VK Logger Ham Radio Forum Archive

I've recently discovered a quite attractive switch mode power supply advertised by Smith & Co. It offers 13.8 V @ 23 amps and is said to be suitable for transmitters and other high load requirements. It's claimed to be virtually immune to RF interference, but there is no comment about whether the deal works both ways - i.e. how much RF interference does it produce?

Has anyone tried one these, and if so, how much RFI does it produce - especially in the amateur HF bands?

It looks like a good deal at the price, provided that it doesn't wipe out the receive side of the transaction .

Here it is:
http://www.dse.com.au/cgi-bin/dse.store ... View/Q1755

Any real life observations appreciated,
73
Terry
VK5ATN

Hi Terry,
I have used one of these for about a year, and like it! It generates no discerable hash and runs silent most of the time. I run my FT897 on it and am thinking of getting another one to run my 1296MHz transverter.
Les
VK4ALH

Hi Terry,

I have 2 of the DSE Q 1755 power supplies, and have found them to be very good. They are immune to RF as far as I can tell, ie, I have had no issues yet and run everything
from 80m to 23cm. Looking at the DC output on a CRO there is a tiny amount of what looks to be about 4MHz superimposed on the DC output, but tuning around on the HF
receiver I could not detect it, ( I suspect that a non polar cap across the output would probably get rid of it altogether but I haven't needed to yet)

These supplies are manufactured by a company called Manson, and are rebadged all over the world. I also have the larger 60A SMPS that DSE sell (Q 1775) which is a rebadged
manson and the output on this model is absolutely clean. They make quite a variety of supplies, and seem to be of good quality.

The Q 1755 23A model is small light and quiet, it would be suitable for a suitcase "fly away kit" or field day work.

Hi Terry and others interested,
I mentioned above that I was thinking of getting another PSU from Dick Smith. Instead I found a new line of Soanar switch mode PSUs at Jaycar. I got a 12V 100W unit. It is adjustable from about 9.5V to 13.5V and the voltage regulation is such that at 8 Amps the output drops 100mV (13.5 to 13.4). I sat it next to my FT897 and could not detect any noise or birdies from 80m to 70cm. I'm using it to drive my 1296MHz transverter and find it well worth the money!
Les
VK4ALH

Hi all, Just brought a IC706 MK II G last xmas and I also brought one of these great suppys to run it, had no problems at all, was recommended by a member of VK3BEZ, other members in the club have also brought them an like them as well.

Tom
VK3KST

I have one too. It produces NO interference.

It is much quieter than my D3800 (DSE 25A linear). The D3800 fan is LOUD.

Adrian

VK5ATN wrote:...Any real life observations appreciated

Terry, did you end up getting one?

I purchased one last week, specifically for Field Day and fly-away-kit use.
Out of my two nearest DSE stores, there was only one unit left, not to be restocked.
Be aware that most DSE stores are in the process of dumbing down, and dropping many traditional stock lines, such as components, and any residual ham/cb orientated items.

This PSU was used for Winter Field Day last weekend, and I should point out I was operating out in a semi-rural area, the nearest houses being 100's of metres away... in other words, I had very low noise floor.
As others have noted above, I could not detect any discernible noise from this PSU.
At $115, I reckon it's great value.

I note that Andrews have this same PSU listed for $99, but whether they actually have stock of these advertised items is, at best, questionable.
By the time you add freight, you might as well go to a local DSE... if they still have them.

G'day Adam,

Apologies for the delay in my reply - I've been out of the country for the past three weeks or so.

Yes I did get one from DSE in Adelaide; it was quite some time ago - soon after this discussion when it was clear that they offered what I was after. They had to go upstairs to get one - and it took a while to find. This suggests that they were possible in the stages of last stock even then.

That said, I have yet to commission it. I need to make up some dedicated leads from the screw terminals to the 6pin DC power outlets which my current HF rig(s) use.

There have been a few too many (no AR) projects here which have demanded priority. Getting this box into service is one of them. At the price they offer a very attractive option - especially for portable use where one of my conventional transformer based units makes for heavy baggage.

Best 73,
Terry
VK5ATN

G'day all

I was interested in one of these supplies. Great for the inside shack.

DSE price was $115. But I asked them if it was there best price. The sales rep said that it was on special last month (June) for $99. I asked if he could do it at that price. He said yes. So one was quickly bought. However not all DSE Stores have them. So if you want one, then best to ring to locate one and reserve it until you get there.

Hope this helps.

Wayne VK5APN

I got my PSU on sale for $79 when the list price was $99. From time to time they also sell their 25A linear PSU for $150 instead of $300.

Tricky Dicks and their pricing is always a bit of a lottery. Over the years I have purchased various items at crazy "quit stock" prices.

Note that Andrew's also sells the same supply with a different brand name (Manson SPA8230) for $99.
http://www.andrewscom.com.au/site-section-09.htm

Adrian

I have one of these and been using it for over a year. No problems at all and have not noticed any birdies from it.
I use it to drive my 756pro3 and my 706mk2g. I originally bought a 500W power supply on ebay from HK and that produced various birdies practically wiping out 80m!

Cheers,
Dave

Hi Guys,
Had a look today and the price currently is $110 in Rockhampton.
Brian 4QB

Hi Guys,
This power supply is probably the best value from the Tricky Dick fold, as the bigger brother the Q1775 at $669 and 60 amps is more than 3 times dearer and has less that 3 times the current than the Q1755. Also if it goes plunk then 3 times as many transceveirs wont go., or, dont put all your eggs into one basket.!!!
Brian 4QB

I bought one about 18 months ago; it performed beautifully until about a month ago when it blew the mains fuse. The reason turned out to be the dual Shottky diode array that rectifies the output; this in turn burnt out both the switching transistors.
The transistors were available quite reasonably from WES Components but I ended up buying the the Shottky array from the US; the postage cost much more than the component of course.
Since replacing the 3 parts and the fuse all appears well.
Has anyone has problems?
73, Peter VK7PD

Has anyone has problems?

Yep, same thing happened to mine recently. Heard the momentary hum of high current draw then no radios. The fuse was a charred mess on the inside - it didn't go quietly. Thankfully, no damage to the radios. It was reasonably new so I returned it under warranty.

This circuit came my way the other day. Some may find it of interest.
I too have had one repaired under warranty.

Since making the repair in November the P/S has been working faultlessly. With the help of VK7DA, I even found an online schematic for it at: www.pdffactory.com It is called SPA-8230-000.sch. This was after I repaired it. Serves me right for not looking earlier doesn't it?
It may turn out that they had a crook batch of Schottky rectifier assemblies. Here's hoping I bought one from another batch...

Yes thanks vk2dvz, that's the same as the one 7DA found for me. Thanks for the interest.
Peter

Had one for a year and can't fault it so far

I've had mine for quite a while and use it with the IC-910H.. Never missed a beat.

cheers,
VK1JST