The AM Forum

I recently acquired a Central Electronics (CE) Model A Signal Slicer in really nice condition.

It came with some kind of original CE plug-in module that I believe may be a filter option of some sort. It appears to plug into the 6-pin socket on the rear of the Signal Slicer. Is anyone familiar with the purpose/function of this plug-in module?

Has anyone ever used this model CE Signal Slicer, and if so, what is it's level of performance compared to the TMC GSB-1, TMC CV-591A/URR, or similar SSB receiving adaptors??? I know it uses the phasing method of SSB detection.

Any help with this request would be very much appreciated.

Thanks & 73,

Bruce

Bruce,

Does the module have a crystal in it (or a crystal socket)?  If so it is a converter designed so the ~455 Khz slicer can be used with IF frequencies far removed from 455 Khz.  One of my slicers came with this module and I think I have a schematic for it.  Another plug in module was designed to provide an easy "no load" interface to the receiver.  I think it is documented in the instructions but I cannot recall the model number.

The Slicers work well.  I have one attached to an RME-4350 and another with my 51J-3 (it works fine at 500 Khz. without the converter module).

Hi Rodger,

Thanks for the reply.

No, the plug-in module does not have a xtal in it. It may well be the IF buffer module you had described. Unfortunately, there is no model number or other descriptive information present anywhere on the module.

The fact that the Signal Slicer SSB detection is via the phasing method is intriguing to me, as the only SSB receiving-type convertors I have used, such as the TMC GSB-1 and the TMC CV-591A/URR, employ the more popular product detector with xtal filtering. Perhaps the phasing detection method offers better receive audio quality, as you do not have to contend with the ringing distortion inherent in the xtal filters as used within the other convertors I have mentioned. I'd be curious to hear the opinion of other users of the Slicer in this regard.

73,

Bruce

Bruce,

There is a rough line drawing of the AP-1 adapter in the manual so that may help you identify your module.  CE describes the AP-1 as an outboard IF stage and you will see an IF transformer and 6BA6 mounted on top.

I think you will be very happy with the "slicer" and it provides good sounding audio.  I recently acquired the matching RME (also phasing) SSB adapter for my 4350 receiver but I haven't had a chance to compare the two yet.  With the Slicer added the 51J-3 sounds very good on SSB but I could really use a 4 to 1 reduction tuning setup for it!

The Central Slicer is one of the best outside SSB adapters, IMHO.  The audio is outstanding, and opposite sideband rejection once it's aligned is very good.

The downside is that it doesn't offer additional selectivity, like the GSB-1.  A strong signal in the receiver passband can still be rejected by the Slicer, but that signal will still be working the receiver AGC.  If you're listening to a relatively weak LSB signal with a strong signal in the receiver passband, you may not hear the strong signal due to the slicer's rejecting the USB - but because of the AVC action you may not be able to copy that LSB signal.  If paired with a receiver that has good IF selectivity to begin with, that's not a problem.

I would think it would be easy to modify the Sllicer for sync AM detection.  All it needs is an audio phase detector and a reactance tube, or varicap diode to lock the LO.

Anyway enjoy that slicer, I'm sure you'll like it, Bruce!

Astubula Bill runs a BC-348 with a CE Sideband Slicer and has for years!

Thanks for the information, guys. Very much appreciated.

I think I will go ahead and recap this unit and put it into service here in the shack. I could take the low-level audio output of the Slicer and route it directly to my audio patch panel, so I can patch it into the station monitoring bus.

John or Rodger: do you guys possibly have the factory alignment procedure for the Model A? I was able to download the operating and installation manual off of the Internet, but the information I found does not provide the alignment info.73,

Bruce

Page 22 of this pdf document Bruce http://bama.edebris.com/manuals/ce/slicer/

I found it easier to set the BFO in the Slicer at 455 KHz with the freq counter in my scope, then look at pins 1 and 5 respectively with both channels of the scope in X-Y mode.  Adjust the RF Phase trimmer for a 90 degree phase shift between the two channels (a circle).  Now that you have the 90 degree RF phase set it's a breeze to set the two pots for max opposite sideband rejection.  Because all of the adjustments interact to a certain extent, a touch up of the RF phase trimmer and repeating the pot adjustments for max rejection gave me good opposite sideband rejection.  Using the scope on the output gives a better indication than your ear.

Notice that the * components in the schematic need to be right on.  They were, in mine, but I had a bum 12AT7 that made it impossible to get good balance between the I and Q channels.  If you don't see dramatic opposite sideband rejection, measure the * components and try new tubes.

I would think it would be fairly hard to get good results trying to align this thing without a scope.

Hi John,

Yup, there it is. Thanks for directing me to this alignment information. The procedure is obviously very simple and straightforward.

And I agree; a scope is probably a necessity in order to maximize the unwanted sideband suppression.

I'll probably get around to working on this Slicer sometime after the new year. A full recap is in order, considering this unit is probably close to 55 years old.

Thanks again to all who provided their insight and guidance on this piece of equipment.

73,

Bruce

I have the complete CE setup now. including the VFO, Scope and Slicer.  I dont use the slicer because you have to hack up the radio pretty good to get it installed. As a result, I have never used mine. I use a BW SSB converter instead. This just plugs into most radios and your done.

C

Hi Clarke,

I have several receivers where the 455 Khz IF is brought right out of the receiver, such as the R-390, R-390A, SP-600, and GPR-90, and GPR-92.

I agree; if these (or any of my other) receivers did not have the IF output readily available, I would never modify them for use with the Slicer. And I intend to route the audio output from the Slicer to an outboard audio monitor; I will not route it back into the receiver audio section.

I'm really curious to hear how the phasing detection system of the Slicer compares audio-wise with my other TMC SSB receiving converters that use product detection with xtal filtering. I have the GSB-1, CV-591A/URR, and the CV-1722/URR; I have never been too enamored with the receive audio quality of any of these units.

Thanks & 73,

Bruce

???

You can plug it right in to your SP-600, no modification whatsoever.  Use a cheap stereo amp or amplified computer speakers on the output.