| N4UE |
Rating:      |
2021-03-12 | |
| Still incredable performance |
Time Owned: more than 12 months. |
Hi, this is still a fantastic receiver. Yeah, mine is an 'oldie' but it has been upgraded.
In addition to the paper cap replacement, I suggest replacing the mica caps as well. Although only one of mine was 'leaky', they don't age well.
The only reason for the 'update' is that Electric Radio has a NEW book with every known fact/improvement ever found for this great old radio.
My IC-7610 and TS-890 will be LONG gone before my 75A-4.
But, I'm an OF....
ron
N4UE
Hi, let me preface this by stating I collect receivers. I have a lot. My pride and joy, is a perfect example of the state of the art in 1955. I own serial # 029. I purchased this radio sight unseen upon the recommendation of K8DR, from W4XO. I was told that my radio was "nice, but needed the usual recapping, etc" , a 'working radio'. The radio arrived in the most elaborate packing I have ever experienced! Even the Xtal calibrator was removed and wrapped in styrofoam, as were the filters. The condition of the paint was near perfect. This radio had the 4:1 knob and gears installed, which I feel is mandatory. I immediatly thought that this radio needed a companion speaker. After having sticker shock at the 270 series Collins speakers, I ordered one (reproduction) from Mort Jones. I defy anyone to tell it is not origional. What is really amazing is that the paint is a perfect (and I speak as a car builder) and I mean perfect, match to old # 029. Several ham buddies simply cannot believe how good it looks. They swear it is a matched pair. Mort, I don't know how you do it.....unbelievable......
Back to the radio......It played perfect, out of the box. part of 10 M was dead, but that was just a matter of tweaking the osc. coils.
I left the radio alone for about a year, because it worked so well, I just couldn't imagine it being any "better". And this is from a ham of 45 years, (and a retired EE), who can't leave ANYTHING alone! During this time I acquired many new HF radios including an Icom 756Pro, a 706G (both bought by me, in Tokyo and carried on the plane back). The A4 could hold it's own. One day I decided to re-cap the thing. I gathered all the information on the WWW and gathered the necessary parts. I bought the 75A-4 video from the CCA and followed Chuck Rippel's advise about the 'deadly caps'. Sure enough, all (!) the bypass caps were NFG as were several of the micas. I did the mod to remove the B+ from the: 500Hz. 1.5KHz. 2.1KHz and 3.1 KHz filters I had acquired. I did a complete alignment. Some specs were right on, othere were WAYYYYYY out. The result? Probably the best radio I have in my museum/collection. I have a mint '67 EAC R390A with a CV-571A SSB converter (yet to be 'refreshed') so I can't rule this combo out..... However, the only other tube radio I have that can play with the A4, is my Collins 51J3. Recently, I purchased a PD-1 (Product Detector) for the J3, and I have not used it yet.
To 'spruce up' the A4, I polished the tube shields, painting the inside of them black. The chassis is absolutly 100% mint and sparkles like the day it was made. I put the dial drum in my lathe, turned off the old decal and put on a reproduction.
Digital pictures of this radio cannot possibly do it justice! It has earned it's own dedicated table in my museum.
When my new shop/shack/museum is completed this year, I hope to be able to replicate these efforts for any Collins fan at my cost. These are unbelieavable radios and you should acquire one at any cost! They are worth every penny. Trust me!
ron
N4UE
Moving to Lake City Florida
EM80 |
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| KA4KOE |
Rating:      |
2021-03-11 | |
| Nice receiver |
Time Owned: more than 12 months. |
I have a mid-production unit, serial number 2325. If you obtain one of these receivers, you must replace the seven "deadly" capacitors; these are caps that will take out other expensive components if they fail. You must also do the mechanical filter shunt feed mod to take B+ off of the filters. An electrical failure elsewhere in the radio can destroy whatever filter is in-line at the time. Original filters are hard to find; however, Dave Curry manufactures plug-in replacements that are as good, if not better than the originals.
I purchased the radio from dear friend Liz K4GHT about a year before she passed at a bargain basement price. I did not know she was dying from cancer at the time. Liz is sorely missed by her friends. Fine lady and a class act all the way.
There are other recommended Collins mods out there that are intended to improve performance. Whether or not you choose to implement one or more of them is up to you; be aware that some may hinder, not help.
73
Philip |
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| W7MBR |
Rating:      |
2019-02-05 | |
| Collins Masterpiece |
Time Owned: more than 12 months. |
| I am a major collector of vintage radios including lots of Collins transmitters and receivers. The 75A-4 along with its companion KWS-1 transmitter were largely responsible for the switch from AM to SSB back in the late 50's and early 60's attesting to just how good both of them are. Unlike some reports of bad audio I agree with Art Collins statement back in the 60's about Collins audio: We make great communications receivers not HI-FI equipment. Its stability is legendary and the mechanical filters provide excellent selectivity. I have personally measured the sensitivity of the 75A-4 and it averages .06uv from 160-10 meters, as good or better than most of its contemporaries. I rate it a solid 5 and to rate it a 1 or 2 simply shows you are one of those Collins haters or you just aren't familiar with vintage equipment. |
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| W6XY |
Rating:      |
2012-08-15 | |
| A great vintage ham SSB and CW receiver |
Time Owned: more than 12 months. |
The 75A-4 is my favorite vintage amateur band receiver. I cannot think of another receiver from the 1950s that is so often compared to the performance of modern receivers. The 75A-4 was designed primarily as a SSB and CW receiver and was paired with the Collins KWS-1 transmitter.
At least one previous reviewer mentioned the high mixer noise level, yet the 75A-4 has a measured MDS of better than -140dBm (see measurements at http://www.w1vd.com/Collins75A4.html).
My two 75A-4s compare favorably with my Drake R-4C with all the Sherwood Engineering mods for CW. The enhanced performance of the Drake is due mainly to the excellent added filters, and it's obvious when operating the Drake that reception improves greatly by cascading filters and narrowing the IF bandith. All of this is to say that appropriate filters should be used in the 75A-4 for optimum reception. I'm looking forward to getting a Dave Curry mechanical filter for 300Hz!
My 5 rating is for the 75A-4 in the vintage receiver category. |
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| W7MHZ |
Rating:      |
2012-04-04 | |
| The All Time Standard |
Time Owned: 6 to 12 months. |
If you have a Collins 75A-4 and it does not sound good. It needs repair.
These are great receivers. Stable, Low Noise, Sensitive, and Excellent Audio. |
|
| KB2FCV |
Rating:      |
2012-02-06 | |
| Stable, it holds its own |
Time Owned: 3 to 6 months. |
I've owned my 75A-4 for a few months now. So far I am very happy with it. I've owned hallicrafters, heathkit and hammarlund receivers before, but so far I think this receiver is far superior. Once it's warmed up, the receiver is absolutely stable. If listening to a net that runs for an hour or several, I never have to touch the dial. I think the PTO was definitely ahead of it's time and was leaps and bounds better than any other manufactured ham gear (not counting the R-390, which was not manufactured as ham gear)
I decided to do some comparisons with my IC-746pro. While yes, the IC-746 pro does hear a little better, the 75A-4 did a very respectable job at pulling weak signals out. It's not fair to expect it to receive just like your modern DSP transceiver, but I was impressed that it held it's own when I copied stations that were weak on both radios.
The receiver does ok with filtering out nearby ssb or cw stations. My Icom was the clear winner but for what it was able to do, it did ok. I'm not expecting modern contest grade performance out of a 50+ year old receiver. I can imagine back in the day, it did a fantastic job compared to what else was available.
I haven't done much receiving on AM, but then again I've heard that if you want to use AM, get a 75A-1 (which I have.. under restoration), A-2 or A-3. AM sounds ok on the receiver so far, but I suppose I'd like to hear it against my A-1 before I can really give a good review.
Bottom line, I've owned alot of boatanchor receivers over the last 20+ years from the 1940's - early 60's. This is by far the best perfoming I have owned and it's a joy to operate. |
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| KG8LB |
Rating:   |
2011-02-08 | |
| OK just OK |
Time Owned: more than 12 months. |
| Another of the "trophy" boutique offerings from the St James Grey folks. The receive audio is lack luster with more than a fair amount of distortion. The mechanical filters color that already poor audio . There are many receivers that will outperform the 75-A$ quite easily. Smaller packages and lower prices to boot. A very business looking box, it really fails to deliver up to the expectations . The Harley Davidson of radio, the Collins 75-A4 is overweight, overpriced and under-performing. |
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| WN3R |
Rating:      |
2010-11-28 | |
| Memories |
Time Owned: 6 to 12 months. |
| I never had any Collins gear when I was first licensed, but my elmer did. I just hooked up a borrowed 75A-4 with a sweet sounds speaker and it felt like the late 1950's again. Even the AM stations sounded good. CW was a bit of a challenge with the 3KHz filter. My new Ranger is now plugged in and all tuned up into a dummy load. It has a slight chirp but sounded sweet anyway. There's somethng to be said for the days when radios were not as good as they are today. Next week I'll add the coax relay and make a contact or two. I encourage the youngsters in the hobby to visit your local old timer and listen a bit to the older gear. It was fun then and nothing has changed. |
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| KC2NYQ |
Rating:      |
2008-02-03 | |
| Great receiver for it's time |
Time Owned: 6 to 12 months. |
I bought this receiver last summer from a local Collins collector. It
was restored by Howard Mills. This receiver for it's time and even today is one of the best I've owned. I've read that people state that
it's not a very good receiver need to keep in mind the time it was made and what it was made for. |
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| WB6YZZ |
Rating:      |
2007-02-10 | |
| Better than expected! |
Time Owned: 0 to 3 months. |
I'd been missing the old BIG receivers with BIG knobs, space between them and linear slide rule dials, analgous to an analog watch. You can "see" where you are in the band without having to calculate how far you are from one end of the band or the other. So I decided to get an old receiver with that in mind. The best receiver out there seemed to be the 75A-4.
First I bought the "Modification Compendium" to see just how much it could be improved so that it was actually usable. I was impressed with the implied results, so I nabbed a 75A-4 off eBay with the vernier dial, the 3 standard filters and NO RUST for just under $1100! It performed and sounded better than I expected. I almost decided not to modify it, but I just don't feel right unless I get inside my gear and do SOMETHING to it ;-) So I made the AVC and the front end mods to improve gain distribution and IM response.
The receiver sounds great, with an old Radio Shack Minimus 7 "stereo" speaker. The tuning is smooth and easy. After a complete alignment, I compared it to my FT-920 and was amazed to find that it was as sensitive, but better sounding. I think the wider mechanical filter contributes to better fidelity, depending upon the transmitting station. AM, of course sounds terrific, with the 6KHz filter.
I'm not a DXer, but a casual listener and occasional rag chewer. I am very happy with the 75A-4, my now prefered radio.
I will now pair it up with either another boat anchor transmitter or maybe a homebrew job, and really enjoy ham radio, the way it was back when I first got my ticket! |
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