Once or twice a year an A&R Cambridge A60 arrives with the top cover on back to front. Looks odd as there's a big overhang at the front. Worse though is the strategically placed foil shield which screens the high gain phono stage from unwanted noise is now at the other end & causes increased hum.

Proabably the earliest A&R Cambridge A60 ever seen here with a serial number in the hundreds and produced just 16 months or so after it was released in late 1976. I wonder if the 'JD' that signed this one as calibrated was one of the two original founders of A&R Cambridge (now Arcam) - John Dawson?

Another day, another sickly Cyrus One arrives for the workbench. This one looks as if it's previously been attended to by Messrs Bodgit & Scarper having failed to master any real directional control of a soldering iron thus melting the electrolytics sleeve but then failing to solder it in at all!

First patient of the day a Cyrus Two whose owner complains of noisy input selector. They didn't even comment on the poor bass response on the right channel (green - left/purple - right) just measured before I start on it! Plenty of duff electrolytics in this one I predict!

Planning on purchasing an Arcam internal phono card for your Delta 290 or Alpha 9 ? Do ensure that the plug on your amplifier PCB where the card fits onto matches the socket colour on the phono card you buy. Otherwise it won't fit properly as there are 2 types. Most common is the white one.

Wednesday’s @thetimes.com cartoon times.newsprints.co.uk/peter-brooke...

A&R Cambridge A60 on the workbench fully loaded with all options: MC Cartridge loading module and preamp (price £8.50 and £24.95 in 1982!) The upside down PCB is a pre-out buffer amp on what was the Aux input DIN as this amp is an A60AP with split Preamp/PA instead.

A nice NAD 3020 just fully overhauled complete with new RCA's and speaker terminal upgrade and now on it's way back to it's owner.

A great example of 40+ year old capacitors leaking the chemical used to form the electrolyte between the coiled up internal plates. Quite common now with earlier versions of the A&R Cambridge A60.

First example of this rare Cyrus amp seen here. Looks like a Cyrus 2 but no input RCA's and plenty of 4mm sockets at rear. It's basically a bass only amp for the Mission 767 speakers with minor adjustment available. Known as an LFAU or Low Frequency Alignment Unit. Same faults as a Cyrus 2 though!

In 40 years I don't think the number of failed ceramic caps I've seen has made it to double figures yet! From an NAD3020 PA stage & should be 100nF not a few ohms & caused a 4v dc offset on the output (should be zero). Time consuming to trace but luckily for the customer it's a fixed price repair!

Cyrus Two with left channel reported quiet. 1st graph shows left channel lower trace and right upper with former having a severe roll off all the way from 50Khz down to a few Hz. Cause is those 2 dying brown electrolytics that form part of the PA feedback path. 2nd graph is what it should look like.

An interesting 1982 price list for A&R Cambridge products found in an handbook passed on by an ex-A60 owner. If the A60 were still on sale at todays prices then it would be almost £750 including VAT.

A reminder in the sky yesterday from a site once used by ARS before switching to BlueSky perhaps?

Interesting short article in What HiFi about the original NAD3020. www.whathifi.com/hi-fi/stereo...

Test of a Cyrus 2 before overhaul clearly shows slight left to right channel imbalance and also a small phase difference between channels in 1st image. Almost always down to electrolytic failure as indeed was the case with 2 completely dead electrolytics in the PA stage. 2nd image after replacement.

Really nice to see this recent UK start up producing amps/sources with British components/materials and really hope they succeed especially having designed these with repair and long term support in mind. www.whathifi.com/news/fell-au...

Common damage on an Arcam Alpha 9 not correctly packed to survive transit. A knock during shipping to the balance/tone controls just snaps potentiometers clean off the PCB. Even a risk during overhaul unless you remove the metal rear fascia to avoid accidentally stressing it while on the workbench.

Planning on purchasing a used Cyrus One or Two amplifier (or 'preloved' to use the current fashionable term!). See this concise handy buyers guide here before potentially handing over your money for a flaky Ebay example and ending up disappointed! www.amprepairservices.com/cyrus-buying...

Two early Musical Fidelity A1's this week both with the same fault causing channel loss. This input selector switch has several broken solder joints on the pins that solder to the PCB. Caused by slight movement each time the switch is operated eventually fracturing solder joint (no mechanical mount)

It's rare to find a Musical Fidelity A1 where the PCB holes line up with the base threaded inserts. This one just had the 2 M3 studs at the rear and the 3 M3 screws for the front were just left out at the factory! Not bad amps though, produce a typical 12W Class 'A' before entering AB then ~26W max.

Replacement RCA sockets now available for the NAD3020 as an option when your amp is at www.amprepairservices.com for overhaul. These mate far better to modern RCA plugs. Also red inserts are used to identify the right channel inputs and white for left as this can be confusing as designed by NAD.

An electrolytic that forms part of the phono stage power supply on a Cyrus One has blown it's top and let all the microfarads escape! It's quite common now to find these Roederstein branded components failing in these amps which are nearly 40 yrs old. The black rubber seal has failed due to gassing.

This is the built in phono stage in an Arcam Alpha 8 amplifier. It's hard to get much simpler than this! Even most external 'boutique' phono stages though are often little more than a couple of chips (often NE5534, NE5532) and a few equalisation components totalling a few £'s in a fancy box instead!

This 41 year old NAD3120 (3020 minus tone controls) resembled something recovered from the sea bed on arrival. Much more respectable looking and sounding as good as new now after a full day on the workbench.

#Evri. Suggestion for your next driver training course. In the UK we often have 'doorbells'. When pressed occupants will open the front door in person within a reasonable timeframe. Hence no need to lob parcels over a side gate. Exactly why Evri will never be used for customers parcels here at ARS!

All but early NAD3020's have a crude FET switch between pre & power amp. It connects preamp to PA after power on with a few secs delay & a brief low buzz in each channel which is normal but if louder/longer than this then not so. Uses a crude capacitive discharge circuit to switch gates on each FET.

Poorly packaged amp with owner having ignored clear packing advice + Royal Mail = a knackered amp. Royal Mail are great at flat pieces of paper in envelopes or a weekly supply of junk mail ads, less so at handling parcels so not recommended for shipping. UPS, Parcelforce, Fedex, DHL much better!

If sending amps for repair by courier they will be dropped, chucked onto conveyer belts/into vans & probably have several heavy boxes stacked on top in the van. Pack according to the clear advice given and they'll take all this abuse without issue. Ignore it and expect damage!

Not listened to Cold War Conversations yet? Here's one reason why you should give it a go... www.podchaser.com/podcasts/col...

Nothing like leaning a hot running (~50 deg C) driver transistor up against an electrolytic for a few decades to properly slow cook it. Things that designers and assembly lines know little about!

For those Arcam Alpha 9 or Delta 290 owners wishing to use a turntable but lacking the optional phono stage then a small number of original Arcam ones are usually available here. Fully refurbished and tested, enquire via contact page here: www.amprepairservices.com/contact

A nice Musical Fidelity A1 with the rare chrome plated front panel. Only the second one I've seen in almost 13 years. Pretty much the same inside though apart from an extra pair of 10,000uF electrolytics in the power supply and a few other minor details.

Same Delta 290 now on test showing results of incorrect bias on left channel (blue trace). This had zero bias on it's output stage thus producing the distorted sine wave. Perfect once bias set up correctly as per Arcam specification.

This pair of relays are for the speaker 1 & 2 outputs on an Arcam Delta 290. Barely any output from amp when tested, unsurprising when there are tens of megohms across relay contacts when energised! (this should be virtually zero). Worst example of failed relays I've ever seen!

Update on classic HiFi amps thru the workshop so far: Cyrus 1/2-768 Arcam Alpha 9/Delta 290/Alpha 8 -456 NAD3020-269 Musical Fidelity A1 -89 A&R Cambridge A60-102 NAD3130 -48 Musical Fidelity B1 -12 NAD C320 -5 NAD 3155 -1 NAD3240 -3 Over 1750 amps with a new lease of life!

New apprentice (or 'unpaid' Intern as seems the norm these days) for workshop security 'Monty' has joined the team recently. Currently being taught by Bonnie the Westie to announce the arrival of a courier van loaded with wheezing amplifiers gasping their last breaths of music.

A recent NAD 3020B in with the awful quality grey 'YEC' branded electrolytics with most having failed. This made a real mess of the amps frequency response as 1st graph shows (owner said it sounded 'dull'). 2nd graph after overhaul is as it should be with all new electrolytics.

NAD seemed to think even small capacitors needed glueing down before soldering with a strange rubbery sealant when built. 40 yrs on in many cases this sealant is now partially conductive on some examples as it degrades! Causes some very weird & difficult to find faults at times!

Video clip shows spurious oscillation of the tone circuit on the Arcam Alpha 7/8 series amps. when switched in with the 'direct' switch (this is instability into low RF region). Often caused by PCB/chassis earth issues & sometimes the Op amp itself. Often death for o/p Mosfets!

I always like to see these boxes when a 'dead one' arrives for repair. Little did Arcam know 30 years back when having these boxes printed that it really was 'HiFi with a future'!

Todays patient is another NAD 3020. Looks like this came from Miss Havisham's house. Time to fire up the air compressor!

Update on classic HiFi amps thru the workshop so far: Cyrus 1/2-768 Arcam Alpha 9/Delta 290/Alpha 8 -456 NAD3020-269 Musical Fidelity A1 -89 A&R Cambridge A60-102 NAD3130 -48 Musical Fidelity B1 -12 NAD C320 -5 NAD 3155 -1 NAD3240 -3 Over 1750 amps with a new lease of life!

Multiple transistors found failed short circuit in this Cyrus 1 amplifier. 2 resistors in the collector supply for 2 stages burnt out as a result and finally the fast blow supply fuses failed to halt further destruction. Quite time consuming to eliminate all failures in this one!

Some Arcam Alpha 9 models had a poor quality volume potentiometer fitted with terrible channel balance at low settings. Probably 10-20% seen here suffer this. Solved with a nice precision Alps RK27 pot. The earlier Delta 290 never suffered this as it had a much better one fitted.

Wondered why this wouldn't unscrew on a recent Cyrus 1 in for repair, it was simply jammed in the hole. Whoever assembled this amplifier originally failed to notice the M3 machine screw had no thread! Hole retapped and new screw.

Looks like even the factory put electrolytics in the wrong way round sometimes! Must have been a late Friday afternoon when this Musical Fidelity A1 was assembled a few decades ago. Fortunately in the signal path & not across power rails as they turn into mini mortars otherwise!

Interesting video here from Linn about how they started up with the LP12 turntable and their impressive factory in Scotland. Nice products but you need deep pockets, I prefer to buy secondhand and preferably broken to ease the cash outlay! via @YouTube

Customers often ask what are the benefits of having all electrolytics replaced during an amplifier overhaul. Hopefully this page on the Amplifier Repair Services website answers in a little more detail: