Valves: Where to put them?

[georgev]

I am currently running an all solid state system. Transport/Dac/Pre and power amp.
Just heard a valve set up and was quite intrigued by the sound. It was a very small setup.
I am keen to try and introduce valves into my system. I don't have the luxury of trying it out in my system before I buy.
Where in the system would it make the most impact. Pre/Power? Source?
I quite like the authority that my Solid State Power amp has and would not want to lose that.
Thoughts? Suggestions? Experiences?

[Kevin P]

You say you like the SS power amp, so put in a tube (valve) preamp.

[dyazdani]

I would also try that first. I've tried every combination of tube/SS from CDp to preamp to power amps.

[wkhanna]

I have tried a few combinations in the past few years. I currently have a hybrid-tube pre-amp in my system, with all other sources (FM turner, HT processor, DVDp, CDp and main power amps) being SS, aside from my turntable & tube phono-pre. I run all source signals for my front main speakers through the tube pre. I use this setup to give me the best sound for music, based on my personal preference. I hear it as more warm, liquid & realistic with digital sources, while still maintaining good dynamics & speed with transients, and plenty of low-end energy. Overall, it seems quite balanced to me.

[soundhound]

Pre's can make the most noticable difference.
Don't write the amps off as not being able to handle speaks through the full frequency range, as they can, and can add to the overall sound stage.

[Johnloudb]

This is a wonderful sounding tube preamp, if you don't need a tone control.

http://www.audibleillusions.com/products/M3A_main.htm

[wkhanna]

I will take two, Please!
BTW, we don't need no stinking 'tone' contols' !

Disclaimer: this is the internet. this statement about tone controls is meant as a joke. do not take this personally. to those of you that use your tone controls....more power to you! we are all here to get the sound we need.

AFA valve amps, in my limited experience, I have found that the sensitivity of your speakers has a significant effect on how valve mains effect your system. A speaker with a low sensitivity will not resolve the same low frequency dynamics that a speaker rated at a higher sensitivity will.

Just this weekend, I had the chance to audition an Opera Consonance, 40 watt via 4 KT88’s. Gorgeous mids, but they couldn’t drive my < 4 ohm speakers in the low end.

I listen to acoustic jazz mostly, so if you like a more ‘aggressive’ style of music, you may find a valve main lacking in the bass region without a speaker that is rated in a region above 88 dB at 8 ohms, or so.

[georgev]

I am leaning towards the pre side, but one reason I asked also is 'cos a Ref 110(power amp) has come up for sale here in Johannesburg and hence the dilemma. Should I go fo it or rather get a pre. I am hoping to try the 110 in my system(if possible).

[Johnloudb]

I am leaning towards the pre side, but one reason I asked also is 'cos a Ref 110(power amp) has come up for sale here in Johannesburg and hence the dilemma. Should I go fo it or rather get a pre. I am hoping to try the 110 in my system(if possible).

Like Bill said, tube amps work best with speakers that have a fairly high impedance, and good sensitivity. A tube amp can drive a speaker with low sensitivity if it has enough power. I heard a some Quad ELS63 speakers once driven by a VTL amp and I was blown away. Very dynamic with a huge soundstage.

What speaker are you using? Equipment matching is very important for best results.

[Johnloudb]

Oh, Audio Research Ref 110 huh? Great, buy it!

Well, still, tell us more about your speakers. Sensitivity? Impedance?

[Victor]

Where in the system would it make the most impact. Pre/Power? Source?
Thoughts? Suggestions? Experiences?

It is an interesting question.

Usually people use valve-based electronics in order to experience a particular distortion pattern that tube-based gear generates. That is not to say that tubes cannot be designed to have a very low distortion, naturally it is doable, but then you may as well use transistor-based boxes.

It seems to me that the ‘tube-sound’ will be most evident in a power amplifier and not in a pre-amp. Reason being is that the even order distortion products that single-ended tube electronics produces is most evident with increase in power. The pre-amp, being a low power circuit should have less distortion and consequently less ‘tube-sound’.

regards
Victor

[wkhanna]

Then maybe that explains why my tube pre takes the often overly bright, harsh and brittle sound of my digital music and subtlety transforms it to sound more like the live music I am used to hearing?

[georgev]

Oh, Audio Research Ref 110 huh? Great, buy it!

Well, still, tell us more about your speakers. Sensitivity? Impedance?

I am using the B&W N802's and currently driving them with a Mark Levinson 336 power and a 380s pre, also ML.

[Johnloudb]

I am using the B&W N802's and currently driving them with a Mark Levinson 336 power and a 380s pre, also ML.

The B&W 802s are a sensitive speaker (90dB), but they're impedance also drops to 3.5 ohms in the bass due to the two paralleled woofers. I own some Nelson/Reed 804B loudspeaker of 93dB sensitivity but like the B&W the impedance drops due two paralleled woofers. And the bass could sound uncontrolled and bloated with the wrong amp, even some solid state.

However, I once tried an Audio Research Classic 60 (60watts) which sounded quite nice with them. So, the audio research might sound really good. I can't really say though.

I've tried the Audible Allusions preamp too, and it's a very musical peamp and has a 'tube' sound. If your system sounds on the bright side, that might be the way to go.

If you buy the Audio Research be sure to try both the 4 and 8 ohm taps on the output transformer. Surprisingly, I found the 8 ohm tap sounded much better on my N/R speakers.

I'm probably not helping much here.

[Victor]

Then maybe that explains why my tube pre takes the often overly bright, harsh and brittle sound of my digital music and subtlety transforms it to sound more like the live music I am used to hearing?

Well, if your digital source is making an “overly bright, harsh and brittle sound” then perhaps there is something wrong with it.

These days digital systems will routinely output a virtually distortion free signal. It is not uncommon to get a clean 16 or even 18 bit output. That would mean that you are listening to what has been recorded on the CD or the DVD you are using without any spectral alterations. And if the sound is still “overly bright, harsh and brittle” then that is what has been recorded for you to hear.

The tube-based electronics in the processing chain will, in the other hand, introduce noise and distortion and you will most likely get a 12-14 bits output. The output will be spectrally different from what was recorded. Also tubes might change the frequency response of the output data. In the business this practice has a name, - it is called voicing. Usually we prefer the spectral impact the tubes …and it is all about our preferences.
Regards,
Victor

[Johnloudb]

Well, if your digital source is making an “overly bright, harsh and brittle sound” then perhaps there is something wrong with it.

These days digital systems will routinely output a virtually distortion free signal. It is not uncommon to get a clean 16 or even 18 bit output. That would mean that you are listening to what has been recorded on the CD or the DVD you are using without any spectral alterations. And if the sound is still “overly bright, harsh and brittle” then that is what has been recorded for you to hear.

The tube-based electronics in the processing chain will, in the other hand, introduce noise and distortion and you will most likely get a 12-14 bits output. The output will be spectrally different from what was recorded. Also tubes might change the frequency response of the output data. In the business this practice has a name, - it is called voicing. Usually we prefer the spectral impact the tubes …and it is all about our preferences.
Regards,
Victor

The is much more to this. Some types of noise and distortion are much less tolerable and perceived much louder. Where the 2nd order harmonic distortion found is some tube gear has a pleasant euphonic quality. It doesn't reduce the resolution as you may think. Measurements don't tell the whole story. And the there are room acoustic issues which you may not have much control over. And there is that taboo subject of tone controls :B - helpful sometimes.

Like you say, it's a matter of preferences. Whatever sounds more like live music would be my preference.

[Victor]

The is much more to this. Some types of noise and distortion are much less tolerable and perceived much louder. Where the 2nd order harmonic distortion found is some tube gear has a pleasant euphonic quality. It doesn't reduce the resolution as you may think. Measurements don't tell the whole story. And the there are room acoustic issues which you may not have much control over. And there is that taboo subject of tone controls :B - helpful sometimes.

Like you say, it's a matter of preferences. Whatever sounds more like live music would be my preference.

I agree that noise and distortion can be tolerable. But this is not important; - the point is that noise and distortion are still noise and distortion. The issue here is that our hobby is all about sound reproduction and not sound generation.

In order to faithfully reproduce what has been recorded one needs a distortion free signal processing chain. Naturally distortion free is theoretically impossible to achieve, but these days we can get real close with even a low-priced electronics easily doing 0.01% of THD+N or better with around 18 bits demonstrable precision. In human terms this is perfect.

The noise always reduces resolution, no matter how you look at it, - it is just you can’t detect it with your ears and we are not discussing dithering here.

As far as room acoustics is concerned, well, - there are many options. We have an illustrious DEQ2496 a wonder-box from Behringer that for less then $250 will tame nearly all resonances in your typical room and if one takes care to use it with digital input and output, it will do it with virtually no penalty to the perceived sound quality. It can also tailor the sound to nearly anything you desire.

Measurement is definitely not the entire story, - there is more to the signal processing then that, - there are issues of warrantee, price, built quality, brand loyalty, etc. My experience has been that the gear that measures well always produces the sound I expected.

In general tube-based electronics is capable of creating one of the best sounds I ever heard, but it does that at the expense of signal integrity. The fact that we may prefer it that way is a personal choice, but an engineer in me says that it is contrary to what the intent of what my HI-FI rig is all about.

regards,
Victor

[wkhanna]

These days digital systems will routinely output a virtually distortion free signal. It is not uncommon to get a clean 16 or even 18 bit output. That would mean that you are listening to what has been recorded on the CD or the DVD you are using without any spectral alterations. And if the sound is still “overly bright, harsh and brittle” then that is what has been recorded for you to hear.

That is a good point. And maybe it has to do with what is 'not' recorded in the digital domain that can at times give it an unrealistic sound. Not to mention the unremarkable engineering that goes into most digital (redbook specifically) music.

Yes, I voice my system. And I admit to using a fallible standard, my ears. I also use a reference, that being the ‘live’ acoustic jazz and classical music that I hear in the plethora of venues our town has to offer. The effects of the tube distortion and coloration that each individual component within my system adds to its overall sound are what define its synergy. I have and will continue to evolve my system to reproduce as closely as possible what my brain tells my ears they hear when I am sitting in my favorite concert hall or jazz club.

I could not agree more with you, Victor. It is all about individual preference. :T

[Victor]

... And maybe it has to do with what is 'not' recorded in the digital domain that can at times give it an unrealistic sound. Not to mention the unremarkable engineering that goes into most digital (redbook specifically) music...

There is a perception out there that the process of digital recording misses something. That is to say that when the data is sampled something is lost. THis is not so.

Let me put this this way, - no information is lost within the signal-to-noise ratio.

THese days we can do 20 bit recording with no problems. The problem is in actually reproducing the 20-bit signal. Commonly availably solid state electronics cannot quite do that, although it will come close.

But then again the common tube-based electronics cannot really do any better then 14 bits anyway. So any data recorded with better noise floor is lost if you have anything tube-based in your system.

I am not at all saying that tubes are bad. I am saying that one needs to be aware of their shortcomings.

regards,
Victor