Which is better, 845 or 300B?

Dear Dr. Jon Wong,

How does 845 compare to 300B? They are both direct heat triode. But in the market, most of the amplifiers are built with 300B. As 845 has higher gain, some amplifiers cascade 300B and 845. I am in fact very interested in this kind of configuration. The China made Cayin 9084 uses this configuration and cost about HK$2X,000. Is it a good amp ?

Mark

Hello Mark,

The 2A3, 300B and the 845 are actually very common for DIY enthusiasts to build single ended amplifier. The fanatics can only listen to single ended and must be direct heated valves. The Japanese are really into this, and have published many circuits and field reports.

You cannot say which valve is better, because any amplifier is dependable on the following:

1/3 Circuit Design 1/3 Component Quality 1/3 Quality of actual layout and built

and of course, also the taste of the individual listener.

So far, I would say that the 300B and 845 are very seductive at the mid range. But they are not all rounded amplifiers. Also they need care and maintenance. They must be matched to very high efficiency speakers. 300B is more popular because people find its sound more silky and transparent, and in terms of female vocal, 300B is the KING.

Unfortunately, I cannot say much about China made amplifiers. My personal experiences with them are not good, even though there are exceptions. The QC is horrendeous, and if something happens you are really stucked. You are faced with back up problem and very poor second hand value. I think we have to wait a long time more before seeing somthing trustworthy from PRC. Sad to say this. 10 years ago I used to help Joe’s HiFi Corner to check and service so many China made amplifiers. Today, I still see many giving problems. Unless you really love the amp, and there is good back up, my advise is to think twice.

Attached please find a RCA 50/845 circuit diagram for your reference. The following is from a Japanese source and they use Tamura transformers. The coupling is transformer coupled. These will have much better specs and performance than those from China. Instead of spending so much money for something that is made in China, why not you give our local Larry Hi Fi a call? Why not you build them yourself?

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