[Jon L]

Really, really like the 2A3 triodes, the mother of hi-fidelity!

I'm really digging the 2A3 SET sound lately myself, even after trying 45, 300B, etc.  If you can get away with 3 watts, definitely give good 2A3 a shot..

[dado5]

Really, really like the 2A3 triodes, the mother of hi-fidelity! The 50 triode is also very nice followed by the 300B, VT-25A... A lot of people like the 45 triode...not enough power for me and to me not as sweet sounding as the 2A3.

My $0.02,
Pete

I put in my original reply that the 300b is better at 2 or 3 watts than it is at 8 or 10 as well as being better than the 2A3 IMO.  My guess is that this is because it is just loafing along, but I have no real explanation.

My vote for ultimate still goes to the 71A, if you can get by with the power (and I'd wager anyone with 100dB + speakers  can). Low current, low plate voltage, low drive voltage, an rp/rl/rk that allows good quality film or oil caps on the cathode and an irresistibly pure sound all wrapped up in one low cost package.

[dado5]

Really, really like the 2A3 triodes, the mother of hi-fidelity! The 50 triode is also very nice followed by the 300B, VT-25A... A lot of people like the 45 triode...not enough power for me and to me not as sweet sounding as the 2A3.

My $0.02,
Pete

I put in my original reply that the 300b is better at 2 or 3 watts than it is at 8 or 10 as well as being better than the 2A3 IMO.  My guess is that this is because it is just loafing along, but I have no real explanation.

My vote for ultimate still goes to the 71A, if you can get by with the power (and I'd wager anyone with 100dB + speakers  can). Low current, low plate voltage, low drive voltage, easy to work with filament current, an rp/rl/rk that allows good quality film or oil caps on the cathode and an irresistibly pure sound all wrapped up in one low cost package.

[keith]

I currently own WE 300B's, KR 300B's, RCA 50's, Sylvania VT-10A's as well as Philco 10's.

Hi Pete.  Just curious ... which triode is your favorite among all those you've owned or tried? 

Keith

Really, really like the 2A3 triodes, the mother of hi-fidelity! The 50 triode is also very nice followed by the 300B, VT-25A... A lot of people like the 45 triode...not enough power for me and to me not as sweet sounding as the 2A3.

My $0.02,
Pete

Thanks for that Pete.  My old favorites are 2A3 > 45 > 300B ... new fave and reference now is the 6C33C ... but I still own the other three still. 

[jon_010101]

I would love to build a 300B push-pull amp.  I have not heard any 300B single ended amps that I would have an interest in owning.... but I'm admittedly a push-pull guy... I can make exceptions for SE 211s and 845s and GM70s, though 

[Quiet Earth]

Reliable, replaceable, affordable. These are good questions when considering tubes.

So far I have used the Western Electric and the JJ 300B for aprox. 12 hours a day, 5 days a week, for three or four years (mostly the Western Electrics). The tubes do not run "hot" or heat up the room, but they are power tubes and they do get as warm as you would expect them to. Don't grab one while it's on  . Both the JJ and the WE 300B sound very good to me in my amplifier and they prove to be reliable and long lasting. The JJs are a bargain tube, but they need several hundred hours of burn in time to relax and become more natural sounding. They are a little more forward, dynamic, and lively souning than the WE, but the WE are more organic/natural/human sounding to me. The WE's are my favorite so far, but I think it's important to explore more 300Bs and have some for back up.

Right now I am listening to a pair of Valve Art 300Bs.  I only have about a week of burn in on them so it would be unfair to make a real comparison. However, I am very impressed with these tubes, both for their sound and for their "matched pair" price of 183 dollars. They seem to land somewhere in between the WE and the JJ for sound quality. They are easy to listen to, so perhaps they err on the side of omission, not commission. That said, I don't feel like I'm missing anything. If they last long, they will be a terrific value.

I would like to try the KR 300B (regular) and maybe the EAT 300B. If WE ever gets it together I will definitely buy another pair of those.

There are a few things in this thread that are noteworthy to me.

1. How long a 300B lasts can depend on the design of the amplifier. Some designers might try to push the tube a little harder and the tube may not last as long. You will have to do your own homework on the amplifier that you are interested in. You should get reasonably long life and about 8 watts from the 300B in a well designed amplifier.

2. IMO, the 300B is a beautiful sounding triode. I think that its "beauty" would be wasted in a push pull design. Consider that if 8 single ended watts isn't enough power for you, then 16 push pull watts probably won't be enough either. Dare I say that 16 parallel watts may sound rather busy compared to it's simpler, more beautiful sounding 8W single ended brother? I hope I'm not offending anyone. Why bother with a 300B if you have the appetite for power?

3. The O/P transformer, the power supply, the circuit design and the supporting parts all make the world of difference in a 300B amp. This is a given in any circuit, as you know.

4. A very good sounding, well made tube amplifier will sound very good with common tubes, but a mediocre amplifier will still sound mediocre with the most awesome and expensive tubes. Food for thought when shopping for tubes.

[Browntrout]

Here is the data sheet published by the manufacturers of the tubes I use.......
http://www.emissionlabs.com/datasheets/EML520B-Datasheet.htm
   I think they cost £650 per pair. The thing is they are hand made, the machines they use to make them are also hand made and the chaps and lasses that make them have been making tubes for years. If you look at the figures they are quite exceptional, they do not suffer from the previously stated (earlier in the thread) problem of low power output.
   Employing people who have learnt a skill and dedicated themselves to making something well is a good thing. Taking advantage of global markets and Communist Totalitarian governments to obtain cheap inferior products is in my opinion not good.
  At the risk of sounding like a big hippy it's actually the amount of love that someone puts into making something that determines how good that thing is.

P.S I agree with what Quiet Earth said and Triode Pete is spot on and far more eloquent than I appear to be this evening.

[Triode Pete]

Really, really like the 2A3 triodes, the mother of hi-fidelity! The 50 triode is also very nice followed by the 300B, VT-25A... A lot of people like the 45 triode...not enough power for me and to me not as sweet sounding as the 2A3.

My $0.02,
Pete

I put in my original reply that the 300b is better at 2 or 3 watts than it is at 8 or 10 as well as being better than the 2A3 IMO.  My guess is that this is because it is just loafing along, but I have no real explanation.

My vote for ultimate still goes to the 71A, if you can get by with the power (and I'd wager anyone with 100dB + speakers  can). Low current, low plate voltage, low drive voltage, an rp/rl/rk that allows good quality film or oil caps on the cathode and an irresistibly pure sound all wrapped up in one low cost package.

I have a 71A Stereo Single Triode Linestage Preamplifier with separate dual regulated tube power supplies. Extremely sweet sounding with just enough gain. Toughest part is getting non-microphonic 71A tubes. Currently using a pair of RCA Radiotron UX-171A globe triodes. The ST-shape ones were too microphonic.

[dado5]

I have a 71A Stereo Single Triode Linestage Preamplifier with separate dual regulated tube power supplies. Extremely sweet sounding with just enough gain. Toughest part is getting non-microphonic 71A tubes. Currently using a pair of RCA Radiotron UX-171A globe triodes. The ST-shape ones were too microphonic.

The one pair of globes I have is more microphonic than my ST bottles, but they all vary quite a bit and all are more microphonic than a 300b for sure.

Is the preamp transformer or RC coupled at the output?

I use the tube in both a headphone amp (single stage xfrmr output) and a power amp (ECC99 xfmr coupled to the 71). The amp will run out of gas much sooner than  300b's on the same speaker, but I never actually get there in normal listening - I would guess my average listening level is in the mid 80's which translates to 50, maybe 100,  milliwatts on my 101dB speakers. This is also a reason why a low power operating point worked so well with the 300b in my set up.

BTW, I agree with your profile comments on power conditioning - it's never improved a system I've had and made things worse more often than not.

[jrebman]

Is the 300b worth it? for me, my tastes, and in the right configuration, absolutely yes.  For the power-hungry there is always the Karna, and Jack Elliano has a few designs for multiple 300bs that offer heftier power output.

Dado5, when I read the initial mention of the 71a, my first thought is that I bet it would make a killer headphone amp tube, so while a bit off-topic, I'd like to know more about your 71a headamp.  PM would probably be best.

After going through too many amps of all kinds -- SS, tube, SE, PP pentode, triode, etc., the two amps I've settled on for my two systems are a single-ended el84 Carina, and a pair of Wright Sound Mono7 300B monoblocks.

Everything I've had had it's plusses and minuses, but in the end I'm ssettled on what I have even though they themselves are not perfect.

Good thread.

-- Jim

[Plink]

I would love to build a 300B push-pull amp.  I have not heard any 300B single ended amps that I would have an interest in owning.... but I'm admittedly a push-pull guy... I can make exceptions for SE 211s and 845s and GM70s, though 

another one to look into would be SRPP 300B SET

[Plink]

a single-ended el84 Carina

this looks like a great product.  i had never heard of it before!

[JoshK]

I would love to build a 300B push-pull amp.  I have not heard any 300B single ended amps that I would have an interest in owning.... but I'm admittedly a push-pull guy... I can make exceptions for SE 211s and 845s and GM70s, though 

another one to look into would be SRPP 300B SET

Do you mean the output stage in SRPP or the driver?

[Plink]

I would love to build a 300B push-pull amp.  I have not heard any 300B single ended amps that I would have an interest in owning.... but I'm admittedly a push-pull guy... I can make exceptions for SE 211s and 845s and GM70s, though 

another one to look into would be SRPP 300B SET

Do you mean the output stage in SRPP or the driver?

I think most of these designs are SRPP in the drivers are they not?  I think the advantages are excellent drive and tighter, cleaner bass or in some cases, an elimination of a second stage.  My amp is SRPP (James Burgess built) but come to think of it, I don't know whether the drivers are SRPP or the outputs.  The amp exhibits these sort of characteristics over other SETs I have heard but still retains that fleshy/meaty 300B sound.  I use it with Altecs but I would suspect that with the rights sort of speakers, such an amp may please "a push-pull guy".

But this is just discussion.  I suppose with the right builder and right parts or mini-tweaks, most all SET circuits can sound very good.   

[JoshK]

I was 98% sure you meant the driver, but found it somewhat strange to refer to it as an SRPP 300B.  If it were an SRPP output stage it would have 2 300B output tubes, not output much if any more than one 300B and would be super inefficient (twice the voltage, more dissipation in heat, twice the filament current, etc).  That is generally why it isn't done as an output stage, although never say never.

An SRPP driver is an OK driver, although it is increasingly unpopular in the DIY/hobbyist arena.  If you have interest in the benefits/trade-offs, Morgan Jones Valve Amplifiers has a good chapter comparing a number of stages including the SRPP, mu-stage, beta-stage among some others.  I've never built and compared driver stages for 300B myself to know how they differ in sound, I just know their theoretical trade-offs.

[JoshK]

A 71A makes a good 300B driver (in a 3 stage design).   

[Rocket_Ronny]

I once owned a tricked out Sun Audio 300B amp with western electrics in it. It was very 3 dimensional, which I like  , offered great clarity, but ultimately I found to be boring. While my Cayin el 34 amp, running in set mode for 4 watts, did not have the 3d, or clarity, it was way more toe tapping. I sold the Sun Audio and kept the Cayin.

As I understand it from and audio engineer, the 300B tube is just way too slow to be good for audio. I would agree. My McAlister PP-150 I now own has the clarity of the 300B, images almost as well, has solid state like bass, and the treble rings like a bell. To retube the thing is about $200.00 for all the tubes, and the driver tubes should last 7,000.00 hours.

Do yourself a favor and skip the 300B idea and pick up a used McAlister SE 44 for around $1,200.00 dollars, or support the cause and get a new shiny one from Peter. At 22 watts per channel, you will never look back. If buying new I recommend bypassing the SE 44 and going for the PP-150. They sound the same with the PP-150 being a very robust 75 watter.


Rocket_only slightly opinionated_Ronny   

[Plink]

An SRPP driver is an OK driver, although it is increasingly unpopular in the DIY/hobbyist arena.  If you have interest in the benefits/trade-offs, Morgan Jones Valve Amplifiers has a good chapter comparing a number of stages including the SRPP, mu-stage, beta-stage among some others.  I've never built and compared driver stages for 300B myself to know how they differ in sound, I just know their theoretical trade-offs.

Duly noted.  I've been meaning to buy that book but haven't got around to it.  Yeah, I'm well aware of the unpopularity attributed by some who post on forums regarding SRPP.  In a couple years, people will like it again.  I think some of these people are going for a specific sound and it's not the sound I'm going for.  Compared to what I have heard, the SRPP is a more modern sound and the bass and drive is the best I've heard from a SET.  It's not like the Naim equipment in my other system, obviously, but it does avoid the pitfalls of the typical slow 300B sound which I abhor and which I have heard on numerous occasions.

[JoshK]

Plink,

Take a look at Alan Kimmel's mu-stage and George of Tubelab's powerdrive circuitry.  These are the SRPP concept on steroids, especially George's.  They go one step further in allowing more current to drive the output on demanding peaks, but in normal passages are similar to an SRPP in many ways.

[JoshK]

As I understand it from and audio engineer, the 300B tube is just way too slow to be good for audio. I would agree.

With all due respect, then you don't understand it.  There is no fast/slow when it come to output stage.  The result of a poorly designed (which many commercial SET amps are, Wavelength & Bottlehead excluded) driver stage is a subjectively slow sound but it has nothing to do with the 300B being fast or slow. 

"Slow" sound it typically the result of too much (and predominantly 2nd order) harmonic distortion.  This results from a chinless driver stage, and is the fault of the driver not having the machismo to drive the 300B.   Unfortunately, this type of design is hugely prevelant, because it is easy to design and cheap, but gives the uninformed the opinion that it is the 300B amps that are that way. 

The 300B is not the most difficult output tube to drive but it requires relatively high gain with low distortion AND a fair amount of standing current.  Most small signal audio tubes need not apply, especially, or should I say particularly, in a 2 stage design.  But then 3 stage designs cost more and carry a stigma, meaning they don't sell as well.

The tubes out there that can get the requisite gain that audiophiles are accustomed to (whole other debate) and have the cohones to drive the 300B aren't tubes that most would recognize.  They are also harder to work with because it means high gm which have more variability between tubes, are much more prone to oscillation which requires more care/analysis/skilled layout.  Or, the driver needs to be a compound or hybrid driver (the horror, the horror! sand in our SET amp). 

This has nothing to do with your preference for McCalister or other amps, just that I think your inferences are a bit misguided.