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Reviews For: Astron RS-35A

Category: Power Supplies

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Review Summary For : Astron RS-35A
Reviews: 97MSRP: 150.00
13.8 volt 25 amp continuous 35 amp peak rated DC Power Supply
Product is in production
More Info:
# last 180 days Avg. Rating last 180 days Total reviews Avg. overall rating
N4UE Rating: 2019-11-12
"HUM" Time Owned: more than 12 months.
As Bob Seger used to say..."Like a Rock...". I bought this jewel at a yard sale back around 1982. It has been installed at many QTHs and been modified by me, many times. I have added cooling fans, Volt and Amp Meters, remote voltage adjust, etc.
It has never complained. About 2 months ago, I was using it in parallel with a large deep-cycle Marine battery. My 2 Meter SS brick draws too many amps for the Astron. NO PROBLEM. Unfortunately, there was a fire down the street and my AC went out. This killed the 35A. However, there is a ton of great info at "" about Astrons. This failure is a common one using the external battery when the AC drops.
To make a LONG story short, I could not fix the P/S no matter what I did. I replaced every thing but the transformer and covers!
I had an issue with my VOM and the problem was two fold:
1. using transistors I bought off of ePay from China for cheap
2. all 4 of the Emitter resistors were open.

In desperation, I called Astron. Although he was a little bit difficult to understand, the Tech helped me find the trouble pretty quick. Yes, I did repair that VOM also!! ha ha

Neither of these are the fault of the P/S. It's now running with a set of HD transistors.


Hi Just wanted to address several reviews of this P/S and the 'metered' version, being reviewed as having 'hum'.
There are 2 types of 'hum', electrical and mechanical.
The electrical 'hum' is probably a dried out filter cap.
But in many cases (even here), the 'hum' I experienced was mechanical.
The transformers used in these power supplies is MASSIVE. As such, it can couple it's 60 Hz noise to the covers, or even the bottom cover if the p/s has been shipped without proper packing.
I remounted my transformer to the bottom cover, soundly. I even fabricated a new top cover (since my yard sale 'bargain' had already been 'modified').
I added some small 24VDC muffin fans to the heatsink area and even one to exhaust warm air out of the unit. When run on 12VDC, these fans are COMPLETELY silent.
The p/s runs at room temperature.

Don't let the reviewers complaints about 'hum' prevent you from getting one of the best p/s made. I put meters in mine for cheap.

I also have an Astron 70A model as a back-up.

If you ever have ANY concerns, the "repeater builder" website has answers for ANY question you will ever need to know about these. Simple, NO switching noise and my Astron powers my 7300, 7610 and TS-890 without a bit of strain.
DU7SJF Rating: 2019-06-23
Rock Solid Since 1993 Time Owned: more than 12 months.
I have had the rs35A since 2010 and an rs20 since 1993. Both solid, not one problem with the design, For the rs20, perhaps in the 1994 time frame the unit would often shut down during transmission. I traced that to a bad RF grounding problem where the RF triggered a shut down at times. The problem went away after solving the grounding. Although I have had no problems over the years, this is a linear and I am beginning to wonder what might happen to my equipment if the supply failed and went out of regulation. I have seen repair videos where the full rail voltage was supplied to a transceiver when the SCR crowbar circuit failed and did not blow the fuse. Also, does the crowbar act quickly enough to prevent serious damage? Linears like this fail high but switchers "usually fail low into foldback (but not in rare cases where the PWM might lose supply voltage). I guess I will not worry about that as I know of not one actual case where an Astron failed at high voltage.
K4LSX Rating: 2019-04-29
Tip Top Time Owned: more than 12 months.
I have two of them, going wicked strong for several years. One died recently. I replaced the bridge rectifiers and the regulator circuit board with very reasonably priced parts and up and going again! The help from Astron in obtaining the reg. board was terrific.
N2MDV Rating: 2019-04-29
The perfect supply for 100W HF rigs! Time Owned: more than 12 months.
This supply is not mine, but my brother-in-law's. As I've written about the Astron's RS-20M, that supply is not quite enough for a wide open 100W HF rig. The RS-35A is, and my bro-in-law has let me borrow his for a time. Nice supply that powers wide open HF 100W rigs and more, and doesn't flex a muscle. And, this supply is very self repairable. I'm still an old school believer in big transformered, linear, power supplies. And, if you want less noise to work and power rigs on Field Day, this is the supply to have. No RF hash. Just too bad that I'll have to give this supply back.
N8FVJ Rating: 2019-04-16
Quieter than Switchers Time Owned: 0 to 3 months.
The RS-35A if excellent. I had an old RS-20 and I could draw a peak of 22 amps and it would still stay in regulation despite being rated at 20 amps maximum.

I decided to upgrade to the RS-35A rated 25 amps continuous and 35 amps intermittent. Likely never draw more than 22-23 amps, but it is more heavy duty. Paid $179 shipped from HRO on 4-15-2019.

These linear type produce less than 5mv AC ripple at full load and do not make any noise on the HF receiver like some switching power supplies. Play it safe and get a linear type Astron power supply.
W4KPA Rating: 2018-02-04
Reliable for decades Time Owned: more than 12 months.
I have two of these that date from the early 1990s, so they're both well over 25 years old. Last year I finally had to replace the power switch on one of them (even though I don't turn them off and on that often). I made a quick call to Astron and had the part in a couple of days for minimal cost. It took about 15 minutes to change it out. Most of that was removing and replacing the case. So, they're reliable. They don't hum. I have them out of sight in an adjoining room. I never think about them, except when a storm comes through and I turn them off and pull the power plugs out of the wall. Otherwise they're on 24/7. Will I buy another one? Well, yes, but given their durability I may never get the chance. They're heavy, of course, but that's what makes them last.
W9SA Rating: 2018-02-04
Solid and Reliable Time Owned: 0 to 3 months.
I just got my second one of these. The first one ran 25 years without an issue and finally shut down. I figured that was a pretty good reason to buy another. Much to my surprise when I called Astron to inquire about repair they said did you turn it off and back on? Once I did I found that it in fact had reset itself and worked fine. I now have two (which I needed anyway because I got a new rig) and can only say thanks Astron.
AG6QR Rating: 2017-03-11
Minor QC issue, but solid Time Owned: 0 to 3 months.
This is what everyone says it is: Big heavy, and RF-quiet. I bought mine new from HRO in February of 2017. Being curious, I took off the cover to take a peek inside, and found that the main capacitor and the regulator board were floating around loose in the cabinet! There was a clamp to hold the capacitor securely to the cabinet floor, but the screw had never been tightened on that clamp, and the capacitor had fallen out of its clamp during shipping. It was a simple fix, and it hadn't caused any problems, but it shouldn't have escaped from the factory like that. There are exposed terminals that could short out if things are allowed to rattle around loose inside there. I'm also not really crazy about the use of two diode bridges in parallel with no effort to equalize the load between them. I may substitute a single higher-rated diode bridge one of these days. But the good news is that there is ample documentation on how to maintain these simple supplies, and I expect mine to last a very long time with minimal care. I don't plan on drawing much more than 25 amps peak out of mine, so it should run cool and outlast me.
WA6KYR Rating: 2015-06-20
Great lasting supply Time Owned: more than 12 months.
I had another manufacturer supply fail about 20 years ago so I picked up an Astron 35A. It still works fine, just turn it on and forget about it.
No problems.
N0FPE Rating: 2015-06-20
excellent Time Owned: more than 12 months.
I picked up 4 of the old style 35M supplies at a county surplus auction years ago. One has been running my shack 24/7/365 for over 15 years now. A second one has been running my UHF MASTR II repeater for 7 years 24/7/365. The other 2 are spares and get used once in a while just to keep the electrons from leaking out of them. I have a couple of the 30amp switchers but nothing beats the heavy iron for solid operations!!

Earlier 5-star review posted by N0FPE on 2009-10-21

hard to stop. I have 3 RS-35M units in service. One has been powered on 24/7/365 for 15 years. Never as much as blink unless the power company dropped the line. yes i have a newer switcher. But it is only for temp use when i am cleaning the dust off the astrons.