Tubes-More is better?

KCF

Ignorance gives rise to this question...(duh!)
Re. tube components, e.g. preamps, is there a general correlation between the number of tubes in a unit and the quality of the sound? It seems from general survey that this is not necessarily the case, i.e. some of the more well-regarded components may have only ONE tube, whereas some others have two, three or four. Would it be fair to say that the increase in number of little glass spheres render more of the tube desireables, i.e. warmth, definition, etc? Or is the TYPE of tube and circuitry in a given configuration more the determining factor?

HBombToo

Originally posted by KCF
Or is the TYPE of tube and circuitry in a given configuration more the determining factor?

I think you nailed it here IMHO... SET's from what I have read are the most simple setups but you need very high efficiency speakers since you don't have the available power.

I am a rookie at the tube deal so I may be off my rocker.

HBomb

rskarvan

I'm thinking more tubes means more power handling ability.

RuSsMaN

It's all in the circuit design, and tubes chosen for that circuit.

More is not always better, or more powerful (amp wise).

Cheers,
Russ

KCF

Okay, I've seen the SET designation, (but don't know the definition). Apparently this is a good thing. Can the lack of power handling ability be compensated for, by use of a tube-pre (SET) and SS amp with plenty of "juice"?

madmax

Sure, but it is a trade off. More juice but less definition. Tubes are special. They pull you into the sound. My experience was that I totally enjoyed the tube/ss combo for about an hour of listening. With tubes I have to pull myself away after many hours.
madmax

KCF

Okay, so does this mean that it's better to go straight tube-to tube in a pre/ amplifier set up, or SS to SS, as opposed to mixing? I'm thinking maybe of experimenting to see if I like the tube element, but it appears the tube amp thing may be out of my reach right now, in order to have an amp with sufficient juice to cut the mustard. It appears you don't want to have insufficient muscle to provide power AND definition to your system (as apparently may be the case with 10-12 watts of tubes).

I see that at some point Mr. Russ used a tube pre-amp set up, but not clear if it was ALL tubes.... or whether there were some transistors in there as well?

Thanks for the info..

K.

--Oh, and P.S> Since it appears that a full blown (no pun) tube set / replacement for pre AND amp can run into some heavy dinero, I hoped that this might provide a cheapo but satisfying alternative...

madmax

10 to 12 watts is insufficient unless you have the proper speakers. 50 to 60 watts per channel is a different story. You can find many integrated options for $400 to $600 used. Dinero not that heavy.

HBombToo

I run tube peramp with an ss amp and really like what I hear. Max called it right by stating that there is just something about the tube sound that pulls you in.

I think you achieve the best of both worlds by mixing the technologies much like tube outputs on cd players.

HBomb

madmax

At this point I can come right off the vinyl into the tube preamp, through the amp to the speakers and not one tube electron is defiled by the nasty silicon.

Well, maybe a few, I have two diodes in the amp power supply. When I get brave enough I may add a rectifier tube to solve that problem.

madmax

mhardy6647

Nope. more tubes doesn't mean better, just more!
In the 1930's and 1940's, radio manufacturers literally put extra (!) tubes into some designs so that they could claim more tubes than a competitor. The 'extra' tubes were in the circuit, but were inessential.

Generally, a power amp can get by with one gain stage (voltage amp) driving one main amp stage (power amp). As implied by several earlier posts, the power output capacity of a single output tube is rather limited (except at VERY HIGH plate voltages... let's not go there for this discussion). More output power can be had by paralleling output tubes and/or by going from Class A to Class B operation and/or from single-ended to push-pull operation. This is all also absolutely true for classic (analog) transistor power amp design. "Digital" amps are different.

A push-pull amp will also need a phase-splitter (to separate the "+" and "-" components of the signal). This is usually another tube, but can be done other ways (e.g., with a transformer).

I won't go into the high power/low power debate here, but suffice it to say that for modern speakers of low/medium efficiency, yes, a push-pull power amp with, say, two EL34's per channel (or other, similar output tubes like KT88's or 6550's, etc) -- ca. 30 to 50 watts -- is probably reasonable.

As to preamps: well, you generally would have one gain stage and a 'buffer' to provide a low impedance output to the power amp (so that you can get away with long interconnects from preamp to power amp). The buffer can be tube or solid state.
A phono preamp (MM cartridge) would require another gain stage.

Beyond that... well... there are good and bad reasons to add more tubes.

RF circuits (tuners) can sometimes follow the "more tubes is better" maxim... but that's another story.

Hope this helps more than it confounds!

organ

Seems like the other members have answered your question. It really depends on who you ask. The purists will tell you SET (Single Ended Triode) is the best because it's the most basic design. The downside is that you'll need super efficient speakers to make a SET amp play loud (100db/w/m or more). I think the 300B triode tube will only put out 8w max. Some SET amps are only 2w/ch or less.

These people look for speakers and amp combo that will only need 1w to reach the desired spl level. The theory is that the most dynamics and purity in tubes is to be found on that very first watt because doubling the power will only increase the output by 3db. Makes sense to me but how the hell can I afford a combo like that? Big $$$ and speakers.

For the rest of us there are more powerful output tubes with different designs to choose from. I have a push-pull amp that I've converted to triode output operation. Puts out around 12w/ch but it's enough for my speakers (98db/w/m). I'd like to have one of those "mega watt SS punks" come over one day, pump up the volume until the speakers smacks them across the face, tell them it's only 12w/side and see the look on their face. That would be priceless.

One thing that haven't been mentioned is the use of tube or SS rectification. This converts your AC to DC. Tube rectification will add another tube to the unit. I haven't heard a tube amp using SS rectification but going from a current production Russian rectifier tube to a NOS made a BIG difference in my rig.

Maurice

KCF

Thanks to all for your very well-informed replies. Organ, I see you've gone Dynaco, ST-70. Isn't that rated at 35 wpc rather than 12? I've been considering that option, it seems like a classic workhorse.. What about connections, don't they have an odd connector system with that model, what do you do about conversion? Is you NAD tube as well? Last question, seems Klipsch are hi-efficient. Whatabout Polk Rti's?

Thanks,

K.

amulford

Whatabout Polk Rti's?

Around 89 - 90 db/w/m. Not bad, but not the kind of efficeincy your getting from those Klipsch. I've seen some up to 102 - 105 db/w/m. That's what you want for an 8 wpc tube amp, if your looking for high spl. Most of the time your going to be near fielding with those types of amps, so SPL isn't really an issue, whereas faithful reproduction, clarity and invisibilty are the highly chased virtues...

organ

KCF,
Dyna said it's 35w/ch but a lot of people say it's overrated and it's actually around 24-25w/ch. This is the stock configuration using the "Ultralinear" design. Slightly less power than pentode but a little cleaner. I've converted mine from ultralinear to triode which reduces output by half. The triode is superior IMO. So basically I'm running pentode tubes as triode. This is referred to as "triode strapping".

If you know how to solder and understand the simple basic stuff in electronics, this is a great sounding amp. The only problem is age. Many parts will need replacements. Dyna amps are more high maintanance than today's modern tube amps but they sound very sweet. It's so much fun to restore and mod this amp.

Yeah, it came with some funky connections. I installed binding posts on mine. I've done plenty of work on it. New power supply cap, bias caps, coupling caps, some resistors, gold plated rca inputs and new gld plated, ceramic tube sockets. The tube sockets was the most challenging.

My NAD is Class A SS. I used to run an Antique Sound Lab AQ2004DT tube pre, but it broke down on me. I've been too lazy to take it to the repair centre which is about 1hr away. I have a much better pre coming next week (Golden Tube Audio) which is a SET linestage.

Amulford made a good point about RTi's. I wouldn't use them on 8w/ch amps. I've had experience with the RT800i and Dyna which was VERY good. This is in the stock ultralinear connection, not triode. It was able to play loud and you can clearly hear the tube warmth, bloom, etc. The sound was very 'liquid'.

I might get slammed for this but I'd take the 800i powered by tubes over my LSi9 any day! That of couse is IMO.

But the Klipsch RF-35 are the best speakers I've heard. Before that I had the 800i and LSi9. Sold the 800i but still have the LSi. Klipsch is a different animal than Polk. You'll either love the sound or hate it. The Polks lets you hear a very good reproduction of music while the Klipsch creates a 'live' event(and their motto..."Just Like Live"). They sound more like concerts than normal speakers. They very strong dynamics. Rim shots on a snare drum can scare the crap out of you. If you enjoy the sound of amplified concerts, you'll enjoy the Klipsch sound.

If you're seriously thinking about getting into tubes you need to either find a tube amp that will work with your current speakers or find another pair of speakers and an amp that will work great with them. Most tube lovers prefer high eff with tubes. IMO, tubes and horns is a match made in heaven.

Maurice

KCF

Ah, muchisimas gracias. Graduate level tubal education for the asking..
Some over my head (what's spl?) but very helpful in general. Sounds like the Dyna would work with my Rti70s in the ultralinear mode. If I were going this way, I would look for upgraded unit.. With the SET pre-amp it appears you're REALLY going lo watts. Apparently the key is all in the speaker set up.
Cheers, and thanks again.

Kevin

HBombToo

Originally posted by organ
IMO, tubes and horns is a match made in heaven.

Maurice

one step at a time:p

twin

mhardy6647

spl = "sound pressure level"

Generally measured in deciBels... dB's... you knew that already :-)

The Bel(l) was named after Alexander Graham... but turned out to be too unwieldy a unit, so the decibel (one tenth of a Bel(l) became the common unit of SPL measurement.

BlueMDPicker

These are at the top of my wish list:

DIY Hedlund Horns