SURFING MUSIC SOUND-WAVES

10 June 2008: Breaking in Capacitors

 How many times do we come across those stubborn  capacitors  who demanded very long break-in period before they start to sound fabulous ? Frustrating isn't it ??!!...

Black Gate's are one example of those notorious capacitors ; they need to be broken in for around 200 playing hours. Before they are fully "trained", they sound just "sh..." 
Using your precious NOS exotic tubes in your amp just for  long periods breaking in caps ?.. Its a waste !! - Remember that CD Players laser eye's  have limited life span too.....

Try building this cheap but ingenious gadget to "train" those stubborn caps .  I have used this for a long time. Signal caps may need a more complex gadget  since music signals consist of different frequencies . I am trying to devise another one ....will keep you informed....but should  you want to try train those signal caps on this rack...do it.....its perfectly safe anyway...!

 Click here : The Cap Training Rack.pdf

 10 June 2008: OHMS LAW CHART

 You may be aware that I am not a electronic engineer, nor did I have a electronic education background.

For those DIY'rs like myself, I found myself a simple effective OHMS LAW chart , easy to use and refresh  ourself .

 Click here :  Ohms Law Chart.pdf

 11 June 2008 : Capacitor Voltage Bleeder

Amplifiers , whether it be Solid-State or Tube,  may contain lethal (!!!) high voltages.

Before doing any DIY jobs, make sure that you bleed the remaining high  voltages off,  in particular from the power- supply capacitors. Top quality capacitors can store their voltage content for many days.

Use of a bleeder (100K is sufficient)  resistor across the main voltage supply rail to GND is a very sensible practice. Devising a DIY Voltage-Bleeder cost you nothing - it does preserve your health.

Remember :

There are too many solder-gun heroes already dead, our DIY forum can not afford to lose another .

Chiao !! ................

 13 August 2008   Power Supply

 A lot of people still believe that power supply is power-supply, nothing else. They much concentrate on the signal circuit .

To my understanding this is a wrong paradigm.
How can you ensure that enough reserve is there when the amp has to process music transients  and be able to reproduce those BIG slam and dynamics faithfully without running out of breath ?  What happened when there is not enough muscle ?

Since the start of my DIY, I habitually  "overstate" my power-supply requirement. I feel that power-supply is critical to the output  - not only the signal  .

When they saw how I build my power-supply, people sometimes laugh, think or comment that I am just too lavish in spending  , went the wrong way , am bit dumb or crazy to allow myself to be dragged into power-supply issues. Example : they think its not necessary to prepare ample supply to each channel - as I "normally"  did install dedicated rectifier tubes ( supply..) to each channel for instance -

My transformer friend, Setiawan is  in high gear after we succeeded in the 2nd generation CCS.

See his new product....<<< more >>> . Its amazing what stable, clean, adequate and ample power-supply can contribute to your  sonic footprint  out of your speakers.

 15 August 2008          on IMAGING

 I happened to come across this topic and liked the vizualization so much that I wish to share with others on the "so simple"  understanding of what IMAGING is...

The term IMAGING in the Oxford Dictionary means  " the impression you have or get " , "what you imagine" , in  the Hi-Fi context is "when hearing the reproduction of the music through your speakers".

 At it's  base, it is the "illusion" one can get when hearing the music,  one's presence  or integration within the whole ie. the orchestra, the players, the artist, the environment.  Within it, you get also illusions of correct instrument timbre, separation between each instrument, its placements when performing  , the size and contributory factors of the venue, the crispyness of each instrument sound, the "size of the venue ..etc etc etc.....

One will also  imagine that speakers "disappear " in the process

Lets see the  three main illusions which  I like to share with you in pictures, so you hopefully can discover it further by  yourself  with your own system. 

ALONG AXIS

gives you the illusion that the source is at a straight line at the speakers 

LAID BACK

gives you  the illusion that the source came from the back of the speakers

 FORWARD PRESENCE

the illusion that the source of music (artist, players)  is doing their job  in front of your seat /  your speakers 

Which one is best ? You decide , it's  your taste. 

Naturally , aside of the systems ability to good quality reproduction , it demands from you also a appropriate set-up of your gear . The better quality of your system and a good set-up  , the better imaging you can get out of it.

For those guys interested in more advance imaging conceptuals , read the following  academic paper :

16 August 2008

 And to  make this topic  more interesting , one smart guy came up with a more elaborate  version of understanding and sent me this  . Thanks mate !!

 Have fun with your system !

 12 September 2008

Many times are we confused over the jargon used by people to describe the sound they hear.

Below is a concised list  of terms I took from www.lalena.com/audio/calculator/xover. We could adopt it to come to a "common understanding" of what we mean.

 What are these terms used to describe speakers ( or sound) ?

• Airy: Spacious. Open. Instruments sound like they are surrounded by a large reflective space full of air. Good reproduction of high-frequency reflections. High-frequency response extends to 15 or 20 kHz.
• Bassy: Emphasized low frequencies below about 200 Hz.
• Blanketed: Weak highs, as if a blanket were put over the speakers.
• Bloated: Excessive mid-bass around 250 Hz. Poorly damped low frequencies, low-frequency resonances. See tubby.
• Blurred: Poor transient response. Vague stereo imaging, not focused.
• Boomy: Excessive bass around 125 Hz. Poorly damped low frequencies or low-frequency resonances.
• Boxy: Having resonances as if the music were enclosed in a box. Sometimes an emphasis around 250 to 500 Hz.
• Breathy: Audible breath sounds in woodwinds and reeds such as flute or sax. Good response in the upper-mids or highs.
• Bright: High-frequency emphasis. Harmonics are strong relative to fundamentals.
• Chesty: The vocalist sounds like their chest is too big. A bump in the low-frequency response around 125 to 250 Hz.
• Clear: See Transparent.
• Colored: Having timbres that are not true to life. Non-flat response, peaks or dips.
• Crisp: Extended high-frequency response, especially with cymbals.
• Dark: Opposite of bright. Weak high frequencies.
• Delicate: High frequencies extending to 15 or 20 kHz without peaks.
• Depth: A sense of distance (near to far) of different instruments.
• Detailed: Easy to hear tiny details in the music; articulate. Adequate high-frequency response, sharp transient response.
• Dull: See dark.
• Edgy: Too much high frequencies. Trebly. Harmonics are too strong relative to the fundamentals. Distorted, having unwanted harmonics that add an edge or raspiness.
• Fat: See Full and Warm. Or, spatially diffuse - a sound is panned to one channel, delayed, and then the delayed sound is panned to the other channel. Or, slightly distorted with analog tape distortion or tube distortion.
• Full: Strong fundamentals relative to harmonics. Good low-frequency response, not necessarily extended, but with adequate level around 100 to 300 Hz. Male voices are full around 125 Hz; female voices and violins are full around 250 Hz; sax is full around 250 to 400 Hz. Opposite of thin.
• Gentle: Opposite of edgy. The harmonics - highs and upper mids - are not exaggerated, or may even be weak.
• Grainy: The music sounds like it is segmented into little grains, rather than flowing in one continuous piece. Not liquid or fluid. Suffering from harmonic or I.M. distortion. Some early A/D converters sounded grainy, as do current ones of inferior design. Powdery is finer than grainy.
• Grungy: Lots of harmonic or I.M. distortion.
• Hard: Too much upper midrange, usually around 3 kHz. Or, good transient response, as if the sound is hitting you hard.
• Harsh: Too much upper midrange. Peaks in the frequency response between 2 and 6 kHz. Or, excessive phase shift in a digital recorder's lowpass filter.
• Honky: Like cupping your hands around your mouth. A bump in the response around 500 to 700 Hz.
• Mellow: Reduced high frequencies, not edgy.
• Muddy: Not clear. Weak harmonics, smeared time response, I.M. distortion.
• Muffled: Sounds like it is covered with a blanket. Weak highs or weak upper mids.
• Nasal: Honky, a bump in the response around 600 Hz.
• Piercing: Strident, hard on the ears, screechy. Having sharp, narrow peaks in the response around 3 to 10 kHz.
• Presence: A sense that the instrument in present in the listening room. Synonyms are edge, punch, detail, closeness and clarity. Adequate or emphasized response around 5 kHz for most instruments, or around 2 to 5 kHz for kick drum and bass.
• Puffy: A bump in the response around 500 Hz.
• Punchy: Good reproduction of dynamics. Good transient response, with strong impact. Sometimes a bump around 5 kHz or 200 Hz.
• Rich: See Full. Also, having euphonic distortion made of even-order harmonics.
• Round: High-frequency rolloff or dip. Not edgy.
• Sibilant: "Essy" Exaggerated "s" and "sh" sounds in singing, caused by a rise in the response around 6 to 10 kHz.
• Sizzly: See Sibilant. Also, too much highs on cymbals.
• Smeared: Lacking detail. Poor transient response, too much leakage between microphones. Poorly focused images.
• Smooth: Easy on the ears, not harsh. Flat frequency response, especially in the midrange. Lack of peaks and dips in the response.
• Spacious: Conveying a sense of space, ambiance, or room around the instruments. Stereo reverb. Early reflections.
• Steely: Emphasized upper mids around 3 to 6 kHz. Peaky, nonflat high-frequency response. See Harsh, Edgy.
• Strident: See Harsh, Edgy.
• Sweet: Not strident or piercing. Delicate. Flat high-frequency response, low distortion. Lack of peaks in the response. Highs are extended to 15 or 20 kHz, but they are not bumped up. Often used when referring to cymbals, percussion, strings, and sibilant sounds.
• Telephone-like: See Tinny.
• Thin: Fundamentals are weak relative to harmonics.
• Tight: Good low-frequency transient response and detail.
• Tinny: Narrowband, weak lows, peaky mids. The music sounds like it is coming through a telephone or tin can.
• Transparent: Easy to hear into the music, detailed, clear, not muddy. Wide flat frequency response, sharp time response, very low distortion and noise.
• Tubby: Having low-frequency resonances as if you're singing in a bathtub. See bloated.
• Veiled: Like a silk veil is over the speakers. Slight noise or distortion or slightly weak high frequencies. Not transparent.
• Warm: Good bass, adequate low frequencies, adequate fundamentals relative to harmonics. Not thin. Also excessive bass or midbass. Also, pleasantly spacious, with adequate reverberation at low frequencies. Also see Rich, Round. Warm highs means sweet highs.
• Weighty: Good low-frequency response below about 50 Hz. Suggesting an object of great weight or power, like a diesel locomotive.

 Cheers !!!..

Orienting Unmarked Capacitor Legs

All those nice paper (PIO) and non-polar caps,...... Although  it really does not matter anyway, question is : which leg is the input leg then ??? …..  a bit of home work.. isn’t it .....??!!..

This little cheap trick will help us to determine which  unmarked plus/minus  legs are the + or – leg. No need to buy a expensive oscilloscope, but if youre  one freak who always wanted a 120% perfection and do have the dough to spend......why not ??!!.....

Picture 1 : Preparation

1)

Prepare a small step-down transformer , primary 220-240Vac , a  12-15-20Vac secondary winding is sufficient.

Prepare a Digital Volt Meter.

2)

Determine and ensure to use the correct polarity of the primary and secondary windings.

3)

Attach two wires with crocodile clips on the other end to the secondary + and – secondary taps. Solder one 1K resistor in serial with the – crocodile clip wire. (see picture) The 1K resistor is just a safety trick ; if the measured cap suddenly short-circuit - you have protected your transformer.

Your little gadget is now ready.

Picture 2: Usage

1)     

Attach one  cap leg to the + crocodile clip , the other leg to the – clip.

2)

With the transformer in <ON> mode, start measuring:

* Set DVM to “Vac mode “

* Red DVM probe to the + secondary transformer tap.

* Black DVM probe to the outer metal skin of the capacitor

3)

Read the result on your DVM and  remember it.

4)

Reverse the caps leg connection  and re-measure as in point 2

5)

Read the new result on your DVM and compare to point  2/3

6)

The lowest reading (inductance reading) shows the correct connection :

The cap leg in this is connected to the + tap , the +/positive cap leg.

This serves as the INPUT leg point.

7)

Caps with non-metal body shall be wrapped with aluminium foil before measuring.

Do not measure caps with voltage ratings below your secondary transformer voltage  (ie.  6Vdc caps on the 12Vac secondary windings )

Have fun !!!

For those with money, and  perfection mentality ; buy yourself a nice oscilloscope  and use it to measure the inductance.

I will let you know how to use the oscilloscope in the next posting...

 Happy New Year 2009. All blessing and best wishes to my friends.

At times we came across a unmarked output transformer and we wish to know how much is its primary impendance ratings.

Here is a simple trick, using  a digital multi meter. Dont forget to detach the transformer wires off the amplifier circuit, else your readings will not be accurate

Click here  : <<< Determining Unknown Output Transformer Impedance.pdf >>>

I like to explore alternative tubes. It give me a comfortable feeling that I will not run out of my favorite tube types. Being a bit lazy in changing and re-soldering different sockets- if required,  the best alternative for a "Plug and Play" method is devising socket converters.

 So far I have managed to devise  the following converters:

 UX4 to B4/B5 :  Accommodate B4/B5 such as RGN2504 etc.  to replace UX4 tubes ( 5U4 -5Z3  etc..)

 UX4 to Octal  : Accommodate 6B4G to replace 2A3 tubes

Octal 6SN7 family to Loctal : Accommodate alternative 7N7 / 14AF7 in lieu of the expensive 6SN7 tubes 

 I like to explore Octal  to  9-Pin converters, UX4 with the Phillips tube sockets etc.. in the future. The size made it a bit tricky..

This is how you do it ( example of..... converting Octals to UX4 ) : 

 Have Fun......

Note : These converters are being sold for US$25/piece < wow..> on eBay... Quite pricey for just a short evening work

A few of my friends have a bit of a problem with their installed volume pot. Either the sound  is  just too loud with only little opening of the pot or vice versa.

 Read these two articles of GoldPoint , the famous ( and expensive ) maker of  stepped attenuators.

Basically the information can be applied to non-stepped attenuators too.

Try it with cheapy resistors, once you found your exact value - change it with a high quality resistor. Mind you, the resistor is in the path of the signal and thus it does much contribute to the sound quality .

Have fun..... no harm in trying anyway..........

Choosing the right attenuator

 Adjusting my attenuator