SERVICE SANSUI AU 9900A
An excellent machine all time classic by Japanese manufacturer made to last for ever ... thanks to excellent mechanical construction and quality of parts .... enormous capacitors .... serious quality parts huge toroid .... beautiful choice ... beautiful phono stage generally a more serious amplifier that I've seen in vintage machinery ....
The only downside I think is the space and the distribution of the material ..... i take it for sure that today such a machine would work wonderful if placed in a giant CHASSIS or a giant construction .... the onlyi found wrong with this machine was the upright side plates with known problems in electrolytic and other heat stress plus cabling from one to another
Nevertheless the results are I would say at least spectacular .... be informed that the machine after 30 years of operation had not the slightest problem and the work done inside was done and had absolutely no relation to any damage with any damage....just service .
Changed all electrolytics without any discrimination ... Checking for dry solder a good cleaning regulating and ready for another 30 years ...
even in the picture someone may see that beyond all the above they have taken care of even the lovely looks and everything is very nicely placed on the boards
fotos and schematic available
An excellent machine all time classic by Japanese manufacturer made to last for ever ... thanks to excellent mechanical construction and quality of parts .... enormous capacitors .... serious quality parts huge toroid .... beautiful choice ... beautiful phono stage generally a more serious amplifier that I've seen in vintage machinery ....
The only downside I think is the space and the distribution of the material ..... i take it for sure that today such a machine would work wonderful if placed in a giant CHASSIS or a giant construction .... the onlyi found wrong with this machine was the upright side plates with known problems in electrolytic and other heat stress plus cabling from one to another
Nevertheless the results are I would say at least spectacular .... be informed that the machine after 30 years of operation had not the slightest problem and the work done inside was done and had absolutely no relation to any damage with any damage....just service .
Changed all electrolytics without any discrimination ... Checking for dry solder a good cleaning regulating and ready for another 30 years ...
even in the picture someone may see that beyond all the above they have taken care of even the lovely looks and everything is very nicely placed on the boards
fotos and schematic available
SERVICE MUSICAL FIDELITY
A machine that belongs to a forum member and there is a relevant thread on the greek forum .... diy Generally it was a job we did in cooperation with the owner at a cost of 3-4 hours of work, a pizza, a sprite and half pack of cigarettes .... However we had a good time !
What I found ....
--- Generally a machine that had several years in his back
--- Various old electrolytics tired particularly in local stabilization of the integrated power supply
--- 4 large electrolytic capacitors mounted horizontal which I did not like
--- Several dry solder and pcb problems
What we did
--- fitted new caps placed properly and wiring.
--- Fitting the power supply board which has star ground / ground plane / differential ground frame ... which hosted 8 electrolytic nippon KMH 15.000 mfd 63V 105
--- Add bypass Wima MKS together with decoupling capacitors
--- Removing restrictions input filter upward and downward
--- Change trimmers for the quiescent current adjustment and reset
Generally the owner complained of abnormally high temperatures in the operation of the machine which probably was a result of high bias or oscillations and other imbalance issues derived from the electrolytic worn out from here and there. After repair the actual "press" as we say in our language and the temperature dropped.
Now regarding restrictions on the input filter is generally my intention to deliver machines as possible freely (which is obviously against the machine safety) is sufficient for the listener to be honest and kind to the machine and not intends to do with this rave party.
In terms of measuring the before and after bandwidth exceeded above 20 kHz easily . Similarly, the same happened a downwardsA machine that was for an syforoumiti there is a relevant thread on the field .... diy Generally it was a job we did in cooperation with the owner at a cost of 3-4 hours of work, a pizza, a sprite and half pack of cigarettes .... However we had a good!
What I found ....
--- Generally a machine that was several years in his back
--- Various electrolyte tired particularly in local stabilization of the integrated
--- 4 large electrolytic capacitors mounted horizontal which I did not like
--- Several cold solder and printed vasanakia
What we did
--- Unraveling electrolyte plates and wiring.
--- Fitting the power supply board which has star ground / ground plane / differential ground frame ... which hosted 8 electrolytic nippon KMH 15.000 mfd 63V 105
--- Anikatastasi all electrolyte above the plates
--- Add bypass Wima MKS together with decoupling capacitors
--- Removing restrictions input filter upward and downward
--- Change in tripartite governing the quiescent current and reset
Generally the owner complained of abnormally high temperatures in the operation of the machine which probably was not effective but high bias oscillations and other anissoropoion derived from the electrolytic worn out from here and there. After repair the actual "press" as we say in our language and the temperature dropped.
Now With regard to waivers of restrictions on the input filter is generally my intention to deliver machines as possible freely (which is obviously against the machine safety) is sufficient for the listener to be honest and kind to the machine and not intends to do with this rave party.
In terms of measuring the before and after we saw where in general above 20 kHz had a clear bandwidth change, Similarly, the same happened to the low end thanks to a larger input capacitor .
Rather English sound after all this. I will not hide that I am negative with these machines and the sound of them i never liked. For example the Japanese amplifier SANYO PLUS 55 will be playing by far better and relaistic next to any MF .
--------------- Hearings ...
When powered up sounded almost terrible .... I forgot of course that none of these machines works cold .... ... cold only thing sounded right was the midle .... After a 15 minutes started showing the nature of the sound ....warm , transparent , beautifully detailed with careful body enough nerve and a rich sound stage The crystal mids and sweet treble. (Reminded me greatly of the sound of NELSON PASS B1) I think after a few hours BURN IN for new parts will play even better.
here is some foto
A machine that belongs to a forum member and there is a relevant thread on the greek forum .... diy Generally it was a job we did in cooperation with the owner at a cost of 3-4 hours of work, a pizza, a sprite and half pack of cigarettes .... However we had a good time !
What I found ....
--- Generally a machine that had several years in his back
--- Various old electrolytics tired particularly in local stabilization of the integrated power supply
--- 4 large electrolytic capacitors mounted horizontal which I did not like
--- Several dry solder and pcb problems
What we did
--- fitted new caps placed properly and wiring.
--- Fitting the power supply board which has star ground / ground plane / differential ground frame ... which hosted 8 electrolytic nippon KMH 15.000 mfd 63V 105
--- Add bypass Wima MKS together with decoupling capacitors
--- Removing restrictions input filter upward and downward
--- Change trimmers for the quiescent current adjustment and reset
Generally the owner complained of abnormally high temperatures in the operation of the machine which probably was a result of high bias or oscillations and other imbalance issues derived from the electrolytic worn out from here and there. After repair the actual "press" as we say in our language and the temperature dropped.
Now regarding restrictions on the input filter is generally my intention to deliver machines as possible freely (which is obviously against the machine safety) is sufficient for the listener to be honest and kind to the machine and not intends to do with this rave party.
In terms of measuring the before and after bandwidth exceeded above 20 kHz easily . Similarly, the same happened a downwardsA machine that was for an syforoumiti there is a relevant thread on the field .... diy Generally it was a job we did in cooperation with the owner at a cost of 3-4 hours of work, a pizza, a sprite and half pack of cigarettes .... However we had a good!
What I found ....
--- Generally a machine that was several years in his back
--- Various electrolyte tired particularly in local stabilization of the integrated
--- 4 large electrolytic capacitors mounted horizontal which I did not like
--- Several cold solder and printed vasanakia
What we did
--- Unraveling electrolyte plates and wiring.
--- Fitting the power supply board which has star ground / ground plane / differential ground frame ... which hosted 8 electrolytic nippon KMH 15.000 mfd 63V 105
--- Anikatastasi all electrolyte above the plates
--- Add bypass Wima MKS together with decoupling capacitors
--- Removing restrictions input filter upward and downward
--- Change in tripartite governing the quiescent current and reset
Generally the owner complained of abnormally high temperatures in the operation of the machine which probably was not effective but high bias oscillations and other anissoropoion derived from the electrolytic worn out from here and there. After repair the actual "press" as we say in our language and the temperature dropped.
Now With regard to waivers of restrictions on the input filter is generally my intention to deliver machines as possible freely (which is obviously against the machine safety) is sufficient for the listener to be honest and kind to the machine and not intends to do with this rave party.
In terms of measuring the before and after we saw where in general above 20 kHz had a clear bandwidth change, Similarly, the same happened to the low end thanks to a larger input capacitor .
Rather English sound after all this. I will not hide that I am negative with these machines and the sound of them i never liked. For example the Japanese amplifier SANYO PLUS 55 will be playing by far better and relaistic next to any MF .
--------------- Hearings ...
When powered up sounded almost terrible .... I forgot of course that none of these machines works cold .... ... cold only thing sounded right was the midle .... After a 15 minutes started showing the nature of the sound ....warm , transparent , beautifully detailed with careful body enough nerve and a rich sound stage The crystal mids and sweet treble. (Reminded me greatly of the sound of NELSON PASS B1) I think after a few hours BURN IN for new parts will play even better.
here is some foto
SERVICE MARANTZ 1090
Here is a beautiful machine that came from Northern Greece which has every chance to make a beautiful repair and even find a use in a today system ...
A key advantage of the machine is excellent Structure of the magic selector switch provides as less possible ""walking"" of the signals from here and there
... In small upgrade we've had to change all small electrolytics made a small operation such as multiturn trimmers, input capacitors and better filtering in some places ... Minor repairs were needed to replace the volume pot which were borrowed from the local Yamaha store that has wonderful stock of parts . The potentiometer is not compatible in the legs but at least it is compatible in quality, the use of loudness, but also the linear response to volume control.
other the above no actual damage nice and quite machine with many of the colors of the past but still accurate enough for today's use.
some foto and schematic available
Here is a beautiful machine that came from Northern Greece which has every chance to make a beautiful repair and even find a use in a today system ...
A key advantage of the machine is excellent Structure of the magic selector switch provides as less possible ""walking"" of the signals from here and there
... In small upgrade we've had to change all small electrolytics made a small operation such as multiturn trimmers, input capacitors and better filtering in some places ... Minor repairs were needed to replace the volume pot which were borrowed from the local Yamaha store that has wonderful stock of parts . The potentiometer is not compatible in the legs but at least it is compatible in quality, the use of loudness, but also the linear response to volume control.
other the above no actual damage nice and quite machine with many of the colors of the past but still accurate enough for today's use.
some foto and schematic available
SERVICE NEC AUA-6300
The NEC AUA-6300 was never any serious machine ... still though its a very rare machine ...
gentle, quiet, clean, without huge power reserves, nothing unreal ..... perhaps little more than modest. But we have said that the value of these material (handmade Japanese) is more sentimental value it may have for the owner deserves a little love and a little kindness (along with a handful electrolytics) .
All electrolytics have been replaced and upgradet (higher voltage / capacity / temperature) which gives the same body linearity and durability ....
The funny and remarkable was that the amplifier has been burned a couple times in the past (the 55 years now owner apparently HAS BEEN a party animal) and someone changed the STK IC but at their back instead of thermal take he placed classical silicone glue same type used in glass factory .... amazing ...
foto but no schematic
The NEC AUA-6300 was never any serious machine ... still though its a very rare machine ...
gentle, quiet, clean, without huge power reserves, nothing unreal ..... perhaps little more than modest. But we have said that the value of these material (handmade Japanese) is more sentimental value it may have for the owner deserves a little love and a little kindness (along with a handful electrolytics) .
All electrolytics have been replaced and upgradet (higher voltage / capacity / temperature) which gives the same body linearity and durability ....
The funny and remarkable was that the amplifier has been burned a couple times in the past (the 55 years now owner apparently HAS BEEN a party animal) and someone changed the STK IC but at their back instead of thermal take he placed classical silicone glue same type used in glass factory .... amazing ...
foto but no schematic
my intention is to place a few fotos and add a few comments from the repaired equipment in order people that interested in vintage amplifiers and gear to get some more information and then discuss here issues related to the above equipment...
Hi Sakis
You have done great work in your presentation and comments here. Your selection of models is something I am familiar with too.
I think a lot of forum guys will be pleased to see what is inside these for when they become available for purchase.
That is a very impressive rework of Crescendo. It may not perform the best but I'm sure that's the best I've ever seen it built. Congratulations and a good Christmas Season to you.
You have done great work in your presentation and comments here. Your selection of models is something I am familiar with too.
I think a lot of forum guys will be pleased to see what is inside these for when they become available for purchase.
That is a very impressive rework of Crescendo. It may not perform the best but I'm sure that's the best I've ever seen it built. Congratulations and a good Christmas Season to you.
SERVICE CREEK EVO
A machine that seems to worth a bit more time
--- I think for a production machine is very intelligent and well-structured
--- For an English philosophy machine is very warm in its sound and not any more poor, narrow British sound.
--- The quality of construction and materials is the best could be at the expected costs.
---- Positively selector relay from takamisawa which works perfectly even with more than one active source in the input .
--- While the board is designed for production from robots in a large proportion of its design have been met most of the rules .
---- there is bass enough and extremely informative and tight the high is relatively clean but a little-kept back i think .
--- The machine is well "guarded" regarding bandwidth so the low not to go as low in frequency as is supposed to be (reasonable because the amplifier's power stage should be larger and the cooling should be more efficient) also the high don't have the absolute purity and crystal clear which you find in a rather larger machine.
--- The idle is relatively low resulting in very low power operation of the unit is extremely sweet but at some point and then i think it gets a bit dirty ..
I would say that is one of the machines that I particularly loved the way it is structured and simply deserves to be called a small high end machine and I think that the manufacturer correctly and wisely has made the compromise between the cost of the machine and the performance available.
here i dlike to say once more that CreEk evo is one of the machines designed to be produced in mass production but still preserve as many as possible of the rules of audio design ...To my opinion that in the Number one reason that makes it so good
few pics of the interior and remain at your disposal at any other information needed
A machine that seems to worth a bit more time
--- I think for a production machine is very intelligent and well-structured
--- For an English philosophy machine is very warm in its sound and not any more poor, narrow British sound.
--- The quality of construction and materials is the best could be at the expected costs.
---- Positively selector relay from takamisawa which works perfectly even with more than one active source in the input .
--- While the board is designed for production from robots in a large proportion of its design have been met most of the rules .
---- there is bass enough and extremely informative and tight the high is relatively clean but a little-kept back i think .
--- The machine is well "guarded" regarding bandwidth so the low not to go as low in frequency as is supposed to be (reasonable because the amplifier's power stage should be larger and the cooling should be more efficient) also the high don't have the absolute purity and crystal clear which you find in a rather larger machine.
--- The idle is relatively low resulting in very low power operation of the unit is extremely sweet but at some point and then i think it gets a bit dirty ..
I would say that is one of the machines that I particularly loved the way it is structured and simply deserves to be called a small high end machine and I think that the manufacturer correctly and wisely has made the compromise between the cost of the machine and the performance available.
here i dlike to say once more that CreEk evo is one of the machines designed to be produced in mass production but still preserve as many as possible of the rules of audio design ...To my opinion that in the Number one reason that makes it so good
few pics of the interior and remain at your disposal at any other information needed
i find that unexpectedly nice ... ( see other people's work )
one thing to say though
Number one rule for repairs like that in our shop is that here is no question about which electrolytic to replace ... Just replace them all
in the Luxman there is some that even can be seen with a naked eye that have been under thermal stress ... also there is some others that originally been placed horizontal ( these one should be dead too )
more or less is the same story for the Teac
kind regards
happy new year
sakis
one thing to say though
Number one rule for repairs like that in our shop is that here is no question about which electrolytic to replace ... Just replace them all
in the Luxman there is some that even can be seen with a naked eye that have been under thermal stress ... also there is some others that originally been placed horizontal ( these one should be dead too )
more or less is the same story for the Teac
kind regards
happy new year
sakis
It is easy for a repair shop. How about doing it for your own amp.
Many vintage amp uses high quality caps. Axial cap (where they are positioned horizontally) is usually a good one. Many of them have a long useful life. First question, if it isn't broken why fix it?
You may have experienced that changing old quality caps with new standard ones may bring no improvement to the sound. Often a degradation. So, what's your opinion?
I am sorry to say that in my opinion your all approach is wrong from every possible aspect .
--- none of the vintage amps actually used exotic caps ... probably the best at the time but nothing exotic ..this is the rule but there might be some small exceptions
( for example inside one amplifier one elna capacitor 220mfd /6.3 volts is rated for 2.000 hours of life under stress ... expect a nippon rated at least 63 volt for 105degrees to live 20 times more )
--- under no laws of physics there should ever be axial caps ...it is simply impossible to last long read , see how a capacitor is made ( paper foil aluminum foil and fluid place it horizontally in long run the fluid will stay in the lower side ) obviously now days no company ever uses axial caps
---One vintage amplifier may still play even with 99% of the capacitors inside damaged so if it plays or not was never the question . Question is how well it plays and if at least is close to the original specs ( regarding power and sound quality ) The point is that vintage owners generally not only aim to restorations to keep the machine in original shape but also long time run and if possible to any upgrade in the sound .
---To be more technical and be able to provide you a real picture one and only leaky electrolytic capacitor in the feedback chain of your amp might degrade the sound quality far more than 50% .One and only leaky capacitor in the auxiliary power supply might be able to completely stop your amplifier from operating ...
---A fresh set of capacitors with the option of higher quality /voltage /temperature and capacitance will always provide better linearity better filtering and by far better endurance .
finally the approach """if it isn't broken why fix it?"" is at least childish and think in another way : you may have a 25 year old Ford Fiesta ( never properly serviced ) to go from home to the mall but can you drive with it safely in a high way with 100mph ? obviously not
you could if you had the engine serviced, fresh tires, fresh shock absorbers, cooling system , exhaust ,carburetor ,and electrics properly working .... in this case yes being 25 years old has more to do with comfort performance and safety standards other than that you may drive with it at 100mph ...
kind regards
sakis
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More caps than pictured was changed before they went back to service.
I have also no reason to withold an old cap for sonical purpose.
And, any 25+ year old electrolytics are just waiting for an excuse to fail...
Those I find close to "hot-spots" (fairly common in old equipment), I always swap for 105 degree types.
And, I drill vent-holes in pcb, if there is room.
BTW, modern capasitors of same type would probably have a longer life, and much better
quality (also sound).
Arne K
I have also no reason to withold an old cap for sonical purpose.
And, any 25+ year old electrolytics are just waiting for an excuse to fail...
Those I find close to "hot-spots" (fairly common in old equipment), I always swap for 105 degree types.
And, I drill vent-holes in pcb, if there is room.
BTW, modern capasitors of same type would probably have a longer life, and much better
quality (also sound).
Arne K
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here is some ""end of the year " interesting facts
this year we repaired 387 amplifiers and consumed 5.350 capacitors of various types less than 2.200 mfd ( bigger is another story )
obviously 5.350 was also used in construction of things not only service ... but that was the general picture
kind regards
sakis
this year we repaired 387 amplifiers and consumed 5.350 capacitors of various types less than 2.200 mfd ( bigger is another story )
obviously 5.350 was also used in construction of things not only service ... but that was the general picture
kind regards
sakis