[Amps] New Amplifier

[Glen Zook]

Add that most transistor amplifiers are "dirtier" than most tube type amplifiers.
 Glen, K9STH 
Website: http://k9sth.net

      From: Catherine James <catherine.james at att.net>
 To: Amps group <amps at contesting.com>; Bill Turner <dezrat at outlook.com> 
 Sent: Sunday, April 9, 2017 8:55 PM
 Subject: Re: [Amps] New Amplifier
   
Bill Turner <dezrat at outlook.com> wrote:
> I can think of several ways where transistors are superior to tubes:
 
> 1. When not abused, transistors are far more reliable than tubes.

My SB-220 still has Eimac tubes in it.  I suspect they are the 40 year-old originals, though I cannot prove it.  Tubes should last a very long time in routine amateur service.

It will be interesting to see how long my 811's last; they been used off and for over six months without any change in performance.  Ask me again in a couple of years. When they do go, I can spend a few bucks and change them simply by plugging and unplugging them in sockets.  Can you change the transistors on the heat sinks in the sold state amps as easily?

> 2. Safer. A 50 VDC supply is essentially harmless. 3 kV will kill you instantly.

Can't argue with that.
 
> 3. No expensive filament transformer needed. 

Instead, you need an expensive auto-tuner and protection circuitry, whereas a tube radio is fine with a manual transmatch.  I use an ATR-30, which will tune just about anything.
 
> 4. A 1500 watt transistor is cheaper than a 1500 watt tube. 

Fairly meaningless given the expected lifetime of both (very long). What matters is up-front cost and ease of replacement when needed.
 
> 5. No warm up time.

The warm up time of my 811 and 3-500Z amps is essentially zero.
 
> 6. The amps you mentioned are not rated at 100% duty cycle at 1500 watts of carrier (RTTY, FM, etc.) The PowerGenius XL is (ICAS).

As I and others said, if this amp were capable of 100% duty cycle CCS (not ICAS), the additional cost would make more sense.

A $7K amp is at least $3K more expensive than a comparable tube amp.  It's hard to see where any of the above would justify the extra $3K.