About Vacuum tubes, Class A, & Hi-Fi

triac wrote:ano po ang avantage ng vacuum tube sa transistor or IC?mayroon sa father ko noon pro sira na.

first is you don't want to be seen around watching your fave TV show in a Tubed tv set, tube is far less efficient than bjt's or ic, the only reason tubes existed & continue to be manufactured in today's modern world is audio, to be specific High End Audio , but it does not mean to expensive & will be discussed sooner or later, God willing.

Now, why some people choose tube in an audio?

Here are some few facts about tubes:

1. tubes are non-linear, if overdriven, the curve is rather squashed or compressed, this is the main reason why many professional electric guitar players prefer tubes over semiconductors, Eric Clapton is one of them, another one is BB King.

2. tubes can distort even if not overdriven, but this distortion are mostly even order harmonics, these are prevalent (and sought after) especially in a single ended topology like pure triode or triode connected pentode.
This is the "magic" of single ended where pinoy tube fans call it "lambing", instruments sound very natural the way they should sound, human voice convey emotion, sometimes we call "vocals to die for", listener fatigue is almost non-existent even for several hours of continuous listening at a conversational level & even higher if the amp is built properly

Let's turn to Solid State:

1. As we know it, they are linear devices, once overdriven they begin to clip, a mixture of odd & even harmonics which causes annoying dissonance, listener fatigue sets in even for a few minutes of listening, try to ride in one of the jeepneys plying the montalban - cubao route with heart pounding subs & ear bleed highs then you will know what i'm talking about.

but advance technology of today paired with highly respected design engineers has come up with designs they claim as sounding "tubelike" (the irony of it )

And based on my own experience, a transistorized amp can be made to sound "tubey" if driven by a tube pre-amp, especially if they are operated in class A, even gainclones (IC amP) can exhibit that certain tube sound if driven by a tube pre-amp.

To be continued...

by the way Triac, yung tube amp ng father mo is a good start on tubes, revive it, tube amp are far more simple than semiconductor types. Sir Tony of e-lab also restores vintage tube amps, he mentors me from the time i was starting my journey on tubes up to the time i was actually building my own, i owe him a lot

welcome dito sir efren. buti napadpad kayo sa forum nato.

Hertz wrote:welcome dito sir efren. buti napadpad kayo sa forum nato.

thanks sir Hertz

nerfe wrote:weehh, di daw alam oh

pero para sa kaalaman ng di pa alam (exept master admin ultra )

ngeeehhh di ko tlga alam ang detubo sir efren, di ko kasi inabutan ang Era nyan. sayang nga eh.. gusto ko din mg DIY sa bahay kaso di nmn available dito sa area ko ang mga tube...
nkpag experience lng ako ng Vacuum sa tv lng noong my nagpakumpuni sa aking na detubo na monochrome television eh kaso... power supply lng ang problema. pumutok ung fuse.. sa pgpalit ko gumana agad.. winarm up ko ayon tapos tuloy, ang probz lng di ko masxadong npag-aralan (^_^

btw sir efren... ung 10W class A amp na gawa ni sir arkin sa elab.. pwde na ba yung panimula namin? transistorize din xa...

pa ot: speaking of sir tony.. sana maligaw din xa dito

my nbili sana akong books about tubes,kaso binaliwala ko na lng.prang hirap kc sa availabiity ng parts d2..it range from 20-100w amp design.prang UK ata gling yon.

btw sir efren... ung 10W class A amp na gawa ni sir arkin sa elab.. pwde na ba yung panimula namin? transistorize din xa...

pa ot: speaking of sir tony.. sana maligaw din xa dito

opo, 5W per channel, ginawa din yun ni sir marcelino, kinonvert nya yung guitar amp na gainclone to class A, here is the link:
http://www.redcircuits.com/Page80.htm
This is my first encounter with class A

if you're serious about solid state hi-fi, i highly recommend this, tried & tested ko na yan

(for much more improved sound quality, replace 2N3055 with MJ15003)
the use of a full range, high efficiency (95dB up) speaker is highly recommended, but any 3 way "bookshelf" type will do.

10 Watts per channel is more than enough for home use, if you want power i recommend stick to class H or class D & see what 300W can do inside your home...
Be warned: class A is addictive once you tried it

it came from this link
http://www.tcaas.btinternet.co.uk/jlhnotes.htm

to truly appreciate the sound quality, use a good quality CD player, FLAC, or other format but not MP3, due to its highly compressed audio files, sound quality suffer a lot...

Before I forget, the use of capacitance multiplier in class A is mandatory, otherwise you will be disappointed with the result...
Here is a circuit to power up your class A dual rails.
http://sound.westhost.com/project15.htm

By the way here are some constructors comments regarding the JLH class A: http://www.tcaas.btinternet.co.uk/jlhsound.htm

tnx.. sa class A sir efren..
dami ko nang "soon to be project" bago mg pasko
40W class AB ni sir danny at ito (^_^


xa nga pala sir, maitanong ko ilan ang voltage per rail nito ?


pwde na ba 12V para 24v lhat. tulad ng gnawa ni sir marcelino

nerfe wrote:Before I forget, the use of capacitance multiplier in class A is mandatory, otherwise you will be disappointed with the result...
Here is a circuit to power up your class A dual rails.
http://sound.westhost.com/project15.htm

kala ko ok lng na ordinary split supply. mlaki pala ang effecto
tnx dito sir efren +1 ulit sau
na aware ako

medyo nawala ako
hehehe medyo na busy
playing catch up ako muna

ultrasonic wrote:
xa nga pala sir, maitanong ko ilan ang voltage per rail nito ?


pwde na ba 12V para 24v lhat. tulad ng gnawa ni sir marcelino


http://sound.westhost.com/project15.htm

kala ko ok lng na ordinary split supply. mlaki pala ang effecto
tnx dito sir efren +1 ulit sau
na aware ako

yes pwede yan, anywhere from 12V above transformer secondary, just be aware of the e-caps working voltage & the transistors data sheets, I even use cap multiplier in high voltage power supply of my tube amps, i consider cap multiplier mandatory even in tube amps, specially Single Ended class A designs

...and yes, power supply greatly affects sound quality of class A designs, very low kasi ang PSRR, you feed it with impurities it will spew out trash

Many thanks for the point

thank u sir.. +1 ulit.. mpag preactisan na nga to (^_^

Di ako makasunod.

Ano po ba dyan ang tinatawag na cap multiplier? noob question.

james wrote:Di ako makasunod.

Ano po ba dyan ang tinatawag na cap multiplier? noob question.

shortened "capacitor multiplier"

the 470uF connected to the base of BD139/BD140 is multiplied by 100 (assumed hFE of the given transistors)then the circuit sees a 47,000 uF plus the main filter cap value, replace 470uF with 1000uF, that will give you 470,000uF...

Sir Nerfe, is that really 470,000uf or 100,000uf?


Ganyan pala ang daya nyan. Compare to a real capacitor bank ano po ang deference nila in terms of performance or anything?

james wrote:Sir Nerfe, is that really 470,000uf or 100,000uf?


Ganyan pala ang daya nyan. Compare to a real capacitor bank ano po ang deference nila in terms of performance or anything?

so sorry my mistake....

with a hFE of 100 times 1000uF that will give you roughly 100,000uF...

compared with a real capacitor bank, as far as i know, no difference at all.

Oi ganyan na lang gawin ko kaya, para makatipid sa gastos, cap mulitiplier maliit pa footprint ko, since no difference naman pala sa tunay na cap bank.

^it's worth a try

sir efren dun ba sa ibang store na naituro mo meron din mga vacuam tubes?

San pa kaya pwedeng makakuha?

^try to contact sir tony of e-lab, he has hundred of tubes, he is selling driver tubes for less than a hundred pesos (6AV6) & power tubes (6AQ5) for less than 300 pesos

good price

Paabang na lang muna kay sir admin sa kanyang gagawin.

Good thread sir efren. +1
welcome to the Aelexian Empire

sub...para sa mga master ng audio..

sad news mga guys, pumanaw na po si sir efren due to a stroke,
nakakalungkot itong balita na to kasi andami pa sana nyang maitutulong sa atin :'(