Sherwood Engineering SE-3 Synchronous Detector

[Opcom]

Alas this is no longer made. It seems a very fine solution, and locks on to somewhat drifty and imperfect stations. It's great for SWL too.

Before buying one, I had used a Rycom R1307A/GR to listen to the 455KC I.F. output from the R390 or SX-28, and convert that signal to audio.
https://bunkerofdoom.com/lit/rycom/index.html

The R1307 however was not synchronous, that is, wouldn't lock precisely on to the incoming signal and follow it around, which the SE-3 does and which is useful depending on the driftiness of the AM receiver in use.

For practical reasons, the SE-3 is much better that just about anything else for adding versatility to the old AM receivers. Is there anything that replaces it and is at least as good?

The SE-3 really seemed the penultimate contemporary synchronous detectors.
http://www.sherweng.com/

I wonder if the creator might allow anyone else to produce it since he has retired.

[Pete, WA2CWA]

Here's a construction article:
http://www.arrl.org/files/file/Technology/tis/info/pdf/9307028.pdf

Here's another one:
http://www.premium-rx.org/ref/amsynchronous.pdf

[Opcom]

The ARRL project by Vermasvuori "...info/pdf/9307028.pdf" is the most modern of the two suggested, and as of today all parts are available. It includes a few of the special functions of the SE-3, in diferent but useful forms.

The Surrey Electronics one "...amsynchronous.pdf" is interesting in the way it does signal switching at a PLL_controlled 4fc frequency via cmos switches. It's very versatile and also includes some functions of ther SE-3. With some mods could come fairly close to performing most of the functions of the SE-3. The input amp is a 3N201 FET which also receives AGC via an averaged audio signal at the unit's output. This keeps the unit in a condition where the signals are full but do not overload, despite I.F. level.
The only disadvantage with this design is to source IC1, the Siemens S-041-P IC, which is a limiter-amplifier-detector made for FM reception in '87, now obsolete. There may be broker with stock, or a substitue-able component or a simple set of components.

I would say that while I myself, and most others, would be happy most of the time with either of the above proffered designs, I believe the Sherwood Engineering SE-3 MK IV design is probably better than the former two. It too uses the NE602 and '604, but is more modern, using FETs where they may be advantageous over bipolars, and a low-noise NE5534 as the i.f. input amp.

I have the SE-3 schematic only given to customers for the purpose of eventual repair and I've owned the rack mount version since 2012 and had zero trouble from it. Any could be built I suppose, but I find despite being retired I don't have enough time day to day to finish up what I have started, so no new projects. Thus the interest in the technology and the SE-3 itself. Maybe a good used unit either what you mentioned or another se-3 would fill the bill.


Just for fun a list of adapter manuals/articles:
1948-Vol3Nr6_ssb-adapt_GEhamNews
1951-Vol6Nr4_signal-slicer_GEhamNews
1955-03_ssb-conv_MIL_CV-216
1955-10_sync-det_MIL_CV-157
1958-10_ssb-conv_MIL_CV-591
1963-02_ssb-conv_Mars-Elect_RC-288A
1964-02_ssb-conv_MIL_CV-1758
1967-09_sync-det_73_Nagle
1971-08_ssb-conv_MIL_CV-2712
1982-04_sync-det_P-E_Hershberger
1988-06_sync-detector_Surrey-Electronics
1993-07_sync-det_QST_Vermasvuori
2012-04_sync-det_Sherwood-Eng_SE-3

If one has a synchronous detector that will also demodulate ISB, then an ISB exciter is mandatory.
The TMC SBE-3 / O-503 is a classic but there are newer.

[Les Locklear]

Here is a link to the Kiwa MAP Synchronous Detector.
I'm not sure if this still works.

https://acrobat.adobe.com/id/urn:aaid:sc:VA6C2:657e8628-db02-445a-bb6b-cbaf5b44b898

And another Synchronous Detector.

https://acrobat.adobe.com/id/urn:aaid:sc:VA6C2:fae7ea8a-66d7-41c0-aebf-fae467daefb9

[WBear2GCR]

Having owned an SE-3, but not the version with the switch for the wider lock.
I was less than impressed with the unit.
Otoh, Bruce W2XR loves his.

I also own a Drake R-8 with a button for synchronous detection.

Typically I have found marginal benefit to using synch detection - maybe it is
helpful for signals just above the noise that have some QSB.

For years I read about sync detectors, and imagined "how great that would be"!
Fwiw, not terribly impressed so far.

Many of them make good SSB product detectors, if so equipped.

At this time my "solution" is to take the IF out an run it into a Malachit stand alone
mini sized SDR as the detector. They are now EOL, and not so easy to source from
The Peoples Republic, fwiw. But they do sync, SSB, and have SDR brickwall skirts,
with (more important to me) astoundingly good noise reduction.

My 2 cents, which today is "round-off error" anyhow...

                        _-_-randalfo el oso

[w3jn]

There are many threads here on AMFone on sync detectors and their advantages.  No fading distortion, nor distortion on highly modulated signals.

It's really easy to convert the Sherwood to fast lock.  I wrote that up here some years ago and Rob Sherwood apparently saw it as a worthy mod, and subsequent SE3s cam with a "AR" (Amateur Radio) switch so it would fast lock in the case where you're in a QSO with guys not all being zero beat on the frequency.

[Opcom]

I use 'AR' mode on mine.