Genalex - Gold Lion PX-300B

6 Reviews
SKU: GL-300B

Availability: Usually ships within 24 hours.

USD $‎205.95
In Europe during the 1930's the GEC (Genalex) / Marconi-Osram PX4 and PX25 power triodes were considered the finest audio triodes of their day. In keeping with the tradition of Genalex to provide the highest quality tubes, New Sensor has released the Genalex Gold Lion PX300B audio power triode. This tube is the highest quality 300B type available and is considered to be an upgrade in any 300B amplifier.

Be sure to read the great 300B tube review and comparison from the Wall of Sound.

Other Genalex - Gold Lion tubes300B Tube Types

Additional Information and Downloads

300B Tube Reviews

Genalex - Gold Lion PX-300B Datasheet (PDF)

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Warranty Information and Return Policy

Warranty Period: 3 months

All our tubes are guaranteed for 3 months from the date of purchase. (Any exceptions will be noted on that tube's Warranty tab)

If you receive a tube that does not perform to the manufacturer's specifications, please do the following:

- contact us to get a return authorization
- return it via regular mail within 90 days from when we shipped it, and we will provide an exchange or refund of the full purchase price of the tube.

Returns not related to warranty or defect will be considered at our discretion, and are subject to a 15% restocking fee.

We can not accept returns that don't have an authorization, are past 3 month, or are returned improperly.

These guidelines may be updated without notice.

Ratings & Reviews

6 reviews

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Clear Winner of my comparison review


I recently reviewed the whole fleet of 300B tubes. The Genalex Gold Lion PX300B won - it ranked #1 in 7 out of my 8 music tests, using two single-ended amps. This tube is detailed, musical and just consistently a joy to listen to. It basically does everything "right". For my full review see my website,

Excellent tubes


I was waiting for Noam to finish that review of 300B tubes. I wanted something really good that cost less than the other premium tubes out there. (Not that these are cheap, but compared to some of those other really high priced ones!!)
I was using Electro Harmonix and JJ 300Bs in my two amps. I knew the JJs were the better of those two. When I plugged in those Gold Lions and they was a No Brainer; these are really good tubes. They do everything beautifully. I can't imagine that those other high priced tubes will do much, if any, better. The Law of Diminishing Returns starts after the Gold Lions.

Great performance !


I picked them up based on existing reviews, without knowing anything about Gold Lion version of 300B. When amp was ready and up for party, I was amazed about power over clarity, nice frequency coverage and sound richness. I totally recommend this tube.

A well made affordable 300b !


I'm running this tube since a while now, basically as my all day working tube. I do own a pair KR Audio 300b as well. The Genalex Gold Lion 300b doesn't have the same sheer rock solid sovereignty like the KR. She sounds a little more flourish less sober and less detailed compared to the KR but offers a very wide soundstage nonetheless and a very good tonality over the complete spectrum and is or course detailed. Bass is a bit less dry compared to the KR . But don't forget the KR is a 400€ tube and the Genalex a 150€ tube. I've heard a few others in the Genalex price league and this Russian tube clearly beats JJ and EH for example with ease even if Eh comes effectively from the same house!

So those of you searching for an affordable all day tube should give this Genalex a shot, In this relatively unequal fight, KR vs. Genalex she has pulled out of the affair very well without major injuries which is why she get my recommendation

IMO one of the best if not the best 300b in this price class!

Great product !


Have used them in a DIY amplifier in a combination with top preamp tubes (E88CC Telefunken) and amorphous audio transformers. Delivers an outstanding detailed sound, very good coverage on high and low frequencies. It is a very good one !