3-500z pay the price, take your chance ?

Ahoy

last spring got Hunter Bandit, last few weeks the power has been dropping off
60 watts drive 2oo watts out 100 watts drive 200 watts out
so guess its time for a new pair of 3-500z

my question
all the different types / brands (excp. for old stock) are Chinese
so what is the difference
are they all coming from the same factory in China

RF parts prices 3-500ZGprc is 169 bucks, 3-500ZGtay is 184, RF parts brand 3-500ZGrfp $199

then there is the Machlett brand being sold on Ebay

and the Amertron 5-500 from DX Eng for $219

what is your guess as to reason for price difference
name on bottle and length of warranty?

mean time thank goodness the stalwart NCL-2000 is still perking away

still in the stacks
mac

 

3 years back I replaced th tube in the Heathkit SB-1000 with a RF Parts 3-500ZG own brand, never looked back working perfct, even sending it to Europe in double packed boxes insured and all.
Had even a bit more gain as the old (30 year) tube that it replaced.

 

This is not an answer to your questions. Its just a little info. I recently built a 2 x 3-500 amp running 3800 vdc on the plate and needed tubes. I bought 2 tubes from RF concepts and they have performed very well.
http://www.rkrdesignsllc.com/products/transmitting-tubes/

 

thanks for the tip
will keep RKR in mind
yours truly
mac

PS
just checked 3-500Z from RKR is back order
same for 811A and 3CX800A7

 

You might call Merit Arnold at RFP to see what he says, but it "seems" the difference between the three Chinese tubes they sell is the warranty period: Cheapest is 1 year, next is 2 years, most expensive is 3 years.

It's possible they're all the same tube but the longer warranty ones are tested differently -- I really have no idea. Merit should know.

 

572Bs, where is a good place to buy a pair?

 

Last time I checked, I could get a pair of 8163s at a reasonable price. Unfortunately I can't check right now.

Have you tried that route?

By the way, I hope you have, or plan to, do something about the fan. It's severely underpowered.

 

I just got 2 572B from RF Parts - send them an email and ask to be put on the list

 

Ahoy

last checked only 8163 /3-400 i could find were going for $279 each
yes the fan is under powered it has been replaced, but may go still go bigger
thinking about getting some air to the tube pins/socket connections
remember Bill Orr writing about getting air to 3-500 pins

its a nice amp, but boy it sure is bare bones
interlocks! who needs interlocks
first mod was larger fan, second mod was switch to open antenna change over relay circuit

next will be a HV relay so high voltage does not simply go on when turned on
also looking to change out the caps, diodes, ect

yours truly
still in the stacks
mac

 

Mac

I did a little searching this morning and could not even find a price that good! So, the 3-500 is probably the way to go at this point.

Matt