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Hi Fi Myth versus Scientific Facts


What the Hi Fi enthusiast need is more facts,
less hype,
less myths.

I hope that I can clarify or dispel some Hi Fi Myths.

I apologize that
some Hi Fi Myths can only be explained with boring technical explanations.

Please do not give up on this article,
if you have trouble understand the more technical parts of these article.

Please skip the boring technical parts,
and find the useful bits that makes sense to you.

Some of this article MIGHT explain the Hi Fi Myth
and stop you from spending a lot of your hard earned money
and buying a lot of hype
(that does very little to improve the sound of your Hi Fi system)


 
Black Gate capacitors , Jensen capacitors ,
Silver Mica capacitors , negative feedback 
and huge output transformers

I notice that our advertisement was put next to a magazine article about how to design amplifiers.

The article was recommending 
Vishay resistor , Black Gate capacitor and Jensen capacitors.
The magazine (or it's sister company) sells these capacitors..

The article discuss a lot of different aspects about amplifier design,
like feedback, resistors, capacitors, the effect of loudspeakers on amplifiers, valve rectifiers , etc
but it forgot to mention about the importance of the output transformer !

The most important and expensive component of a valve amplifier are
the valves and the transformers !

"Hyped up" volume controls, "hyped up" resistors , "hyped up" capacitors ,
"hyped up" silver wires are cheap,
compared to our transformers !

The transformers of our "High End" are huge,
and they sell for £250 + £150 + £250 = £650.
If we could achieve the same improvement to the sound
with £10 volume control and £10 capacitors,
we could have save ourselves a lot of money !

Even the transformers of our more modest range are big,
and they sell for £100 + £150 + £100 = £350.
If we could achieve the same improvement to the sound
with £10 volume control and £10 capacitors,
we could have save ourselves a lot of money !

Just compare the size of our transformers with £3,000 American valve amplifiers,
and you will find that we have not "skimped" on the very important transformers !


The article also talks about "negative feedback",
and the problems with "negative feedback".

Most (but not all) amplifiers (transistor or valves) uses "negative feedback".

When you use "negative feedback" (over a number of amplification stages),
you will probably have a problem with "stability".

The traditional way to improve the "stability" of a amplifier (valve or transistors)
is to use "Silver Mica" capacitors.

You improve the "stability" of  amplifiers by modifying the frequency response.

It would help matters,
if the capacitor "behaved itself"
and modified the frequency response,
in a matter that you expect !

Due to stray inductance, leakage current, piezoelectric effect, etc,
some capacitors do very odd things !

"Silver Mica" capacitors are "very well behaved",
so that is why the traditional amplifier designers and us
use "silver mica" capacitors (in most of our amplifiers).



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I notice that our advertisement was put next to
a magazine article criticizing solid state power supplies,
that is used in millions of transistor amplifier, the famous Dynaco ST-70,
umpteen dozen famous "high end" valve amplifiers
that makes the price of our inexpensive amplifier look like "beer money" !

An article in an English Hi Fi magazine said that
"Power supply (with solid state rectifier) are painfully crude.
Drawing pulse of current from the mains instead of drawing current steadily"

Whilst this is true, it will mislead most Hi Fi enthusiast !

I think the writer should have mention that
"Most (but not all) power supply (using valve rectifiers) are also painfully crude.
Drawing pulse of current from the mains instead of drawing current steadily"

You have the same problem,
regardless of whether you are using valve rectifiers or solid state rectifiers !

I think the writer should have mention that
you can use valves (or solid state rectifiers !)
to draw current from the mains steadily,
if you use a "choke (inductor) input filter".


Unfortunately,
the "choke input filter" only works properly,
when you are drawing a fair amount of current from it (by using "bleeder resistors").
If anything went wrong with a "choke input filter",
the voltage could increase by about 40%.

I thought about this point,
looked at all the safety aspect of how can I design an amplifier,
that could cope with 40% increase in voltage
+ another 10% increase from "legal" fluctuation in mains voltage 
and I gave on "choke input filter" after a few months !

That is why we do NOT use "choke input filter".
We use a choke (inductor) in power supply (in a safer configuration).
Our power supply is a capacitor , bypass capacitor , choke , capacitor.

People who go on and on about Black Gate and Jensen capacitors should try
the traditional method of bypassing big capacitors (with lousy high frequency performance)
with small plastic film capacitors (with good high frequency performance),
and adding a small choke (better high frequency performance than most big chokes)
plus more capacitors
and listen to the difference on high quality "3 way" speakers.

I can hear the difference,
and 90% of our customers, who keep our amplifiers,
like the difference !

Our choke (inductor) is 1 Henry,
which is the "choke" equivalent of 1,000,000 micro Farad.

Please remember the mF marking found on capacitors means micro Farad (and NOT milliFarad) !
So, the 10,000 micro Farad capacitors found in transistor amplifier is very small,
when compared to 1,000,000 micro Farad or 1 Henry !


Let us look at the practical side of valve rectifiers versus solid state rectifiers..

Old stock of old valve rectifiers are disappearing rapidly.
Old "popular" valve rectifiers are incredibly expensive (due to scarcity, not necessary quality !)

Valve rectifier have to provide power to 2 or even 4 power valves + a few small valves.

Valve rectifiers are "stressed" 2 or even 4 times more than the power valves,
so modern valve rectifier have a terrible reputation for reliability.

Our solid state rectifiers and high quality EL34 valves & KT88 valves are reliable,
with 2 years guarantee (when you buy the amplifier)
and 1 year guarantee when you buy replacement valves.

Please ask the person selling valve rectifiers to give you 2 years guarantee !

We do NOT use modern valve rectifiers
because we do not trust the reliability of modern valve rectifiers.

We do NOT use "popular" old valve rectifiers
because the prices are insanely expensive (due to scarcity, not necessary quality !),
and the supplier will not give us a 2 year guarantee on old valve rectifier.
It is stupid to pay a lot of money for an old valve rectifier,
if the supplier has no confidence in the reliability !



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300B valve have cathodes

An article in an English Hi Fi magazine wrongly said that
"300B valves do not have any cathode"

This is NOT true.
300B valves have cathodes !

The filament / heater of the 300B valve is also the cathode.

This design is a very efficient way of "producing" a lot of electrons,
for the smallest amount of "heating" current.

Unfortunately, it does have one big disadvantage.

If you "heat" the valve with AC (Alternating Current) direct from the transformer,
the 300B valve tends to hum (through the speakers)

If you "heat" the valve with DC (Direct Current),
any ripple on the HUGE CURRENT DC supply (at least 1 ampere),
the 50 hertz, 100 hertz, 150 hertz, 200 Hertz, ....... cause by rectification,
and the nasty pulse caused by imperfect "switch on" and imperfect "switch off" of the rectifier,
is connected directly to the audio circuit !
Some people describe this as "giving a metallic edge to the sound".

Most amplifier (transistor or valves) have some of this problem,
but the power supply is "kept further away" from the valve (or transistor),
by capacitors, bypass capacitor, choke, capacitors, output transformer
(in our valve amplifier). 

Modern valves
like EL34 , 6550 and KT88
have a cathode
surrounding a separate heater.

This solve the "hum" problem,
but you have to provide more "heating" current,
to "produce" the same amount of electrons



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Please email your reply, and we will post your reply

Question: I live in Paris and would like to know where I can listen to your KT88 models. 
          I believe that MAGMA sells your EL34 model under the brand valve audio ? 

Answer :

Magma amplifier and our amplifier are different.

Please compare our GBP 600 EL34 valve amplifier with Magma EL34 amplifier.

Our "main transformer" (the big lump of metal at back of the amplifier) is slightly bigger.
This gives a "less processed" sound.
The main transformers uses thicker copper wire, with less resistance,
to produce less heat,
and runs cooler than the "standard" main transformers
used by Magma and our cheaper GBP 500 amplifier.
This is a good idea when you have a hot summer.
Our big transformer will last longer.

Many customer think that
our Svetlana EL34 valves
sound a bit more mellow
than Chinese EL34 valves used by Magma.

Many customer think that
our American "military grade" 5670 valves
sound a bit more mellow
than Chinese 6N3 valves used by Magma.

The frequency response of Magma amplifier will go up to 6 times above human hearing.
This is excessive, it is pointless for an amplifier to go 6 times above human hearing !
We have used 2 Silver Mica capacitor
to reduce the frequency response
to 3 times above human hearing.
This make our amplifier sound more mellow.
(We cannot reduce the frequency any less than 3 times above human hearing,)
(or we will spoil the frequency response, around 20 kHz.)

We also put in another ultra sonic filter to 
reduce the ultra sonic noise from CD player
(or ultrasonic resonance of Moving coil cartridges)

I hope that you can agree that
there are a lot of difference for 
GBP 100 (about 150 Euro) difference in price
between Magma amplifier
and our GBP 600 amplifier.

Most people will agree than our GBP 600 amplifier will sound
more mellow, with sweeter treble than Magma EL34 amplifier.

------------------------

Our GBP 700 EL34 valve amplifier has 6 Silver Mica and sound even more mellow, with sweeter treble.

It also has a modification to improve the balance of the "push pull" and reduces distortion
WITHOUT INCREASING FEEDBACK.

We know this because we measure EVERY amplifier for distortion and "stability" !

This is a quick "quality control" procedure to make sure that
the EL34 valves are PROPERLY MATCHED,
to produce less distortion.

 
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