ARMSTRONG 621  623  624  625  and  626 amplifiers,   tuners,   tuneramps,  receivers  and  the  other  favourites:-

Below is a table listing models from the 60s to 1980.  

221      421      521      621       Amplifiers (with moving magnet cartridge input)   

222                                         Amplifiers (with crystal/ceramic cartridge input)  

223      423      523      623       am/fm tuners

224      424      524      624       fm only tuners  

225      425      525      625       fm tuner/amplifiers 

226      426      526      626       am/fm tuner/amplifiers (with moving magnet cartridge input)

127      227                              am/fm tuner/amplifiers (with crystal/ceramic cartridge input)      

Note the code.  A number ending 21 is an amplifier with magnetic input, 22 ceramic only, 23 am/fm tuner, 24 fm only tuner, 25 fm receiver, (tuner amplifier), 26 am/fm receiver, (tuner amplifier).  27 is for an am/fm receiver with ceramic only input.          

More detail in the text below



12 months guarantee on all equipment repaired covering the equipment itself, not just the repairs

(obviously excludes repairs carried out free of charge!).

How do you go about having an Armstrong amplifier, tuner, receiver or other item of hi-fi equipment repaired here at London Sound?

And what is our interest and connection with the company - by Mike Solomons.


Don't want to wade thru the lot?  Email Mike Solomons with your queries, at:-



Telephone 020.8868.9222

When 'phoning, select option one on hearing both messages.

emails usually replied to within an hour during shop hours



The picture above is Mike Solomons in the workshop at the back of our shop, with the computer that you'll be emailing to in the background, (well, actually the old computer - we've updated twice since this 'photo and I'm a bit older!).


Now read on to learn more about us!

By Mike Solomons


I was in my teens when I first came across Armstrong hi fi units - a friend owned an early valve receiver, and the youth leader of a voluntary service group I had joined, Dr John Cohen, also had one at home, built into a cabinet.

Fast forward to the early days of London Sound, when it briefly merged in an informal way with Sound Distinctive. Through my partner, Ron Morris, I met Ron Sheppard of Armstrong Audio, (around 1970), a man who turned out to be a unique and very special friend until he died many years ago, and for long after the demise of Armstrong Audio Ltd.

After a while, Ron Shephard came to see me as a reasonably competent repairer. He passed on to me customers with a whole range of early Armstrong valve units, through to the then recent Armstrong 127, and the 221, 222, 223, 224, 226 and 227 valve component hi-fi units. Later, I came to be recommended as a repairer of the transistor units - first the 400 then the 500 series, and then finally the 600 series, the last produced by the original company, (the 700 series were produced by an offshoot after the original company went into liquidation).

First a guide to the numbers:-

221      421      521      621      Amplifiers (with moving magnet cartridge input)

222                                        Amplifiers (with crystal/ceramic cartridge input)

223      423      523      623      am/fm tuners

224      424      524      624      fm only tuners

225      425      525      625      fm tuner/amplifiers

226      426      526      626      am/fm tuner/amplifiers (with moving magnet cartridge input)

127      227                             am/fm tuner/amplifiers (with crystal/ceramic cartridge input)


The valve and early transistor units

I set my stamp a long time ago, by finding a manufacturing defect to be found in many of the early valve tuners. At a trivial cost, I restored these tuners in a unique way to as originally conceived - and to a far higher standard than in original production, simply by spotting a bit of corner - cutting. Quite simple really - laziness led to soldering certain components to parts rivetted to the chassis, yet the rivet made an imperfect electrical contact after some years. A little solder applied in the right place makes an incredible difference!  Please note, as this concerned radio frequencies, the phrase "applied in the right place" is critical - a blob over the rivet is not sufficient!  As this affects the alignment of radio frequency circuits, realignment is necessary following the critical "blob of solder".

Similar trivial problems have beset the later units, and other problems have appeared as well. A particular problem in the 400 and 500 series results in a small amount of distortion that is inherent in the design and cannot be resolved. Huh, said I, and I now resolve it on all units repaired at negligible cost!

Replacement of the output transistors on these units has represented a considerable problem, resolved by a small circuitry change, allowing modern silicon transistors to replace the old germanium transistors. Far better than the usual advice "parts not available - buy a new unit"!

The Armstrong 600 series

I reserve my best to last - the modifications applied to all 600 series amplifiers and receivers. The power supply capacitor can fail, spraying corrosive fluid onto a circuit board, causing massive damage. Often the volume control is noisy, (due to a design defect). The output circuit is slightly unstable, and cannot, therefore, be set to the minimum distortion levels achievable by this circuit. My modifications to resolve all three issues was so modest in cost, it was included in all repairs!  Unfortunately, now over 30 years on, I find that too many of these capacitors fail despite the above mentioned modification that I now replace all of these capacitors as a routine service item, but by bulk buying of these parts I have still managed to keep the price down.

And now read below our general notes on repairs:-


Parts not available

If another repairer has told you this, he may be right - but. That BUT is a very big but! For example, if the output transistors of an old amplifier have failed, it is not unusual to find that transistors of that type number are not available, but that others are currently in stock! It can happen that we are unable to find spares, but then we either modify the equipment to use other parts - or make them!


The key benefits of repair at London Sound:-


High standard of workmanship, (we couldn't give a 12 month guarantee otherwise)!

With rare exceptions, all equipment repaired by Mike Solomons is guaranteed for 12 months. Mike has over 45 years professional experience, (it was a teenage hobby before then!). (Or, as he has often said, "put another way - nice people like you bring me interesting equipment to work on - then actually pay me for it!  What better way to earn a living!  For you, the benefit that, happy in my work, I do my best for you.")

We give Free Estimates and stick to them.

We operate from a high street shop with, (during our opening hours), an open door, (not a private home or industrial estate with a locked door to block out complaints).

This is not a selling operation, (so either we repair, or make no money - no false advice to buy new!).

12 months guarantee on all equipment repaired. Clearly, in writing. The only exception is for work carried out free of charge.

We specialise in older equipment, (Why? Usually good equipment is quite old when it first breaks!) How old is 'older equipment'? Most units repaired here are between thirty and sixty years old!

We hold a wide range of spares and service manuals.

When spares are not available, we have the required knowledge and data to substitute and repair. Our facilities include basic woodwork and metalwork, for re-construction, and modification where required, as well as, as you would expect, full electronic research and development facilities.

We are here to stay - Mike Solomons personally owns the freehold of the shop - without a mortgage - so you won't come here one day to find we've gone because of a rent review, (He says, "I now give them, but fairly, not suffer from them!").


So what comes next?

Email, telephone, write or call into the shop, for a free estimate. Note, our estimates are completely free, you only pay us if your equipment is repaired in accordance with the estimate.

Free means free!

If such repairs cannot be carried out, then we charge exactly nothing, even if we have carried out a partial repair then found major further difficulties! The only cost to you is transport.


ALL equipment repaired is guaranteed for twelve months. "All" means "all", not just some. Whether old or new, whatever the equipment age, the guarantee is the same. We've even guaranteed the repairs on some mid 1930's vintage radio and radiogram units for twelve months - without difficulties! How? If the work is done properly, it isn't a problem!

The only exception is for work carried out free of charge.

Not quite the same as buying new, as you don't have all the shiny new instruction books to read, packaging to dispose of etc! Neither do you have to research, purchase, or learn how the new item works - and find out what to do if it doesn't quite have the same facilities as your old unit!


So why do we give a twelve month guarantee?



Where you get a guarantee on repairs, (some repairers give no written guarantee at all), the "Industry Standard" is usually either one or three months.


It gets worse than that, as most repairers' guarantees are usually very tightly restricted just to the basic repair carried out - so, for example, if a volume control is replaced, but weeks later the amplifier fails again - as long as the volume control itself still is OK, you automatically have to pay again in full for repairs!


At London Sound, the repair guarantee is for twelve months. Clear, bold, in writing, and unambiguous.  It covers the whole equipment, not just the repairs carried out, so is similar to the manufacturer's original guarantee.



So - how much will it cost?









1)   On the 'phone, we can often give a rough guide. It is also possible by email and by ordinary mail - it just takes longer, as we may ask questions, and have to wait for replies. "Longer" isn't all that long - apart from holidays, we usuaslly reply within 24 hours.

2)   Usually, when you bring the equipment here, on a brief assessment of the fault while you wait, we will give a free estimate. We will also give you a further much higher figure, to be a 'fixed ceiling', not to be exceeded without your written consent. This procedure is called a Qualified Estimate, and is much safer for you.

3)   If you agree the estimate, the goods will be accepted for repair. You will be given a written copy of the estimate, with the upper ceiling figure clearly in writing, so you know you are safe. Normally, you will soon receive an invoice on completion of repairs, which will not exceed the 'fixed ceiling'.

4)   However, if repairs cannot be completed within the original agreed estimate, a further written estimate or report will be sent. In this case, for your protection, unless a revised estimate is agreed by you in writing, with an advance payment made to prove acceptance, you may collect the unrepaired equipment, with no charge at all to pay.

5)   BY MAIL. We can also carry out repairs by mail. Even then, the estimates are free, but the cost of carriage both ways is your responsibility.



So why is London Sound Different?


From the start, I have tried my best to carry out repairs to a high standard. Why? It is far better to do the work properly, than to try to evade responsibility for cutting corners and getting it wrong. Everyone would agree with that, but not everyone has the skills, integrity and self confidence!


I have to admit that, many years ago, in the early stages of my business, I lacked the required confidence, and only gave the usual 3 month guarantee. However, on the rare occasions when things went wrong within less than a year, I never felt able to charge. And yet as I became more experienced, breakdowns after the first few days became rare - and I found myself having discussions with regular customers about repairs carried out five, six seven or more years previously - with the equipment still OK!

A typical example of such a discussion occurred in 1980, as London Sound moved into its shop in Eastcote. I remember it well, as a man with me at the time, (the B.T. engineer fitting in a 'phone with our "old" number, which had provided some problems), had been deriding the idea of customers remaining loyal over a period of years. On the 'phone, a man said, "You repaired my Rogers Cadet III about 8 years ago. Don't worry, it's still OK, but I have a problem with another piece of hi-fi - - -" Not only had the Rogers remained in good working order for 8 years, but so had my reputation! Amazingly, another owner of a Rogers Cadet III telephoned me with an almost exact copy of the first message, in 1990, when we moved to the present shop!

So firstly, why do breakdowns occur within days? Sometimes what we jokingly call a "faulty customer" - a failure to use the equipment correctly! But sometimes it is genuine - and then, whether after days, months, or even a year, if I am wrong, I always prefer to put things right, rather than argue. As, I would hope, but rarely find, should anyone else.

So what triggered the decision to give a written twelve month repair guarantee? It was those discussions with past customers, with tales of equipment which I repaired lasting for such long periods after the work was done! I simply decided to claim credit for what I was doing anyway!



Some notes

Most repairers of audio and hi-fi equipment either do not mention guarantees or warranties, or alternatively issue highly restricted ones.

It is not unusual for the guarantee to be for 30 - 90 days, occasionally 3 months and rarely 6 months.

The London Sound guarantee is for 12 months.

The guarantee length is only part of the picture as we also have to look at what is guaranteed. Normally a repairer will guarantee the work he has actually carried out. This is of very little use as it usually means that if the unit goes wrong again shortly after repairs have been carried out there is almost always a way for the repairer to evade responsibility - "not quite the same fault guv".

The London Sound guarantee covers all faults that may develop over the 12 month period specified on the bill and has only three exclusions. One concerns items that wear, e.g. styli that if used heavily will deteriorate during the guarantee period and the second, effects of externally applied damage. The third exclusion concerns "cosmetic faults", e.g. case and cabinet appearance are not covered.

The resulting effect is protection that is similar to that offered on brand new equipment with no exclusion for age.

For all contact details, please look at Basic Information.


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