crisp compared to later lower end CD players with digital filters. Theres very little “grit” from jitter. This machine sounded good on my former amps but it came to life in a new way with A60. The audio has depth and breadth that I didnt hear before. Believe it or not, I have really been revisiting my extensive CD collection lately. Now, if it a poorly mastered disc, it still sounds like crap but a well done CD is a joy to behold with this setup. Im not sure whether this has to do with the performance of the amp or whether it just is a case of having a better impedance match between the player and the amp. Either way, Im happy. The built in phono preamp is just as quiet as the rest of the amp and the hum rejection is total. I have yet to hear any hum from any of my turntables and cartridges at all. I have noticed that the phono section is a bit anemic sounding with AT carts but the Ortofon 2M Red seems right at home. AT carts also seem to be more distorted than with other amps. Capacitance mismatch? Improper loading? I know that my Vinyl Liberator preamp made be Edger Green before he passed away a few years ago to my specs for the AT92E and AT120E carts I had at the time doesnt not show nearly the same type of grainy rattle I hear with the A60s phono stage. I must say, though, that I am using the Sony Linear tracker to test AT P-Mounts and this table adds an active a mute circuit in line with the output from the cart. It also has permanently installed RCA cables so I cant swap them with my heavy Acoustic Research phono cables. Furthermore, it grounds though the shields instead of using a separate ground wire for the lug on the A60. All of this can affect how the cart interacts with the amp. At some point, Im going to fire up the Liberator and plug it into the Tuner input and than I can do a side by side comparison. Im happy with my Ortofon for now, though. I really cant come up with a way to capture the sound of the A60 in a few words. Many years ago, an engineer I was working with described Crown power amps as being “a wire with gain.” Honestly, that describes this little amp. Just when I think I have figured out its particular sound, the song changes and so does the over all sound. There is a lot of detail, the bass is smooth... Maybe just a bit mushy at times but very clean and consistent. Mids are sharp and the highs seem to just go on forever. Theres plenty of volume for my Sony B3000 speakers to work with and even when I have it cranked I dont sense the amp struggling to deliver enough power to accurately portray the transient peaks in the music. I really, really hate to use this over-used, foo-foo term but I gotta... The soundstage is very wide and deep with this amp. There, I said it. The channels are just about perfectly balanced and I can detect very minor phase shifts between them. All it takes is just a tiny bit of group delay in an inferior amp to totally destroy the phase relationships of good stereo imaging. There is none evident in the A60. Im still very intrigued by this little amp. I dont think Ive heard everything it can do. I tend to forget its there at all and just listen to the music... Isnt that what an amp is supposed to do? Its just so unusual to actually hear one that does it, I guess.
Posted on: Sat, 15 Nov 2014 04:02:00 +0000
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