What Can I Expect??

[wb1ead]

Hey gang..I soon will be a "Pepere" to a couple new to me rcvrs this weekend..a Collins 75A2 and a BC-348-P..what I'd like to know is this..providing they are in working condition..which one would be the "prize" of the litter?..in other words who's more manageable and less likely to pitch fits overall?..one of the "boys" could end up a main rcvr of sorts in a mostly AM enviroment hopefully married to a Johnson Ranger or suitable beau..no experience with either one so I'm looking for basic thumbs up/down..

PS: Todd these actually might be attached in the very near future to that 80/40mtr wire..just don't ask at Nearfest OK?

                                                            thanks gang!!              73 de DAVE

[w3jn]

The 75A-2 is in many respects a really good receiver.  However the AVC sucks and the audio is terrible.  There was a recent thread discussing it and the cures.  A search will bring it up if you can't find it.

The BC-348 has its own charm, but its selectivity is really too wide for serious work.   If it hasn't had all of its postage stamp bypass caps replaced, you'll need to do that or be faced with one shorting every time you turn it on.  Interestingly I have a BC-348C will all original components, including the dynamotor, (except one trimmer cap and perhaps tubes) that works perfectly.

[wb1ead]

Hey tnx John!..just what I'm seeking..basic info as to whom sits on the shack table and who might leave for better pastures..yup I saw the links to the Collins info..found some too on the BC-348-P..there's a large cache of parts coming with these..I saw a drawer full of the mica caps and some electrolytics that looked to be pulls..let's hope..can't complain as no $$ involved..
                                  Thanks agn John!..hope things are gud fer you!    73 de DAVE

[wb1ead]

Agn tnx John as I did take time and scout thru the back postings on the 75A-2..found two were quite helpful with all kinds of "tips" thrown in ..the ones by N2IDU and WB6VHE in particular..put a posting on AM FOREVER for a PDF to the manual as BAMA doesn't seem to have..not really asking for one here until I hear from the gang there..was kinda disappointed a bit there were no other like/dislike comments but I did post this as a non-specific "what's ur opinion" kinda thing anyhoo..so der ya go..one of these bad boys will be on the "extended" AM vintage desk taking shape in the shack..no room left now on the 2nd story shelf! 73 de DAVE

[KM1H]

I have the same 75A2 comments as John. The full manual is on the CCA site.

I wouldnt let a 348 into the house

Carl

[w3jn]

Dave, manuals can be found here --> http://www.collinsradio.org/html/manuals.html

[wb1ead]

John thanks much for the link..it IS a BIGGIE as I expected..not sure if the FM unit or calibrator is with it..right now I'm looking at the Collins as the "leader of the pack"

Karl no BC-348 for you?..there has to be a story here as to why..so please tell..why not?..inquiring minds wanna know
                                             73 de DAVE

[KM1H]

A 348 wasnt even up to the hamband task in 1946 when they were everywhere dirt cheap. They were OK for the brand new ham fresh from the war and a familiar item. They were an improvement for the OT still using a SW-3, some Howard POS or similar. Read the old QST's and CQ's, AM in particular had exploded in popularity and 348/342/312 users were bearing the brunt of the QRM.

Poor selectivity, high noise level, horrible tuning rate on 20M especially, poor audio compared to several prewar sets that cost about the same on the used market. Once postwar production got cranked up the WW2 sets went on the shelf except for the diehards. Granted they were better in some ways than a S-20R, S-40, S-53, but even a RME 45 was better which is really saying a lot

There were a zillion 348 mods published from great to half assed to full assed junk

As a point of full disclosure I do have a BC-312 paired with an ATC (Navy ART-13) but the PO converted it to SS and it lives on 17M AM where there is no QRM most of the time. The audio is also fed to an external small guitar amp/speaker where it sounds a hell of a lot better.

[Opcom]

http://www.collinsradio.org/ - they seem to have no interest in military or commercial items. I got no reply when asking them about those topics. I don't know if it is just a lack of interest, an opinion that those sets are not worthwhile or popular enough, or that they have to avoid them for some reason.

[wb1ead]

Honey she's home!..shortly I will relate my opinion in depth of the 75A-2 which now rests on my elect bench..a couple of observations 1st of all..it's DANG heavy!!..and I'm DANG old!!..accuracy is outstanding..and so is sensitivity..3' wire brings in all bands including 10mtrs with no problem..SSB is the nicest audio I've heard in a long time..however dat ol' man AM ain't so sweet no how..it DOES have two plug in additions..a xtal factory calibrator and what looks like a factory product detector..I'm wondering if that product detector may be the restricted audio?..it also has 2 xtal filters plugged in near the front next to the VFO..OK I'll keep "adjusting" the front panel controls to get used to 'er..and maybe slap on the big National spkr to see if it improves the lackluster audio..more comments and thoughts later                  73 de DAVE

[KA3EKH]

The BC-348 is a good radio for SWL use; couple simple audio mods can make a big difference especially changing the original output transformer. I have some stuff about modifying them on my web page at: www.ka3ekh.net the whole 75A line reminds me of the fifties autos, big and lots of heavy sheet metal. Had an A2 and an A4 and they worked well. The Collins people think there is something exceptional about their performance and will tell you that the 75A4 is the greatest receiver ever but most Collins collectors are so brain washed they refuse to accept that anything can be equal or better.

[KC4VWU]

Dave,
         If the A2 feels heavy, you don't want to lift a 32V transmitter!

The filters are an update that Collins offered to upgrade it like the A3. Probably both pretty narrow; 2.? Khz for slopbucket rx and 500 Hz for CW? That will definitely pinch up the already compromised audio for AM. The only bummer is just 2 slots, so one mode will have to take a back seat. You'll need a filter for AM, 6 KC's or so, and that big speaker. Even better, bypass the audio section altogether and run the signal into a stereo amp. You can find all that info right here in the forum or the AM window.

I have an A2 & A3; both stock and waiting for attention ... someday. Honestly, I have a NC-125 that sounds waaaayyy better.

If I were you, I wouldn't bounce that BC-348 just yet either. It may be the start of a military gear obsession; a bug that is easily caught.

Any way you look at it, you really made out like a bandit on the deal!

73, Phil

[wb1ead]

Tnx guys fer ur input here!..Ray I've decided to part with the BC-348 for now..and yes I do believe it has had the mods you mentioned as there was a boxfull of parts that went along with what looks like an original transformer..the SK owner was a electronic tech with Sylvania and worked on cell towers back when..very accomplished man looking at the interior work on both..

Phil I DO agree with you as I have an almost completely finished NC-125 under the bench awaiting knobs..they DO sound gud!..my main rcvr is a restored NC-173 for AM..for now

Tom W0TDH suggested unplugging the product detector to see if that improves things..??..one filter is stock..the other a "homemade" affair..??..if I can find an AM replacement then OK..but methinks I'll have to visit the mods/tips presented here in the archives and the AM Window..one thing that blows me away is it's stability..not just AM but SSB..lock unto a sig and it ain't about to move!..YO!

More thoughts coming as I dig deeper into Art and his gear       73 de DAVE

[K5UJ]

http://www.collinsradio.org/ - they seem to have no interest in military or commercial items. I got no reply when asking them about those topics. I don't know if it is just a lack of interest, an opinion that those sets are not worthwhile or popular enough, or that they have to avoid them for some reason.

I have not looked at that website in a while.  Last year I scanned the instruction book for my 75A-3 and gave it to them, because there is supposed to be some kind of b.s. deal where the CCA can be the only ones with Collins manuals on the internet or something.  They had it available but I see now it is gone.  Only 75A-2 and A-4, no A-3.  The A-3 is probably so similar to the A-2 it doesn't matter, but the Collins collector lunatics are supposed to be so obsessed I figured they'd want complete coverage.   I've learned hams who exalt only one manufacturer above all others have questionable judgement.   Here's a variation on an old joke:

There's this ham, we'll call him Joe, who runs TMC gear--has the 750, 90 rx, everything.  Joe goes SK and arrives in Ham Heaven.   St. Peter is there in the process of tuning up a GPT750, and he even has the modulator.   Ham Heaven is great--everyone who ever worked at or owned TMC, Meissner, National, Raytheon, Federal, RCA, or who homebrewed their own plate modulated rigs is there, and there's no QRM, no slopbucket, no contests, no storm QRN, great audio, IOW, the one or two really good nights on AM every year is the norm.  

After a while, Joe sees this high wall way over in the distance.  It goes on one way and the other as far as he can see.  Joe asks St. Peter what's up with the wall?  He says, "On the other side, we have this sort of quasi Ham Heaven, -- it's not so great, kind of like purgatory.  Art  Collins, Bob Drake, Al Kahn are all over there with all the Collins, Drake and Ten Tec whacko fanatics.   We're adding on to make room for Elecraft and Flex Radio SKs too.  From time to time a guy who can prove he only owned A-line and earlier is allowed in on this side on probation, if he never let any S-line darken his doorway.  Conditions aren't so good over there but it doesn't matter because they spend all their time arguing over which is best and how to find OEM parts to keep their gear pure and unmodified.  We had to build the wall so they think they're the only ones up here."

[Todd, KA1KAQ]

The audio will never sound like a Super Pro, Dave. Collins made communications receivers, not entertainment gear. In this role they work quite excellent. There are a few tricks you can pull to make it a bit better, though.

I doubt the product detector is causing you any problems as it should be switchable in or out of the circuit, usually by a small bakelite knob beneath the tuning dial or in place of the winged emblem at top. Is the product detector in a copper-clad box plugged into the NBFM adapter socket?

Your limiting factor right now by the sounds will be the mechanical filters. Very doubtful that there's a 6 kc filter installed (since it's been modified for SSB). More likely a 3.1 filter is restricting your audio. Can't recall exactly what the CW filter is, 700 or 800 cycles? 1.2? Can't remember.  Anyway, my suggestion would be to build a little LC network for AM reception and plug it into slot #2, move the 3.1 to slot #1 for hand-to-hand combat conditions, and go from there.

While Collins did modify some of these receivers for the filter suite, most were done via a kit Collins offered. This made the receiver into a 75A-2A. I had one of these for a few years, it now resides in the Vortex Museum of Wireless Curiosities. Had all of the A-Line receivers at one point, ended up letting the 2 and 3 go. Nice receivers, but it's tough to keep 'em all, as they say.

That BC-348 is a fine little receiver for its day. You might enjoy having it as a bench or garage receiver. They sound decent, work well, and are pretty simple to use. True, they don't keep up with today's Yaecomwood corntesting radios very well, but so what? They're old radios. I bet they were a big step up for the post-war hams who could afford them, and a lot better to use than an old console radio, Sky buddy, S-38 or whatever else one could afford then. I've got a Q model modified with an AC supply sitting out in one of my garages.

Having schlepped my 32V-2 in and out of the cabinet a multitude of times over the last year or so to fix crap outs, we don't need to get into the weight comparison. It is substantial, makes the A-2 seem light. That's good enough! 

[wb1ead]

Bob thank you for the chuckle!..I heard that a l-o-n-g time back..tnx fer jogging my memory!..

Hi Todd..well it's not copper plated but ya know if I didn't know better I'd swear it was the stock FM unit re-vamped for a product detector home brewed..the two tubes are in the identical posistions with the addition of a small pot/knob on top..one of the tubes is a 12AU7A..the other no markings seen..on the filters the one in #2 slot is Collins F-455B-3..the other is like ur describing to make Todd..a homebrew thingy out of a plastic end off a box containing what appears to be a multi multi turns hair thin wire in a coil approx 1/4" X 3/4" attached to a postage mica to a 1/4 watt resistor..values unknown as I can only peek in thru a slit in the made up plastic box..

On another note this rig has 6BA7s as the mixers..also the addition of three knobs not seen on the pic outta the Collins site when ya click unto the 75A-2..they are..small tone control and large sensitivity knob and small AVC off/on/slow..these look factory installed and lettered

Dat's it for now as other chores draw me away..thanks guys for the smiles and great tips thus far..the saga will continue
                                                              73 de DAVE

[KC4VWU]

Sounds like the LC network is in place already.

My A3 has 2 filters installed, but I haven't had time to really check it out fully.

Todd, remember fixing IS the fun part! At least you've had some operating time on yours; mine is still packed up in the crumpled shipping carton awaiting a post mortem from UPS abuse. Whether it was in working shape before is unknown, but it definitely isn't now.

[KM1H]

My one owner, before me, A3 has factory 6kc and 500cps filters, calibrator and FM module. Havent got into the AVC and audio mods yet, too much other stuff to do.

The 32V2 here is surely a hoss to move but the pair of HT-9's have it beat and Im still looking for a HT-20.

Carl

[wb1ead]

A couple updates as I mosey along..I've sent a letter with a 35mm pic to Howard Mills..I did this because quite frankly I have no clue as to why it sports "extra" controls..not that I can't figure them out but just why..I have "learned" to adjust the different controls and the addition of a "better" National spkr has raised the bar for audio response..Todd mentioned adapting/building a LC network that is now in slot #2..(a homebrew affair for sure)..any links or info about that would be greatly appreciated!..I can if asked remove the top part of the plastic pill box and give ya the components therein as a reference..not sure if I mentioned it but it has two resistors on the opposite pin ends with a coil and a postage mica cap in the center..that's the whole works..pretty basic..the plug-in product detector IS I guess homebrew and sports two 12AU7s..
          I sure hope I'm OK in sending Howard what info I have as I think he may have had a hand in this based on other stuff I've seen and read..maybe not             OK more coming and agn if anyone can pass along info on constructing a simple LC network OR modding the one already in place..PLEASE PASS IT ALONG........thanks guys!        73 de DAVE