Armstrong 626 Receiver

Hi all - I have owned an used an Arnstrong 626 since about 1969 and it has always been my go to quality amp . I've made numerous repairs including three sets of volume / balance /bass and treble pots but recently had a real problem with heavy thumping in my B&W speakers at any high volume. I changed all main power supply components but didn't clear the problem until I replaced the voltage stabiliser components - now it works as good if not better than ever. The exact replacement NPN transistors were just not available so had to use equivalents . If anyone has a similar problem don't despair it can be done . more info on equivalents available on request. I have a full digital Naim set up but to be honest i really miss the smoothness of the 626 which is currently used for monitoring duties.  

I sold Armstrong receivers in a shop called Westwoods in Oxford . Recently I took a 625 out of hibernation . As all have said a lovely sound . I also have a Kenwood KR 750 which is equally loved .

Westwoods was connected with Armstong as he ( sorry I forget the name ) bought his components from Leslie Westwood when a student . This man visited me not long before his death to show the 800 series ( fantastic and advanced design ) . He named the company after his favourite motor car an Armstrong Siderley if I remember it correctly .

I find a remarkable quality in this design apart from those stated . It never is loud . The sound is to be heard everywhere in the house thus is loud .

Technically, the power amplifier design uses a single input transistor having a double feedback loop with double NPN quasi complimentary outputs. The ouput is capacitor coupled . The driver load is by bootstrap capacitor ( A high grade here might be an idea . 50 uF from memory . 47 uF 100 v now ) I remember Armstong saying testing would have to be with a dummy loudspeaker network to get the stated distortion . Hi Fi news retested and confirmed that . The drivers are TV CRT transistors. A good choice as the requirements are similar . I wonder if this real loudspeaker loud situation explains the above average sound ( many tube amps are not this good ) . Also it is rare to take feedback after the feedback capacitor . It can make an amplifier unstable , Armstrong made it work .

The only modification I would recomend is to replace the power amplifier input coupling capacitor with a 1 uF film type . This will reduce volume control noise and is big enough to do the job . Armstrong use 10 uF from memory . Check the big power supply capacitor from time to time . Any increase in hum will be a danger sign . WD 40 is excellent for restoring switches etc , I suspect it is sonically the best of such treatments .

The FM is as said a reference for other designs .

Thanks for the recommendation.

Hi Sherod ... you could try this guy - http://www.londonsound.org/

Good luck from NZ
Alasdair@operamail.com

Would it be difficult for a good technician to replace the Din connectors with basic RCA,etc. types?

I purchased mine in Melbourne in 1978. It has been a great centrepiece of my HiFi listening.... Recently the AM tuner died and the thermal cut out goes off after 2 to 3 hours of listening...then it cuts back in.
I am regretfully thinking of selling it, as repairs will be either expensive or difficult to replace the parts,
I find it fascinating that its slim piano key face still has it looking very modern and with it...alas they don't make them like they used to!!!!

Wadkar1

I have one and I agree that it is a particularly good sounding receiver. Mine will be up for sale shortly. Got to get rid of some of the excess gear I have accumulated.
Back in the '70's Jim Boyk included the Armstrong in his recommended components along with the Polk 7 the LS3/5a and the Yamaha CR-1000.
I have owned everything except the Polks and heartily agree with his recommendations.

Thank you, although I did post this thread almost 4 months ago, I am glad to see that some will go through the old archives and respond. I have found the same site, and subsequently found out some things that I didn't even know about the unit. That is a very good site.

Hi there....
For the first time in a couple of years or so, I searched on the internet for info on my Armstrong 626 and..... you might be interested in what I found.... thrilling stuff at
http://www.st-and.demon.co.uk/Audio/armstrong.html.

Cheers from NZ......

Al