[Amps] Want to build first amp

[Jan Erik Holm]

GS35b costs MUCH less then 8877´s or 3CX1200 tubes.
For a 160-6m amp I would try a GS35b any day.

73 Jim SM2EKM
-----------------------

Steven J Fraasch wrote:
> Tomm:
> 
> If it was your first, given your gain requirement (1500w out for 50w in
> or 14.8 dB !), I would recommend an 8877 in grounded grid.  That tube
> should provide 13 - 15 dB of gain depending on tube and bias.
> 
> There is an excellent 8877 design by W8ZR in the 21st ed of the "Radio
> Handbook" by Bill Orr, W6SAI )late 70's edition).
> 
> I modified a Henry 3K over to an 8877 and was very pleased with the
> performance, especially the gain.  One disadvantage of the 8877 is the
> relatively long warm-up, about 3 minutes.  It has a reputation for a
> fragile grid, but is much more indestructible than is given credit (ask
> Rich, AG6K).  I limited the current on mine with a trip circuit to less
> than 125 ma with a fairly slow time constant, on the order of 200 ms.  I
> never lost a tube to grid failure, and used the 8877 for 16 years.  I
> popped the grid current relay a few times due to mis-tuning, but never
> lost the tube.  The Henry 4K, Alpha 77D and SX (pair), and Ameritron
> AL-1500 use the 8877.
> 
> The other tube to consider is a 3cx1200, which is very rugged, has quick
> warm-up, but a little less gain, 11 - 13 dB.  But, it is excellent as a
> grounded-grid choice.  The Ameritron AL-1200 and Henry 3K Ultra use this
> tube.
> 
> A pair of 4cx800s is worth considering, but the power supply will be more
> complicated adding a screen supply and commensurate protection.  The QRO
> HF2500DX, Alphas 91 and 99, and ACOMs use this tube.
> 
> Good luck with the project,
> 
> 73, Steve K0SF
> 
> 
> On Thu, 20 Jan 2005 03:58:09 +0000 Tomm Aldridge <KD7QAE at ARRL.NET>
> writes:
> 
>>Learned listmates,
>>
>>I want to embark on building my first HF tube amplifier.  I would 
>>like 
>>to know what to start with, GG triode or Grid Driven Tetrode.  I am 
>>
>>looking for legal limit plus and will provide 230V for operation.  
>>GS35b 
>>tubes have caught my eye as have GU84b units but I am open to 
>>suggestions.  Oh, and this will be a deskside unit with a 19" rack 
>>as 
>>its basis and it will be expected to provide service from 160m to 
>>6m. 
>>Lots of great material out there on both flavors.  I am looking for 
>>
>>reliable operation, ruggedness (tolerance of my errors), 50 to 100W 
>>
>>drive from my Kenwood to full output, simplicity and cost 
>>effectiveness.
>>
>>I am an experienced EE with PSU and systems experience but have not 
>>ever 
>>tackled a tube amp below 10GHz (grin).
>>
>>Waiting for all teh great guidance.
>>
>>KD7QAE
>>