dacboy

The Sennheiser HD201-203 series look good but I don't know where to get them locally and price. Tried Amazon but they don't ship to Singapore. Any other options?

 

For Sennheiser,there is a shop on the third floor of Sim Lim Square to the left in front of the

escalator.Sorry I can't remember the name.

hahaha i see

so its no good?

 

sooo... what do you suggest? right now im just looking for an amp first

 

i would like to go test the amps out but i wanna narrow my field first..

HI fir3dp,

You are the boss my friend and by the time you set up a good system

you would have spent a considerable amount of money.Well if money you must spend then

spend it on something that do the job.Since PC sound is what you most listen to ,

Creative EMU 0404 midi interface

It is USB 2.0 and has a headphone output meaning builtin opamp but the power supply is switchmode

so not exactly audiophile standard.To really experience what is high resolution 24/192khz. digital audio.

Of course you will need the required software like flac and what is described in the advanced mod below.

However for advanced modders you can upgrade to audiophile standard here

Which I think you are not up to it so don't attempt it but may give you ideas to improve?

You can go down to Creative's showroom in Jurong east and have a look. regards.

I am not answering your query but I would recommend you look at amps with built in USB DAC, unless you have budgeted for a standalone DAC. If listening to computers, a good DAC is worth the money.

 

Regards

Hi, Unfortunately the Common PCM290X chips by TI/BB or other brands implement a cheap solution

so you are back to square one.Manufacturers go for lowest cost ,highest profit margin and easy

trouble free design in fact they just use TI recommened circuit. A separate usb interface with a standalone

DAC ic is better but I have not seen any on the market. . regards.

BTW the X can ver8 sports a PCM2706 so you are really back to square one and it has a tube buffer.

like I said they slap on a cheap solution ,add a tube buffer and brand label and charge a hefty

profit for it.That's Musical Fedelity UK style. Hey it's your money. cheers.

Hi , By the way there are some help or readme files in english in the main directory after installtion of VA.

I have since discovered that if you use 16 bit sound card like soundblaster live,in the settings tab, device tab

you can select your soundcard and increase the spectrum analyser bandwith with 96khz. sampling to get 40Khz.

but if you use 24/196khz. soundcard you can get 93khz. as Nyquist theorem states that half of sampling

frequency is possible.

I have notice my soundblaster live card shows soundcard noise to average around -120db.I was hoping

to make it lower or cleaner as the peaks are all over the place.Apart from using better caps I don't think

I can't do much because it is troublesome.

regards.

I'm interested to know on real life test, how much improvement on the sound quality, using Walter Jung super regulator compares to common regulator such as LM317.

 

Have you ever test them?

 

Thanks for the nice article!

Hi bribadi,

I have not built the jung super regulator as you know the people who help

to implement it at diyaudio is very protective of it's IP ( interlectual property) of the circuit

but as you know one cannot copyright a circuit so it is in public domain so to speak.Nonetheless jung

had some clever tricks done.On paper the design is easy but when you want to make it there are a number

of obstacles such as the components used like LM329 which by now could be obsolete or NS only makes it

as a 6.8v voltage reference is not commonly used nowadays though you can still find it in electronic catalogs.

The last revision was in 2000.Looks like it's largely "forgotten" and the following paragraph may reveal the "difficulty".

If you try to substitute the original components or change values you may get an unstable circuit.

so this is a major hurdle as I see it.I am trying to find a less complicated solution of course with not as good

performance as jung super regulator but still serve a purpose in high end audio like a MC phono stage.The Lm49990

can be a part of the solution.By the way the jung super reg does use a LM317 as preregulator to inprove performance in a floating arrangement.

Regards.

Hi,

This is only my opinion.

Are you sure there are no reviews diferenciating between DT880 models? Or are you an audio virgin?

Well to be fair I can't blame you but you have to learn your craft or else you will be conned through

and through or as they say the sharks will rip your clothes off.By the way I'm not a guru but I'm

knowledgable enough to give you some advice or tips?

First look at DT880 frequency response http://www.headphone.com/headphone/beyerdynamic-dt-880.php

In speaker design you try to achieve a flat frequency response in order to say it will reproduce

all frequencies at the same amplitude or level which make it sound neutral.But in real life it is not but you still

try and look at DT880 a hump at the mid frequency (voice) where your ears are most sensitive ,a dip from 1khz to 5khz and jagged peaks at the high frequencies at around 10khz.This will mean the highs are over emphasized and will sound bright.

You have to be knowlegable and read between the lines of reviews.Although the reviewer's job is to sell

the product but some reviewer does not want to betray his own conscience so he puts it in a diplomatic way

in order to appear that he sides the product but is also telling the truth in an oblique way. See the 6 moons review of DT880. http://www.6moons.com/audioreviews/beyer/dt880.html

Here 6 moons say DT880 is bright and the highs are "noticeable" and is not as neutal

in true audiophile fashion.Mind you it is advertised as a studio monitor headphone and as a recording

engineer you would want a neutral one to do mixing and mastering.

I'm not too sure about the product development stages and timeline but it appears that DDT880 pro was introduced in 2005 and the impedanced was and still is 250 ohm.Lately there is a 600 ohm version.I wonder if

there is a 32 ohm version as this is a "high end" one.As to the different models... Pro,consumer they are just cosmetics.Although there is a difference being that the first DT880 of 2005 is a close back one where else the 2008

DT880 I think is stated as semi closed .

All this diversion and you will notice Beyer nor anyone talks about the star which is the driver in the headphone.

Makes you wonder does'nt it? Are they all the same? well if to look at DT880 frequency response the plot is of a

raw driver or in the enclosure, there could be no equalisation added (filter) and that's how most headphone drivers are so it boils down to housing or enclosure to makeup for the deficiency in actual frequency response or sound.

Ultimately you are the one who decides if you prefer the coloured sound or a neutral one.

There is no right or wrong you are paying for it but convention and scientific way is a flat response so that

others can be judged at the same criteria or standard.Hope this helps.

http://www.testfreaks.com/headphones-heads...amic-dt-880-pro

Hi chknbll,

This is only my opinion basing on science and experience.Many audio virgins think that

what is missing in sound quality is the price tag of a pair of headphones,more cost equals quality and technology.Because of business and marketing the truth is actually ignored and suppressed to impress

the gullible.Research has been done long ago and the facts established,you can search online or buy

books that talk about headphones or speakers and transducers as such.

Does that mean all is known about the science of headphones/ hearing? Well research cost money

and it depends whether a company wants to stay ahead of the game.Currently the main components which

is the transducer or "speaker" which technically what it is are standard ,the big ones (40mm) and the tiny in ear buds.So the difference between them is the quality of maufacture,materials used (magnet material) and cosmetics

or the packaging that give the impression of quality and luxury.

I don't want to talk about the earbuds because in reality one cannot expect the optimum

sound quality due to it's tiny size.Now let's come back to the big ones with 40mm diameter transducers

or "speakers".In general they have a thin sheet of plastic (mylar) over the magnetic driver or in speaker

terms the plastic sheet is the cone and magnet assembly, the voice coil and magnet.So it all boils down to construction or build quality and type of magnet.The cheap ones use ferite material,ferites are not metalic but have

electromagnetic properties,in essence they behave like magnets have north and south polarities.They better ones

are made or rare earth elements,I'm sure you have heard it in the news about rare earth material/supplies

allegedly being controlled by main producer China that made Japan look towards exploiting/finding rare earth

elements in their own backyard so to speak.Rare earth elements are the over 20 types of elements that you

learn in basic chemistry and it is the mastery and technological use of them to make things that basic metal

or iron/steel alone cannot possibly make a modern car engine for instance.

The better transducers have what is commonly termed neodenium magnets what that means

is that the magnet material contains neodenium which is one of the rare earth elements.See how important

they become to headphone people? You may have heard of alinico magnets in conventional speakers

of old.The basic advantage of these magnets is that they have what is commonly known as high magnetic

flux or power to push or drive the cones that is to vibrate thus having greater efficiency and therefore

improved sound output.Alinico magnets contain alluminium,nickel and COBALT which is also a rare earth

element of which the USA has designated as STRATEGIC RESOURCE so it controls worldwide the stockpile

of rare earth elements.You may like to know that cobalt is used in steel making, imagine steel

plates for battleships and armour piercing artilery shells. It can make many "useful" things.

Why is it called rare earth? Well because it is rare or not commonly found and the quantities

are small or less in the earth as a whole.Nobody calls iron rare only diamonds which you know as rare

and expensive. Our housing prices are increasing not because they are rare but controlled, an

artificial lack or "rare" if you like.It's basic economics of supply/demand and greedy people take advantage of it.

That's how the world works.

Back to topic The construction and housing play an important role in the sound quality.

You may notice that some housing are half dome and fully enclosed that is there are no holes or openings.

Now these can have boomy base as the enclosure behaves like a resonating chamber as everything in

this 3D world or universe resonates or vibrate like electromagnetic energy.Then there's the open back

type or hear through ones which don't have a cavity or less of it behind the transducer.So open types

sound "open" unrestricted feel airy.

The rest of the construction is mainly ergonomic that is it follows the contour of the human

anatomy in the case the part surrounding the ears and head for comfort and efficiency.The exterior

cosmetics like syntethic leather trim and chrome/gold plating make you think there is a high tech transducer

in there when like putting spoilers on commercial stock cars don't make them a Lotus or Ferrari sports

car.

Now come the most important info when it comes to audio.Since you say that it is the laptop

or PC that you listen to ,everybody and now's the time for you to know that the PC is a noisy environment

when it comes to signal to noise ratio.What that means is that the PC was never intended as the ideal

piece of equipment to use as an audio device.What with noise radiation from 50 hertz AC supply to

gigahertz digital signals floating around literally.But of course the marketing people say humans cannot

hear beyond 20 Khz. so that shouldn't bother you but research has shown that higher frequency

signals as high as 200Khz. can be felt by humans thereby giving the sensation of a fuller sound.

Check the Stereophile magazine archives for the article.So in short there is more than a good pair

of headphones for you to start enjoying music as the whole is the sum of it's parts.

Remember this and you can make your way to audio nirvana.

Good luck.

Hi all,

I came across this free and powerful PC scope and spectrum analyser with a new ZRLC meter.

As you know a RLC is a Resistance, Inductance and Capaitance meter in addition it can also measure

impedance.Although mesuring range is conservative but good enough for general use. If it was me I'll

add a speaker testing and design module and it will become a killer application yes?

Alfredo Accattatis an Italian PHD holder said he could have comercialised ver.2010 next 2.4 but

decided not to because he has a passion for electronics and heart for diy audio hobbists.

I loaded the beta 2011 version to see what is latest you may download the more stable ver2010 next 2.4.

But I still think using beta 2011 ( I am adventurous) and if you give feedback he may do something about it in his SPARE time.He has to work for a living and it's free so don't complain.

Documentation is minimal but it's intuative but he is compiling a manual so be patient as

most of the help screen are blank.So you need to be familiar with electronics,instrumention and

digital signal processing.But if you are a newbie this is a good time to learn and he has a forum to

ask questions or help.But remember they are Italians not english speaking people so there may

be something lost in translation.

WARNING If you are using your fancy notebook PC,it is not recommended as most

soundcard inputs can only take 1 - 5 volts maximum and you risk frying the sound chip or

expensive soundcard. Like tube circuits with high DC/AC voltage.

Better to use ( old ) desktop PC with a decent soundcard like Creative soundblaster or

newer models.If you use standard 16 bit soundcard you will get 20 khz. bandwitdh which is sufficient

for audio ( 20 -20khz.)But if you have 24 bit /192k soundcard then you get about 100khz. which is better.

What you need is a soundcard interface as an attentuator and level setting with buffer because

there are long cables etc.Although you can calibrate it in soundcard (software) it may not be easy.There is also a ZRLC interface articles but they are in italian but the circuit schematics are easily understood by electronic hobbist like yourself.

Alternatively a cheap digital multimeter can be easier?

Visual Analyser download- http://www.sillanumsoft.org/download.htm

Edit: Download Translated VA doc. by diyaudio member of VA thread on pg.6--

http://www.diyaudio.com/forums/software-to...cr-meter-6.html

PC soundcard interface- http://www.pmillet.com/ATEST.htm

PS the soundcard interface is not cheap because of the true RMS converter ic AD536 so may you can omitt it

and use multimeter( not true RMS unless buy more expensive one) but if you are an advanced hobbist you may prefer the convenience.

Have fun.

Hi all,

Just saw this yesterday and thought you might like something new to do

for 2011. Well this is just a standard hookup of an instrumentation amp ( 3 opamps-LME49990) and

a high current buffer LME49600.Now these are National Semiconductors new line of high performane

opamps designed for audio as most opamps are for industrial uses.

The thread in diyaudio -

http://www.diyaudio.com/forums/headphone/1...ifier-pcbs.html

He is offering 2 channel amp pcb + power supply at US or CAN $20 combo only and partial kit at $98 but may

go down as more people join in.But I think you can save a little if you source locally but if you don't want

the hassle he says he's not doing at cost as last group buy he made a loss .

Anyway I checked Farnell singapore ( they now renamed their site- 14 elements sg)

PS. The pcb is smt (surface mount technology) so may be tricky for some people.

LME49990 - $7.21 you need 3/channel total= 6

LME49600 - $13.70 at 1/channel total=2 subtotal = $70.66 before GST.

Edit- Sorry,mistake in calculation ,now show correct amount.

Looks like you may really save if you add $20 pcb + smt resistors + caps.

You can do the math and it's not a cheap project.If I had my way I'll not use instrumentaion style circuit

but modify the 3 opamps and connect them in parallel by doing so you lower the noise level like Nelson

Pass' Pearl2 phono amp.He parallels 4 jfets so that will get 6db reduction of noise level theoreticallly.

But bear in mind if you modify the amp it may not be stable so there's the catch.

I will not use the supplied generic power supply but make a Walter Jung super regulator instead and that will

move this amp in the real very high performance level also theoretical.

Super regulator links: the most recent is the 2000 version.Be careful with the part selection ,use the recommended

ones like PN2907 and not 2N2907 and LM329 voltage reference.If you can't get LM329 then use

a 6.8 zener(noisy) or series other voltage ref. but costly,then of course there are cheaper alternatives.

Edit- wrong part number X 2709 X previous.

Super regulator is a challenge to construct from what I've read,if you are not up to it then stay with conventional type.Which is based on the same principle except with regards the refinements and complexity.

http://waltjung.org/Regs.html

There's one easy to read page titled opamp regulators ,see if you can search it.

So just see the pics and test results made with a Audio Precision test setup.Quite impressive.

But then again despite the claims I cannot vouch for the sound quality as it varies with individual's

taste and experience.

Welcome 2011. Cheers.

So does it mean I have to be docile and impotent? Can't related my experiences? lol

I didn't come here to market, just felt bored and came in to share.

Assuming you have a full time job and running an online audio shop and say you are bored

and you want to share? Try sharing cheer and goodwill instead of sarcasm.

Edit: You have your online shop and blog where you can share to your heart's content.

Quite a lame excuse don't you think? http://audiohub.com.sg/blog-entries/a-new-home/

However since you did mention about being a billboard, i shall keep up with your impression of me -

 

Please remember that what you put in writing here is "forever".Who is being juvenile?

Don't need to para-phase "claim", you can see it for yourself.

One man biasing and QCing about 10-15 amps a day.

 

Real world application seldom uses text book answers, things need to get done as they are required.

Didn't you learn that in the army?

 

I've seen far worst practices as sailing in the navy going to foreign ports.. dock workers actually jumping off the pier; stepping on the fenders without life jacket and it's a 4-5 meter drop into the sea inbtwn the ship side and the dock.

 

The monos are 300b/845ABSE - 100 watt monos with 1k volts running thru them.

 

http://audiohub.com.sg/pictures-gallery/an...-zhuhai-part-1/

 

you can view more pictures here.

 

But seriously, troll harder.. the scarasm over the "kind comments"...juvenile and utterly nonsense.

You seem to be an intelligent person but your ego is getting the better of you.

EDit: Yes theory is just theory and real life is what you said but bear in mind that this real world

don't care what's really happening when something bad occurs they want some "heads to roll"

or take "responsibility".Scapegoat in short.so if you say ,they did this all by themselves (free will) and

that's life or karma is not going to go well with the authorities.They only see only 3D realities,not philosophy

or quantum physics.

Only I'm allowed to touch the products, there is a big sign printed at the bottom - authorized personal personnel only.

 

However I can't stop them from trying, can I?

 

Just joking -

Most customers become my friends, they'll consult me first prior to them actually having to stick their fingers into it.

Do you think your customers will consult you if you say irresponsible things?

The moderator has taken notice of you and in fact this forum has the proper section (Announcements/offers)

for people like you to market your products but it is not enough for you that you have to"stick it in the face"

so to speak here.Have you no morals or ethics?

I shall not comment and indulge you any further.

Happy and prosperous new year to all.

Actually it'll just give a very nasty shock.

 

I was at the mingda factory where the technican was pulling out hot tubes with his bare fingers and poking around the mono blocks with his bare hands while it was on.

 

Not that I have been shocked before but I think I can trust a person who does it for 6 days a week for the past 3-4 years.

Hi ,

It is obvious to people that what you are doing is "bill board" advertising with the attempt

at replying to posts and not being helpful.If you visit tube diy sites at the begining or end of the article

there is always a disclaimer alluding or warning that high DC/AC voltages is present and to avoid serious

injury to your own person or equipment.Now this is to avoid being sued in the event that anyone who attempts

such a project have been warned or advised and a reminder of the potential risks incured.As the saying goes

"fools rush in where angels fear to thread". Imagine, heart defilibrators used in emergency hospitals are a few

thousand volts to jump start a dead heart.What do you think it will do to a live,pumping heart?

As to your revelation at Mingda factory claims that the technician pulls out tubes while it is still

powered may indicate he is trying to locate a fault.I can assure you that is bad practice as most people who

work with tubes and have read enough of tube/valve design books will point out real life examples of such

actions that with certain circuit configuration can lead to excessive voltage to tubes that

will lead to damage. Good way is power off and then pull out.If you assume this is harmless then it is "blind leading the blind".PS would you like to pull tubes like big transmiting ones like 211,845,805 at around 1000 volts?

Now I do not object to your method of "marketing" for that is human nature but there are

better or effective ways of doing it.Given what you saw at Mingda factory would I want to recommend

people to use Mingda's products? It's like they say "don't go into the kitchen of a restaurent,after that you

don't want to eat there" or "what you don't know will not hurt you".Best practices will always prevail.

If you are operating a real or virtual shop ( online) and is sincere and you want to offer

good and well designed products that are priced fairly, to genuinely have your customers at heart and

not just profit margin then "word of mouth" is more effective than all the advertising in the world.It is the goodwill and trust/love that you engender and attract that is priceless, lasting or of long term benefit.

It is your intentions that count.Try it you will be amazed.

Cheers. Happy and prosperous new year.

Thanks for the heads up!! i've experimented with diy solid state amps, now i wanna move up to tubes and hopefully sounds decent in combo.. xD

Hi,

As a further expansion of the art of audio, here is a presentation by the ETF

( European triode festvial) held every year where tube artists gather and exchange ideas

and do shootouts of tube equipment and present "new" research on all things audio.

http://www.triodefestival.net/index.php?pa...8-presentations

Lecture in 2008 by Menno Van der Veen , a well respected designer of toriodal output

transformers and tube amps and author titled: The philosophy and application of observations.

In it is a scientific explanation of the superiority of single ended amplification vs pushpull.

It's in the low level signal details that single ended amps can "extract" vs pushpull.

By the way his torodial output transformers did not make the final round (etf-2009) which was won

by Audionote UK. So theory is theory but the art is really a black art,you need to read

about the japanese tube masters to have a glimse of the magic, scientific or is it in the mind

or senses? Very philosophical and deep.Low thd specifications of transistor amps is nothing,

there is more unseen/undiscovered factors at work,for instance the human ear hearing is

non linear yet the basis and foundation of electronic design is linear.What have we missed?

Cheers.

anyone knows?

Hi,

Most of the "kits" here are designed in China or Hong Kong i.e.

they are adaptations (meaning they are not carbon copies as some details are omitted like phono,selector and

even the types of tubes used originally ) of copies of well known tube preamps that audiophiles

wish they could own but can't afford as it's use as headphone amp is not as

popular here or asia plus salelability.Nonetheless they can drive a standard headphone.

Just substitute the rca output connectors for headphone 1/4 or 3.5mm ones or include both with a appropriate

switch so you can have it used as standard preamp.But take note that these amps can put out more signal

voltage than what a pair of headphones need....

Koba at Peoples park shopping center 3rd. flr has some pcbs plus parts so

go ask Wee Kok the son of the proprietor for the list of preamps like

Jadis jp200

Marantz M7

Kondo Audionote M7

Audioresearch

Matisse and many more.

Price wise they cost around $38 - $40 each but some like matisse or Marantz M7 include the power supply

section on the board but audionote m7 or jadis jp200 has separate amp and power supply

so I don't know if the price includes both sections to complete the amp.

Many people start off with a Marantz M7 where there are many positive reviews but it uses 2 tubes/channel some

would find the cost of 2 small tubes not attractive as running costs matter but small signal tubes are not that

scarry.

Then there is the design part in terms of sound quality.As tube artists say less is more or if you are a

single ended enthusiast ,by the way all /most preamps are single ended,then the less tube stages the better.

So if you are a novice then a pcb with everything on it may be easy and less mistakes encountered or if you

are more into the fine art of tube sound then separarate pcbs for amp and power supply is the way to go

plus choosing the "right" part as oppose to most expensive or commonly used but good sounding parts don't

come cheap as there is a "audiophile" label attached.

I would recommend the Kondo audionote M7 as it uses only one tube per channel ( 12AY7) which

you can find at Martin at Burlington sq. ground flr. square opposite Sim Lim sq.I don't know if the power supply is

solid state ie. it has silicon diodes or the original design of tube diodes ( 6X4).

For beginers there is the problem of getting a suitable power transformer for your kit as commercially

available ones may not have the exact voltage like the audionote 200 AC volts where at Martin they may

have 250V or 300V as preamp usage.So you need to drop the voltage by using resistors.All in all expect

to spend "substantial" money but if you are knowlegable about transformers you can use off the shelf ones

commonly seen at sim lim tower,of course you real estate or space and weight requirements will increase alot as you may need

to connect them in series or parallel.

Come to think of it you can download the famous audionote M7 circuit (old version use 5687 tube) foc from the net plus tube power supply and wire it point to point which is the "right" way to go instead of pcb, plus tube power supply and with the right parts can kill many commercial store bought ones.Do you know how much a real audionote m7 costs?

There is one compulsory WARNING though as tube amps involve HIGH DC and AC voltages it CAN KILL.

Although this fact is true begginners take the plunge anyway but if you are a tube virgin then get someone

experienced to guide you or do it for you. Good luck.

Hi ,

Googled the Shure e3g, what an exorbitant priced pair of earbuds,even the

pdf broshure does not explain what technology or how it works.So secret that

people believe the marketing.The specs say it is 29 ohm impedance just a little

shy of the standard 32 ohm so this should not pose a problem to any well

designed/proven headphone amp.

Since I believe the Shure e3g is new the wires should be in good condition

so that leads me to suspect the earphone jack on the cmoy or components may have come loose

on the pcb.Check with your multimeter or visual inspection.

Good luck.

Hi Andre,

You are pretty smart with electronics ... what with that software scope...I myself have

not been successful finding one on the net... mostly trial or crippled ones.But I have a 60 Mhz.

scope on hand if I have tough dog problems like this.

Now if I assume your soundcard is or has low noise performance,I'm looking at purely

the 1 Khz. signal then the little wiggles at the top and bottom peaks of the sine wave is evidently

the intermitant noise you hear and it varies from half cycle to cycle.Noise like this may be hard to trace

but from what I mention about the input section of you measuring almost zero volts should tell you

that that part is very suspicous.If I assume the resistors are all correct then my logic will have to

assume Q5/6 may be faulty.Small transistors like that can easily damaged by insert them forcefully

into the pcb,that is making them sit close to the pcb thereby stressing the leads to break from

the silicon chip,the gold wire or maybe copper is very thin.so essentially you have a break but

it may still be in contact with the pad so partial contact is made.

Use your scope to probe Q5/6 one of them may give more distortion and the other one may

see a perfect sinewave.I don't have to tell which one is bad right?

Probe also the jfets 2SK74/SJ70 ...by the way these have stopped production but still availabe

at Sim Lim tower.

I normally assume the opamp is good which most times and seldom give problem.Yes it looks

like it balance out the dc offset.

R16 if you measure 900k ohm in circuit then it's close to the 1 meg value, yes you got it right.

You can use dale resistors which are prefered by audiophiles but double check or measure them before

stuffing into pcb.

You can do it Andre.

I have managed to get some sound on both channel after replacing the output transistors and resoldering all the solder joints. However it is still extremely distorted and intermittent. DC offset on both channels is around 0.5mV. However voltages across the board are still not the voltages they are supposed to be.

 

I am at a loss as to what to do now.

Any DIYer in Singapore looking to do a kind deed/for a challenge?

Hi Andre,

What the heck do you think I'm doing? Actually I've done this kit for a friend

years ago,he said he's not familiar with electronics and it went without a hitch.

Can I assume you have taken the advice of my fist post and confirmed that all

components are accounted for in the schematic vs pcb? If so then all should work as designed.

So you have replaced the BD138/139 and got sound but intermitant and distorted,well something

is still not right other than "replacing" all the transistors one by one which is a valid form of

troubleshooting it is tedious and costly.Don't forget the OPA134 opamp too.Although I don't

suspect faulty capacitors,this calls for injecting a signal and looking it in an osciloscope

which I think you don't have by which you would have gone down that path by now.

Secondly by resoldering all joints you may have overheated a component although

chances are that if you are careful this will not occur.

If I'm not wrong the CK2 designer has put voltage readings in the schematic for checking

and from there you should roughly know where the problem is.The dc offset of 0.5mv is as good as you can get I think.You mean it should be less? (I see it should be in 10uV...a lot less)

What I can say is check for shorts between joints and also for breaks of pcb trace.

Use the meter/buzzer for continuity.

Here is what I can tell from the schematic:

1. The voltage at R8/9 is almost zero when it should be about -3V.

2. Same for R4 when it shoud be 2.7V

This is the small signal section or input please confirm that R1 - R11 are correct in value and R16 is 1megaohm

or 1 million ohms.Check also the copper trace is not broken again with the buzzer or low ohm range @ 200 ohm range.

That's for now. Good luck.

Hi,

Congratulations on picking a commonly viewed machine as well made japanese style.Marantz has

capitalised on the Ken Isihwata name to mount a clever marketing campaign in 2009.This being the

30th year of the famed designer's career at marantz.It has also made a pitch for the younger generation

for PC interface with USB and iPod compatibility.Which in past years of audio cd players were much

lacking although demand was growing,I think it was that the older generation of engineers was not prepared

to fool around noisy pc circuits when the audiophile segment shun such inclusion into their hallowed audio

beliefs but as time went on I guess they have to accept the encroachment into hifi.

Marantz limited 500 pcs of the big brother Pearl KI is mostly distributed to it's resellers to make

consumers salivate over such a cd player when few could afford/ hard to obtain.What with it's solid copper chasis

(did I get it right? or is it still copper plated like the old KI series).But the electronics are still rather

similar.It even says that they put in a low noise power supply for the flouresant display,I wonder

if it makes any difference when all along designers never considered it a problem,could it be they are

running out of ideas to temp consumers?

So with the lite version Marantz came a conquering,the dac is crytal semiconductors flagship

chip CS4398 which have been around for some time.I think it being on the market has garnered a

trust worthy reputation.It's all quite political when you think about it like the english supports the

Wolfson dac and the Chinese put in any one that is the flavour of the month.Of course the US ones

will back their own exports.

I bet the tweakers will have a field day with the KI lite.PS there are some diy dac kits

sporting this chip.

edit: After reading Stereophile's review of the DCS' Scallati cd player combo at US $80K (Sing $104K)

as the saying goes "Imitation is the best form of flattery", it is noteworthy that Marantz in the

Pearl KI cd player also sports similar features like offering 2 types of digital filter instead of 4

by DCS and the low noise power supply for the display.

Cheers.

I'm looking for a cd player (budget below $1200). It's meant to output to my headphone amp (Meier Concerto), driving Beyer DT880 (600 ohm). And I do not wish to use external DAC. My choice of music is classical and jazz vocal music.

 

Sad to say that I've been looking around in Harvey, Best Denki, but nowadays, CD player is limited.

 

Would welcome anyone giving some suggestion.

Tachi.

Hi,

You have a rather generous budget for a audio cd player and I'm surprised you

went to the places quoted above. If I had your budget I'll head to Adelphi shopping center.

You could peruse the common hifi mags or go online to find out. My recomendation is if you are

not brand conscious then your budget could land yourself a MIC (made in China) player with

a tube output buffer. Or to save money get a diy tube DAC.

PS on second thought a vintage VCD play with analog power supply will also do.

Good hunting.

Hi Andre,

Well it happens to the best of us no matter how experienced we are at diy.

From my guess it's rather hard to fail if you're building from a proven/tested circuit board.

At least you have the correct supply voltage of +/- 15V.

If you had followed the silkscreen orientation of the transitors and IC you are half

way there although you could have inserted the wrong type i.e. npn or pnp .So recheck each

location(part number eg. BC 560c) tallys with the schematic.Then come the resistors,I believe they are the 1% metal

film type with 4 colour band ID.If you don't know the clour band code then at least measure them

in circuit although there will be places where they don't measure as coded on their colour band.

Nonetheless it gives a pretty good indication of correct resistor values.If all this tallies then

you have got a working circuit.

So check this for now. Good hunting.

Hi,

Dear friend,as if you don't know the throw away culture here and anyway casette tape has gone the

way of dinosaurs.Though Sony has at that time a professional model it's not that compact.It was mostly

used by serious audio/video people or journalists.The prices then was expensive so don't expect many to

survive the ravages of time.Even if you could find one the rubber belts and smt (surface mount technology)

meaning miniture components will give any electronic expert headaches.

Either you're a collector or you want to transfer precious recordings, sentimental or otherwise,

then there are still useable machines available if you know where to find like the sungei road thieves

market.Of course you will have to service them.For new ones try Sim Lim Tower.

PS I do have a Yahama cassete deck if you're interested which is easier to use for transfers.

You can have it foc just email me. Good day.

Hey all, ive decided to tube roll my SRM-T1S...only problem is that i dont have tubes!

 

So, does anyone know where to get matched pairs of tubes? Im looking for 6CG7/6FQ7, preferably Toshiba, Matsush*ta, Raytheon or RCA clear tops

 

Thanks!

Hi,

I,m always amused when experienced as well as newbies ask about "matched pairs"

of tubes.This shows that most people accept claims that are unproven and in the wrong context

of tube technology as well as reality.Let's say you've got a "matched pair" ,how long will it stay "matched"

in your circuit or amplifier? Why are people so obedient or gullible? Well it seems you have been played

into the hands of marketing since the days of hifi / highend profiteers.Matched tubes cost more!

Even more if you want NOS tubes.

Matched tubes are or may have relevance in the amps that use pushpull

circuits where the top and bottom halves of a signal is processed by 2 tubes.Bear in mind that the

frontend or preamp before the phase spliter is single ended which means the full signal is not chopped

in half to feed the power tubes.

Now the question you should ask is, "What circuit do I have?".In most cases like

headphone tube amps is that they are in the majority "single ended".So in reality you don't need them

to be "matched".You may ask, "don't the stereo channels need matched tube?" Then you are talking

about the gain or amplification or apparent difference between channels which I can assure you that

they are probably within accepted levels to your ears.If you can hear the difference then the circuit or

tubes may have aged.Other than than it is badly designed in the first place.

Let's come to the reasons or circumstances that matched or quality standards should

be present in terms of electronic performance, yes, tubes in their day IS electronic technology.Is is well

known that electronic circuits are sensitive to small changes in parameters and therefore affect performance

especially during world war 2 and during the "50s era of coldwar between US and Russia/Soviet Union right up to

the 70s.

Radio and radar technology are high tech then and even now.There began in the US military investigating

ways and means to minimise tube failures which will mean life and death and perhaps military success in the

field situations.This the begining of the the concept of quality control during production as well as maintenance.

Flashback to modern day with the recall of hundreds of thousands or cars by famous manufacturers.Get the idea?

Now let's come back to the subject proper.Do you really need matched tubes?Does it make a difference

to the quality of sound or music that you hear? I have to give that different people hear differently so what makes

matched tubes superior? There really is an ART to sound or music because you are involved intimatedly with the

things that constitute reality as you know or don't know it.The parts is the sum of the whole as is frequently

mentioned.It is time to understand just like the Japanese who know so well that what you seek in terms of sound

or music is BEAUTY.Human beings intuitively understand and feel beauty.You don't need to be an artist or philosopher

to know this.So learn what is beauty in terms of music,learn from the japanese masters of tube amplification

and other white converts who have come to know it's secrets.Yes it takes effort but you won't be wasting

your time wondering about matched tubes, it's more than that, much more....

So purleezh don't ask about matched tubes anymore. Good luck.