[Amps] SS Amps are expensive...why?

[Manfred Mornhinweg]

Lee,

> Why are solid state amps so expensive?? Even the kits are lots of
> dollars.? ?What makes them so? 

Here is my view on this matter:

The high price of SS amps is caused by a number of factors. I will list 
them, in random order:

Capacitors: SS amps are broadband, and so they require lowpass filters, 
ideally one per band, although one can skimp somewhat and manage two 
close-by bands with one filter. So an amp that covers all ham bands from 
160 to 6m will need between an absolute minimum of 6, and an optimal 
number of 11 filters. If two-section elliptic filters are used, at least 
5 capacitors are required per filter, and possibly more if some value 
has to be implemented by paralleling capacitors. Each of the capacitors 
needs to handle roughly 1000V and 10A, to be safe and reliable, or at 
least 500V and 5A, but then it has almost no headroom for slightly 
elevated SWR. Such capacitors tend to cost between 10 and 20 dollars 
each! So we are talking of $300 to over $1000 just in capacitors for the 
lowpass filters! Add to this a few capacitors of comparable 
specifications that are needed in the amplifier proper. And if the amp 
includes an antenna tuner, as many or most do, add another considerable 
number of them in the tuner! So a premium amp might contain $1500 just 
in RF capacitors.

Homebrewers and very small companies might get away cheaper, by using 
junkbox specials, Russian military surplus, or even homebrewing the 
capacitors, but companies that want to produce under well controlled 
conditions can hardly do that.

Inefficiency: Essentially all ham HF amplifiers you will find are class 
AB designs, which tend to have an efficiency of only around 50% at 
envelope peaks, dropping from there at lower parts of the envelope. Due 
to still unresolved problems coupling the drains of push-pull 
transistors, class AB broadband SS amplifiers are significantly less 
efficient than tuned, narrowband tube-type class AB amplifiers. This is 
a problem of low impedance broadband push-pull operation versus high 
impedance, single-ended, tuned operation, rather than a fundamental 
problem of solid state versus tubes. The low efficiency requires the use 
of enough transistors to safely handle the heat, together with huge 
heatsinks, copper heat spreaders, powerful fans, maybe even 
watercooling. It also requires larger power supplies. These power 
supplies tend to be much better than tube amp power supplies, delivering 
well regulated DC voltage over a wide range of line voltages, and 
usually also include power factor correction circuitry, which makes them 
easier on the power lines. All this costs money.

Engineering: HF communications is a niche market, ham radio is just a 
part of this niche market, and the proportion of hams buying new SS amps 
is tiny. So the sales numbers of ham SS amps are very low, which means 
that all engineering costs need to be absorbed by relatively few units. 
So each amplifier sold carries a considerable amount of engineering costs.

Manual labor: For the same reason (small amounts sold), companies making 
amplifiers or kits cannot automatize the whole production. A lot of 
manual labor is used. And these days anyone who works in electronics 
rightly wants to get paid a decent hourly rate. This reflects on the 
price tag. Manufacture of cabinets, front panels, etc, is also more 
expensive for small runs.

Rich customers: Most hams nowadays are old people, or at least adults, 
not school kids. The typical ham these days is retired, has time for 
playing, has worked for many years, and has earned enough money. In his 
old age he wants to play radio, putting his money to good use. If he 
gets interested in a piece of ham gear that costs $5000, or even 
$10,000, he might just pay that price, for the joy of having that nice 
piece of engineering in his shack! After all nobody can take his savings 
into the grave. Use them or lose them.  This has created a small but 
open-handed customer base, which some companies are serving with 
overpriced, luxury ham gear. Icom for example offers a $12,000 HF 
transceiver. It has good specs, sure, but the practical advantage it 
gives over a transceiver costing a small fraction of that is tiny, if 
there is one at all. Yaesu follows with a $9000 one, and Kenwood, more 
modest, "only" charges  $6500 for their flagship. All these radios are 
made to give rich hams a lot of knobs to play with, adorned with 
gold-colored stripes and the like, while a $2000 radio already can 
feature all the performance modern technology allows. And something 
similar is happening with amps. Several companies are striving to offer 
"no compromise" SS amps, offering 1500W CCS, fully automatic operation, 
the largest possible color LCD screen (as if that was important...), one 
company even has been caught advertising the large number of lines of 
code in their amp's control software... In short, the companies are 
trying to offer the best amps they can, with cost being no issue, to 
serve this small but attractive market of well-off hams willing to spend 
a lot of money for a piece of equipment they fancy. The interest in 
serving price-conscious (AKA cheapskate) hams with legal-limit, simple, 
straighforward, budget amps is far lower, probably because the size of 
that market isn't enough to let manufacturers earn a decent amount with 
small-margin products aimed at that market.

So let's home-brew! That's the essence of ham radio, anyway.

Manfred

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