My buddy, Jeff MacMahon, over the Herculodge, forwarded the following message from his reader, Val:
[P]robably some people who are still interested in AM radio will be surprised to see pictures of the Sony SRF-59.
[The] Sony SRF-39FR is an excellent receiver made special for Federal Prison in US.
It is an incredibly sensitive and selective receiver able to pick up every AM frequency.
Somewhere on the Internet, I found a picture of the SRF-59 [which implied that it had the] same circuitry as the Sony SRF-39FR.
I bought SRF-59 from Source Electronic to compare two radios. I was so disappointed after testing the SRF-59.
It is absolutely a different receiver compared with the SRF-39FP. It doesn’t stay close for performance. I opened it (see photo above) and (surprise!) it was missing a few capacitors…What a shame….
Thanks for sharing this, Val.
My advice? Don’t throw the SRF-59 away yet, Val! While it isn’t quite on par with the SRF-39FP, it is still quite an amazing MW DX ultralight.
I would suggest that you check out Dave Richard’s blog where he details how to tweak the SRF-59 for top performace. Dave’s article includes excellent detail and great photos. Click here to view.
This thread is a couple years old. But I wanted to leave this here. I just recently purchased a SRF-39, non FP clear and I have to say I’m amazed by the DX capabilities. I went for the 39 based on the information posted here and elsewhere.
What a fantastic radio. Rivals my SRIII in every way.
How does the SRF-49 compare with the 39 and 59? I bought one about 10 years ago, and it performs great on AM, although there’s now some scratchiness when adjusting the volume. Last year I bought a sealed SRF-49 on eBay, and I compared it to my older one. Sensitivity and selectivity were the same up and down the AM band.
From a QC standpoint,the 49’s were not as bad as
the 59’s were.
I saw brand-new 49’s with shot tuning capacitors
and also new ones that were fine…it’s just that
the “good” ones became rarer with 59’s.
This was not as bad with 39’s but remember 39
production stopped around 1994 or so and you
have to factor in age.
39fp’s are generally better but you can still get a
bad one.
The SRF-29 was IMO the last of the breed that Sony
really did care about.You get a 3v board,better audio
and the same CX-series IC.
And you can get brand-new SRF-19’s on the ‘bay
very reasonably;it was the forerunner of the 29,
main difference is AM only goes to 1640.
BTW spray a little tuner cleaner into the volume control,
it’ll be fine.
If you would like to have a go with an
older Sony,here are some links for your
convenience:
SRF-19:
http://www.ebay.com/sch/i.html?_from=R40&_trksid=p2050601.m570.l1313.TR1.TRC0.A0.H0.Xsony+srf-19.TRS0&_nkw=sony+srf-19&_sacat=0
SRF-29:
http://www.ebay.com/sch/i.html?_odkw=sony+srf-19&_osacat=0&_from=R40&_trksid=p2045573.m570.l1313.TR0.TRC0.H0.Xsony+srf-29.TRS0&_nkw=sony+srf-29&_sacat=0
Note that Sony made the 19 in two
styles,the light grey cabinet and then
the plain dark grey version.
I have a theory as to why…the SRF-21
was a flop.Had some,they all had a
flat-out weird auto-bandwith thing when
tuned on FM or AM.It rendered the 21
useless at night on AM.
This has also been noted on the AM
Stereo SRF-42,BTW.
And you can’t find a 21 service manual
for love or money either;they must have
not made very many.
Sony may have resumed 19 production
in the dark grey case until the 29 was ready as a result.
Just a Theory… .
The problem with the 59 was an almost total lack
of Quality Control.Sony didn’t care,they just
churned them out.
The 39fp was “some” better but you can still get
a bad one.
BTW the 39fp’s board will fit the 59’s cabinet if
you use the 59’s battery tabs,etc.
Looking at schematic those caps look to be in the audio and AGC. Might limit the volume on the P models. Just a guess.
I guess that none of the Federal prisoners using the Sony SRF-39FR are listening to NPR on FM? Maybe the anti-Fed AM talkers on AM are more to their liking?
The transparent Sony SRF-39FR is pretty cute. No cover for razor blades or drugs.
My guess about the Sony SRF-39FR audience is this: most listen to FM rather than AM just like the rest of the population. Those that have a grudge against the Federal system will listen to AM talkers if they were busted for theft or tax evasion. Most will listen to NPR if they were busted for drug related offenses or have racial minority status. Most Federal prisoners will listen to ethnic music twaddle of their choice on FM due to superior sound quality. Jammin’ in jail.
You have some pretty sick ideas.
Interesting, in the picture above the SRF 59 shows missing caps. In the pictures that are on the link at Dave Richard’s blog the caps are there. Did Sony cheapen the SRF 59 at some point by leaving out components? I’ll have to open mine up and see if all the caps are there or not.
Stranger yet, the photo at the top of this post shows the caps missing from the srf 39fp. What’s the deal? Do they make a difference? Can the values be supplied and caps added after the fact to improve the radios that don’t have them?
The photo at the top of the page is one I included that I took of my SRF-59 and 39FP a few months ago. The photo in the body of the post is Val’s. There’s a good chance that the board layouts vary somewhat.
Circuit boards may be arranged to allow different configurations, but other times to accommodate different components. If that source of capacitors runs out, you don’t want to be stuck with parts that don’t fit the board, so the circuit board will have extra traces and pads. Then you use what fits the parts you have. I once had some surplus am/fm tuner boards, and there was lots of empty holes for different parts.
Just filling holes with parts probably won’t change things, you need to look at the circuit.
Mchael