[Elecraft] Small HF amp suggestions

[Dyarnes]

Hi All,

I just read the post by Bill Schmidt, K9HZ, who defended the RM Italy "HLA 
series" amps as not being as bad as many folks seem to think.  I had posted 
a similar response earlier, but thought I should add some substance to my 
defense (and perhaps to Bill's).

I think much of the confusion stems from the fact that RM Italy makes 
several different series amps.  Some were apparently only intended to be 
single band amps (CB perhaps?) and did not have very effective filtering. 
However, the "HLA" series amps are intended to cover multiple bands, and do 
have decent filtering.  I own an HLA-150 amp, and have found it to be a 
decent performer, although it does have lots of deficiencies.  As I said in 
my earlier post, Tom Rausch, W8JI, made some extensive tests of that same 
model amp, and though he found some serious issues, he defends the amp's 
adequacy when operated conservatively--that mainly being to not run it much 
above 90 to 100 watts output.  Hopefully most of you are familiar with W8JI, 
who has considerable credentials in the ham community regarding amplifiers 
(he designed many of the more popular amps being used today), and is very 
knowledgeable on other topics as well.  Anyway, here is a link to Tom's 
website wherein he discusses the pros and cons of the HLA-150.  You might 
want to take a peek at it.

http://www.w8ji.com/rm_hla-150_test.htm

I'm not suggesting that this amp is a great piece of gear, or the equivalent 
to new stuff coming out currently--just that it might be usable, and not 
nearly as inadequate as some would suggest.  I also think there are many 
other choices, including the upcoming Elecraft amp, which would undoubtedly 
be a better choice.  However, I got my HLA-150 pretty cheap (used), and I 
think they tend to be sold at fairly low prices on the used market, which 
might make them attractive--at least as an interim choice--while you wait 
for some of the newer ones to become available.

Just a few watts will drive an HLA-150 to 100 watts plus.  The amp is auto 
band switching, which is a very handy feature.  It is moderate in size and 
weight.  Supposedly it will work just by using RF sensing, but I have found 
that to be problematic.  On CW the amp seems to cut off the first dit or 
dah, so it really needs to be used with a keying line from the transceiver. 
Also, it's not really a QSK amp, and that is a big deficiency in my view. 
You can bet the Elecraft amp will have good QSK, and I think the new Ten-Tec 
418 amp does as well.  The HLA-150 doesn't purport to cover 6 meters either, 
and that is another issue which other alternatives will solve.  I doubt 60 
meters is covered by the HLA-150, but the Elecraft amp will cover 60 meters, 
as will the new Elecraft amp.

Personally, I'm a little reticent about the Ten-Tec 418 amp for various 
reasons.  I'm not so sure they didn't "overcook" it a bit.  First of all, it 
looks too big.  It's twice the size of my HLA-150 (and HL50-B), and weighs 
twice as much.  Is that necessary?  All I've seen of the new Elecraft amp is 
a picture, but it looks more reasonable--and practical.  The Ten-Tec 418 
incorporates, among other things, a big LCD display, and two fans--things I 
wouldn't have thought were necessary in a small amp, but maybe they are.  I 
still have an old Ten-Tec 405 linear, which will run 50 watts+, and is less 
than half the size and weight of the 418, no fans, but has power and SWR 
metering included.  It still works FB too, even after 30+ years!  Apparently 
the new Ten-Tec amp covers 60 meters, but initially I don't think it was 
going to.  By the way, the new Ten-Tec QRP rig doesn't cover 60 meters or 12 
meters, and I think their amp was originally going to skip these bands as 
well.  I'm genuinely confused by Ten-Tec's omission of these bands, but 
that's another issue.

So, if you are just looking for something reasonably affordable to boost 
your QRP rig a couple of S units, and not too concerned about "bells and 
whistles", then the HLA-150 might be a good option--at least in the interim. 
I certainly wouldn't expect many of you to just take my word for it, but I 
think W8JI's discussion is more convincing.  Sooner or later though, most of 
us will probably yearn for the kinds of features and capabilities that the 
new Elecraft amp will undoubtedly offer.  For versatility I ultimately want 
a small amp that has good QSK, and when I want to use it with some of my 
simpler QRP rigs, I'd like to have good, effective RF sensing (hopefully 
that's a reasonable expectation).  I also want it to cover ALL of the bands 
through 6 meters.  If the new Elecraft amp does all of this, and at a 
reasonable price, I'll probably get one.  I can unload the HLA-150, and my 
THP HL50-B, and probably not be out of pocket much, if anything.  Well, I 
might have to look around for something else to unload as well, but 
hopefully it won't be a problem.  The new Ten-Tec amp is pretty expensive in 
my view.  8 bucks a watt seems pretty rich to me.  I'm not exactly sure what 
to reasonably expect, but hopefully I'm not being too naïve.

I'm also not being critical of those who find fault with the HLA amps.  They 
may very well have valid criticisms.  It's just that most of them don't 
explain very well exactly what the basis for their criticism is.  Perhaps 
the info from W8JI might explain some of it--and how to avoid the problems. 
In some cases, though, I think criticism of the HLA series may be due to 
inappropriately extending valid criticisms of non-HLA series amps to the HLA 
amps themselves.  Also, I can't say that all of the HLA series amps are a 
good bet, but the HLA-150 does seem to be a limited, but decent, option.

Dave W7AQK