Tubes Warmer Sounding?

[rankaudio]

Many have stated that tubes tend to have a warmer sound, however, my findings indicate otherwise, particularly when compared to solid state amplifiers which often tend to sound more rolled off. Is it possible to select tubes which may offer a warmer sound signature? What are the opinions of others? Do you sometimes get the impression that solid state amps sound warmer? Thanks

[MeloManiac]

On 10/13/2020 at 4:54 AM, rankaudio said:

Many have stated that tubes tend to have a warmer sound, however, my findings indicate otherwise, particularly when compared to solid state amplifiers which often tend to sound more rolled off. Is it possible to select tubes which may offer a warmer sound signature? What are the opinions of others? Do you sometimes get the impression that solid state amps sound warmer? Thanks

 

I read somewhere that tubes that are popular among guitarists are different (warmer?) than the more 'accurate' tubes popular among audiophiles. Still, some say it is the architecture of the amplifier that determines the warm sound, not the tubes.

 

Leben, a famous Japanese audiophile brand, builds their amps around the stock of NOS valves they have on their shelves. For instance, the Leben CS600 is now replaced by the Leben CS600X, which has different tubes. Inside, the architecture has been changed dramatically by the engineers, though the outside of the ampl looked identical.

 

What you are asking is like asking for the 'secret formula' of Audiophile Universe. Many have opnions on this, few are experts. (I know I am not...)

 

https://www.psaudio.com/article/whats-the-warmth-in-tube-amps/

This is what I gather from the artilce: According to the linked article, the warm sound has much to do with the 'darkness', the noise the amp produces. The signal-to-noise ratio is crucial here, for phono stage, and another spec I would look at is the 'total harmonic distortion': some amps have 0.3, while others are 0.03 For hifi, the latter is better, for guitar amps, some will find the 0.3 more interesting. While at first sight, there is little difference between 0.3 and 0.03, but in fact it is huge, and certainly audible, esp with efficient speakers such as Klipsch.

 

 

[robert_kc]

There are countless existing threads on numerous hi-fi forums on the topic of solid-state vs. tubes.   Google is your friend.

 

For hi-res recordings of classical music, I generally prefer tubes.

 

Here’s one of my relevant posts:

 

 

[henry4841]

Instead of saying warmer I would rather say more lush sounding, at least some of them. One has to remember when comparing tube vs SS that there are very few SS single ended amplifiers. Most are push pull which sounds very different that single ended SS amplifier. I have both single ended and push pull SS amplifiers and the SE could be called warmer sounding than their push pull SS ones. And the majority  of tube amplifiers are single ended with just one output tube per channel. When one compares a quality built push pull tube amplifier with an comparable built SS push pull amplifier the difference in sound is not so prevalent. A SS single ended amplifier has a sound much like a single ended tube amplifier. I like the sound of both depending on the mood I am in and the music I am listening to. Before one can truly say a tube amplifier is warmer sounding they need to listen to a SE SS amplifier. Firstwatt has made some in the past and has one, the F8, for sale now. 

[MicroMara]

On 10/14/2020 at 6:18 AM, ILI said:

 

Leben, a famous Japanese audiophile brand, builds their amps around the stock of NOS valves they have on their shelves. For instance, the Leben CS600 is now replaced by the Leben CS600X, which has different tubes. Inside, the architecture has been changed dramatically by the engineers, though the outside of the ampl looked identical.

The LEBEN CS 600 was built exclusively with NOS Tubes. The model change is based on the fact that these NOS Tubes that were used are no longer available on the market. In addition, both models still allow tuberolling. My cousin owns the CS 600 and replaces pre and power amp tubes, as he likes.

 

[MicroMara]

Basically tubes need a long playing time, the so-called "Burn In". If I haven't used my tube mono power amps for a long time, it takes 2 to 3 hours before the sound opens up properly and the so much described " warmth " is achieved. With transistor amplifiers there are different tunings of a sound image. For example, Marantz amplifiers sound warmer than, say, a Yamaha. 

Disadvantages of transistor amplifiers is that you have only one sound you choose, this sound is product related like the example Marantz > Yamaha. Both brands sound very good, but have different weightings in the tonal adjustment. If you want a different sound you have to buy a new / different amplifier. With tube amplifiers you have the possibility to influence the performance of a sound by tuberolling.  

 

In principle Transistor and also tube amplifiers need always 30 to 60 minutes before it makes really fun to listen to music. Most people also forget that the speakers themselves take a certain amount of time to develop their full sound image. There is the internal wiring, Crossover, voice coils, beads etc. which also need their operating temperature first.

[JohnJ]

I'll disagree with you a little there @MicroMara my 1990 Yah had a variable loudness that I used to warm it up a little to my Heresy IIs that I had just bought. Agree with you that it was not as dramatic as the Nakamichi (Nelson Pass) STASIS that I had for a while.. that was warm sounding.

[MicroMara]

39 minutes ago, JohnJ said:

I'll disagree with you a little there @MicroMara my 1990 Yah had a variable loudness that I used to warm it up a little to my Heresy IIs that I had just bought. Agree with you that it was not as dramatic as the Nakamichi (Nelson Pass) STASIS that I had for a while.. that was warm sounding.

There is no reason for an disagreement between us . You´ll need to know that I never ever used the bass or trebble controll  or a loudness function in my whole life. I´m a freaking  linear fetisch ......the Naka´s were great

[JohnJ]

Cool, that variable thing helped me keep that receiver for decades with those Heresy. The Nakamichi was $$$ and it had less wattage  so my head banging stuff back then got put back through the Yamaha.

[MeloManiac]

44 minutes ago, MicroMara said:

The LEBEN CS 600 was built exclusively with NOS Tubes. The model change is based on the fact that these NOS Tubes that were used are no longer available on the market. In addition, both models still allow tuberolling. My cousin owns the CS 600 and replaces pre and power amp tubes, as he likes.

 

Your cousin is a lucky guy, and tuberolling can be fun indeed. If I ever win the lottery, that CS600X is coming my way!

 

Still, the Leben engineers must have had a specific 'sound identity' in mind (the "Leben-sound" perhaps), or else they would not change the architecture of the CS600 to adapt to the different stock of NOS tubes:

The Leben CS600X is replacing the current CS600. As it is now difficult to obtain a good quantity of the 6CS7 valve which is used in a current CS600, Leben was compelled to modify this model to use a different valve. Consequently, a new CS600X is equipped with 12AU7A & 12BH7A instead of 6CS7 tube, thus the main difference of CS600X is that two tubes(12AU7A and 12BH7A) are sharing a job of 6CS7 tube and  some modifications have been made to the circuit accordingly. Leben still is holding a limited quantity of 6CS7 valves, so for now they will continued to sell the CS600 and CS600X simultaneously. (source: https://hifipig.com/leben-cs600x-stereo-integrated-valve-amplifier-released/ )

 

I'm not sure where hifipig.com got this information, because the official Leben website only mentions the CS600, not the CS600X. Maybe the English language website hasn't been updated properly. https://lebenhifi.com/products/cs600.html

[MicroMara]

1 hour ago, JohnJ said:

Cool, that variable thing helped me keep that receiver for decades with those Heresy. The Nakamichi was $$$ and it had less wattage  so my head banging stuff back then got put back through the Yamaha.

My sound philosophy and my claim was and is that a stereo gear must be able to reproduce a linear sound image from 20 Hz to 20 KHz without any influence of a tone control, a loudness function or an equalizer. If this is not the case, then there is something wrong in the tuning of the components among themselves, or it is due to the room acoustics that makes it  neccessary  to use the tonal sound changes in the high-midrange or in the bass setting. YMTC

[rankaudio]

Thanks for the feedback guys. I have much to learn.

[MechEngVic]

On 10/12/2020 at 7:54 PM, rankaudio said:

Many have stated that tubes tend to have a warmer sound, however, my findings indicate otherwise, particularly when compared to solid state amplifiers which often tend to sound more rolled off. Is it possible to select tubes which may offer a warmer sound signature? What are the opinions of others? Do you sometimes get the impression that solid state amps sound warmer? Thanks

Here's my take in the broadest of generalities.

There are two big differences between tube amps and SS amps. One is the output impedance, and two is the harmonic distortions of tube circuits that SS amps lack.

SS amps can be designed to have an almost ruler flat frequency response throughout their power output range. This is combined with low output impedances and massive power supply filter capacitances. Very powerful, stable, reliable, and flexible.  

Tube amps can and have been designed with flat responses but it's almost impossible to eliminate the harmonic distortions. There is no perfectly linear tube, and if you're into tube amps, you don't want it. This combined with relatively high output impedances makes tube amps varied in their color.

Throw in your choice of speakers and you start being able to grasp all the different ways an SS or tube amp can come off as sounding flat, bright, or rolled off. I honestly feel that the main contributor of sound signature is the speaker/amp combination.