[Amps] new amp race

[Jim Thomson]

Date: Sun, 21 May 2017 10:07:13 -0400
From: "Carl" <km1h at jeremy.qozzy.com>
To: "Catherine James" <catherine.james at att.net>,
<amps at contesting.com>, "Jim Thomson" <jim.thom at telus.net>
Subject: Re: [Amps] new amp race

<A 2 el Shorty 40 isnt out of anyones capability as Cushcraft has proven for 
<several decades and now more brands are available with decent performance as 
<compared to the rotary dummy loads of the past.

<There are several 2500-3000 W amps on the used market using commonly 
<available tubes and homebrew is still alive and well with the bigger Russian 
<tubes as well as Eimac. The Chinese 3CX3000A7, built with Eimac supplied 
<tooling, is a fine tube and a bargain in the $800 range. Use one of the 400W 
<rigs or an AL-600 booster amp. A SB-200 works fine if 160 isnt requires. 
<Bigger Eimac and European/Chinese tubes are readily available.

<Carl 

##  A 3CX-3000A7 is a superb bang for the buck, instant on too.  50 ohm input,  –59 db IMD3.
4 kw ccs anode dissipation.   225 watt  CCS grid diss. 
50 w in = 1.5 kw
100w   =  2.5 kw
150w = 3.5 kw
200  = 5.1 kw 
400 =  8.5 kw

##  Its the ultimate...sleeper tube.   Heres the ultimate blower for the 3x3 tube.
http://www.goldmine-elec-products.com/prodinfo.asp?number=G20814
Puts out  70 cfm  @  1.2 inches of water pressure.   With that back pressure, current
draw is only .4 amp  from the 120 vac line.  It uses an EC motor instead of an AC motor or DC
motor.   Variable speed is built in....using an external 10 K pot. Blower doesnt even run luke warm.
Tube requires 67 cfm @ 1.2 inches of water pressure...@  40 deg C inlet air temp = 104 deg F. 
Now you will never have 104 deg F in the shack, nor will  you ever diss  225 watts of grid diss...so the
actual blower requirements are even less.  The tube is essentially doing nothing at 5-6 kw out, not even breaking
a sweat on rtty.   Not bad for a tube that is only 4.94 inches in diam. 

Jim   VE7RF