Manager - NA4M
Manager Notes

Reviews For: Astron RS-35M

Category: Power Supplies

eMail Subscription

Registered users are allowed to subscribe to specific review topics and receive eMail notifications when new reviews are posted.
Review Summary For : Astron RS-35M
Reviews: 176MSRP: 169.95
Astron 35 amp (ICS), 25 amp (continuous) linear regulated power supply.
Product is in production
More Info:
# last 180 days Avg. Rating last 180 days Total reviews Avg. overall rating
KW6LA Rating: 2023-07-26
Still the one Time Owned: more than 12 months.
30 glorious years and working fine. Very pleased with spending the big bucks for a quality PS.
KT4WO Rating: 2023-07-25
1992 still going Time Owned: more than 12 months.
31 years now----
And it is never turned off.

24/7/365 for 22 years....(except pwr outages)
What more can I say.
N9XAW Rating: 2023-07-24
Good with a quirk Time Owned: 6 to 12 months.
I ordered two RS-35M supplies. One has worked fine, the other has developed a quirk. If turned off over a week end, the next time turned on it shows 0.8 Vdc. Turning it off and on does not help. Leave it off for several minutes and turn it on and it goes to 13.8 Vdc the rest of the day. Astron tech support recommends sending it in for repair. (just out of warranty )
The other thing is it produces a huge amount of heat with a 7 amp load. So much I am careful not to let the heat sink touch anything. The heat seems to be coming from the transformer instead of the pass transistors.
N4ST Rating: 2023-05-17
New Ones Not as Well Made Time Owned: more than 12 months.
I have been using an Astron RS35M for well over 15 years. It has been a solid, reliable performer for me.

Such a great supply, after almost 30 years of operation and having been zapped by lightning and repaired by me it is still chugging along.

HOWEVER, I have attempted on two occasions to retire this beast by buying new RS-35M power supplies. Neither of them lasted two years! They are in the closet waiting until I get around to repairing them. They don't make them like they used to, and I think this model has been discontinued having been replaced by the RS-35M AP at a substantial price increase.
KE5CTT Rating: 2021-09-28
Very nice piece of equipment Time Owned: more than 12 months.
I've had mine for a little over a year now and It's just a great power supply. Simple enough to fix if that's ever needed. The meters are a nice plus, and I can watch the current meter swing in step with my CW paddle. Sometimes it makes an audible noise when I turn it on, and sometimes it doesn't. I think this is caused by the state of the residual magnetism in the transformer when it was turned off vs the magnetizing current at the instant when it's turned back on.
KA5CNT Rating: 2021-01-20
Great Power Supply Time Owned: more than 12 months.
I have owned many Astron power supplies over the years and have had no problems with any of them, but I have one RS-35M that I have owned since 1972 and I have had it in use EVERY day that I have owned it and it has been flawless in it's performance, and I expect it will continue to serve me well.
WB7VTY Rating: 2020-05-20
Solid Supply with bad habits Time Owned: more than 12 months.
At its heart I believe this is a good solid DC supply. Unfortunately it has some very annoying habits right out of the box and needs some help / polish. Amp meter was fairly accurate but the volt meter was way off and unstable. You power cycle the supply and the meter would indicate 2 volts different than the prior use. Monitoring the output with a Fluke digital meter indicated the output was rock solid at 13.7 Volts. I opened the supply and exercised the voltmeter calibration pot and then set the meter to read correctly and it seems to now be fine. Dirty pot or bad meter mechanicals, who knows. Next, I recently added a mobile HF rig to my herd of gear. Simply powering up the HF mobile rig caused my other gear powered by the astron to reset. Turning on the HF mobile radio was apparently causing the Astron to current limit and the voltage to sag. Swapped out the astron with another supply and everything was fine so that confirmed the astron had an issue. I figured out what part of the regulator circuit controlled current limiting in the astron and determined nothing had failed, it was just too sensitive to the added load / current inrush of the new rig when powered up. After the new rig powered up, all was fine. The part of the astron circuit that set this limit had some scabbed on components that were clearly added to "tweak" this very parameter. I am the original owner of the supply so it was done at the factory. I had a new circuit value in mind but after removing part of the hacked on mess, the supply had no more issues and electrically has been flawless since then. Lastly, it produces more heat setting idle with no load than any supply I have owned when operating under the normal loads I put on them. It also hums and buzzes loudly enough to be pretty distracting. Inspection revealed no loose hardware etc, or mechanical issues with the transformer itself, although it is the majority heat source. Astron has been building supplies for a very long time, and again, I think at its core, its a very solid supply. However, the Astron linear supplies are simple supplies that have followed the same formula for I believe, literally decades. There should be NO scabbed on components to make it work right. Everything should be well understood, and all components installed on the circuit board by now, with adjustments as needed. I also believe the quality of the power transformer must be an issue. Transformers always produce heat, but this is a little much, probably due to the way the core is assembled and probably why all the humming and buzzing, but Im no expert. The only reason I would recommend this supply is because again, I think its solid at its core, and because switching supplies are nightmares to repair and I have yet to find a switching supply that doesnt generate noise. Meter quality is disappointing as well. I have swapped it out for the best switching supply I have found so far (Samlex SEC-1235) simply to get rid of the orchestra of heat, hums, buzzs, and vibrations on my desk. Maybe there is an aftermarket transformer you can put in them to eliminate most of that. OR, just a better linear supply. If you have any questions feel free to email me at 73, Joe Korpela, WB7VTY
KF4HR Rating: 2020-02-13
Great PS Time Owned: more than 12 months.
I've owned several Astron Linear power supplies for many years. They're great. (I steer clear of switching power supplies.) As for humming, many times just tightening the transformer lamination hardware and other hardware inside the PS will fix the problem.
K4TK Rating: 2020-02-13
Like a brick............ Time Owned: more than 12 months.
As many others here have mentioned, I've had my Astron 35M for a LONGGGGGGG time. As in, I bought mine in 1990. So 30 years now. The ONLY thing that ever went just this last year, the on/off switch finally "bit the dust". The little red light on it had been coming on and off for years....but the PS always turned on. A trip to Grainger (local store) and $2.69 later....I had a replacement switch....the EXACT same one. So now I'm good for another 30 years! Oh, I bought a second switch I'm probably good to go until I pass on.......

My only complaint, as others have since day one....this thing really hums pretty darn loud. It's bearable....but very noticeable. the moment you throw the switch on...........HMMMMMMMMMMMMMMMMMMMMMMMMMMM..............................

Some times I get my mics on the boom too close to the PS....and others will comment (we can hear some hum in your audio we don't normally hear). I move the mic/boom away, and all is good. Put another way, the hum is almost as loud as the fan on my 1200 Watt amplifier................

But it's solid and reliable. Powers both HF rig and 2 meter rig (though I never transmit on BOTH at the SAME time).

update 13 Feb 20: I got to thinking about all the articles I've read lately...about transformers starting to separate (the metal in the transformer)....and the coating cracking....and how they start to vibrate more and more with age (and could eventually even fail). And I wondered, is that why my 30 year supply is so loud? So I tried doing some of the tips to quiet it down....and I got it a little better.

But then I thought, why not buy a new one with the backlit meters. See if it is quieter. BINGO.....the new one is QUIET. And I love the backlit meters. I still have the 30 year old one....and it still works (though with considerable hum), but the new one is VERY quiet and hopefully gives me another 30 years of so of service......
N7NSL Rating: 2020-02-13
Great unit! Time Owned: more than 12 months.
Bought mine used around 15 years ago. I have it on all of the time. Don't even know its there!!

I've repaired a few Astrons for friends. The are basic power supplies and are easy to work on.