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Armstrong 626 nenewal!
I've just been going though the process of having one of my old Armstrong
626 recievers serviced/modified by Mike Solomons of London Sound. I actually sent him both the examples I owned and he then worked on the one judged the 'best' for service and improvement. I understand from the courier 'tracking' that it should arrive soon. All being well, it is promised today. So I have the relevant home-made adaptors, etc, and eagery await delivery so I can give it a go. :-) Feel anxious in case the carriers manage to damage it on the last leg of its trip away from me. OK, the 626 - even with mods - isn't the technical peak of audio perfection. But they do look nice and can sound good. Still feel it is a shame no-one makes anything that looks like them today. But no doubt they'd fail all the modern 'elf and safty' rules. Wooden lid that is easily removed without tools. Plastic tray lower section, similar. etc. Fingers crossed. Jim -- Please use the address on the audiomisc page if you wish to email me. Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html Audio Misc http://www.audiomisc.co.uk/index.html |
Armstrong 626 nenewal!
If you like that style, I have an old A&R Cambridge T21 Tuner somewhere.
I'll be moving in a months time so if it turns up do you want it? It was working the last time I used it, many fortnights ago. -- David B http://waterfalls.me.uk |
Armstrong 626 nenewal!
In article , David B
wrote: If you like that style, I have an old A&R Cambridge T21 Tuner somewhere. I'll be moving in a months time so if it turns up do you want it? It was working the last time I used it, many fortnights ago. Thanks, but no. :-) Agree about the style. However to me the 600 range look is pretty special. One of the reasons I like the 626 is that I used to work for Armstrong, and the set in question previously was owned by Ted Rule. He designed the electronics and I developed it a bit later on. So its a nice slice of my personal history as well as looking/sounding good. Its an unusual example because it now has a mix of mods added by Ted, then me, and now also Mike! I did dither about which set to upgrade as the other set is a later model. But Mike was able to update the older one anyway. FWIW I also have a working Yamaha 7000 FM tuner which has a nice retro style as well as being a great tuner. However in practice the bulk of my radio listening tend to be via a more modern means. I now fetch BBC iplayer files using get_iplayer than then play them via a USB DAC into the amp. For a few years I've been using a modern 'bland silver box' amp (Cambridge Audio) in the dining room/office because the 626's needed TLC. Now I hope to replace that with the 626 again. :-) Used with a pair of Spendor LS3/5a speaker and fed via a DAC Magic. Although for live radio I'll probably now use the 626's tuner, in practice I tend to prefer the flexibility from get_iplayer and the iplayer site. Curious blend of old and new... Jim -- Please use the address on the audiomisc page if you wish to email me. Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html Audio Misc http://www.audiomisc.co.uk/index.html |
Armstrong 626 nenewal!
On 31/07/2015 11:14, Jim Lesurf wrote:
I've just been going though the process of having one of my old Armstrong 626 recievers serviced/modified by Mike Solomons of London Sound. I actually sent him both the examples I owned and he then worked on the one judged the 'best' for service and improvement. I understand from the courier 'tracking' that it should arrive soon. All being well, it is promised today. So I have the relevant home-made adaptors, etc, and eagery await delivery so I can give it a go. :-) Feel anxious in case the carriers manage to damage it on the last leg of its trip away from me. OK, the 626 - even with mods - isn't the technical peak of audio perfection. But they do look nice and can sound good. Still feel it is a shame no-one makes anything that looks like them today. But no doubt they'd fail all the modern 'elf and safty' rules. Wooden lid that is easily removed without tools. Plastic tray lower section, similar. etc. Fingers crossed. I have one of those - very nice too, and still works perfectly. It hasn't been in daily use for some time now, though.The only slightly annoying thing for me is the DIN speaker sockets. What are the mods you're having done? -- Cheers, Rob |
Armstrong 626 nenewal!
In article , RJH
wrote: On 31/07/2015 11:14, Jim Lesurf wrote: I have one of those - very nice too, and still works perfectly. It hasn't been in daily use for some time now, though.The only slightly annoying thing for me is the DIN speaker sockets. What are the mods you're having done? I plan to write something about this in detail for my website. However I should say up front that Mike was happy to give me full details of the mods he makes *on condition* that I don't disclose all the details because they are his ideas and his bread and butter. That seems fair enough to me, so I agreed happily. Journalists have to respect their sources, particularly when they are very helpful. All that said... The standard changes are simply to restore and repair. e.g. what I sent to him had meters that didn't work properly and lamps that had failed. Some switches/sockets were intermittent. All the predictable signs of a long life of use for such old kit. The returned set I now have here has all the meters, lights, etc, working 'as new'. (If I can manage I'll take some photos for when I write about this, but I'm a lousy photographer.) He also checked things like the IF/RF alignments, but since the set had been owned by Ted Rule, then me, found these were spot on OK. I think he also installed new heatsink compound, etc, for the output devices to ensure the thermal sinking. And old electrolytics may get replaced. Essentially where possible he fixes/replaces what has gone wrong or seems likely to go wrong soon. The main area where this is limited is if there is physical external damage and he doesn't have a suitable replacement lid, or whatever. Meters can be a problem. For my set he actually had to shave a small bit of plastic and slightly bend the meter 'hand' as it had been sticking because the plastic had slowly warped with time from the heat of the pea bulbs. This perhaps gives you some idea of the detailed work he is prepared to do when needed, and that it all depends on the specific set and the wishes of the owner. The main mods are that: 1) He fits a circuit to suppress the 'whoosh' which can arise if you change the volume too soon after switch-on. This tends to occur eventually with the earlier sets with the carbon based tracks. FWIW I used conductive plastic pots in a later version and these are less likely to get the problem. So if a set is one of the later versions you may not experience the problem. But earlier sets are very prone to it. This mod also tends to reduce the switch-on thump I found. 2) He also modifies the power amp to be more thermally stable and less likely to develop crossover due to thermal tracking differences. The result seems to be more consistent and lowered distortion in normal use. This change means he can set a higher bias current safely, so get smoother results. 3) Along with (2) he tends to fit better drivers and splitter transistors. So the amp should finding driving low loads easier, etc. I'd expected him to remove the old thermal delays and change to using higher rated diodes in the PSU. However he feels that this isn't necessary if the delay still works. On reflection I ended up agreeing with him. I changed the sets to lose the thermal delay because these were causing most of the set returns under guarantee. However talking to Mike I realised this was because some delays were dud. Once they've worked for a few years they'll last forever. So by this stage they are unlikely to become a problem as the survivors are the good ones! :-) He may make other changes depending on the state of the set and the precise details of the version. Bear in mind that the actual production circuit was changed in detail many times as it 'evolved'. Alas, no-one now has any clear record of them. [1] All minor, but each designed to tweak an aspect of performance. e.g. The output caps and reservour cap values were increased more than once to get more power at LF and into low loads - once the drivers, etc, could cope! FWIW As per an earier posting I'm using a set of DIN speaker adaptors I made, based on some 'new old stock' plugs Dave kindly found and sent to me. (Again, thanks Dave for those! :-) ) Currently listening to Radio 3 using the 626's FM tuner. Even though I've not yet sorted out a sensible VHF antenna it sounds very good to me. (Currently I'm using a set-top UHF TV antenna in the loft as the VHF antenna! Need to get into the loft. 8-] ) Cheers, Jim [1] You may have noticed that there are two different Armstrong circuit diagrams that were released with the 600 range sets. The change that confuses most people is the change to the output bias current from 5 to 20 mA. But there are other changes that people miss. And in reality there were many more 'versions' than two! One of my biggest regrets now is that all the production paperwork was discarded and so I can't tell now how many sets were made, and which changes were made, when! If I'd realised in time I'd have tried to rescue the info. But it was too late by the time I started writing the Armstrong webpages and asked others about this, and other details now lost. :-/ With that in mind I wonder if it is worth asking people who have a 600 set what serial number it is and when they bought it. Might be possible to recover some details if enough sets are about. Should ask Mike as well as he might have worked it out... -- Please use the address on the audiomisc page if you wish to email me. Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html Audio Misc http://www.audiomisc.co.uk/index.html |
Armstrong 626 nenewal!
On 01/08/2015 12:44, Jim Lesurf wrote:
In article , RJH wrote: On 31/07/2015 11:14, Jim Lesurf wrote: I have one of those - very nice too, and still works perfectly. It hasn't been in daily use for some time now, though.The only slightly annoying thing for me is the DIN speaker sockets. What are the mods you're having done? I plan to write something about this in detail for my website. However I should say up front that Mike was happy to give me full details of the mods he makes *on condition* that I don't disclose all the details because they are his ideas and his bread and butter. That seems fair enough to me, so I agreed happily. Journalists have to respect their sources, particularly when they are very helpful. Very well worth knowing about London Sound. FWIW I had some repairs and mods done to a Beard valve amplifier by Chris Found - involved going round to his home somewhere in/around central London. Can't speak highly enough. Also loosely intrigued that you would let somebody else loose on a design you must know more about that most (anyone?!). Is that because he's maybe more up to date? Better at say soldering? And/or you have better things to do? All that said... The standard changes are simply to restore and repair. e.g. what I sent to him had meters that didn't work properly and lamps that had failed. Some switches/sockets were intermittent. All the predictable signs of a long life of use for such old kit. The returned set I now have here has all the meters, lights, etc, working 'as new'. (If I can manage I'll take some photos for when I write about this, but I'm a lousy photographer.) He also checked things like the IF/RF alignments, but since the set had been owned by Ted Rule, then me, found these were spot on OK. I think he also installed new heatsink compound, etc, for the output devices to ensure the thermal sinking. And old electrolytics may get replaced. Essentially where possible he fixes/replaces what has gone wrong or seems likely to go wrong soon. The main area where this is limited is if there is physical external damage and he doesn't have a suitable replacement lid, or whatever. Meters can be a problem. For my set he actually had to shave a small bit of plastic and slightly bend the meter 'hand' as it had been sticking because the plastic had slowly warped with time from the heat of the pea bulbs. This perhaps gives you some idea of the detailed work he is prepared to do when needed, and that it all depends on the specific set and the wishes of the owner. The main mods are that: 1) He fits a circuit to suppress the 'whoosh' which can arise if you change the volume too soon after switch-on. This tends to occur eventually with the earlier sets with the carbon based tracks. FWIW I used conductive plastic pots in a later version and these are less likely to get the problem. So if a set is one of the later versions you may not experience the problem. But earlier sets are very prone to it. This mod also tends to reduce the switch-on thump I found. 2) He also modifies the power amp to be more thermally stable and less likely to develop crossover due to thermal tracking differences. The result seems to be more consistent and lowered distortion in normal use. This change means he can set a higher bias current safely, so get smoother results. 3) Along with (2) he tends to fit better drivers and splitter transistors. So the amp should finding driving low loads easier, etc. I'd expected him to remove the old thermal delays and change to using higher rated diodes in the PSU. However he feels that this isn't necessary if the delay still works. On reflection I ended up agreeing with him. I changed the sets to lose the thermal delay because these were causing most of the set returns under guarantee. However talking to Mike I realised this was because some delays were dud. Once they've worked for a few years they'll last forever. So by this stage they are unlikely to become a problem as the survivors are the good ones! :-) He may make other changes depending on the state of the set and the precise details of the version. Bear in mind that the actual production circuit was changed in detail many times as it 'evolved'. Alas, no-one now has any clear record of them. [1] All minor, but each designed to tweak an aspect of performance. e.g. The output caps and reservour cap values were increased more than once to get more power at LF and into low loads - once the drivers, etc, could cope! FWIW As per an earier posting I'm using a set of DIN speaker adaptors I made, based on some 'new old stock' plugs Dave kindly found and sent to me. (Again, thanks Dave for those! :-) ) (I did get a few DIN plug screw-type cheapies - fine for my purposes) Currently listening to Radio 3 using the 626's FM tuner. Even though I've not yet sorted out a sensible VHF antenna it sounds very good to me. (Currently I'm using a set-top UHF TV antenna in the loft as the VHF antenna! Need to get into the loft. 8-] ) Cheers, Jim Very good! Sounds interesting, and look forward to the write-up. [1] You may have noticed that there are two different Armstrong circuit diagrams that were released with the 600 range sets. The change that confuses most people is the change to the output bias current from 5 to 20 mA. But there are other changes that people miss. And in reality there were many more 'versions' than two! One of my biggest regrets now is that all the production paperwork was discarded and so I can't tell now how many sets were made, and which changes were made, when! If I'd realised in time I'd have tried to rescue the info. But it was too late by the time I started writing the Armstrong webpages and asked others about this, and other details now lost. :-/ Well, I hadn't noticed ;-) It's testimony to something that you still see them popping up on ebay. With that in mind I wonder if it is worth asking people who have a 600 set what serial number it is and when they bought it. Might be possible to recover some details if enough sets are about. Should ask Mike as well as he might have worked it out... Quite happy to supply photos etc of mine if it helps. SN 610455 -- Cheers, Rob |
Armstrong 626 nenewal!
In article , RJH
wrote: Also loosely intrigued that you would let somebody else loose on a design you must know more about that most (anyone?!). Is that because he's maybe more up to date? Better at say soldering? And/or you have better things to do? Well, we probably discussed the changes/fixes in more detail than most of his customers. :-) Alas, I don't trust my eyes/fingers/judgement as much as I used to. Afraid I've developed a tendency to clumsiness and muddle. I'm still happy to work on simple circuits and ones I don't mind trashing and having to redo. But I didn't want to end up doing more harm than good to my 626s. Particularly for the set Ted owned before me, which was the 'best' in many ways despite being an early version. In addition both sets had problems with failing meters, etc. So really also needed some mechanical TLC and parts I lacked. I've never been any good at mechanical issues. Mike also could offer doing his mods which I decided to try because they seemed like the kind of thing I'd have done at the time if things had gone differently back in the days when the sets were being made. I was curious to hear the results. Now pleased I did. :-) And in the end I decided it might help others if I had Mike do this and I could write about it. That might help others in a similar situation. Having been though the process I'd now happily recommend it on the basis of experience. Jim -- Please use the address on the audiomisc page if you wish to email me. Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html Audio Misc http://www.audiomisc.co.uk/index.html |
Armstrong 626 nenewal!
Jim Lesurf wrote:
The main mods are that: 1) He fits a circuit to suppress the 'whoosh' which can arise if you change the volume too soon after switch-on. ** A sure sign of electro caps charging via the track of a pot, temporarily causing DC voltage and so noise when the wiper is moved. I see in this case 10 and 22uF electros feeding a 100kohm volume pot - so it will take around 20 seconds for the voltage to disappear, if it ever does. A couple of 0.47uF film caps are the go there. 2) He also modifies the power amp to be more thermally stable and less likely to develop crossover due to thermal tracking differences. ** The schem on your pages shows two ITT44 diodes for bias temp compensation while a quasi-complementary stage normally requires three - one for each driver and one for the upper output transistor. If both ITT44s are mounted in contact with the heatsink, bias may be overcompensated and if only one then it will likely be under. A good compromise is to use three diodes, with one attached to the heatsink and select a series resistor on test to get 20mA at idle. I'd expected him to remove the old thermal delays and change to using higher rated diodes in the PSU. ** So would I, seeing 1N4003s in the PSU puts my teeth on edge. In the early 70s, I built a quite similar stereo amp for my own use - but with an extra TO3 transistor providing a regulated B+ rail of 64VDC. There was also a thyristor crow bar circuit that instantly shut down the B+ if the peak supply current exceeded a safe level for the 2N3055 outputs. Input connectors were 5 pin DIN and it drove a pair of heavily modified KEF KIT 3s (same as the Concerto) - until I discovered Quad ESL57s. .... Phil |
Armstrong 626 nenewal!
Le 31/07/15 13:00, Jim Lesurf a écrit :
In article , David B wrote: If you like that style, I have an old A&R Cambridge T21 Tuner somewhere. I'll be moving in a months time so if it turns up do you want it? It was working the last time I used it, many fortnights ago. Thanks, but no. :-) Agree about the style. However to me the 600 range look is pretty special. One of the reasons I like the 626 is that I used to work for Armstrong, and the set in question previously was owned by Ted Rule. He designed the electronics and I developed it a bit later on. So its a nice slice of my personal history as well as looking/sounding good. Its an unusual example because it now has a mix of mods added by Ted, then me, and now also Mike! I did dither about which set to upgrade as the other set is a later model. But Mike was able to update the older one anyway. FWIW I also have a working Yamaha 7000 FM tuner which has a nice retro style as well as being a great tuner. However in practice the bulk of my radio listening tend to be via a more modern means. I now fetch BBC iplayer files using get_iplayer than then play them via a USB DAC into the amp. For a few years I've been using a modern 'bland silver box' amp (Cambridge Audio) in the dining room/office because the 626's needed TLC. Now I hope to replace that with the 626 again. :-) Used with a pair of Spendor LS3/5a speaker and fed via a DAC Magic. Although for live radio I'll probably now use the 626's tuner, in practice I tend to prefer the flexibility from get_iplayer and the iplayer site. Curious blend of old and new... Jim Jim, If one day you wish to offload your CT-7000, please note that I am more than willing to give it a warm and loving home!! :-) Thankfully the DAB industry is in total tatters here in France and we have yet to hear any government official predicting the end of FM broadcasting. -- Froggy Baldrick: I've got this big growth in the middle of my face. Blackadder: That's your nose, Baldrick. (Blackadder the Third) |
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