how much of a tube amps power output is dependent on circuit design and how much is actually dependent of the flavor of tube for a given type. I've been looking at a variety of 300B designs and have seen various power out ratings (some as high as 20W) all for a 5V heater current. The filaments for these were really long as compared to other tubes I've seen. At $500/pair they are expensive but if they increase your power output...well you get what you pay for. Anyway any guidance would be welcome.

I'm not an expert in tube amps -i just have my first tube amp a few months ago - still, i'm always learning and...here's an interesting page from Stereophile about the 300B tubes :

In Search of the Perfect 300B Tube

From EnjoyTheMusic.com

What are the best sounding 300B tubes?

This recording is done by all and pure Tube Recording equipments.


BTW, do have an Audio Note Tube amp ?

I was told, that average burn-in times is about 200 to 300 hours to get the true performance of 300B. Patience is the virtue as always!

Some 300B Tube Reviews

Nine 300B Tubes Review -- 300B Shootout!

TJ Mesh Plate 300B Gold Pin

Svetlana 300B Tube review

AVVT 300B Review

The 300B Tube Lives Again!

300B -- The valve of last century

I thought about the audionote kit really bad. i am probrably thinking of the bottlehead kits instead. I have the cash; I just need the time to sit down and build stuff. Lately I've been seeing alot of these that claim to produce 2x the watts of a 300B. This also comes with the claim of "845 slayer" too. I just wanna know if I can get 16W from an 8W amp.

http://www.diyhifisupply.com/images/TJ300B%2B.jpg

That´s a weird looking 300B.

I understand in prallell-feed SE designs you can double up power, but that takes more than one tube per channel. I believe the output trnsformers have to be different too.

Otherwise, I seem to remember reading about getting around 20 watts from 300B´s in PP designs, which also means a couple of output tubes per channel.

Jorge

Ah the magic of SET.

The real key here is the speaker/amp matchup. I have owned three SET amps. My first was a AES SE-811 which put out 13 wpc. Later I acquired an Art Audio Diavolo which put out 13 wpc using KR 32B. My current amp is a pair of Electra-Print 300DRD which put out 13 wpc, with TJ Meshplate 300B. Somehow I got stuck in amps that put out 13 wpc, go figuire.

While 13 wpc is a largish amount of power in the SET world, it is still limited in what speakers it can drive. I have run some speaqkers that were SET friendly on paper, but my experiences proved them to be otherwise. It is important to have a speaker that has a 6 to 8 ohm overall impedance, with minimal dips. Efficiency is also a factor, but so its also important to have a simple crossover network. Complex x-overs jsut soak up ower, and SET amps usually do not have the wattage to spare. Actually, a full range driver is a viable solution in the SET world. I currently am listening to some Audio Nirvana Super 12 which have an efficiency rating in the mid to high 90's and no x-over network.

Which is the best tube, well that all depends on what the amp is designed for. Builders will voice their designs to a certain tube, and in many cases, the amp sounds best with those tubes. My Electra-Prints came with TJ Meshplares. I tried a pair of Tesla/JJ Audio 300B in them, and the sound was soft and lifeless. And the JJ is a well regarded 300B. So in reality, there is no "best" 300B(although some aruge that the Western Electric is unequivicilby the best) just the right 300 B for an amp or system.

In the end, the power output of a SET amp is a function of the power supply. If enough voltage and current can be passed to the tubes, you can generate a significant amount of power from 300B. Although 13 wpc seems to be the cap, unless you go to the KR or Vish style tube. Then 18 is possible from what I have seen. However, it is far easier to use a complimentary speaker for SET than try to generate large amounts of output power. It is just the nature of the beast, and having the correct type of speaker for SET is essential.

Regards
Mister Pig

Mister Pig,

You're right; it turns out that the power and current to the heater is the biggest limiting factor when using the godzilla-sized 300Bs. I am likely going the bottlehead route b/c I want monos and I can biamp with a SS amp that I have. My speaks are 91 dbs, so I think this will work. I'll eentually replaced the SS amp with a KT88/el34 amp.

You´re on the right track IMO.

If you´re considering bi-amping you can probably go one step further and think of an active crossover. This way you will avoid the power hungry crossover components in your speakers, effectively doubling ( at least ) your speakers efficiency, not to mention better damping of the woofers, etc.

I´m currently using a tri-amped rig with SS for the low bass bellow 120 hz, and a couple of stereo PP tube amps ( one KT88 and the other 6550 ) for the rest of the sepctrum. I´m hoping to add a SE 805 amp to power the midrange from 800hz to 7000 hz soon.

Tube amps are really happier looking into 16 ohm impedances, like the Altec 515. I´ll never understand why such drivers are rarely seen in production nowadays.

Jorge

What speakers do you plan on using?

Actually the GR Reasearch Paradox1 that I tried with my Electra-Print's were 91db efficient, and 8 ohm impedance. They never bloomed with the SET amp. However, the Monarchy Audio SM 70 PRO with 35 wpc of single ended transistor power made them sound like a million bucks. The amp/speaker relationship is far trickier to perfect than with traditional amps.

You know, a friend of mine is a big Bottlehead guy. He built some paraglows, a highly modified Foreplay, Seduction phono kit, and a pair of Straight 8's. The full meal deal. However, these days he is less than impressed with DOC's new kits. They seem to be more flexible, but not the same innovative thinking as the other ones were. He's really kind of lukewarm on them these days. says he wouldn't buy the current offerings. I am not a DIY'er, but I do trust his feeling in this regards.

Actually this friend thinks the Electra Print DRD circuit is quite good. It's a simple direct coupled design. It's available on the EP website. I know Wellbourne pretty well copy's it, but doesnt built a killer power supply with their kits. Not recommended.

Interesting part about SET is that there are so few parts in a SET amp, that everyone of them makes a noticable contribution. So parts selection can be a bit of a trial and error process, fortunately you don't need alot of them. However iron is always critical. If you were to adapt another sites circuit, there is alot of good iron to choose from. Electra Print makes a nice transformer, and the upper end Magnequest are quite good. Then there is Tango or Tamura. All fantastic stuff. If you choose to build a circuit and eschew the kit route, I am sure the SET and DIY pages at Audio Asylum could offer lots of good insights.

Since you have your speakers already, I would give it a shot with them. See how it works out. But in the back of your mind, be prepared to bring in another canidate in orer to hear what your amps will be capable of.

Regards
Mister Pig

I have response audio SP AV1s that claim to be good with as little as 10W. the extended forplay has been used recently in some very complex systems at a few shows. I am sure they are heavily modded with all that good stuff but for $1000 bucks what do you expect? I am sure it is still a very respectable offering. I am on the fence about the paramounts although the website states that these are the docs best amps to date and these were offered only recently. Their S/N ratio is not so great but we all know that depends on the tube (78Db). The smar-*test*-('") thing to do right now for me I think is to go with the mid-powered cayin I've wanted for several months. It has a pre-in, so I could build the kit later and add it. There are alot of bottlehead fanatics that do like doc's current gear BTW. As for the welbourne stuff, it seems a little advanced for me to build and too expensive for me to buy assembled ($3.6K on sale). I'd rather go with the manley stuff at that PP. If I do get the Cayin I will be free to upgrade the other aspects of my system next year and I can do some power tube rolling!!! I won't be forced to budget 2 years worth of funds for amp building. I have an understanding wife that lets me put a little over a grand a year away for this hobby plus any b'day and xmas cash. Finally, the electraprint website no longer works. Thanks. My quest to enter SETdom may have to wait (but I do like the extended foreplay).


Thanks everyone.

I just took a moment and found your speakers. I would suspect that the AV1 would not be SET friendly. They have marginal efficiency for SET, an a complex xover network. 4th order Linkwitz-Riley, and a low xover point-1K. While they may wok with a 845 based amp, 30B would be pushing it IMHO. Of course I have been wrong before, and will be wrong again. But I believe that you won't get the best performance that speaker is capable of with Paramounts, or any 30B based amp.

You know what you might want to consider? Redwine Audio makes a 30 wpc battery powered single ended transistor amp. The Signature 30 is quite an innovative little piece. Battery power supply deliminates the need for expensive power cords, or power conditioners. They sell for 1.5K, but sometimes can be found on Audiogon, if your patient enough.

But a good little push/pull tube amp would work well with your speakers. If you can find a pair of VTL Tiny Triodes, or Quicksilver Mini's, both do a fantastic job. But a PP amp is probably the best combo with your speakers, if you want to go tubes.

Regards
Mister Pig

If today's speakers seem too inefficient for low powered tube amps it is simply because speaker manufacturers are too cheap to spend the money on quality magnets, precision voice coils and low loss filter components.

Suddenly, the whole amp speaker interface became a new problem. These kind, less efficient speaker designs required higher power, higher current sourcing ability and higher damping factors than even the big McIntosh, Harman Kardon, Fisher and Marantz amps of the 60's could provide.
The introduction - mostly - in the 70's mass market of the sealed-box speaker was the beginning of the decline of the tube amplifier in those days.

The promise of small, cool and cheap SS with better sound turned out to be false. Now we have big and hot and expensive!

Time has shown us that to drive the demon loads of the speakers of the 80's and early 90's, we really needed big solid state amps that are heavy, hot running, unreliable and expensive. Also, just as digital has not improved upon the sound quality of analogue - these big, expensive solid state amps have never exceeded the sound quality of even the average vintage tube amp.

There are many paths to audio nirvana. Solid state can sound good, and there is a place for it in the audio world. For instance, driving a pair of electrostatic or ribbon speakers is not a job that man tube amps are up to, and the ones that can are brutally expensive. Cetain loudpseaker designs, such as mini-monitors can benefit from being matched with solid state amps. While I have owned tube amps for the last 25 years, I will say that there are SS amps I would consider owning. For instance, the Monarchy amps are very good sounding, so are the Pass Labs ones. The classic Classe DR-9 are timeless.

I remember the first time I heard Clesestion SL-600, the were used with some McLaren amplifiers, and it was stunning. Also haerd te Apogee Duettas with PSE mono-blocks, once again beautiful presentation. It just becomes a matter of what path you want to travel....planars, horns, mini-monitors. I believe that once the speaker canidate is chosen, then an appropriate amplifier can be auditioned.

For a long long time I waas an analog man. My last table was a Teres 255/Eminent Technology II arm, Dynavector 17D2 cartridge. It was a darn fine table. However, I no longer enjoyed the care and feeding records took, nor the room the consumed. Only recently have I found a DAC that makes me forget about vinyl. Mind you, it does not sound LIKE vinyl, but does let the music through in the manner that a good analog rig can. I can rest in peace these days, and spin my silver discs.

Regards
Mister Pig

Yep, I am ordering the cayin soon. the paramounts were tempting as part of a bi-amp config but the s/n is kinda low. It defeats the whole purpose to me. I am still interested in the foreplay cuz it will give me the chance to bi-amp at an affordable price. I'll use the NAD I have now and add something else later to replace it (if needed).