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Reviews Categories | Electron Tubes | 813 Help


Reviews Summary for 813
813 Reviews: 5 Average rating: 4.6/5 MSRP: $N/A
Description: Power Amplifier Tube
Product is in production.
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W9WQA Rating: 5/5 Mar 11, 2014 08:02 Send this review to a friend
ez to homebrew  Time owned: months
Ive used 2 with 3400v for years of light duty. lucky i have 6-8 spares! one of my best was $3 at Peotone h fest.
With a brief cw tune at 50 ma grid .5 amp plate my so so watt meter reads 800.
I had to make a socket for my first 813 amp as i had just one.i now have sockets and a filament trans.
I would like to make a compact single tube amp for 160-40 if i find an old rca tv transformer!
i had one fail on turn on and considered it a ? odd failure. otherwise they just really cook!!
oh the input is not tuned but adding a tapped toroid seemed to help matching input.
i do have my ft450 internal tuner tune into the amp and it makes a difference, some bands being necessary to satisfy the 450 swr ckts.
i run30 - 50 watt input.
i had to tinker with the pi net tap on 20 mtrs to get decent power.
i dont so far do much above 20 though.
73, listen for my big sig on 40!
 
M0BTZ Rating: 5/5 Oct 9, 2013 16:15 Send this review to a friend
Tough as nails. Great for lower bands  Time owned: more than 12 months
These amazing old tubes still give great service in my homebrewed (1kW input) HF amplifier built a decade ago as a student.

These tubes can be found at flea markets for a bargain price for what they are capable of, and they withstand abuse (though I still ensure I tune up the amp at low power first). The only slight drawback is finding a suitable filament transformer to drive the current hungary filaments. Fortunately I had managed to locate an old RCA transformer with 2 10V 10A windings which was ideal.

The amplifier works great for operation from 160 - 20m with reduced output on the higher bands, but that suits me fine as I tend to operate mostly on the lower bands anyway (Casual Low band DXer).

Operation is very docile when used in grounded grid, and pair put out a potent signal on the lower bands. I use a pair of big axial fans to provide cooling.

I also love the glow from the tubes and the amp doubles as the shack heater during the winter : Nice and toasty!

The valves are still giving full output after so many years, and as long as they continue to work well, I see no point in modding the amplifer to use a different tube.

Amazing old tubes - tough as nails.
 
K1ZJH Rating: 5/5 Mar 27, 2012 10:06 Send this review to a friend
Energizer Bunnies!  Time owned: more than 12 months
These tubes were designed in 1937, and yet it is hard to find anything comparable on the market today! They are far more stable in GG operation than either 811 or 572 tubes, and usually can be run without parasitic suppressors. According to data presented in the last edition of Orr's Radio Handbook, they even have better IMD performance than a 572 or 3-500Z. Just remember to use a pi-net input for best performance. A pair will run at 600 watts output conservatively, but many hams have pushed them much harder. They seem to be indestructable, and because so many were made they are still reasonably available! Many hams have reported that they have been using the same pair of tubes for decades. The early graphite plate versions probably have a bit more reserve plate dissipation than the metal plate varieties. RCA, GE and others made these tubes. Cooling requirements are very modest, a small fan moving air over the tubes is all that is required.
 
N0NZG Rating: 3/5 Mar 18, 2012 15:53 Send this review to a friend
813 vacuum tube.  Time owned: 6 to 12 months
I have been using a set of 813’s that are over 40 years old in my new home brew GG amplifier for the last year. These tubes are tough as nails. The factory anode dissipation rating on an 813 with a graphite plate is 125 watts, however in practical service in a grounded grid amplifier they will live a long happy life at 175 to 200 watts of plate dissipation in ssb service. I run them with 2800 volts on the plate and others using these tubes in HB amps have successfully run anode voltages up to 4KV. Now obviously this kind of service is way past the OEM rating and borders on abusive treatment. After a year of running these tubes in my amp and heavy contesting, I can attest to the toughness of the 813 tube. They require a very small breeze to keep the seal temps to a safe level. A 3 inch muffin fan is plenty. This kind of service is fine for SSB and CW service ,but I would not use them on high duty cycle modes such as RTTY, SSTV, PSK31 etc…



813 tubes use to seam like they grew on trees ,but as of late the supply of NOS tube looks to be drying up at warp speed. The 813 tube is currently being produced in china and Russia as FU13, GU13 and 813 part numbers in both metal and graphite anode varieties. The graphite plate version is the only one I can recommend for transmitting service. These tubes that are imported into the USA currently are made at one location in China and one location in Russia in a production run of several thousand at a time. Then they are private labeled by many other brands such as Green Stone USA, Sino, Shuguang and others. As of march 2012 the street price of an imported tube is 50 USD and a NOS tube can range from 30 to 100 USD depending on condition and dealer.
At this time availability of import tubes is unclear as there have been a lot of quality control issues in recent production runs and several well know domestic dealers and online retailers no longer carry NEW imported 813 tubes. The 813 has developed a huge following in the high end audio amplifier market and that demand seams to be driving production of tubes and sockets for the time being.



From the perspective of using an 813 in new equipment, my personal feeling is this is a good choice because they are durable, cost effective and will in most cases out last and perform most designs using 811 or 572b tubes. The 813 tube has a very high amount of output capacitance and thus you will have to make a very careful design is you want good performance on 10 and 12 meters. However on 15-160 meter you could expect 700 to 900 watts of output from a pair in GG service depending on design and anode voltage.
 
VE3CUI Rating: 5/5 Mar 2, 2010 14:05 Send this review to a friend
Indestructable(Sp?) Classic Jug!  Time owned: more than 12 months
Why no one has offered-up a review of the venerable 813 is beyond me...!

This vintage survivor from the late 1930's continues to give yeoman's service in my homebrewed kilowatt linear (I use two of them in parallel grounded-grid configuration).

The 813 is practically impossible to damage (short of dropping it onto a cement floor from waist height!), and like the Everyready Bunny, "..It keeps going, and going, and going, and going."

Best of all, the price for these jugs is right, too---even new---and there are TONS of 'em around at Hamfests, eBay, & your buddy's junque box. Why would anyone spend three figure dollar amounts for a tube, when a couple of these are more than up to the task, AND for a fraction of the price...?!

~73~! de Eddy VE3CUI - VE3XZ
 


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