That's quite a glowing report on the Sansui amp and thanks for the kind words, Dean. I know mine was due for new caps years ago, when I last played it and looked at the dust and parts inside but just shelved it, as I was busy building amplifiers for $$$ at the time. I do recall living with a couple of AU 101s when new and my ears were young and sharp though.
One recollection was that phono playback was not the best. To be honest, the simple 2- transistor preamps used to match with magnetic cartridges on most integrated amplifiers of the 1970s, were all pretty grim. The reasons have been laid out by Douglas Self for one, in his Small-Signal Audio Design book. If you wanted to enjoy vinyl, you really need to add a modern type of preamp as an outboard "head amp" but there's no reason one of these couldn't be DIY'd into the amplifier, if the single voltage power supply was compatible.
I accept that many audio fans think that old products are best and any extra distortion they add will be "nice and warm sounding". My view is that amplifiers now have to deal with several modern digital sources with very low distortion and it pays to get the vinyl source as clean and faithful to the disc as possible. Let the amp then add its character the same way as with other sources. Discs will still sound vastly different but why add more spurious noise and distortion than is inherent with vinyl. After all, that's the characteristic sound quality you will be interested in.
One recollection was that phono playback was not the best. To be honest, the simple 2- transistor preamps used to match with magnetic cartridges on most integrated amplifiers of the 1970s, were all pretty grim. The reasons have been laid out by Douglas Self for one, in his Small-Signal Audio Design book. If you wanted to enjoy vinyl, you really need to add a modern type of preamp as an outboard "head amp" but there's no reason one of these couldn't be DIY'd into the amplifier, if the single voltage power supply was compatible.
I accept that many audio fans think that old products are best and any extra distortion they add will be "nice and warm sounding". My view is that amplifiers now have to deal with several modern digital sources with very low distortion and it pays to get the vinyl source as clean and faithful to the disc as possible. Let the amp then add its character the same way as with other sources. Discs will still sound vastly different but why add more spurious noise and distortion than is inherent with vinyl. After all, that's the characteristic sound quality you will be interested in.
Hi Ian
That’s very interesting regarding the quality of the phono section of the Sansui. I’ll definitely give you my opinion when I get round to listening to it. My friend has got a separate phono stage (Project MM ) that we are going to try against the Sansui one so this will be interesting?
Mikstick has kindly offered me a switch off one he bought for spares, so hopefully I can fit that one. The irony is, I’ve decided to do a swap with my friend who doesn’t require the headphone switching (the Arcam has a headphone socket
), but I’m going to do it for him anyway.
I also plan to replace the capacitors that has been suggested by Mooly and confirmed by yourself to be of benefit.
Looking forward to hearing the Arcam with my speakers, I do find that every amplifier I’ve heard with my Goodmans have way to much power and I can barely turn the volume up.
My ambition is to built a high quality low watt amplifier (if that makes sense) but I have absolutely no idea were I would start, which is why I’m going to open another thread asking were do you begin in electronics?
Once again thank you for the help,I have really enjoyed my first thread on this forum because you all made it so pleasurable.
All the best
Dean
That’s very interesting regarding the quality of the phono section of the Sansui. I’ll definitely give you my opinion when I get round to listening to it. My friend has got a separate phono stage (Project MM ) that we are going to try against the Sansui one so this will be interesting?
Mikstick has kindly offered me a switch off one he bought for spares, so hopefully I can fit that one. The irony is, I’ve decided to do a swap with my friend who doesn’t require the headphone switching (the Arcam has a headphone socket
), but I’m going to do it for him anyway.I also plan to replace the capacitors that has been suggested by Mooly and confirmed by yourself to be of benefit.
Looking forward to hearing the Arcam with my speakers, I do find that every amplifier I’ve heard with my Goodmans have way to much power and I can barely turn the volume up.
My ambition is to built a high quality low watt amplifier (if that makes sense) but I have absolutely no idea were I would start, which is why I’m going to open another thread asking were do you begin in electronics?
Once again thank you for the help,I have really enjoyed my first thread on this forum because you all made it so pleasurable.
All the best
Dean
DIYaudio probably has dozens of different projects for each and every imaginable category of audio listening. Here's a well presented, very compact and modern, high quality design to start the thought process. http://www.diyaudio.com/forums/soli...gh-perfromance-lpuhp-16w-power-amplifier.html
Generally, projects here are presented as just a PCB containing one channel of the power amplifier PCB. That way, people who only want the basics to complete for their own requirements, aren't wasting time and money on redundant circuitry or PCBs that only fit one particular case, power supply etc. Pics of individual projects can be found in the "sticky" thread section at the top of the first page if you'd like to see how they wind up with all the added power supplies and periferal circuits, controls and safety devices.
There are plenty of bigger, old style construction projects too but those big 'ol parts are getting scarce and steadily going the way of the dodo as surface mount technology and "digital" takes over.
Chip amps are the way to go for very economical, quick assembly, safe operating and "worked first time" satisfying projects. See examples based on the little transistor sized LM1875, a 5 pin chipamp, in the Chipamp forum. This has been around for decades but is still good for 20W or more, so don't be fooled by the size.
It was certainly good of mikstick to offer the needed switch. I think this was the only real solution all along and you do have cause for celebration - I'd be hanging onto the amp though!
Where to start is really to take stock of where you are now with your understanding of basic electronics, audio circuits, components and construction materials. That gives you a path of learning by study and reading threads about interesting topics and following up with questions, however dumb, to get a grasp on what your next course of action should be as you plan your first project. You have to enjoy that experience to want to continue so I suggest making it a simple and sure-fire one that will sound great too. Yes, a chipamp.
Generally, projects here are presented as just a PCB containing one channel of the power amplifier PCB. That way, people who only want the basics to complete for their own requirements, aren't wasting time and money on redundant circuitry or PCBs that only fit one particular case, power supply etc. Pics of individual projects can be found in the "sticky" thread section at the top of the first page if you'd like to see how they wind up with all the added power supplies and periferal circuits, controls and safety devices.
There are plenty of bigger, old style construction projects too but those big 'ol parts are getting scarce and steadily going the way of the dodo as surface mount technology and "digital" takes over.
Chip amps are the way to go for very economical, quick assembly, safe operating and "worked first time" satisfying projects. See examples based on the little transistor sized LM1875, a 5 pin chipamp, in the Chipamp forum. This has been around for decades but is still good for 20W or more, so don't be fooled by the size.
It was certainly good of mikstick to offer the needed switch. I think this was the only real solution all along and you do have cause for celebration - I'd be hanging onto the amp though!
Where to start is really to take stock of where you are now with your understanding of basic electronics, audio circuits, components and construction materials. That gives you a path of learning by study and reading threads about interesting topics and following up with questions, however dumb, to get a grasp on what your next course of action should be as you plan your first project. You have to enjoy that experience to want to continue so I suggest making it a simple and sure-fire one that will sound great too. Yes, a chipamp.
I think you’re right there, I’ve plugged in the Arcam and the sound is boring, it’s just flat sounding, there is not much contrast in dynamics, makes everything sound monotonous compared to the Sansui?
oh well it’s going to be tricky explaining to my friend that I want it back, I feel that I shouldn’t really because we’ve made the deal and he’s enjoying it so much. I’ll check-out eBay first to see if I can sell the Arcam and maybe buy another Sansui or even look to build my first amplifier.
I need to start at the very beginning Ian.I’ve been practicing soldering for a while but that’s about it ! so what would you say is the "basics" of electroincs.Tools that I've got is a Solder Iron (maplins) and a Digital Multimeter (which I've used to test batteries).Where to start is really to take stock of where you are now with your understanding of basic electronics, audio circuits, components and construction materials. That gives you a path of learning by study and reading threads about interesting topics and following up with questions, however dumb, to get a grasp on what your next course of action should be as you plan your first project. You have to enjoy that experience to want to continue so I suggest making it a simple and sure-fire one that will sound great too. Yes, a chipamp.
I really do appreciate the time and effort you're putting in to help.I will try not to burden you to much and I understand if you haven't the time to go into great detail,just point me in the right direction and I'll do my best not to get lost
.Thats an interesting view that I haven't come across and haven't really thought about.So how do we know we are hearing distortion .I've often wondered how come I can enjoy the sound from some systems for lot longer than others, is this because of less distortion or am I taking nonsense.
All the best
Dean
Distortion is a strange thing because certain types can actually sound pleasing to the ear. What seems to be important in the way an amplifier sounds is the spread of harmonics (the 2nd, the 3rd and so on) and the amplitudes in relation to the fundamental frequency.
Amplifiers like the Sansui, because of its circuit topology tend to emphasise the even harmonics, or lets say the even harmonics can predominate... although there is more to it than just that.
This is where the huge debate over amplifier sound comes in. Some designers push for ever lower distortion in the belief that the amplifier must be better, and to their requirements it is. Just as valid an argument and design is the amplifier that actually sounds wonderful to listen too, the amplifier that has the uncanny knack of making 90% of recordings sound good, not just a few.
Different objectives and goals and no one is right or wrong.
Amplifiers like the Sansui, because of its circuit topology tend to emphasise the even harmonics, or lets say the even harmonics can predominate... although there is more to it than just that.
This is where the huge debate over amplifier sound comes in. Some designers push for ever lower distortion in the belief that the amplifier must be better, and to their requirements it is. Just as valid an argument and design is the amplifier that actually sounds wonderful to listen too, the amplifier that has the uncanny knack of making 90% of recordings sound good, not just a few.
Different objectives and goals and no one is right or wrong.
I think Mooly has nailed the value of distortion in domestic audio there. Things are different in the professional audio world but we often now use amplifiers as the means to add selected distortion, simply because it works so well in some manufacturers' products where other means don't seem to - to the best of my knowledge anyway. It seems strange to say this but it is the particular mix of harmonics we hear as individuals that can enhance many sound qualities, even the "sound stage" or the definition and apparent dimensions of the stereo image.
Effects like this were probably a serendipitous sound quality of some early solid state brands that grew into a carefully guarded black art over the years, some manufacturers sticking to the same designs they found popular, decades ago. To this day, there are high-end products with unspectacular distortion figures, traded off for sound quality, even where it would be feasible at very little cost to build products with 10x better specs.
Re basic electronics. There are stacks of titles on this general subject for schools, higher education and general interest too. However, member rode has a comprehensive website offering DIY projects, articles and audio electronics instruction at the next, or hands-on level. This is a very popular site with many DIYaudio members getting inspiration and a little education there. It is a big site with many articles (see the one on amplifier sound), construction notes, PCB sales, forum and links to a basic audio electronics course too. Have a look: http://sound.westhost.com/
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Oops - It seems the basic course association with ESP has changed - links to this site must have been dropped recently. Anyway, here it is. An advantage of the Lenard pages, is that they are written by a long experienced amplifier and music systems manufacturer, designer, consultant and acknowledged audio expert. They are written expressly in layman's terms so they can be used to train staff in the basics or simply for others to get a better grasp of the subject. Hope you enjoy them as an interesting primer at least.
Hi Mooly & Ian
Once again I appreciate you both taking the time to enlighten me and express your views on the possibly reasons why Hi-Fi equipment sounds different to others.
You’ve opened my mind and encouraged me to think more out of the box.
I think building my own would suit me because I have a desire to now what makes it tick and I can also configure it to the way I would want it to sound.
I guess I’ve been a bit of a sucker over the years believing the hype around Hi-Fi products, I’ve chased my tail for far to long. Being skint has definitely made me think a lot harder about what I want from my Hi-Fi.
We’ve had chance to listen to the Sansui Integrated phono stage compared to a Project one, and I must say we were pleasantly surprised how good the Sansui was. In my friends system it bettered the Project, the sound was fuller, and each instrument had it’s own character ,the music flowed much better than the Project, the Project was dry and cold, sounding flat and lifeless. Perhaps the project is a poor example? it cost around £50. plus you need some interconnect cable.
We really couldn’t see (hear) any benefit in using the Project phono stage. The Sansui equaled it in terms of detail retrieval and had a much more musical approach for us.
The System.
Technics 120 Turntable,Jelco Tonearm and a Grado Gold cartridge on wooden DIY supports.
Acoustic Research 22 speakers on wooden DIY stands. Bedroom dimensions 10x15ft suspended wooden floor, lots of soft furnishings.
Off to look at that link now Thanks Ian
All the best
Dean
Once again I appreciate you both taking the time to enlighten me and express your views on the possibly reasons why Hi-Fi equipment sounds different to others.
You’ve opened my mind and encouraged me to think more out of the box.
I think building my own would suit me because I have a desire to now what makes it tick and I can also configure it to the way I would want it to sound.
I guess I’ve been a bit of a sucker over the years believing the hype around Hi-Fi products, I’ve chased my tail for far to long. Being skint has definitely made me think a lot harder about what I want from my Hi-Fi.
We’ve had chance to listen to the Sansui Integrated phono stage compared to a Project one, and I must say we were pleasantly surprised how good the Sansui was. In my friends system it bettered the Project, the sound was fuller, and each instrument had it’s own character ,the music flowed much better than the Project, the Project was dry and cold, sounding flat and lifeless. Perhaps the project is a poor example? it cost around £50. plus you need some interconnect cable.
We really couldn’t see (hear) any benefit in using the Project phono stage. The Sansui equaled it in terms of detail retrieval and had a much more musical approach for us.
The System.
Technics 120 Turntable,Jelco Tonearm and a Grado Gold cartridge on wooden DIY supports.
Acoustic Research 22 speakers on wooden DIY stands. Bedroom dimensions 10x15ft suspended wooden floor, lots of soft furnishings.
Off to look at that link now Thanks Ian
All the best
Dean
What an interesting, though half-expected result. If you consider the already high distortion spec. of <0.8% for the amplifier, rising to probably > 1.5% at your actual use levels with phono input, in its present 45 year old condition it will be giving very different results to later equipment. That's not right or wrong, but even with the same studio master tape, a digital reproduction system would play as totally different - yes, relatively flat and lifeless.
The difference is the distortion and noise - no question. Many, particularly technically driven folks, come to believe as a maxim that anything added to the signal is unacceptable, however desirable for those who like it. Some actually like the imperfections and at my age I'm starting to see more value in this too, as my ears continue to taper off in HF response and some extra harmonic content helps to redefine the separation of sources in the music and add a little more edge to instruments and voices. I don't think tone controls help much in this area.
That's not to say any or all distortion is good but a deft hand and long experience at "voicing" amplifiers can produce startling high-end results, worth big money indeed to eager buyers.
I'll change what I said earlier and suggest you consider a design by John Linsley Hood from Wireless World, popular around the globe now as simply JLH '69, since there was an updated version in '96. Its a class A design and so burns an amp or 2 off as heat - not always popular in Oz where I'm typing in 36 degree heat. I should think it would be welcome though, this season in Wales.
Good points: compact, more than 1 cheap kit of parts available on the Bay, plenty of old threads discussing newb and experienced DIY builds, kitbashing and mods here. Output power: around 10W/8R. Many folks really like this one and though likely without trying much else, are quite content to live with it.
Bad ones: It runs constantly hot, so needs a fair sized heatsink (see pics and kit details) It has quite distinctive rich distortion that is at once attractive but to some, over-rich. Best with a quality, low noise power supply. Not great with low impedance (4-6R) speakers.
Case, heatsink & power supply are down to the builder, being by far the most expensive parts of any DIY. The common electronic components used are now cheap jellybeans on a dinky little PCB, so what you think is a bargain kit is just the core, like the CPU in your computer.
All said, this may be a modest device but building is more than an evening's entertainment. I haven't done it myself but watched and listened to the results of 2 young friends who have and was quite staggered by the rich-sounding and lively little amp with its sluggish old transistors, just "as-built". A few additions and teaks later, they are a step closer to being really nice sounding amps. Check them out and dig up any JLH 69 threads here. This is the big one - still going since 2002: http://www.diyaudio.com/forums/solid-state/3075-jlh-10-watt-class-amplifier.html
Hi Ian,
I know its silly but I feel a little uneasy about liking something due its distortion, but it seems that’s exactly why I prefer the Sansui
I’ve always considered myself as an analytical kind of person and someone who strives to be as accurate as possible .So this kind of thing turns my perception of oneself on it’s head
It appears that I don’t require the analytical approach to enjoy my music! Perhaps I’m not as analytical as I thought (here I go analyzing myself)
If I where to make a comparison with vision, I would say that the Sansui is more like a Plasma TV compared to LCD TV .The LCD is bright and sharp with plenty of detail, were as the Plasma is smoother and richer in contrast. Technically, maybe the Sony is more accurate? but I enjoy the Plasma more
I’m not saying the Sansui is the b-all and end-all, it might even sound different in another system or to someone else, but for us it’s positives out weigh it’s negatives and if that’s because it’s got more distortion then so be it .
What I do find, is that most Hi-Fi equipment that I’ve listen to sounds tonally too bright .I’ve also found tone controls useless , I don’t find them of any use on the Sansui or any other piece of Hi-Fi equipment that I’ve listen to.
I’ll definitely look-up John Linsley Hood. I’ve heard class A amplifiers in the past (Sugden,Pass labs,Musical Fidelity) and enjoyed their presentation apart from the bass, which I found overly rich .
Thank you once again Ian for taking an interest and contributing so much.
I think the first thing I’m going to tackle is to replace the capacitors in the Sansui and fit the new switch.
Should I open a new thread on this, because I have a few question .
All the Best
Dean
I know its silly but I feel a little uneasy about liking something due its distortion, but it seems that’s exactly why I prefer the Sansui
I’ve always considered myself as an analytical kind of person and someone who strives to be as accurate as possible .So this kind of thing turns my perception of oneself on it’s head
It appears that I don’t require the analytical approach to enjoy my music! Perhaps I’m not as analytical as I thought (here I go analyzing myself
)If I where to make a comparison with vision, I would say that the Sansui is more like a Plasma TV compared to LCD TV .The LCD is bright and sharp with plenty of detail, were as the Plasma is smoother and richer in contrast. Technically, maybe the Sony is more accurate? but I enjoy the Plasma more
I’m not saying the Sansui is the b-all and end-all, it might even sound different in another system or to someone else, but for us it’s positives out weigh it’s negatives and if that’s because it’s got more distortion then so be it .
That wouldn’t really apply to me, I hear things very well and the last (1yr ago) pure tone audiometry tests and AOAE / AABR I had were spot on.
What I do find, is that most Hi-Fi equipment that I’ve listen to sounds tonally too bright .I’ve also found tone controls useless , I don’t find them of any use on the Sansui or any other piece of Hi-Fi equipment that I’ve listen to.
I’ll definitely look-up John Linsley Hood. I’ve heard class A amplifiers in the past (Sugden,Pass labs,Musical Fidelity) and enjoyed their presentation apart from the bass, which I found overly rich .
Thank you once again Ian for taking an interest and contributing so much.
I think the first thing I’m going to tackle is to replace the capacitors in the Sansui and fit the new switch.
Should I open a new thread on this, because I have a few question .
All the Best
Dean
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If you start a new thread put a link too it from here
The Sansui is more like Sony CRT than plasma Have you ever seen standard UK Freeview on a large CRT screen set. It wipes the floor with plasma and LCD precisely because of the imperfections of the CRT (slow response and phosphor persistence).
I've been in the same position with audio. Convincing myself that because I have the "best" technically it must be the best sonically. I fell into that trap for many years convincing myself that it had to be the recordings at fault or whatever.
If you genuinely like the Sansui (and I believe you do) then that simply shows you know the kind of sound you like.
The Sansui is more like Sony CRT than plasma
Have you ever seen standard UK Freeview on a large CRT screen set. It wipes the floor with plasma and LCD precisely because of the imperfections of the CRT (slow response and phosphor persistence).I've been in the same position with audio. Convincing myself that because I have the "best" technically it must be the best sonically. I fell into that trap for many years convincing myself that it had to be the recordings at fault or whatever.
If you genuinely like the Sansui (and I believe you do) then that simply shows you know the kind of sound you like.
Hi Mooly
I’m satisfied with the Freeview picture on my Plasma Tv (maybe not as good as CRT) ,but its better than my mates Sony LCD Tv and it gives me enough pleasure with HD (720p).but to be honest I don’t really watch that much Tv and when I do it’s in HD.
The problem for me was I could easily pick-up on the extra detail or the different presentation with a new system or component but it wasn’t necessarily better , just different .The Hi-Fi specialist would say “don’t bring your own records, they are not well enough recorded to hear the differences” what a load of crock!
I’m trying to be more honest with myself these days and not be led by people who think they know better in what “I” want to hear, and want I want is a sound that just gets on with playing “my” music and not something that dissects and tears it apart into bits for me to analyze and condemn .
If I can, I would really like to build my own low powered amplifier one day but in the mean time, I’m still on the hunt for that cheap low powered amplifier to match my speakers.
All the best
Dean
OK,I'll have a go.
I’ve seen standard Freeview Tv on a CRT, but not on a particularly large screen (29 inch Sony) or with HD free view, I had no complaints with the picture. I've still got a portable CRT working with Freeview and the picture is fine. Where I live, we can only receive a handful of channels from Freeview and no HD , the only option for more channels is Sky or Freesat (which is what I use).The Sansui is more like Sony CRT than plasma
I’m satisfied with the Freeview picture on my Plasma Tv (maybe not as good as CRT) ,but its better than my mates Sony LCD Tv and it gives me enough pleasure with HD (720p).but to be honest I don’t really watch that much Tv and when I do it’s in HD.
So I guess the “imperfections” are not always negative.
Choosing Hi-Fi equipment over the years have been a minefield, I never really found what I wanted, just chased my tail for a very long time and spent way too much money.
The problem for me was I could easily pick-up on the extra detail or the different presentation with a new system or component but it wasn’t necessarily better , just different .The Hi-Fi specialist would say “don’t bring your own records, they are not well enough recorded to hear the differences” what a load of crock!
I’m trying to be more honest with myself these days and not be led by people who think they know better in what “I” want to hear, and want I want is a sound that just gets on with playing “my” music and not something that dissects and tears it apart into bits for me to analyze and condemn .
Mooly,I do like the Sansui Au101 and probably more than most amps I’ve heard but I’ve found that it sounds better in my mates house/system than mine. I’m not to concerned because he’s enjoying it and I can use it as a learning project which would benefit the both of us. The reason I purchased it because I was looking for a low powered amplifier to go with my speakers (Goodmans Magnum K 1965 vintage ) which are ridiculously sensitive and go really loud from a handful of watts? I found the Sansui still had to much power, I could barely turn the volume up past the first notch! I don’t know if Sansui made lower powered amplifier than this one, but I’m going to do some research into it.
If I can, I would really like to build my own low powered amplifier one day but in the mean time, I’m still on the hunt for that cheap low powered amplifier to match my speakers.
All the best
Dean
So you like the Sansui
We would never have guessed Barely turning the volume up and it being to loud isn't actually a "power issue" or having to much power as such, what I think is happening is that you are using the Sansui with modern source components such as CD, DAB etc and these put out far more signal than the older "din" standard of years ago. You are simply feeding to much into it so that all the action on the volume range is over the first few degrees of rotation. What you need are some simple input attenuators (which can probably be built into the amp if you wish)
Not especially cheap but Nelson Pass has a few small and "interesting" amplifier designs with many fans on the Pass DIY forum. The distortion runs very high on some basic class A designs - up to valve amplifier levels - but there are few complaints and lots of devotees.
Thanks Ian.one to think about
Hi Mooly
It's definitely louder with the CD-player than with the Phono (turntable) but it's still too much.I've borrowed some "input attenuators" but found that I lost some transparency and the cost of them (if they worked!) would have been £39 and I've seen some for £100
.As you have suggested I could build them into the amp and just take them out if I don't like them. What sort of component would I use for attenuation ( a variable resistor
) and what value would I need.The Sansui 101 is still with my friend who's enjoying it so much that I can't get it off him to replace the capacitors
.I've sold the Arcam amplifier (which I swapped him for
) and picked-up an old NVA A20 for £25 .I was told that it is low powered and would work well with the Goodmans,It's a completely different sound from the Sansui, if I were to make an analogy I would say the Sansui is like a " Brazilian carnival" (colourful and exuberant) and the NVA is more like a "British military parade" (Precise and organised ) I'm not sure if I like or hate it at the moment Oh,and there is a low level "buzz / hum" coming from both channels -should I be concerned?.It hasn't got a phono input so I need to buy a separate phono stage.I tried the previous "project" one but I didn't like it,sounded really bland.Any suggestions / comments would be most welcome
Thanks once again for your all your help
All the best
Dean
PS please excuse my late reply (been feeling poorly).
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Sorry to hear you've not been so good...
Attenuators. A preset is fine for initially finding the best value (best for overall volume level) but its not essential. All you do is add a series resistor in line with the CD input, preferably at the sockets themselves. If the sockets are PCB mounted then it should be possible to cut the print with a knife to put a break in it, and bridge that break with a resistor. That's only half the attenuator. You then add a second resistor from ground (use the socket ground) to the "amplifier" side of the first resistor. Values... best kept lowish, I would suggest 15k or thereabouts for the series element and then whatever value works best for you for the one to ground. If you used 15k for that too then you cut the level in half and so on. I bet it would be somewhere in the 4 to 8k range that would give you the level you need in practice.
The amp that hums and buzzes. Try it with no inputs connected. If its still present then its a problem with the amp (or just the way it is). If it only hums when connected to a source then it could be a ground loop via multiple ground connections through mains leads.
Attenuators. A preset is fine for initially finding the best value (best for overall volume level) but its not essential. All you do is add a series resistor in line with the CD input, preferably at the sockets themselves. If the sockets are PCB mounted then it should be possible to cut the print with a knife to put a break in it, and bridge that break with a resistor. That's only half the attenuator. You then add a second resistor from ground (use the socket ground) to the "amplifier" side of the first resistor. Values... best kept lowish, I would suggest 15k or thereabouts for the series element and then whatever value works best for you for the one to ground. If you used 15k for that too then you cut the level in half and so on. I bet it would be somewhere in the 4 to 8k range that would give you the level you need in practice.
The amp that hums and buzzes. Try it with no inputs connected. If its still present then its a problem with the amp (or just the way it is). If it only hums when connected to a source then it could be a ground loop via multiple ground connections through mains leads.
Thanks Mooly
I think that's within my capability.I'll have a good study of the layout if I decide to keep the NVA, but if not, I can still see me applying attenuation to whatever amplifier I end up with due to the sensitivity of the speakers!.
I've just disconnected everything from the amplifier and the buzz is still present (actually louder in the right channel ) so what would make it buzz (the Sansui was dead quite ) .I'll try it at my friends house and report back.
Thanks again for your help
Cheers
Dean
I think that's within my capability.I'll have a good study of the layout if I decide to keep the NVA, but if not, I can still see me applying attenuation to whatever amplifier I end up with due to the sensitivity of the speakers!.
I've just disconnected everything from the amplifier and the buzz is still present (actually louder in the right channel ) so what would make it buzz (the Sansui was dead quite ) .I'll try it at my friends house and report back.
Thanks again for your help
Cheers
Dean
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