Re: [AMRadio] 51J3 or 75A3?
Barrie Smith wrote: I hate the thought of doing any modifications to any of my SX-73's, but if I was to make one, it would be to change from single to push-pull output 6V6's. That's plural, more than one SX-73? yessir Well, I feel fortunate having one! I got my first one, an R-274D/FRR, from John/W5MEU(sk - R.I.P.) back in 1985. Somehow, back in my 'Johnny Novice' days (triubute the 'Tron for that phrase) I managed to dump around 5 or 600w of RF directly into the front-end of that thing, and burned the coil front-end up. Went back to John and he sold me (gave... think it was like $2.oo) a roll of 24ga wire. I re-wrapped the inductor, did some 'under-the-magnifying-glass' soldering and that part of the reciever is still working. Yeah, I've got three of 'em. They've all three been modified, to some extent. The one with no holes drilled in it only had a relay added (by John), to remove the B+ from the front-end tubes when activated. That was the first one I got. It's hum problem has been fixed, with a replacement electrolytic, but it now needs probably new tubes and some alignment/sensitivity adjustments made.. . The other two are R-274's. (no letter designator) and while one doesn't need a lot of work done to it, it, too, needs alignment, and the springs replaced for the main-tuning dial. I have no idea what someone was thinking, but there are two BNC connectors that were attached to the front of this reciever, and a standby switch that is in parallel with the Send/Recieve switch. There's an aduio line coming out of it, as well, for line-level output for an amplifier. I've not tried that, but am told that it sounds good coming out of the rreciever like that. The R-274 that I'm using, has had the most extensive horrifications done to it, in that a previous owner replaced the RF Gain pot/AC Switch with a regular pot (no switch) and mounted an ugly, non-plastic protected toggle switch that is mounted in a rather hap-hazardly cut hole in the side of the chassis. There's another hole drilled in it, in the front cover that I can't figure out what it does, other than change the output impedance (I think). It works fine in one position, and that's the one I leave it in. The only problem with it, is that the bottom cover needs to be removed, and some alcohol-dipped cotton swabs need to be used to remove the carbon traces and other reside from the turret connections. I need to do this, pretty soon. heh - believe it or not, I got the last '73 in an even trade for the HQ-170A. The '73 is a better receiver than most folks realize, in my opinion. I've never really attempted to measure audio quality, but it seems to sound good enough for communication purposes, and the sometimes use as a SWL receiver. built like a battle ship, the components inside are well protected from one stage to the next. Still think that any of the Hallicrafters receivers with PP output sound better than any of the other rigs I've owned, at least into a good speaker. No doubt. I think p-p 6V6's would make that reciever 'sing'. Heck, at 16kc wide sensitivity it does a pretty good job, as it is. -- 73 = Best Regards, -Geoff/W5OMR
RE: [AMRadio] 51J3 or 75A3?
Wow! Thanks for all the great insights. It has me rethinking the entire idea of putting together a classic AM station for late night Hi-Fi Radio. My original idea was to recreate the feel of the station in which I took my Novice test back in '64. It was a 75A4 and a Globe King 500B. But that notion has since taken a turn to be more focused on audio quality than nostalgia (while still using classic rigs), hence my original question. Seems I have lots to learn yet before I decide what to do. The suggestion that I go visit some collectors and listen to a number of different receivers is a good one. Any volunteers within a couple hundred mile radius of Charlotte, NC? Thanks again all! Theo K4MO
RE: [AMRadio] 51J3 or 75A3?
Rather then hacking holes in a collectable receiver, its better to tack a wire onto the volume pot or detector and run it to a good audio amp. If you have a lot of vintage receivers, one amp and one speaker makes sense, you also get a tape line out for recording if you want. If you decide to sell the gear, all you have to do is unsolder the wire. Brett N2DTS That makes sense. I bought an HQ-170 at a hamfest, because John/WA5BXO has an HQ-145 that I just 'adore' the sound of. Sure, it's a simple output transformer on the back (I believe) from 600 ohm down to 8-ohm, but there's -plenty- of audio to drive that big 16 woofer he's got under the console to make everyone sound as 'disgustingly natural' as posible. The 170 (that I had) had a 'maximum' of 3kHz bandwidth.How narrow and mechanical it sounded. (blech!) I hate the thought of doing any modifications to any of my SX-73's, but if I was to make one, it would be to change from single to push-pull output 6V6's. Thanks for the post. That helps me a lot. -- 73 = Best Regards, -Geoff/W5OMR __ AMRadio mailing list Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net AMfone Website: http://www.amfone.net AM List Admin: Brian Sherrod/w5ami, Paul Courson/wa3vjb
RE: [AMRadio] 51J3 or 75A3?
feel of the station in which I took my Novice test back in '64. It was a 75A4 and a Globe King 500B. Seems I have lots to learn yet before I decide what to do. Just a thought. Maybe you're worrying over it too much? It isn't as though the receiver you purchase can't be replaced if you decide you don't like it for some reason. I don't think there's an ideal or even best vintage AM receiver. But there are a lot of good ones, ranging from something as pedestrian (but still pretty darn good) as the HQ-129, to the HRO-50T1, to Super Pros (e.g. SP-210), R-390 (no-A), to all the other ones that have been discussed in this thread. Most designed-for-SSB radios do not make good AM radios, with the possible exception of the NC-303. Other than that, it's just more fun to get your feet wet sooner than later :-) Grant/NQ5T
RE: [AMRadio] 51J3 or 75A3?
Yes, all the vintage receivers usually have good points, some only look good, but all are fun to play with. With the Collins stuff, you are going to pay about $1000.00? for a good 75A4 with 3 filters. Maybe more... That is a lot to spend on something that might sound very poor. And since its so expensive, you might worry about playing with it. Gone are the days you could 'experiment' with vintage stuff unless you hit the lottery or something. I like to 'experiment' with my equipment, so before I hacked the nice vintage stuff up, I sold it off and went home brew. I can 'experiment' without ruining a classic piece of gear. Brett N2DTS feel of the station in which I took my Novice test back in '64. It was a 75A4 and a Globe King 500B. Seems I have lots to learn yet before I decide what to do. Just a thought. Maybe you're worrying over it too much? It isn't as though the receiver you purchase can't be replaced if you decide you don't like it for some reason. I don't think there's an ideal or even best vintage AM receiver. But there are a lot of good ones, ranging from something as pedestrian (but still pretty darn good) as the HQ-129, to the HRO-50T1, to Super Pros (e.g. SP-210), R-390 (no-A), to all the other ones that have been discussed in this thread. Most designed-for-SSB radios do not make good AM radios, with the possible exception of the NC-303. Other than that, it's just more fun to get your feet wet sooner than later :-) Grant/NQ5T __ AMRadio mailing list Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net AMfone Website: http://www.amfone.net AM List Admin: Brian Sherrod/w5ami, Paul Courson/wa3vjb
RE: [AMRadio] 51J3 or 75A3?
Grant wrote: Just a thought. Maybe you're worrying over it too much? Ha! Probably so but researching these things is half the fun. I have had lots of vintage receivers in the past (especially Collins), but I usually used them on CW or SSB. The last old gear station I had was a Johnson Valiant and a 75A4. I thought the 75A4 was doing ok (it has an R390A AM filter cobbled into it) until I got a 51J4 which seemed much better on AM. So, I thought for this set up I would spend a little more time learning from the guys who have been more dedicated to 'Angel Music' that I have been. I usually just end up with whatever rig catches my eye at a flea market or whatever. I am hoping to take a different approach this time. Theo K4MO __ AMRadio mailing list Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net AMfone Website: http://www.amfone.net AM List Admin: Brian Sherrod/w5ami, Paul Courson/wa3vjb
RE: [AMRadio] 51J3 or 75A3?
I noticed an nc300 or 303 on ebay some time ago, selling for $200? If you can get past the looks, they seemed to work well when I had them. I would say whatever you can get at a reasonable price is what you wind up with, trying to get a particular model can cost I sold an SX17 in like new shape for $200? a year ago, nice r390a went for $400.00 I think... The Scott SLRM like new fetched $250.00... Brett N2DTS -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of W1EOF Sent: Monday, March 06, 2006 10:59 AM To: Discussion of AM Radio Subject: RE: [AMRadio] 51J3 or 75A3? Great point! WIth minimal invasivness you can add an external amp that will make many receivers sound much better. Maybe a more important consideration is what you want to do with the receiver. A case in point: An R-390 is a *great* receiver. But due to it's tuning/bandswitching design it's not a great band cruiser. Too much cranking that knob around. Some radios such as the early HRO series I mentioned before sound wonderful but require a plug-in coil rack to switch to a different band. I'd say that's not a good choice if you intend on flipping around between 160, 80, and 20. As people have said, there is not ideal receiver. Each one was designed for a target user and use. If I were you, and wanted to buy a single receiver for not so much money I'd look at the earlier Hammarlunds. Maybe a 129 as Grant suggested. They are not that expensive at all even in very nice shape. By all means if you have the opportunity go to some shacks and take some for a test drive. Don't just listen, but tune around yourself. Adjust the filters. Play with the controls. Get a feel for how it works. As a frequent over-thinker who plans and researches too much I can tell you to just jump-in and swim around. Best wishes on your hunt! 73, Mark W1EOF SNIP I don't think there's an ideal or even best vintage AM receiver. SNIP -- No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.1.375 / Virus Database: 268.2.0/275 - Release Date: 3/6/06 __ AMRadio mailing list Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net AMfone Website: http://www.amfone.net AM List Admin: Brian Sherrod/w5ami, Paul Courson/wa3vjb
Re: [AMRadio] 51J3 or 75A3?
I looked for a good SX-73 for quite a few years, and then I found the one I have now by accident.. Called Rick Mish about something and got to chatting. Told him I was looking for the SX-73 and he said he had a museum-quality (whatever that is) example there that he had just restored for a customer. Evidently the customer didn't like the price for the restoration and refused to pay. I didn't like the price too much, either,,, but I paid it anyway. If we are talking about old radios that sound from good to real good, what about the SX-42 and SX-62? Heck, you can listen to FM, too. 73, Barrie, W7ALW
Re: [AMRadio] 51J3 or 75A3?
I restored an SX-62 (caps and resistors) and I agree on the great audio ! FM included. 73, Ken W2DTC -- If we are talking about old radios that sound from good to real good, what about the SX-42 and SX-62? Heck, you can listen to FM, too. 73, Barrie, W7ALW
Re: [AMRadio] 51J3 or 75A3?
Hi Ken the Group, Would you like to share your experiences with the SX-62? I picked up a 62A at Greyslake a few years ago, took the cabinet off and looked her over. Appears pretty virgin, I brought it up an a variac and it plays after a fashion. FM kinda distorted and weak. Higher freqs need help as well. I have not jumped in yet, but I got a couple of big sacks of orange drops for it and its sister SP-600 thats on the shelf in the que. Tnx 73, Jack WA9NQW On Mar 6, 2006, at 5:18 PM, kenw2dtc wrote: I restored an SX-62 (caps and resistors) and I agree on the great audio ! FM included. 73, Ken W2DTC -- If we are talking about old radios that sound from good to real good, what about the SX-42 and SX-62? Heck, you can listen to FM, too. 73, Barrie, W7ALW __ AMRadio mailing list Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net AMfone Website: http://www.amfone.net AM List Admin: Brian Sherrod/w5ami, Paul Courson/wa3vjb
Re: [AMRadio] 51J3 or 75A3?
Sure Jack, glad to pass along my experiences with the SX-62: http://w2dtc.com/w2dtc-sx-62-receiver-page.htm 73, Ken W2DTC === Hi Ken the Group, Would you like to share your experiences with the SX-62? Tnx 73, Jack WA9NQW
Re: [AMRadio] 51J3 or 75A3?
And if you belong to the I'd like a couple 6V6's in the output club, you can probably find a cheap NC240 D. I got one a couple years ago for 90 bucks, and someone had added a Collins 4 kc mechanical filter and a product detector, and it receives everything very nicely. They tend to be cheap, and a nice platform to experiment with if the coil mechanism is OK. 73 Scott
Re: [AMRadio] 51J3 or 75A3?
Great Thread! Under the category of, For what it's worth, I grew up using a 75A4 and about 20 years ago had my own 75A3. I will admit to being mesmerized by the Collins mystique and indeed they are outstanding receivers. Recently, I went out to re-obtain a 75A3 for my shack, along the way I came across a number of other receivers when all was said and done, I found the Hammarlund HQ-160 to be a far superior in an audio than the Collins Equipment. (as compared to the an unmodified Collins) This is not to say a Collins receiver doesn't have a future spot in my shack, however for the difference in price, I am very pleased with the HQ-160. I also picked up a HQ-170A, there is no comparison to the HQ-160 for audio quality, however it is very comparable to the Collins in Stability and dial accuracy. It's a Great Battle Mode receiver. Bottom line, for $100 less than what I was going to pay for a 75A3 that needed repair, I bought 2 outstanding and in there own way comparable receivers. Best Regards, Steve W1TAV
RE: [AMRadio] 51J3 or 75A3?
I've never been able to keep the Hammarlund line sorted out in my mind. What distinguishes the 160??? 73, Mark W1EOF -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Sent: Sunday, March 05, 2006 1:12 PM To: amradio@mailman.qth.net Cc: amradio@mailman.qth.net Subject: Re: [AMRadio] 51J3 or 75A3? Great Thread! Under the category of, For what it's worth, I grew up using a 75A4 and about 20 years ago had my own 75A3. I will admit to being mesmerized by the Collins mystique and indeed they are outstanding receivers. Recently, I went out to re-obtain a 75A3 for my shack, along the way I came across a number of other receivers when all was said and done, I found the Hammarlund HQ-160 to be a far superior in an audio than the Collins Equipment. (as compared to the an unmodified Collins) This is not to say a Collins receiver doesn't have a future spot in my shack, however for the difference in price, I am very pleased with the HQ-160. I also picked up a HQ-170A, there is no comparison to the HQ-160 for audio quality, however it is very comparable to the Collins in Stability and dial accuracy. It's a Great Battle Mode receiver. Bottom line, for $100 less than what I was going to pay for a 75A3 that needed repair, I bought 2 outstanding and in there own way comparable receivers. Best Regards, Steve W1TAV __ AMRadio mailing list Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net AMfone Website: http://www.amfone.net AM List Admin: Brian Sherrod/w5ami, Paul Courson/wa3vjb -- No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.1.375 / Virus Database: 268.1.2/274 - Release Date: 3/3/06 -- No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.1.375 / Virus Database: 268.1.2/274 - Release Date: 3/3/06
RE: [AMRadio] 51J3 or 75A3?
Indeed, the HQ-1XX lines are confusing and HQ's prior to the 160 are also reported to have outstanding AM sound. The HQ-160 was the High End of their General Coverage receivers from 1958-60. At the same time the HQ-145 was also available. (1959-61). And Just to further confuse the issue, the HQ-145A ran from 1966-1969. Based on my read of the specs and difference of the HQ receivers I have tried that came after the HQ-160. The 160 was probably that last one to deliver (out of the box) a pleasing fat sound on AM. The HQ's following the 160 seemed to be focused on Communications Quality sound. This may have been a concession to SSB performance. I have noted that the HQ-180A's command a very high price in that E auction place and I will admit I have not heard one, however if the audio on the HQ-180A is anything like my HQ-170A, the 160 was indeed the last of Hammerlund's great AM receivers. (the 170a is Ham Band only and the 180A is General Coverage) The source of production dates used was Fred Osterman's SW Receivers Past Present 2nd edition. Steve W1TAV
Re: [AMRadio] 51J3 or 75A3?
[EMAIL PROTECTED] wrote: Indeed, the HQ-1XX lines are confusing and HQ's prior to the 160 are also reported to have outstanding AM sound. The HQ-160 was the High End of their General Coverage receivers from 1958-60. At the same time the HQ-145 was also available. (1959-61). And Just to further confuse the issue, the HQ-145A ran from 1966-1969. Based on my read of the specs and difference of the HQ receivers I have tried that came after the HQ-160. The 160 was probably that last one to deliver (out of the box) a pleasing fat sound on AM. The HQ's following the 160 seemed to be focused on Communications Quality sound. This may have been a concession to SSB performance. I have noted that the HQ-180A's command a very high price in that E auction place and I will admit I have not heard one, however if the audio on the HQ-180A is anything like my HQ-170A, the 160 was indeed the last of Hammerlund's great AM receivers. (the 170a is Ham Band only and the 180A is General Coverage) The source of production dates used was Fred Osterman's SW Receivers Past Present 2nd edition. That makes sense. I bought an HQ-170 at a hamfest, because John/WA5BXO has an HQ-145 that I just 'adore' the sound of. Sure, it's a simple output transformer on the back (I believe) from 600 ohm down to 8-ohm, but there's -plenty- of audio to drive that big 16 woofer he's got under the console to make everyone sound as 'disgustingly natural' as posible. The 170 (that I had) had a 'maximum' of 3kHz bandwidth.How narrow and mechanical it sounded. (blech!) I hate the thought of doing any modifications to any of my SX-73's, but if I was to make one, it would be to change from single to push-pull output 6V6's. Thanks for the post. That helps me a lot. -- 73 = Best Regards, -Geoff/W5OMR
Re: [AMRadio] 51J3 or 75A3?
I hate the thought of doing any modifications to any of my SX-73's, but if I was to make one, it would be to change from single to push-pull output 6V6's. That's plural, more than one SX-73? Well, I feel fortunate having one! The '73 is a better receiver than most folks realize, in my opinion. I've never really attempted to measure audio quality, but it seems to sound good enough for communication purposes, and the sometimes use as a SWL receiver. Still think that any of the Hallicrafters receivers with PP output sound better than any of the other rigs I've owned, at least into a good speaker. 73, Barrie, W7ALW
Re: [AMRadio] 51J3 or 75A3?
Theo, go for the 51J-3 because it is general coverage since the 75A-2 is strictly hamband. Also, please support the CRA and join the world's largest Collins group. Dave, W3ST Publisher of the Collins Journal Secretary to the Collins Radio Association www.collinsra.com - the CRA Website Now with PayPal CRA Nets: 3805 Khz every Monday at 8 PM EST and 14255 every Saturday at 12 Noon EST - Original Message - From: Theo Bellamy [EMAIL PROTECTED] To: Discussion of AM Radio amradio@mailman.qth.net Sent: Saturday, March 04, 2006 3:04 PM Subject: [AMRadio] 51J3 or 75A3? I am shopping for a receiver to use on AM. I think I want either a 75A3 or a 51J3. Which one is best for AM use as far as making pleasing sounds come out of the speaker? I used to have a 51J4 and a 75A4, and they worked fine (especially the 'J4), but I have heard that the 'J3 may have the best sounding audio section for AM. True? Thanks, Theo K4MO __ AMRadio mailing list Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net AMfone Website: http://www.amfone.net AM List Admin: Brian Sherrod/w5ami, Paul Courson/wa3vjb
RE: [AMRadio] 51J3 or 75A3?
If you was to ask me, none of the below sounds real good on AM. They sound lots better if you take audio off the detector. You also want something that has about a 6kc filter. Wider is better, but then you get the guys next door. I know there is a wide range of what people think sounds good, some people think a good phone, or a good 2 meter rig sounds good, or really anything that has under 15% distortion and goes 300 to 3000... Some old receivers did have good audio, with push pull output stages with a good amount of power at low distortion, and a good frequency response, but collins never made anything like that as far as I know. The scott SLRM had a direct coupled driver stage going to push pull 6L6's (actually 25L6's), and sounded very good, it also had a 'hifi' bandwidth position (16kc?). Some of the old halicrafters had push pull outputs, SX 17, SX 28 and others, with up to 17 watts out! AM detectors and the agc action also play a big role, collins used a simple diode detector most times, not the low distortion cathode follower type detectors used in some other receivers... If you must have the collins, I would go for the 75a3, its got a nicer S meter, and uses a 455Khz IF, the 51J used 500 khz. You can get nice kiwa filters for anything that runs 455Khz for $50.00. Any bandwidth you want. They work just like mechanical filters, maybe better... I always thought a 75s1 would make a good AM receiver, replace the back to back IF cans with a kiwa filter, or put it between the cans, build a low distortion detector, and it might make a good receiver in a small package. I will pick one up someday and experiment on it. The 75s1 is still reasonable, everyone wants the 75s3 and the prices are crazy. Brett N2DTS -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Theo Bellamy Sent: Saturday, March 04, 2006 3:05 PM To: Discussion of AM Radio Subject: [AMRadio] 51J3 or 75A3? I am shopping for a receiver to use on AM. I think I want either a 75A3 or a 51J3. Which one is best for AM use as far as making pleasing sounds come out of the speaker? I used to have a 51J4 and a 75A4, and they worked fine (especially the 'J4), but I have heard that the 'J3 may have the best sounding audio section for AM. True? Thanks, Theo K4MO __ AMRadio mailing list Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net AMfone Website: http://www.amfone.net AM List Admin: Brian Sherrod/w5ami, Paul Courson/wa3vjb
Re: [AMRadio] 51J3 or 75A3?
Boy, I'll concur. I have a 75A3 that W3HM did for me and the audio sucks. I would go for a National or an older Hallicrafters. Brett, where did you pick up the Kiwa filters? I would like to try something along that line just so I can say I opened the audio. I have the 3.2Kcs mechanical filter and it sounds like crap. Mod-U-Lator, Mike(y) W3SLK - Original Message - From: Brett gazdzinski [EMAIL PROTECTED] To: 'Discussion of AM Radio' amradio@mailman.qth.net Sent: Saturday, March 04, 2006 3:50 PM Subject: RE: [AMRadio] 51J3 or 75A3? If you was to ask me, none of the below sounds real good on AM. They sound lots better if you take audio off the detector. You also want something that has about a 6kc filter. Wider is better, but then you get the guys next door. I know there is a wide range of what people think sounds good, some people think a good phone, or a good 2 meter rig sounds good, or really anything that has under 15% distortion and goes 300 to 3000... Some old receivers did have good audio, with push pull output stages with a good amount of power at low distortion, and a good frequency response, but collins never made anything like that as far as I know. The scott SLRM had a direct coupled driver stage going to push pull 6L6's (actually 25L6's), and sounded very good, it also had a 'hifi' bandwidth position (16kc?). Some of the old halicrafters had push pull outputs, SX 17, SX 28 and others, with up to 17 watts out! AM detectors and the agc action also play a big role, collins used a simple diode detector most times, not the low distortion cathode follower type detectors used in some other receivers... If you must have the collins, I would go for the 75a3, its got a nicer S meter, and uses a 455Khz IF, the 51J used 500 khz. You can get nice kiwa filters for anything that runs 455Khz for $50.00. Any bandwidth you want. They work just like mechanical filters, maybe better... I always thought a 75s1 would make a good AM receiver, replace the back to back IF cans with a kiwa filter, or put it between the cans, build a low distortion detector, and it might make a good receiver in a small package. I will pick one up someday and experiment on it. The 75s1 is still reasonable, everyone wants the 75s3 and the prices are crazy. Brett N2DTS
RE: [AMRadio] 51J3 or 75A3?
I agree with you Brett. The Collins rigs were strictly communication rigs, not HIFI. I had a 75A4 for a long time and compared it to other 75A4 RCVRs at the time and all of them had poor audio reproduction. A good bit of the distortion was with the detection and audio output stages. I built a MOSFET source follower where I picked up the 455KC IF and fed it to another AM/FM stereo HIFI radio with its on 10-15 watt audio output stage. I disable the mixer and OSC in the outboard HF and fed the 455KC from the 75A4 into the IFs of the outboard HF radio. This helped a lot but found some of the distortion was from the mixer of the 75A4. I understand there is a modification for that now, requiring a tube swap to a dual triode and rewiring. The 75A4 and its type are famous for accuracy and stability. As for as stock receivers go on fidelity, the HQ129, HQ145, S-85, NC303 (not NC300) has outperformed all for me. John, WA5BXO
Re: [AMRadio] 51J3 or 75A3?
I concur with the other comments made about Collins audio; however, consider this: Most of the bragging rights about the best of the best in receivers includes an R-390 or R-390A. When you talk to those 390 guys you find them pulling off the audio at the detector, which is a standard feature of those receivers. I have a Collins R-388 (similar to the 51J3) and I bring the audio out of the detector and into an external amp and I think it does fine on AM. Is it one of the best AM receivers, of course not; but sometimes you just want the look and feel of a certain receiver and you can compromise on certain features. I also concur on the general coverage version over the ham band only, but again, it's a personal choice. 73, Ken W2DTC I am shopping for a receiver to use on AM. I think I want either a 75A3 or a 51J3. Which one is best for AM use as far as making pleasing sounds come out of the speaker? I used to have a 51J4 and a 75A4, and they worked fine (especially the 'J4), but I have heard that the 'J3 may have the best sounding audio section for AM. True? Thanks, Theo K4MO __ AMRadio mailing list Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net AMfone Website: http://www.amfone.net AM List Admin: Brian Sherrod/w5ami, Paul Courson/wa3vjb
Re: [AMRadio] 51J3 or 75A3?
No argument here Ken. What awesome sounding audio you get from the diode output of a R-390A. However, the stock audio of my BC-779 is pretty darn good too. Mod-U-Lator, Mike(y) W3SLK - Original Message - From: kenw2dtc [EMAIL PROTECTED] To: Discussion of AM Radio amradio@mailman.qth.net Sent: Saturday, March 04, 2006 4:31 PM Subject: Re: [AMRadio] 51J3 or 75A3? I concur with the other comments made about Collins audio; however, consider this: Most of the bragging rights about the best of the best in receivers includes an R-390 or R-390A. When you talk to those 390 guys you find them pulling off the audio at the detector, which is a standard feature of those receivers. I have a Collins R-388 (similar to the 51J3) and I bring the audio out of the detector and into an external amp and I think it does fine on AM. Is it one of the best AM receivers, of course not; but sometimes you just want the look and feel of a certain receiver and you can compromise on certain features. I also concur on the general coverage version over the ham band only, but again, it's a personal choice. 73, Ken W2DTC I am shopping for a receiver to use on AM. I think I want either a 75A3 or a 51J3. Which one is best for AM use as far as making pleasing sounds come out of the speaker? I used to have a 51J4 and a 75A4, and they worked fine (especially the 'J4), but I have heard that the 'J3 may have the best sounding audio section for AM. True? Thanks, Theo K4MO __ AMRadio mailing list Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net AMfone Website: http://www.amfone.net AM List Admin: Brian Sherrod/w5ami, Paul Courson/wa3vjb __ AMRadio mailing list Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net AMfone Website: http://www.amfone.net AM List Admin: Brian Sherrod/w5ami, Paul Courson/wa3vjb
Re: [AMRadio] 51J3 or 75A3?
In conjunction with this discussion concerning audio properties, I wonder if anyone is using any of the fine Eddystone receivers? I own three of them and my favorite is the EA-12, which was expressly made for the hambands. Would like to exchange notes with anyone using or owning any of the earlier Eddystone receivers. Thank you Dave, W3ST Publisher of the Collins Journal Secretary to the Collins Radio Association www.collinsra.com - the CRA Website Now with PayPal CRA Nets: 3805 Khz every Monday at 8 PM EST and 14255 every Saturday at 12 Noon EST - Original Message - From: John E. Coleman (ARS WA5BXO) [EMAIL PROTECTED] To: 'Discussion of AM Radio' amradio@mailman.qth.net Sent: Saturday, March 04, 2006 4:23 PM Subject: RE: [AMRadio] 51J3 or 75A3? I agree with you Brett. The Collins rigs were strictly communication rigs, not HIFI. I had a 75A4 for a long time and compared it to other 75A4 RCVRs at the time and all of them had poor audio reproduction. A good bit of the distortion was with the detection and audio output stages. I built a MOSFET source follower where I picked up the 455KC IF and fed it to another AM/FM stereo HIFI radio with its on 10-15 watt audio output stage. I disable the mixer and OSC in the outboard HF and fed the 455KC from the 75A4 into the IFs of the outboard HF radio. This helped a lot but found some of the distortion was from the mixer of the 75A4. I understand there is a modification for that now, requiring a tube swap to a dual triode and rewiring. The 75A4 and its type are famous for accuracy and stability. As for as stock receivers go on fidelity, the HQ129, HQ145, S-85, NC303 (not NC300) has outperformed all for me. John, WA5BXO __ AMRadio mailing list Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net AMfone Website: http://www.amfone.net AM List Admin: Brian Sherrod/w5ami, Paul Courson/wa3vjb
RE: [AMRadio] 51J3 or 75A3?
I have the 75A2 a R390 and a 51J3 also a HQ140X the 51J3 beats all but the HQ140X for AM.. 73 Tony Anthony W. DePrato WA4JQS QCWA # 23602 10X # 3621 A1-OP FISTS # 10573 AMI # 1274 NCDXF # 1036 RNARS # 1309 SKCC # 1227 DXCC PHONE DXCC RTTY DXCC CW Lis. 1961 Calls Held VP8BZL VP8SSI 3Y0PI V31SS ZD8JQS WA4JQS/ZS1 WA4JQS/4K1 WA4JQS/KC4
RE: [AMRadio] 51J3 or 75A3?
The R390a is a good receiver, and it has a better AM detector then most collins receivers had I think. I think they are on the noisy side, but otherwise work very well. Other receivers work great with audio off the detector to make up for the 6AQ5 into a postage stamp output transformer. All the collins stuff looks very cool, like REAL radio, every piece (except maybe the kwm1?) looks like a radio should. Brett -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of kenw2dtc Sent: Saturday, March 04, 2006 4:31 PM To: Discussion of AM Radio Subject: Re: [AMRadio] 51J3 or 75A3? I concur with the other comments made about Collins audio; however, consider this: Most of the bragging rights about the best of the best in receivers includes an R-390 or R-390A. When you talk to those 390 guys you find them pulling off the audio at the detector, which is a standard feature of those receivers. I have a Collins R-388 (similar to the 51J3) and I bring the audio out of the detector and into an external amp and I think it does fine on AM. Is it one of the best AM receivers, of course not; but sometimes you just want the look and feel of a certain receiver and you can compromise on certain features. I also concur on the general coverage version over the ham band only, but again, it's a personal choice. 73, Ken W2DTC I am shopping for a receiver to use on AM. I think I want either a 75A3 or a 51J3. Which one is best for AM use as far as making pleasing sounds come out of the speaker? I used to have a 51J4 and a 75A4, and they worked fine (especially the 'J4), but I have heard that the 'J3 may have the best sounding audio section for AM. True? Thanks, Theo K4MO __ AMRadio mailing list Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net AMfone Website: http://www.amfone.net AM List Admin: Brian Sherrod/w5ami, Paul Courson/wa3vjb __ AMRadio mailing list Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net AMfone Website: http://www.amfone.net AM List Admin: Brian Sherrod/w5ami, Paul Courson/wa3vjb
RE: [AMRadio] 51J3 or 75A3?
Hi Theo my 2 cents are either the A-2 or A-3. As far as I am concerned the absolute best audio for AM is the NC183D. It uses a 6V6 audio output and sounds great. I personally do not like mechanical filters for AM. I have a TMC GPR 90 that also sounds great on am... Again my 2 cents worth only. You will get probably 20 different ideas. The best way is to visit as many AMers that you can and listen what is best for you... Bob W1PE -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Theo Bellamy Sent: Saturday, March 04, 2006 2:05 PM To: Discussion of AM Radio Subject: [AMRadio] 51J3 or 75A3? I am shopping for a receiver to use on AM. I think I want either a 75A3 or a 51J3. Which one is best for AM use as far as making pleasing sounds come out of the speaker? I used to have a 51J4 and a 75A4, and they worked fine (especially the 'J4), but I have heard that the 'J3 may have the best sounding audio section for AM. True? Thanks, Theo K4MO __ AMRadio mailing list Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net AMfone Website: http://www.amfone.net AM List Admin: Brian Sherrod/w5ami, Paul Courson/wa3vjb
RE: [AMRadio] 51J3 or 75A3?
I pull audio off the af gain control of my 75A4 and send to an outboard hi-fi amplifier and speaker, and it sounds pretty good. I changed some coupling caps between the detector, noise limiter and af amp, and clipped out the 510 pf caps Collins later added to the design to limit high frequency audio response. A suspect the main source of distortion is not so much the mixer, but the mechanical filters themselves. The R-390A has similar distortion, but the R-390 (with L-C i.f. selectivity) sounds quite a bit smoother. According to the military, the conversion to mechanical filters in the 390-A was a cost-cutting measure, not for improved selecivity. But I find the 75A4, with modified audio and outboard power amp, an acceptable compromise between AM audio fidelity and selectivity/stability/dial accuracy. Don k4kyv ___ This message was typed using the DVORAK keyboard layout. Try it - you'll like it. http://www.mwbrooks.com/dvorak/ http://gigliwood.com/abcd/
Re: [AMRadio] 51J3 or 75A3?
I also concur on the general coverage version over the ham band only, but again, it's a personal choice. To me the biggest drawback to the 51J series is the 500 kc/s i.f. It is much more difficult to find mechanical filters for them, although a few years ago I checked out the Collins/Rockwell website, and they still make them in a wide variety of selectivities. The impedances are way too low for tubes; the modern ones are designed to go into solid state equipment, but it shouldn't be too difficult to use stepdown/stepup transformers to make them match. That's what's inside the Curry replacement 75A4 filters advertised in Electric Radio. Don K4KYV ___ This message was typed using the DVORAK keyboard layout. Try it - you'll like it. http://www.mwbrooks.com/dvorak/ http://gigliwood.com/abcd/
RE: [AMRadio] 51J3 or 75A3?
A friend of mine has an HRO-SR. It has mechanical not crystal filters. He also has a bunch of Collins receivers including an 75A1, 75A2, 75A3, 75A4, 51J4, along with several R-390s and an SP-600. One night we were messing around and listening to some guys on 160M AM with the various receivers. When he switched to the HRO it was... weird, almost ghostly. Honest we were not smoking anything but those guys coming through that National speaker and filling the shack sounded like signals from the past. REALLY long-delayed-echoes. I'm no audiophool but the sound was DISTINCTLY better and had another dimension to it. Ever since that night I moved the HRO-SR way up on my Want one before I die list. I remember him saying that any Collins receiver with crystal filtering really distorted the audio in a noticable way. YMMV. 73, Mark W1EOF -Original Message- From: Theo Bellamy [mailto:[EMAIL PROTECTED] Sent: Saturday, March 04, 2006 3:05 PM To: Discussion of AM Radio Subject: [AMRadio] 51J3 or 75A3? I am shopping for a receiver to use on AM. I think I want either a 75A3 or a 51J3. Which one is best for AM use as far as making pleasing sounds come out of the speaker? I used to have a 51J4 and a 75A4, and they worked fine (especially the 'J4), but I have heard that the 'J3 may have the best sounding audio section for AM. True? Thanks, Theo K4MO __ AMRadio mailing list Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net AMfone Website: http://www.amfone.net AM List Admin: Brian Sherrod/w5ami, Paul Courson/wa3vjb -- No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.1.375 / Virus Database: 268.1.1/273 - Release Date: 3/2/06 -- No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.1.375 / Virus Database: 268.1.1/273 - Release Date: 3/2/06
RE: [AMRadio] 51J3 or 75A3?
If you want AM reception you want an HRO 50-1. Just my opinion of course. Unmodified excepting normal component replacements and upgrades. I have two HRO 50T1s. Now you can bench a lot of receivers that are 50 plus years old and hear different things no doubt. But these receivers in good condition and alignment are very tough to beat for that AM sound. My 50T1s have one purpose and one purpose only. Listening to AM. On higher bands I agree with the previous poster on the NC183D. I just sold my beautiful 183D to a friend. He is a lucky guy. The problem with these receivers is that it is hard to get the audio gain pot past 1 on the knob dial without causing some pain in a normal size room. The bigger the room the better. CRANK IT UP! Use the matching speaker too. Any big speaker will do but the matching speakers work very well and look cool too. I have a Halli R-46B hooked to my TenTec OMNI 6. Even light weight radios sound better with a good sized speaker. So to do a real AM receiver like the SX28s, HROs etc. justice don't strangle them with a so so speaker. I have actually seen guys do that. Don't know why. It should be obvious. Right? K0AZ Mike Sanders 18169 Highway 174 MT Vernon, Missouri 65712-9171 [EMAIL PROTECTED] mailto:[EMAIL PROTECTED] I am shopping for a receiver to use on AM. I think I want either a 75A3 or a 51J3. Which one is best for AM use as far as making pleasing sounds come out of the speaker? I used to have a 51J4 and a 75A4, and they worked fine (especially the 'J4), but I have heard that the 'J3 may have the best sounding audio section for AM. True? Thanks, Theo K4MO __ AMRadio mailing list Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net AMfone Website: http://www.amfone.net AM List Admin: Brian Sherrod/w5ami, Paul Courson/wa3vjb -- No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.1.375 / Virus Database: 268.1.1/273 - Release Date: 3/2/06 -- No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.1.375 / Virus Database: 268.1.1/273 - Release Date: 3/2/06 __ AMRadio mailing list Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net AMfone Website: http://www.amfone.net AM List Admin: Brian Sherrod/w5ami, Paul Courson/wa3vjb -- No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.1.375 / Virus Database: 268.1.2/274 - Release Date: 3/3/06 -- No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.1.375 / Virus Database: 268.1.2/274 - Release Date: 3/3/06
RE: [AMRadio] 51J3 or 75A3?
This is an interesting thread. I agree on speaker size. I have a 1950's 15 Jensen in a total bass ported box being driven by a Rolls 35 watt power amp. I have all me receivers going into the mixer at line input level. This way you can also feed the audio into your PC for recording. Works great Sounds great. The absolute best AM receiver I have is not a BA but a JRC and wow does it play... Anyway guys great discussion and as I told Theo he opened up the Pandora's box with that question.. Bob W1PE -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Mike Sanders K0AZ Sent: Saturday, March 04, 2006 9:41 PM To: [EMAIL PROTECTED]; Discussion of AM Radio Subject: RE: [AMRadio] 51J3 or 75A3? If you want AM reception you want an HRO 50-1. Just my opinion of course. Unmodified excepting normal component replacements and upgrades. I have two HRO 50T1s. Now you can bench a lot of receivers that are 50 plus years old and hear different things no doubt. But these receivers in good condition and alignment are very tough to beat for that AM sound. My 50T1s have one purpose and one purpose only. Listening to AM. On higher bands I agree with the previous poster on the NC183D. I just sold my beautiful 183D to a friend. He is a lucky guy. The problem with these receivers is that it is hard to get the audio gain pot past 1 on the knob dial without causing some pain in a normal size room. The bigger the room the better. CRANK IT UP! Use the matching speaker too. Any big speaker will do but the matching speakers work very well and look cool too. I have a Halli R-46B hooked to my TenTec OMNI 6. Even light weight radios sound better with a good sized speaker. So to do a real AM receiver like the SX28s, HROs etc. justice don't strangle them with a so so speaker. I have actually seen guys do that. Don't know why. It should be obvious. Right? K0AZ Mike Sanders 18169 Highway 174 MT Vernon, Missouri 65712-9171 [EMAIL PROTECTED] mailto:[EMAIL PROTECTED] I am shopping for a receiver to use on AM. I think I want either a 75A3 or a 51J3. Which one is best for AM use as far as making pleasing sounds come out of the speaker? I used to have a 51J4 and a 75A4, and they worked fine (especially the 'J4), but I have heard that the 'J3 may have the best sounding audio section for AM. True? Thanks, Theo K4MO __ AMRadio mailing list Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net AMfone Website: http://www.amfone.net AM List Admin: Brian Sherrod/w5ami, Paul Courson/wa3vjb -- No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.1.375 / Virus Database: 268.1.1/273 - Release Date: 3/2/06 -- No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.1.375 / Virus Database: 268.1.1/273 - Release Date: 3/2/06 __ AMRadio mailing list Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net AMfone Website: http://www.amfone.net AM List Admin: Brian Sherrod/w5ami, Paul Courson/wa3vjb -- No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.1.375 / Virus Database: 268.1.2/274 - Release Date: 3/3/06 -- No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.1.375 / Virus Database: 268.1.2/274 - Release Date: 3/3/06 __ AMRadio mailing list Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net AMfone Website: http://www.amfone.net AM List Admin: Brian Sherrod/w5ami, Paul Courson/wa3vjb
