How to choose the right tubes for your equipment

For many, the search for the ultimate sound started at a random moment, somewhere at a HiFi show, or with a friend, when hearing a demonstration with harmonizing equipment, under the right conditions. Some may hear at such a moment for the first time in their life what is possible at all with good equipment, and when returning at home, the memory of this sound stays with you for ever. After some time, months or years, the idea starts to be develop to establish this good sound at home also. At this moment, a long journey can start, seeking to reproduce this once heard, so beautiful sound, that you have in memory. We can not give the complete help guide here, but is at least some orientation. If you expect a quick answer like for tight bass you need this tube, and for smooth mid range you need this or that speaker cable, you are at the wrong place here. Half of the internet provides that small talk already, but that is unserious commerce. Good sound is not coming from what doing what others tell you, it is coming from understanding yourself what you are aiming at, how you want to get there, what do you have available already, and what is missing. Supposed you need tubes for that, here we have at EML hopefully what you need.


We probably said it before somewhere, and we say it again: The final sound of a HiFi chain is depending on all elements, and how they harmonize. A good result needs awareness of what you expect, and readiness to invest money at the right position. With the elements in a HiFi chain, we mean: the recording itself, the player, the pre-amplifier, the volume control, the power amplifier, the loudspeakers, the listening room, your ears, and your perception of how you want to hear music. Each if those elements can be the weak spot, and over-compensating that with another element is often useless.

Also the question if the elements harmonize with each other must be investigated. Usually here is where the mistakes are made. A classical mistake is very high efficiency loudspeakers, combined with a very high power amplifier. You have not made this mistake? Good! But there are many others possible.

Your ears

Your ears are interesting devices, they have a frequency curve of them self, which is very unlinear. Now, that's normal and the brain simply is more interested in specific frequencies than in others. However in today's world where young people mistreat their ears, they will suffer some grade of hearing loss before they are 30 years old. This is unknowing, and your brain will work around some small degree of hearing loss. However this is not the solution, since additional hearing loss will come above the age of 50 years, and this adds up. In any case, when you are going to tune your equipment, young and old people should visit an audiometrist at least once, and have a hearing plot made. It costs you 15 minutes and 20$ and for that you may get the surprise of your life, finding out you are half deaf of one ear, and strong frequency loss on the other, and yet never felt you missed anything. Even more, you regard yourself a critical listener, with great sense of detail. If this appears so, you are no exception. So when we talk about investing time and money, here is a good place to invest 15 minutes and $20. People with small hearing loss can enjoy music as well as any other, but can greatly improve results with the right equipment. The advise in such a case, is use a smaller size listening room, with a lot more damping materials than average, and use horn speakers. Those will give you (back) the stereo effects you may have been missing, and the higher amount of damping materials will reduce the amount of reflected signal. The reflected signal is particularly with horns a bit less natural, it stresses capabilities of the brain that may be already busy compensating hearing loss of "not so good" ears. Of course also a pre-amp with tone control is the perfect solution when you have hearing loss only in a particular frequency range. The smaller listening room will need less bass power, yet you you don't feel it is missing. This is typical for a small room, and it is beneficial when your ears have some hearing loss So again with small hearing loss, I do not mean half deaf persons, I mean actually average persons. You can easily have 4dB loss on one ear, and never was a You also can not cure it, but you should pay much, much more attention to the listening room in that case

Harmony. The tube amplifier must not be too small and not be too large for the speakers.

The purest triode sound you are seeking for, will develop best when a triode has to work "Medium" hard. Very big tubes that you give nothing to do, sound sterile like a transistor amplifier. On the other hand, a tube amplifier which has barely the output power you need, will sound tired. Many, when not most sins are made here. More about this later.


There are two kinds of distortion, linear and unlinear. Linear distortion means the frequency range is not amplified linearly. So for instance loss of high frequency is linear distortion. Unlinear distortion means frequencies that were not there before, are added to the original signal. This can happen when the loudspeaker cabinet produces some "box" rumble, "wind" noise from the reflex openings, or the sound is too loud for the speakers. Also tubes and transformers can distort.

In the 1980's amplifier manufacturers used to tell, that ultimate sound comes from transistor amplifiers with 0,1% distortion at high power, and who had enough money even bought a 0,001 % distortion amplifier. Well we know now, this is not so. Did you ever realize a loudspeaker can give 10% or more distortion? And horn speakers tend to sound "clearer" while we all know they distort more. Tune amplifiers without feedback sure give more distortion, and yet are said to sound better. So distortion is something normal in the tube world, it is not something "good" but also not something to fight against at any price.

Some Transformer recommendations

Power Supply Design Note-1

Power Supply Design Note-2

What to do in case of a white sparking inside a tube

About the use of getter Materials