Why not 300B?

[tubesound]

Did Conrad Johnson ever build any components using 300B tubes? If not, why not?

[AnotherJohnson]

Very low power. Not that common, although developing a cult following. Maybe they will someday.

Here is a kit

https://tubedepot.com/products/elekit-t ... gLl5_D_BwE

[AnotherJohnson]

FWIW, the WE 300B was developed for application in telephone signal amplification. It was designed to be incredibly long lived. It may actually outlast the owner when it is used in audio applications.

In a semi related story, Leo Fender (of Fender amps and guitars fame) worked in the telephone industry before going into business for himself. According to the folk lore, he copied one of the phone signal amplification circuits for one of his early bass amp designs. And in his early amps, guys who restore them say they find parts in common with the telephone industry of the day.

[tubesound]

I'm still really curious why Conrad Johnson never used 300B tubes.
There are of course ways to get more power out of 300B tubes, like parallel single ended, push pull, ... For example Canary Audio makes 120 watt power amps using four matched pairs of 300B tubes per channel

[AnotherJohnson]

I think it would have been more bizarre if they had. No one of any consequence was using them when Bill and Lew were coming up. I don’t recall seeing them in any highly regarded US products back in the day.

I was pricing them last week along with other tubes, just for the market knowledge. It looks like some folks are really obsessing over them. Some of the flavors make $300 for a KT150 look like a giveaway.

You could call and ask. I doubt they’d be interested in chatting about it, but you never know. At least then you’d have an answer from the horse’s mouth.

[AnotherJohnson]

At $1500/ matched pair from the manufacturer in GA last month

https://www.westernelectric.com/blog/th ... -worldwide

retubing 8 matched pairs would run $12000.

It would have been about $4000 to do 16 KT150s through ARC, or about $2000 to do 16 KT120s through CJ last month.

That might explain it right there.

This spike in tube prices is really making my REF 75 SE with its four KT150s look like a great long term choice. The sixteen KT120s for my pair of LP275Ms look like a greater burden.

[AnotherJohnson]

I think it would have been more bizarre if they had. No one of any consequence was using them when Bill and Lew were coming up. I don’t recall seeing them in any highly regarded US products back in the day.

Qualification … I know there are been VERY small boutique builders swearing by the 300B beginning not long after Bill & Lew started. But you can’t argue that Canary Audio, or the handful of others, are/were important players. Canary, for example, has a total of two US dealers.

CJ is just about as small as you can get and still be considered a serious player. It’s WAYYY smaller than ARC, and both are small compared to McIntosh… which is very small compared to Denon or Sony. You get the idea.

The smaller a builder is, the less of a gamble it would be to use the 300B. CJ is small … but apparently not small enough.

The new reality surrounding Russian tubes may drive the equation back and make the 300B a serious choice for the future. CJ has been introducing lower power higher priced models like the Art 27, and the Art 108A. There may be room in the lineup to offer something based on the 300B.

[admin]

At $1500/ matched pair from the manufacturer in GA last month

https://www.westernelectric.com/blog/th ... -worldwide

retubing 8 matched pairs would run $12000.

This pretty much sums up why using 300b tubes is not ideal. The tubes should only make up a small fraction of the price of the amp. So maybe they would be ok for some exotic $100k amp, but probably not applicable for something in the 4 or low 5 figure range.

[Big Dog RJ]

Yes, that's correct Admin & AJ. Also just to add, I remember my dealer network managers asking this very same question to the C&J crew back in the day... their answer was based on:
1. Cost vs performance of current push-pull design, there's no comparison. Push-pull is far more efficient in linear pentode operation.

2. Reliability factor of 300B circuit is not that great compared to push-pull config. SET Class A requires a certain load and limit, push beyond that limit and things go out of whack... hence only low powered amplifiers are suitable, which CJ doesn't divulge in.

3. If a 300B SET config is to deliver higher power, say over 100 - 200w then trannys need to redesigned, plus additional power supplies just to incorporate added power. Again, not worrh the effort since cost goes up considerably.

Although the 300B SET has a warm romantic syrupy sound... that level of musicality can be achieved with any of CJ's Premier series amplifiers in 'XS' mode, which is Triode operation and halves the output power. These special edition XS models were only offered on the Premier line.

I remember ordering just one of these on the Premier 11A when it first came out, called the Premier 11A XS, which halved the power output from 70w to 35w in triode mode using EL34's. We set it up driving a pair of Quad ESL 63's placed on top of matching Gradient subs, it was superb!

That was my first ever experience into the highend nature of CJ's Premier standard amplifiers and from that point onwards I never looked back!

So, 300B is not really a sound judgement in terms of a sustainable audio business, unless you had a very large range of audio gear to offer, which CJ does not.

Even Manley Labs used to offer the 300B at one point and I think they still do on a preamp but definitely no longer in any of their power amps. They're just not efficient and way too costly to reproduce any high power version that is worthwhile. Leave the 300B designer to others, such as Cary Audio and Jas Audio... but I'm not too sure how these brands are doing business wise

Cheers, RJ

[tubesound]

Interesting! Thanks for your comments everyone

[Big Dog RJ]

The 300B tube is a very low powered SET design, in my opinion. It's warm, fuzzy and has a very syrupy tone, far too sweet for my liking. However, when considering other SET amplifiers, the ones that proved to be stunning on an ultra-high-end level are:

1. Kondo Audio Note Kogaru monoblocks
2. Lamm Audio ML3 series monoblocks
3. Cary Audio CADse 211 series anniversary edition.

I've tried the 3rd ones at home they were fantastic driving Quads ESL2905's and 2912's. I've extensively auditioned the first two, driving Avant Garde Horns and Audio Analysis Omega's, were outstanding! However, Note* the price tags on the Kondo AN & Lamm gear is over 150grand just for the amplifiers... drug !

There are other SET amplifiers that I've heard in horn systems, such as Aries Ceret but their prices are over 200grand, and sky's the limit... so I'm not too sure why such exorbitant spend but all I can say is sonic performance is truly superb, and so is CJ gear!

I'd rather own CJ gear than anything else, real world prices, fantastic entry-level range and also offers SOTA gear if one wishes to divulge in such spend.
Cheers, RJ