[Amps] Alpha 76A drive levels...

[tz4am at aol.com]

Carl:
Got it. I keep the grid at 60 ma max.
But on 40m to get 60 ma, I have to drive with 87 watts which seems a bit much, pushing out 1 KW. On other bands drive is only 40-60 watts but output is only 800-850 watts with 60 ma of grid current.
For my 3-holer, what should be the max plate current allowable?
73, 
Jeff


-----Original Message-----
From: Carl <km1h at jeremy.qozzy.com>
To: tz4am <tz4am at aol.com>; amps <amps at contesting.com>; wa6fgi <wa6fgi at steeltrails.net>
Sent: Wed, Jan 2, 2019 3:43 pm
Subject: Re: [Amps] Alpha 76A drive levels...

 The tubes are rated at up to 30maeach so you can run them all at 60ma as now until they needreplacinrg or a 2 x 3CX800A7 conversion. I tune using the grid current peak only using theLoad control to increase or decrease the grid current and the Tune control to dothe peaking. Carl   
 ----- Original Message -----  From: tz4am at aol.com  To: km1h at jeremy.qozzy.com ; amps at contesting.com ; wa6fgi at steeltrails.net  Sent: Wednesday, January 02, 2019 4:32 AM Subject: Re: [Amps] Alpha 76A drive levels... 
Carl:  
 I have a 3-holer, with so-so tubes. 
 On 40 meters on the SSB setting, tuning to keep grid current maximum at no higher than 0.6 on the scale and a dip in plate current, I get about 1 KW forward power; it takes about 87 watts to get this output with so-so tube. 
 On other bands, the same procedure yields about 850 watts with drive of between 40 and 60 watts. 
 Is this the right procedure for tuning or should I be doing things differently? 
 73,

Jeff

 -----Original Message-----
From: Carl <km1h at jeremy.qozzy.com>
To: tz4am <tz4am at aol.com>; amps <amps at contesting.com>; wa6fgi <wa6fgi at steeltrails.net>
Sent: Wed, Jan 2, 2019 2:24 am
Subject: Re: [Amps] Alpha 76A drive levels...

 As low as required to peak the output at 1200W, about 30-40 ma total with 
 used tubes at 60W or so.
 
 I bought this amp as a basket case, bad tubes, transformer, bandswitch, etc, 
 so do not know what it did when new.
 
 Carl
 
 
 
 ----- Original Message ----- 
 From: tz4am at aol.com
 To: km1h at jeremy.qozzy.com ; amps at contesting.com ; wa6fgi at steeltrails.net
 Sent: Saturday, December 29, 2018 11:02 AM
 Subject: Re: [Amps] Alpha 76A drive levels...
 
 
 Carl,
 
 
 Thanks for the information. What is the grid current reading at 1200w?
 
 
 Jeff
 TZ4AM
 
 
 
 -----Original Message-----
 From: Carl <km1h at jeremy.qozzy.com>
 To: amps <amps at contesting.com>; Gary Smith <wa6fgi at steeltrails.net>
 Sent: Sat, Dec 29, 2018 2:59 pm
 Subject: Re: [Amps] Alpha 76A drive levels...
 
 
 Alpha offered a low drive mod for that series of amps, check their legacy
 
 amp docs.
 
 
 
 My 76PA 3 holer will easily run 1800W with100W drive, I back it down for
 
 1200W.
 
 
 
 Carl
 
 
 
 ----- Original Message ----- 
 
 From: "Gary Smith" <wa6fgi at steeltrails.net>
 
 To: <amps at contesting.com>
 
 Sent: Sunday, December 23, 2018 5:06 PM
 
 Subject: [Amps] Alpha 76A drive levels...
 
 
 
 
 
 > To the group:
 
 >
 
 > Have a friend who recently purchased a Alpha 76a two-holer.
 
 >
 
 > He currently is driving it about 65 watts getting 500 watts or so output.
 
 >
 
 > As he has no instructions on the amp, is this low level of drive okay or
 
 > should it be driven at a higher level of input power.
 
 >
 
 > Thanks to the group,
 
 >
 
 > Gary...wa6fgi
 
 >
 
 > _______________________________________________
 
 > Amps mailing list
 
 > Amps at contesting.com
 
 > http://lists.contesting.com/mailman/listinfo/amps
 
 
 
 
 
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