The 300B: Is it worth it?

Niteshade · « **on:** 6 Feb 2009, 09:17 pm »

I ask a 'few' questions on here-because the people who answer them are knowledgeable and provide helpful answers.

To the question: 300B's are expensive. Around $200 a pair give or take (mostly TAKE).

Do these tubes last longer than, say a similarly rated KT-88? The 40 watt anode is nice- but might it be more cost effective to run 6L6's in single ended parallel, triode mode?

What is the cost/benefit ratio in technical terms (not sonics) vs pentodes. I say this because I believe a pentode can be made to sound just as good.

BillB · « **Reply #1 on:** 6 Feb 2009, 10:19 pm »

Disclaimer...I have not heard a 300b amp.

With that being said I think part of the draw is the shear beauty of the tube (looks wise).

JoshK · « **Reply #2 on:** 7 Feb 2009, 01:09 am »

I too am one who has not heard the 300B. However, the data (curves) speak loudly in favor of 300B's rather than triode strapped pentodes. From what I've seen, the TSPs are no where near as linear for large swings.

Personally, I suspect 300B's have a ho hum consensus because of their relative difficulty to drive which puts higher demand on the driver tubes, which isn't an easy feat to overcome. Second, I think the high linearity makes the fault of the driver more revealed. The higher mu of most of the pentodes puts a considerable advantage in their favor for the drive needed.

I'd like to see distortion curve comparisons (between output grids and plate or speaker terminals) between the KT88/6L6 family of tubes triode strapped and 300Bs over a range of power output without the assistance of feedback to check the inherent linearity. This would tell a tale.

Triode Pete · « **Reply #3 on:** 7 Feb 2009, 01:26 am »

The Western Electric 300B (the original & first 300B) lasts for over 40,000 hours. That's listening to your hi-fi for 24/7 for ~ 5 years straight. The tube was designed for extremely low maintenance & a very long life in licensed Western Electric theater amps (vintage mid 1930's). Some have said that the output tube(s) have lasted over 40+ years in old movie theatres!!

In single-ended mode (SET amps), they output ~8 watts, so generally you will need fairly efficient speakers. 90 db+ speakers with nice impedances (> 8 ohms).

Triodes, in general, are the most linear amplifying devices ever made by man. They do not require sonic degrading negative feedback for linearity...so their main drawback is low, power output.

But in the right application & design (very simple Single Ended Amps with very few gain stages & a low parts count), they sound simply amazing & true, with PRAT!

EDS_ · « **Reply #4 on:** 7 Feb 2009, 02:18 am »

Hey guys,

Thanks for the topic and the very informed posts.

I'm terribly interested in idea of assembling a simple - CDP/Computer, DAC, integrated tube SET? amp, speakers - system mainly for old school jazz.

My one hang-up is I really need (or at least think I need a remote volume control).

Thanks again

dado5 · « **Reply #5 on:** 7 Feb 2009, 02:30 am »

A 300b will run longer than any power pentode. Considering they are priced two to four times higher than a KT-88 (discounting WE or Euro super 300bs), I would say they would likely be cost effective in the very long run. Every pentode amp I've owned (all but one were ultralinear connected) I have replaced the output tubes every two years or so (I always replaced them in pairs if one went bad).

Sonically, I have universally preferred pentodes wired as such (again ultralinear for the most part) over triode wiring. That said, it's important to point out that these were all class AB push pull circuits.
The one pentode I spent time with that was not ultralinear wired was a 6V6 true pentode class A push pull and it is the best push pull design I have yet encountered - I would say this is best low cost alternative to a 300b in its power range.

The only pentode I have heard as a SET was an EL84 and I was underwhelmed.

Now for the 300b. For 8 + watts it's the best choice. If you can go lower, it's wonderful at 2 watts (200 volts, 50 ma, 35 volt bias) - better than a 2A3 IMO. However if you really can go lower, the 71A is best of all - it puts out 3/4 of a watt so 100dB is the entry point for speaker efficiency, but the sound is to die for (and they only cost $30 a piece).

JackD201 · « **Reply #6 on:** 7 Feb 2009, 04:05 am »

I have a pair of WE 300Bs from 1956. I was born in 1970. They both still measure very strong today even if I don't know what the heck these tubes have been through. Somehow I suspect they might even outlive me

I have had to replace new production KT88s in another amp already. This isn't a scientific explanation but the experience has swayed me in an obvious direction.

iGrant · « **Reply #7 on:** 7 Feb 2009, 02:51 pm »

Quote from: Niteshade on 6 Feb 2009, 09:17 pm

I ask a 'few' questions on here-because the people who answer them are knowledgeable and provide helpful answers.

To the question: 300B's are expensive. Around $200 a pair give or take (mostly TAKE).

Do these tubes last longer than, say a similarly rated KT-88? The 40 watt anode is nice- but might it be more cost effective to run 6L6's in single ended parallel, triode mode?

What is the cost/benefit ratio in technical terms (not sonics) vs pentodes. I say this because I believe a pentode can be made to sound just as good.

Hi Blair,

Just to get those numbers right, 300B's start at around $200 a pair and for NOS WE 300B's the price is getting up over $2k, decent new production 300B tubes range from around $300 to $900 a pair. I would suggest getting (or building) a 300B amp to have a comparison to aim for/improve upon with a pentode design. The 300B is just the most popular SET, the magic is really in the SET design and yes I too believe you can build a pentode that sounds just as good. Those that are hooked on the 300B SET sound aren't likely to give it up, no matter what you build, on occasion they will drift to a 2A3, 211, 845, 805, EL84 etc SET, but the comparison always come's back to the 300B as the holy grail.

Now if you can build a 50 watt 300B SET, you will rule the audio world

Cheers,
Ian

Niteshade · « **Reply #8 on:** 7 Feb 2009, 03:12 pm »

I purchased a pair of Electro Harmonix 300B's w/ ceramic bases for a very reasonable price. They sound and work great, but one of them is loose inside-It looks like the top mica wafer is a little too small, so when you tap it it makes a 'thunk' sound from inside the tube. Its mate doesn't do that.

With that said- who makes the best, most reasonably priced 300B? I assume you get what you pay for, but I don't want to get anything overpriced. Do you think the high quality, new production 300B's last as long as those mentioned earlier in the thread?

Seems like a good project would be to make a push-pull 300B amplifier capable of around 30 watts, as to not push the tubes too much. The 6SN7GTB or GTA should be a good driver/phase splitter for the job. They have a much higher plate dissipation rating than the G or GT series.

A note on the Electro Harmonix tubes I purchased: Despite the problem, as I said, they do play without issues and seem to be built well. That problem I have is hopefully not a chronic issue.

Niteshade · « **Reply #9 on:** 7 Feb 2009, 03:21 pm »

"Just to get those numbers right, 300B's start at around $200 a pair and for NOS WE 300B's the price is getting up over $2k, decent new production 300B tubes range from around $300 to $900 a pair. I would suggest getting (or building) a 300B amp to have a comparison to aim for/improve upon with a pentode design. The 300B is just the most popular SET, the magic is really in the SET design and yes I too believe you can build a pentode that sounds just as good. Those that are hooked on the 300B SET sound aren't likely to give it up, no matter what you build, on occasion they will drift to a 2A3, 211, 845, 805, EL84 etc SET, but the comparison always come's back to the 300B as the holy grail.

Now if you can build a 50 watt 300B SET, you will rule the audio world"

I plan on making a 300B SET, push-pull or SETP based amplifier. Most likely all three at some point in time. The 50 watt SET is out of the question unless you'd like a 572B based SET and THAT would be an awesome amp!

Pentodes do indeed sound very,very good.

That reminds me- do those who like 300B's also enjoy their large cousins: 211's, 845's, 572's, etc...?

denjo · « **Reply #10 on:** 7 Feb 2009, 03:22 pm »

IMHO, nothing comes as close to the real thing as the 300B SETs!

While the older NOS 300Bs are nice sounding, I don't believe you need to spend that kind of money to enjoy SET magic. I have tried the newer offings from KR and Cary Audio (not sure if these are JJs or Sophia Electronics) but they sound very good to my ears!

Best Regards
Dennis

woodsyi · « **Reply #11 on:** 7 Feb 2009, 03:37 pm »

No. Too expensive.

JoshK · « **Reply #12 on:** 7 Feb 2009, 06:45 pm »

Quote from: iGrant on 7 Feb 2009, 02:51 pm

Hi Blair,

Just to get those numbers right, 300B's start at around $200 a pair and for NOS WE 300B's the price is getting up over $2k, decent new production 300B tubes range from around $300 to $900 a pair. ...

Correction, if I may

EH 300B's are about $100/pair
JJ 300B's are ~$240/pair

new production WE 300B's ~$1000/pair (actually not sure if they stopped new production)
KR 300B's ~$800/pair

I follow a lot of small time hobbyist/pro builders. One in particular Kevin Kennedy has used just about every 300B made. He says that the WE 300B (new prod) is about the best, but that the JJ 300B's is so close that he doesn't bother with the WE300B. JJ 300B's are $240/pair.

He is not the only one I've heard say this who has actually compared the high end ones to the JJ 300B, so it is just not one opinion.

I bought my JJ's when they were $200/pair and they went on sale for 10% off. Still I think the current price of $240 is still very tempting when compared with Gold Lion KT88's at $80/pair and likely won't last nearly as long.

iGrant · « **Reply #13 on:** 7 Feb 2009, 07:19 pm »

Thanks for the correction Josh. I'll have to get some of the JJ's and EH's to check out. I use some of their other tubes in other gear and they work well and in one case, extremely well.

I don't believe there is any such thing as a 'best' tube, there are favourites and 'ones that work great in my gear' type thing. Every 300B shoot-out I have read ends up with a different top dog.

The WE 300B NOS will always be what 'others' are compared to, rightfully so. Just getting increasingly hard to afford and the new production WE seems to be on again, off again. Hope they get that sorted out.

Hey Blair, offering a 300B tube amp will help you in the long run, lots and lots of potential customers and interest. Technically, sonically or whatever (cost benefits) reasons aside, 300B's are cool

Cheers,
Ian

Niteshade · « **Reply #14 on:** 7 Feb 2009, 09:34 pm »

One of the best prices I've seen is here:

http://www.beyondeleven.com/ProductDetails.asp?ProductCode=Electro-Harmonix-300B-EH

JoshK · « **Reply #15 on:** 7 Feb 2009, 09:45 pm »

Oops, your right. I recalled ~$89 for the EH 300b, but that was each, where most of the others are quoted in pairs. Looks like both the Shuguang and EH are around $165/pair (ebay prices through dealers).

Niteshade · « **Reply #16 on:** 8 Feb 2009, 12:15 am »

Here's some other tubes to try if you're an experimenter:

6N7, G & GT

6SN7GTA & 6SN7GTB (high watt versions of the 6SN7)

6N6 (An interesting tube, but more rare)

6BL7, 6BX7

There are a few others too.....don't forget the 6AS7, 6080 tubes.

Want more power? Just put them in parallel or use a push-pull circuit (or both!)

vett93 · « **Reply #17 on:** 8 Feb 2009, 02:04 am »

How much power does 300B require from 6SN7GT(A/B) to drive it? I have found 6SN7GT sounds better than the GTA or GTB variants.

I really like my 300B SET amp, which is used as a bedroom system. It is delicate, gentle, fast, and musical. It has all the details you want but does not show them at your face.

dado5 · « **Reply #18 on:** 8 Feb 2009, 03:57 am »

Quote from: iGrant on 7 Feb 2009, 02:51 pm

Now if you can build a 50 watt 300B SET, you will rule the audio world

Cheers,
Ian

It's not SET but it is 50 watts of 300b

http://canaryaudio.com/339.htm

PaulFolbrecht · « **Reply #19 on:** 8 Feb 2009, 04:11 am »

You run a tube amp company and are asking if 300Bs are 'worth it' compared to KT88s - but not considering sonics?? What does that mean?

Any power triode, most especially a direct-heated triode, has a sound rather different than a pentode. You should listen and decide if they're worth it. Many of us find them quite superior, and the paper linearity of DHTs (and the subsequently simpler circuits) makes that sensible.

By the way, $200/pr is close to the low end of the scale. IMO the best 300Bs are EML and KR, both running significantly more than that but not nearly as much as NOS WEs.