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Do vacuum tubes really have a sound signature?

MrBurns84

By MrBurns84
in Stereo Amplifiers & Pre-Amps

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Full Range Life Member

Full Range

Posted
Posted
Actually The Tube Forum of DIY Audio is an excellent resource. They actually discuss tube CIRCUITS and how they sound, not much measurement at all.

It's a good idea but what you will end up finding is the best tube for that amplifier. You can't allow for the fact that , say, an EL34 and a KT66 have slightly different "ideal" operating conditions eg plate voltage or output transformer impedance. Your amp will probably "like" a certain tube more than others.

I like tube rolling

I have an amp that was designed for this to happen (Earle Weston Tweaker)

I do also like the idea of calibrating the tubes for optimum performance (as my amp does)

I use it as a way of finding a good tube match for the music one is listening to, as some tubes are great for classical and not for rock & visa versa

A tip for all

First initial impressions are either good or bad because its a change to the norm

A real assessment should only be made after a time of acquaintance and that can take up to 3 months

FR

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everyones_shadow Experienced

everyones_shadow

Posted
Posted

I've looked at diyaudio and find it very interesting. Great for broadening my ignorance into wider fields of audio :P

I think what kajak12 means by measurements might be the constant discussion of component values and tube voltages. Posters are reaaly helpful. They'll design a complete valve amp for you at the drop of a hat.

RoHo: That's true but I think (using the right amp) it could confirm or refute some preconceptions of the "300Bs are sweet" type which I thought was what the OP raised.

Cheers

ES

RoHo Veteran

RoHo

Posted
Posted
I like tube rolling

I have an amp that was designed for this to happen (Earle Weston Tweaker)

I do also like the idea of calibrating the tubes for optimum performance (as my amp does)

I use it as a way of finding a good tube match for the music one is listening to, as some tubes are great for classical and not for rock & visa versa

A tip for all

First initial impressions are either good or bad because its a change to the norm

A real assessment should only be made after a time of acquaintance and that can take up to 3 months

FR

Don't get me wrong, FR, I love a bit of rolling myself. My amp can accommodate EL34s or KT88 or 6550 and I enjoy a change of flavour every so often.

My favourite are EL34 types 'cos they just have more midrange clarity. But most people will say that EL34s are a gentle, warm sounding tube!

But I'm happy saying that in my amp/speaker/room combination EL34s or 6CA7s have a slightly clearer sound.

IMO the sound of output tubes is so tied up in the output transformer/speaker interaction that you can't really talk about the sound of the tube in isolation. Especially with low powered tubes in single ended circuits. This is one reason why there's such a diverse range of opinions about 300Bs.

Full Range Life Member

Full Range

Posted
Posted
Don't get me wrong, FR, I love a bit of rolling myself. My amp can accommodate EL34s or KT88 or 6550 and I enjoy a change of flavour every so often.

My favourite are EL34 types 'cos they just have more midrange clarity. But most people will say that EL34s are a gentle, warm sounding tube!

But I'm happy saying that in my amp/speaker/room combination EL34s or 6CA7s have a slightly clearer sound.

IMO the sound of output tubes is so tied up in the output transformer/speaker interaction that you can't really talk about the sound of the tube in isolation. Especially with low powered tubes in single ended circuits. This is one reason why there's such a diverse range of opinions about 300Bs.

Yes agreed

But alas there are far to many variables

As pointed out by yourself e.g. room, speaker type ect ect

One thing we all universally agree on is, that tubes produce a sound that in pleasing to humans

FR

davewantsmoore Life Member

davewantsmoore

Posted
Posted
Is this fact or fiction?

From my "airchair expert" readings... this is fact... and in the context of a site like diyaudio a very important point/lesson

As others have said, it's also sementics, when you are considering a amp (or a few like amps) ... and changing tubes, as the end result can be described in the gooey audiophile language he denounces.

Zaphod Beeblebrox Grand Master

Zaphod Beeblebrox

Posted
Posted (edited)

One thing we all universally agree on is, that tubes produce a sound that in pleasing to humans

FR

Nope. One thing we can universally agree on is that a properly designed and implemented amplifier, be it BJT, valve, MOSFET, whatever, is capable of delivering an accurate reproduction of the original musical event. The other thing we can agree on is that a poorly designed and implemented amplifier, be it BJT, valve, MOSFET, whatever, is capable of producing a sound that departs from musical accuracy.

The mere prescence (or abscence) of valves in an amplifier guarantees nothing WRT sound quality.

Edited by Zaphod Beeblebrox
Brain fart
andyr Life Member

andyr

Posted
Posted

The mere presence (or absence) of valves in an amplifier guarantees nothing WRT sound quality.

Absolutely agree, ZB! ;)

One thing we can universally agree on is that a properly designed and implemented amplifier, be it BJT, valve, MOSFET, whatever, is capable of delivering an accurate reproduction of the original musical event. The other thing we can agree on is that a poorly designed and implemented amplifier, be it BJT, valve, MOSFET, whatever, is capable of producing a sound that departs from musical accuracy.

Basically, I agree, ZB! :) But ...

Let's take a "properly designed and implemented " glass amp and a "properly designed and implemented " sand amp.

According to your definition, they both must deliver "an accurate reproduction of the original musical event ". But I suggest they would actually sound different. (Which I suspect the measurement guys would say they shouldn't! :) )

But how is this possible if they are both supposed to deliver "an accurate reproduction of the original musical event "? :(

So let's go one stage further - we are using the same pair of speakers with each amp ... and these speakers provide a load which is not stressful for either amp.

Which one sounds better, I suggest, is dependent on your musical tastes. Some will like the better control which a sand amp typically has over the bass drivers (compared to a glass amp). Others will prefer the liquidity/presence which a glass amp typically has in the midrange. :)

Regards,

Andy

MrBurns84 Veteran

MrBurns84

Posted
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Posted

IMO the sound of output tubes is so tied up in the output transformer/speaker interaction that you can't really talk about the sound of the tube in isolation. Especially with low powered tubes in single ended circuits. This is one reason why there's such a diverse range of opinions about 300Bs.

6L6'GC sound the best on mine, but i rotate between them and KT66's.. the KT66's are more suited toward rock music and general playback, but for jazz and female vocal music, those 6L6's sing better in the mids than the KT66's. I tend to tube roll a fair bit on the signal input and gain stage. TJ/Sophia's sound the best at the gain stage, and a NOS Sylvania 6SL7GT V229 sounds 'just right' for me atm at the input. But i agree with some, there are too many variables such as speakers, speaker placement, room acoustics, source equipment etc that all contribute towards the final sound.

Full Range Life Member

Full Range

Posted
Posted (edited)
Nope. One thing we can universally agree on is that a properly designed and implemented amplifier, be it BJT, valve, MOSFET, whatever, is capable of delivering an accurate reproduction of the original musical event. The other thing we can agree on is that a poorly designed and implemented amplifier, be it BJT, valve, MOSFET, whatever, is capable of producing a sound that departs from musical accuracy.

The mere prescence (or abscence) of valves in an amplifier guarantees nothing WRT sound quality.

You commented on a portion of my post Z.B.

I did in fact also say in simplistic terms with regards to variables in an answer to Roho

But alas there are far to many variables

As pointed out by yourself e.g. room, speaker type ect ect

I read this on another forum and its put very aptly

Part of the quote below

A technicians instruments can be very useful, but if you can pay attention! you senses will give a better result every time.

Coarse tune with the instruments then fine tune with your senses.

So I stand by my comment that tubes produce a sound that is pleasing to humans and it has something to do with the senses as quoted above

Although I omitted commenting on SS amp it was due in part to keep my comments on topic

Obviously well designed SS amps produce a good sound but that is another topic or another thread

FR

Edited by Full Range
spell
sligoriverblues Veteran

sligoriverblues

Posted
Posted (edited)
-1 no they dont they still lack the magic

So, how many Labs have you tried in your system to be able to make such a statement? And could you please describe that "magic"?

edit: " " on magic

Edited by sligoriverblues

everyones_shadow Experienced

everyones_shadow

Posted
Posted (edited)
What lab measures magic?

1 The Technocracy have many labs for just that purpose (gee, not something I've thought about for ten years at least)

2 The NRC in Ottawa measures subjective reactions of listeners and correlates their experience to speaker characteristics. I don't know if they've ever done the same for amps.

ES

Edited by everyones_shadow
can't type today
RoHo Veteran

RoHo

Posted
Posted
2 The NRC in Ottawa measures subjective reactions of listeners and correlates their experience to speaker characteristics. I don't know if they've ever done the same for amps.

ES

So we really can assign a "magic factor" to speakers!!

Maybe we should have "star" magic rating like we do with energy efficiency on household appliances. Nothing below a 4 1/2 star magic rating will do for MY system, fellas.

djb Life Member

djb

Posted
Posted

full range glad to hear someone else enjoys a tweaker

earle name d it for my partner annie a cable tweaker who insists on getting the maximum value that specs offer

why she hangs around with mewith standards like these no one knows!

andyr Life Member

andyr

Posted
Posted

5db GNF in my amp

ZB was referring to amps which use large amounts of global NFB.

He is better placed than I to comment but I would think 5dB is only a little global NFB. :cool:

So, yes, you should be able to hear a different sound from different tubes.

Regards,

Andy

Zaphod Beeblebrox Grand Master

Zaphod Beeblebrox

Posted
Posted
ZB was referring to amps which use large amounts of global NFB.

He is better placed than I to comment but I would think 5dB is only a little global NFB. :cool:

Correct. 5dB is an extremely low level of GNFB. A typical, mass market SS amp might use more than 80dB (10,000 times) if GNFB, whilst a valve amp that uses lots of GNFB might use 40dB (100 times) or more. A Gainclone would typically use around 100dB (100,000 times).

So, yes, you should be able to hear a different sound from different tubes.

Regards,

Andy

Of course. Such a minimal Global NFB figure would easily expose differences in components within the amplifier.

Full Range Life Member

Full Range

Posted
Posted
full range glad to hear someone else enjoys a tweaker

earle name d it for my partner annie a cable tweaker who insists on getting the maximum value that specs offer

why she hangs around with mewith standards like these no one knows!

I like it very much & it pairs well with high efficiency full range drivers

Also just found out that Monaro8 also has a Tweaker

May need to start a club :cool:

FR

Tony M Grand Champion

Tony M

Posted
Posted
ALL amplifiers use NFB. Every single one.

Hmmm.......if this is fact, TacTaudio are indulging in fairly blatant false advertising. They state "No negative feedback at all" in relation to their digital power amplifiers which are based on Equibit technology. I understand there is a new NAD amp that is similar - I haven't yet checked if they make similar claims.

Cheers

Tony

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