Can tubes ever be as quiet Solid State

I designed circuits starting in 1958 and continue to this day. I read carefully, every word posted here. Much of it is disappointing and leads me to believe that there are many elitists around without qualifications in metrology or experimental psychology. At the present state of the art, it is ridiculous to ask the questions and give the answers presented here. Think what you want. It appears that the scientific world is being downgraded to a black art and common sense sent back to wherever it began.

I'd love to know what conditions that measurement was taken under to get a number like that.

I thank all off you for your insight thoughts and experiences. I would like to confess a bit more. My "big rig" is all tube and the tubes used are probably old stock not New Old Stock.
I say this but do have many true NOS tubes. Nonetheless for all intents and purposes NOS is virtually extinct as a readily available commodity except as Feil said from carefully selected dealers. These dealers are very honest and also know what is NOS and what is not. BTW I own several testers and strong testing tubes are not NOS just strong. Tubes can get very noisy quickly even if they are NOS. My dealer of 6SN7s was a true expert and only sold superb tubes often for a premium he offered NOS. Even his best would get microphonic that's the nature of that tube. I am lucky to have tubes from him. He last wrote to me that he was going to throw in towel as sourcing these tubes is getting impossible. He sold here by the tag Whoopdeedaooda or close to that. Also LEN on the inmate place.
My phono stage dilmena is still a problem. I switched from an ARC SP6B with gain to knock you over( 6X 12AX7) but every other noise could be heard and using even real NOS and new tubes didn't change that. I am currently running a line stage AE-3 which is great. Maybe its the fact that it uses my favorite tube 6SN7s. I will have to check out Modright. Thanks

I had a Bat 51SE pre that was extremely quiet, but regardless I think Tvad nailed it:

I've owned many more tube components that were "noisy" but musical, than I have solid state that were quiet and musical.

Presently there two 1940's TungSol JAN CTL/VT-231 round plates, two 1940's Sylvania 6SN7W tall bottles, and six Siemens CCa's(beside the eight Winged 'C' 6550's) residing in my system. If there were ANY noise AT ALL at the speakers(with the pre-amp gain cranked to 99.9), I would be forced to find the problem and remove it immediately(I detest noise). My system is dead quiet, and anyone in the Indianapolis area is welcome to drop by and verify that for the inevitable doubters(bring your noise-sniffer). OH- and YES: Sucess IS all about doing your homework!

Thanks for the clarification. Though tubes as gain devices may be inherently more noisy (as well as inherently more linear), the entire device (preamp) isn't necessarily.

I think it is probably true that below a certain price-point valve linestages are noiser in general than transistor. Don't even know that for sure tho.

you are completely incorrect to state that tubed pres cannot match solid-state for quietness.

Paul,

Sorry, I didn't mean to imply that designers simply cannot work around these issues.

Let me rephrase: I guess anyone who has any experience in tubes as a component for use in amplification circuits will realize that there are in general (in the very broadest genralization sense) more noise issues (such as microphonics for example) than you get with solid state.

I reiterate what I stated above as proof that I agree with you: "I don't think it is a big issue - Manley make great tube amps that are extremely quiet - so do others."

Shardorne, you are completely incorrect to state that tubed pres cannot match solid-state for quietness. S/N ratio is a VERY simple and straightforward measurement and there are many top tubed pres that beat all but the most expensive SS designs, and some of them trounce them all.

My Shindo Monbrison's S/N is better than 120 dB. The previously mentioned ModWright 36.5 is better than 130.

I would like to see a list of solid-state linestages with S/N higher than 130 dB.

Not so pathetic, Vic. I find myself factoring convenience into my planning more and more as I get older. I think it is a natural shift in priorities.

I bought the tube amps I have because they are self-biasing and the tubes are supposed to last for years. If there's much hassle, it isn't worth it.

After all these years I've come to a love/hate relationship with tubes. My tubes now reside in the output stages of my front end gear, DAC and tuner. I gave up on the tube phono stages.

I still own a tube amplifier that gets use from time to time or more accurately less and less more out of it's inconvenience than anything else (it must be turned on and off). Pathetic, no?

Vic

06-11-08: Macrojack
"Rowland Capri SS preamp into Audio Mirror tubed power amps into Zu speakers turned up to 95 on the preamp scale causes a barely audible hiss with my ear about 2 inches away from the tweeter."

I've got the Rowland Continuum 500 SS integrated amp, where both the pre-amp (same circuit as the Carpir)and amplifier section (same as the Rowland 501s) both operate in DC. (Power Factor Correction converts any AC to 385V DC). I'm impressed that your tube amp gets so very close in terms of quietness. That's excellent. I hear about the same on my all-SS integrated.

BTW, I generally listen at a setting between 50 (when it's very quiet and I'm reading with music in the background) to 80-ish (when I'm trying to blow myself out of the listening seat with Mahler's 6th). At any of these levels I can't hear anything out of my tweeter.

Dave

>>06-12-08: Pbb
The days of NOS tubes are gone<<

That's crap.

There are thousands and thousands of NOS tubes available. So long as you are careful, know your seller, and look for high value tubes it's not a problem.

Faith has nothing to do with it.

You must do your homework.

The days of NOS tubes are gone. How many old shops and basements can be gone through in search of tubes? Good quality present production tubes are the way to go, unless you have a reliable source and deep pockets for NOS tubes. I find that older tubes are now, more often than not, used tubes and, unless you are equipped to test them, have to take it on faith that then numbers provided mean anything.

Noise is one important factor, but one has to look at the overall performance of a product in context and not just one aspect. Although I have to admit that the noise floor should be as low as possible, but not at the price of doing without the other attributes of tube gear.

Why not have both types of equipment on hand?

Rowland Capri SS preamp into Audio Mirror tubed power amps into Zu speakers turned up to 95 on the preamp scale causes a barely audible hiss with my ear about 2 inches away from the tweeter. The midrange driver doesn't make a sound or vibrate to the touch. These speakers are very efficient and with a normal input signal, if the amps could take that gain, my ears would be destroyed at the 95 setting. Nothing could be heard from the listening position. Is that quiet enough? BTW, with the preamp set at 75, this system is very loud. I would never attempt playing it at 95.

My Modwright SWL9.0 line stage and SWP9.0 phono stage are astoundingly quiet, regardless of topology.

I can turn the volume up completely with nothing playing and there is no sound, complete silence.

Was it plugged in?

I have not even heard SS that can do that - not if you put your ear up to the tweeter with the volume turned all the way up.

Well designed modern tube products are as quiet as any solid state product out there. I currently have a Mac tube pre amp and amp, and I can turn the volume up completely with nothing playing and there is no sound, complete silence. I have both VLT and ARC products completely silent as well.

The trick to getting tubes to be really quiet is the same that is used by transistors- fully differential circuits with really good constant current sources, with a well-regulated bi-polar power supply

This is not to say that such a circuit will be as quiet as the very quietest transistors, but it will sound better and will be quieter than many transistor circuits as well.

Many well-regarded 'tube' phono sections are actually hybrid. Just my opinion, but the idea of installing a solid state filter at the input of a phono section does not work for me. If I'm going to have analog, I want all the detail and the smoothness its known for...

I recently purchased a tube DAC linestage the stock tubes gave a good soundstage and detail. I replaced them with bugleboys and there was a big improvement. I then replaced those with 1950 vintage tubes and the soundstage then became enormous and the dynamics induced anxiety. I have a Accuphase C200 SS preamp that I am going to put back in the loop. As I remember the noise floor was extremely low and it will be intersting to AB the two.

Using a VAC 70/70 MKII which I find gives a totally black background and recently retubed with Sophia carbon plates. The super low noise floor shows defects in related equipment easily. If the Accuphase is as I remember and the upgrade (being done now) improves the noise floor the resulting combination should produce a stunning synergy.

My VAC is as good as it gets but on the pre amp side if the SS is better I would jump for joy as the quality of the smaller tubes produced now does not come close to older NOS tubes. A headache that I can do without.

its been my experience that mcintosh is extremely quiet...and extremely reliable

Equivalent input noise is several orders of magnitude higher with tubes. There is really no way to get around this. Semiconductors come in all sorts - so you can design circuits specifically for low noise depending on gain/impedance requirements etc.

I don't think it is a big issue Manley make great tube amps that are extremely quite - so do others.