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Reviews Categories | Electron Tubes | AMPEREX 3-500ZG Help

Reviews Summary for AMPEREX 3-500ZG
AMPEREX  3-500ZG Reviews: 4 Average rating: 3.8/5 MSRP: $200.00 usd
Description: graphite plate 3-500Z tube
Product is in production.
More info: http://
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KA5ROW Rating: 5/5 Oct 21, 2017 20:06 Send this review to a friend
For me Great Tube  Time owned: more than 12 months
My AL-80B manufacture in 2001 bought used in 2015 has a Amperex 3-500ZG I assume it is the original gives me about 900 watts out, works great. Wish my new AL82 had them in it. But we will see how the Tayler tubes hold up over time. I have been told that I should get a pair of Eimac 3-500G tubes. May look, but some of the people on e-Bay will not offer a refund on tubes that they say NOS. I will not pay big bucks for them unless they have sued them and can assure me they are OK. So after 2 years I will give a 5 for the Amperex
KR3DX Rating: 5/5 Oct 29, 2004 16:12 Send this review to a friend
NO problems  Time owned: more than 12 months
The following is my personal experience and my personal opinion: I installed a new Amperex 3-500ZG in my 17 year old Ameritron AL-80A over 3 years ago and I've not had any problems. I left the filament switched on for about 24 hours before applying HV to the tube. I frequently operate with sufficient current to make the plate glow a dull orange. (this is proper operation, it allows the "getter" to maintain proper vacuum within the tube) The plate in the Amperex seems to have better dissipation and seems to be more rugged than the plate in the Eimac that used to be in my amp. The quality seems very good, the elements seem to be very closely aligned and the envelope and the base are symmetrical and well made. This tube has slightly less gain than the old Eimac's due to increased distances between the cathode, grid, and plate. This also makes the tube more robust, and less likely to suffer a short between the elements. Once the filament was conditioned (when a tube is new, directly heated cathodes must be operated for quite a few hours to enable the Thorium to migrate to the surface of the filament, thereby increasing electron emission) the output power came up to spec and my tube has been performing very well since then. I feel that the Amperex is well worth the extra money it costs, the only other alternatives for this tube type are of Chinese manufacture, and they were initially problem-ridden and of very poor quality. Filaments would burn out (almost unheard of until the Chinese started making them) after several months, prompting those companies to offer longer warranties. Buy cheap, get cheap.
K9COX Rating: 2/5 Jul 28, 2004 09:13 Send this review to a friend
Problem  Time owned: more than 12 months
Had one fail in Ameritron AL-82 after about 20 hrs of filament time and 2 hrs of RF. Apparently intermittent filament to grid short. Other tube still works great, but disappointed in lack of warranty replacement (out of warranty from time of purchase). Others have reported better luck with Chinese tubes which require less drive and have a better warranty.
K0CWO Rating: 3/5 May 2, 2004 14:08 Send this review to a friend
OK  Time owned: 6 to 12 months
My new AL-80B came with one of these. The filament went south on me exactly one year after I purchased the amp new. Ameritron replaced it with a new one under warranty. The second tube performs to specs. I now use it as a backup to a Chinese made 3-500ZG purchased from Tom's Tubes (see review).

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