We can take this thread towards modern substitutes fpr old transistors etc., and also replacing STK modules...
But most of them would be in just better than scrap condition by now, so it may be easier to do a new build.
Like spladski above said, the designs have not changed much...
But most of them would be in just better than scrap condition by now, so it may be easier to do a new build.
Like spladski above said, the designs have not changed much...
If designs don't change, is this due to pattents on inovations?
Or are changes reserved to some ranges of products, for commercial arguments and to preserve small markets?
Or are changes reserved to some ranges of products, for commercial arguments and to preserve small markets?
Basically a push pull amp design is the same, the devices used evolve over time, and as per output requirements.
Like the old 2N3055/2955 and TIP41/42 designs evolved to Mosfet and chip amps.
But there is not much leeway in designing a 3886 amp for example, a few resistor and capacitor values change, maybe power supply voltage.
Like the Gainclone modifications, it is still a chip amp.
The life of a US patent is 17 years I think, so most of the old knowledge is not protected by patents, so infringement issues do not exist.
Restoring an old amp is more a mental satisfaction thing, apart from the sound quality, which can be replicated in new designs.
Like the old 2N3055/2955 and TIP41/42 designs evolved to Mosfet and chip amps.
But there is not much leeway in designing a 3886 amp for example, a few resistor and capacitor values change, maybe power supply voltage.
Like the Gainclone modifications, it is still a chip amp.
The life of a US patent is 17 years I think, so most of the old knowledge is not protected by patents, so infringement issues do not exist.
Restoring an old amp is more a mental satisfaction thing, apart from the sound quality, which can be replicated in new designs.
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@ NareshBrd,
Please avoid brazen language if your answer was aimed at me. All I asked was do transistor age ?
Regards.
Please avoid brazen language if your answer was aimed at me. All I asked was do transistor age ?
OP had mentioned comparison with modern amplifier so i queried about input selection and tone controls/bypass in modern amplifiers. Pardon me for being offtopic.
Regards.
I am 56 in September, so I really am not going to mention age...
Nothing personal
In old amps, mains switch was for primary side, all others were on secondary side of supply.
Mains switch, transformer permanently on, I have seen in computer speakers, generally I change switch to mains, or tell the user to disconnect from mains when not in use, as the transformer will run idle for no reason at all as the switch is on low voltage side.
ICs used in selectors due to cost and noise issues, also some designs had a provision for remote, provided in a higher end version of same circuit.
Transistors do age...see below...but mostly not to failure.
Transistor ageing is also a function of manufacturing process, purity of raw materials, encapsulation quality, and the use conditions in the circuit, how close to max it is run by design, and by the user, temperature and heat sink area are also involved.
Example: STK 403-100 in Pioneer was set at about 39 Volts, and in Sony at +45/-46 Volts, the device limit is +/-50, so Sony is having less margin of error, and will fail sooner.
Now this is not related to the device manufacturer.
And so this will become a long discussion, I am sure you will find more material to read if you search on the net.
Particularly US military and NASA specifications, quite thorough, provided you are interested.
Nothing personal
In old amps, mains switch was for primary side, all others were on secondary side of supply.
Mains switch, transformer permanently on, I have seen in computer speakers, generally I change switch to mains, or tell the user to disconnect from mains when not in use, as the transformer will run idle for no reason at all as the switch is on low voltage side.
ICs used in selectors due to cost and noise issues, also some designs had a provision for remote, provided in a higher end version of same circuit.
Transistors do age...see below...but mostly not to failure.
Transistor ageing is also a function of manufacturing process, purity of raw materials, encapsulation quality, and the use conditions in the circuit, how close to max it is run by design, and by the user, temperature and heat sink area are also involved.
Example: STK 403-100 in Pioneer was set at about 39 Volts, and in Sony at +45/-46 Volts, the device limit is +/-50, so Sony is having less margin of error, and will fail sooner.
Now this is not related to the device manufacturer.
And so this will become a long discussion, I am sure you will find more material to read if you search on the net.
Particularly US military and NASA specifications, quite thorough, provided you are interested.
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3886, as far I understood, its the same chip, and so the transistors could be easy to match by design, including for thermal variations/compensations. Which may not be the case for other non chip basic push pulls?
I've read several JLH 1969/1996 articles discussing such aspects, thermal and gain matching and consequences on distortion in simple designs.
I've read several JLH 1969/1996 articles discussing such aspects, thermal and gain matching and consequences on distortion in simple designs.
None of the replies so far address the OP. Perhaps that's because few of us had any experience with those big and quite expensive Japanese models that ruled the audio waves back in the 1970s-80s.
I think we need to keep the term "topline" in mind when discussing old gear here. Even fully restored, many lesser products of the era wouldn't pass muster today or even in the 1990s when interest had already shifted from Hifi stereo to multichannel, processed home theatre and trashy music centres.
In a controlled listening comparison, back then I would have preferred most topline Japanese products for their sound quality, looks, features and reliability. They were unaffordable for me but I could listen to some good examples at friend's homes. Some models were breathtakingly good, such as those by also Lux, Technics and others (BTW "Luxman" was once "Lux" brand). The midrange and economy models from Sansui, Kenwood etc. seldom performed as impressively but given the reputation of their best topline gear, Japanese manufacturers probably didn't need to do more than just maintain supplies according to the eager demand.
I think we need to keep the term "topline" in mind when discussing old gear here. Even fully restored, many lesser products of the era wouldn't pass muster today or even in the 1990s when interest had already shifted from Hifi stereo to multichannel, processed home theatre and trashy music centres.
Rebuilding a top line model may be worth the effort, specially if done with the proper components and using good quality instruments.
Unlikely to be many available now, so really esoteric now.
Unlikely to be many available now, so really esoteric now.
Actually, quite a few lower end models (the Marantz 1060, 1070, 1030, etc. immediately come to mind) are still revered for sound quality, ditto quite a few lower end Sansui models. My interest stems from the often overlooked fact that the superior dollar:yen ratio in the 1970s coupled with huge demand meant that Japanese built stereo equipment in the 1970s had a very high level of craftsmanship and design. That all collapsed in the late 70s and into the 80s when the yen gained significant strength to the dollar and cost cutting began in earnest.
I'm finding a lot of these responses interesting and even amusing in their linear thinking. You have to think somewhat laterally here to see the potential. Yes, there were a lot of what's now considered superfluous features (tone controls, loudness contours, etc.) but I'm thinking that may *add* to the sound quality. I say that because my goal isn't necessarily stark, distortion-free reproduction. That seems to be a governing mantra in this forum. I'm searching for musicality, the elusive thing that people like in tube gear in spite of its much worse distortion versus solid state ...
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Gainclone made me look at Neurochrome offers and specs. Plus their numbers for IMD.
Earlier, I had read some pages about IMD. I suspect my basic mosfet amp adds a lot there...
Earlier, I had read some pages about IMD. I suspect my basic mosfet amp adds a lot there...
The post was about how they sound...
Bear in mind that they were evolved from valve gear, and could be sold for a high price.
And not many reviewers had THD analyzers to tell the maker what was wrong according to their tests.
Also the listeners had no experience, mostly the reference was valve sets, which are not as precise in their reproduction, and people liked that sound, also they were used to it.
So you had generous supplies. old style capacitors of a different construction from now and so on.
The sound from newer units is different, but then the sound being listened to is also different.
A matter of taste, and also, really worth the effort.
We had a discussion some time back about the LM1875 response...at ultrasonic frequencies. Totally useless for audio use.
So in summary, yes the old sets, even lower end ones are good for listening even today, if properly rebuilt.
How many are available in a condition that will be worthy of the effort to restore is quite a different subject.
Bear in mind that they were evolved from valve gear, and could be sold for a high price.
And not many reviewers had THD analyzers to tell the maker what was wrong according to their tests.
Also the listeners had no experience, mostly the reference was valve sets, which are not as precise in their reproduction, and people liked that sound, also they were used to it.
So you had generous supplies. old style capacitors of a different construction from now and so on.
The sound from newer units is different, but then the sound being listened to is also different.
A matter of taste, and also, really worth the effort.
We had a discussion some time back about the LM1875 response...at ultrasonic frequencies. Totally useless for audio use.
So in summary, yes the old sets, even lower end ones are good for listening even today, if properly rebuilt.
How many are available in a condition that will be worthy of the effort to restore is quite a different subject.
"... I'm searching for musicality, the elusive thing that people like in tube gear in spite of its much worse distortion versus solid state ..." -dreamcatcher
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I have a completely restored au919 with original output transistors and I must say it would hold its own against pretty much anything made these days unless you spend an obnoxious amount of money !
You would think that a top of the line model from established manufacturers would have the best engineering. I have come across old and new gear where something basic got overlooked and the product was marketed looking the part but was sub par.
An example is the Technics SU-9600/SE-9600 pre/power from 1974. The power amp sounded very grainy to the point of being annoying. The bias checked OK. It was so bad I used it for DJ work and it got stolen because it had the look and the name. The preamp needed a noisy transistor replacing. The build quality is exemplary. During the repair I discovered it was very microphonic. This was traced to a pot in a bias circuit carrying a few microamps. Not enough wetting current for the wiper. The fix was easy and now sounds great, but how did these top of line models actually make it to production?
It is best not to trust any piece of gear unless you have the engineering provenance i.e. the schematic.
An example is the Technics SU-9600/SE-9600 pre/power from 1974. The power amp sounded very grainy to the point of being annoying. The bias checked OK. It was so bad I used it for DJ work and it got stolen because it had the look and the name. The preamp needed a noisy transistor replacing. The build quality is exemplary. During the repair I discovered it was very microphonic. This was traced to a pot in a bias circuit carrying a few microamps. Not enough wetting current for the wiper. The fix was easy and now sounds great, but how did these top of line models actually make it to production?
It is best not to trust any piece of gear unless you have the engineering provenance i.e. the schematic.