In April 2012 I reported on this site that Acom had announced a new amplifier. At the time, I had an Acom 1000 and in the comments, I said “I don’t think I’ll be swapping my Acom 1000 for an Acom 1500 any time soon!”. Technically I was correct, it wasn’t any time soon. In fact it was nine years later that I replaced my Acom 1000 with an Acom 1500 as I posted here.
It’s now been about eighteen months since I got the new amp and I thought it was time to write a review. This isn’t a technical review with performance figures, it’s an operator review, talking about how it is to use in real life.
As you can see, I still haven’t taken off the protective film around the edges of my amplifier but that’s OK, I still haven’t taken the protective cover off the display on my Kenwood TS-890.
The main differences between my Acom 1000 and the Acom 1500, apart from the increased power is the internal switch which allows three aerials to be connected. This is really useful for me, I have my Hexbeam which covers 20m – 6m on one socket, the 40m Hexbeam extension on another socket and my 30m dipole on the third output. With the old amplifier, I had to swap the feeder when I wanted to change bands and that could get a bit tiresome at times.
The GU74B valve in my older amplifier was starting to get a little bit soft which is hardly surprising really considering the amount of time I’d run in data contests using full legal power and I’d noticed that I’d had to start increasing the drive to get the required power out out. It’s really nice to have a higher rated amplifier which I can run at even lower input for the same output.
A common ‘complaint’ about valve amplifiers is that they can be a pain to tune. That’s not the case with Acom amps and their tuning aid. You simply tune the load knob to centre the indicator, then the tune knob for highest power and that’s it. I find that the amplifier needs very little retuning as I move around the bands. If I tune in the centre of the SSB section on 20m, I don’t need to retune as I work through the band. I have a crib sheet which gives me basic settings for each band and it only takes a couple of seconds to get going.
The Acom 1500 seems to be absolutely bomb proof. I’m having some problems with my Hexbeam at the moment, it seems to give a random SWR between 1.5:1 and 2.5:1 on 15m but the amplifier handles it without complaining even slightly.
One thing I’ve not seen mentioned on other reviews is that the Acom 1500 is ambidextrous. With the tune knobs being central, it means that it doesn’t really matter where you have it in the shack, it’s equally reachable with either hand. I know that’s picking at straws for positives but because of where I’ve got it in my shack, it would be awkward to reach with my left arm if the main controls were mounted on the left.
It handles everything I can throw at it without even breaking a sweat. I can operate for hours and hours on end in data contests, running full legal UK power and the fans don’t ramp up to the second level, it just sits there, effortlessly. The fans aren’t completely quiet but compared to the high screamer sounds from solid state amps, this is fantastic.
I adore the super fast and super quiet switching “vacuum antenna relays” which make it a dream to work on full break-in mode on CW. If I’m trying to get through a pileup, I can hear when the other station starts transmitting and if I’m still calling, I can simply stop keying.
I always drive the amplifier with zero ALC shown on the meter of my wireless and the output is very clean. I still have the KK7UD IMD meter that I bought years ago to ensure my signal is clean when operating psk31/psk63 and it reports that my IMD is good whenever I use the amplifier. It’s far too easy to overdrive things and have a poor quality signal but I know that with the Acom, my transmissions will always be clean. I’ve seen many bad RTTY and FTx signals on the band and I’m determined I will never have a transmission like that.
I can’t recommend Acom amplifiers highly enough, this is the second one I’ve owned and I would buy another one without even thinking about it.