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| Reviews Summary for Collins 75A-4 |
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Reviews: 19
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Average rating: 4.2/5
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MSRP: $695
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Description: 10-160 meter AM/SSB/CW Receiver
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You can
write your own review of the Collins 75A-4.
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KC2NYQ
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Rating: 5/5
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Feb 3, 2008 07:49
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Great receiver for it's time
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Time owned: 6 to 12 months
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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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K3BB
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Rating: 5/5
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Jul 15, 2007 18:35
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Historic Use Over a period of 8 years
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Time owned: more than 12 months
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Had some time on my hands, so decided to look - see at some past receiver reviews.
In the 1963 time frame, I picket up a mint 75S - 1 receiver, with, lucky for me, the WATERS Q MULTIPLIER.
A few years later, I became the owner of 4, yes 4 Collins 75A - 4 Receivers ; this over the late 1960s into the mid 1970s time frame.
W1WR, Dave, a good friend of mine, was a COLLINS " book of Knowledge ". SERIAL NUMBERS were the name of the game, so I waited for my chance to corner a 3000 plus Serial Number A - 4.
The first baby I was able to put my hands on was # 31XX. Nice radio, beat my SX-110, SX-101,HQ - 170, and my SP - 600 just by " good " looks alone.
Now it was time to collect FILTERS for the A - 4, and examine some of the MODS that were a must, like the VCZ MODS. I managed to pick up a 2.1 Khz, 3.1 Khz, and a 6.0 Khz MECHANICAL FILTERS, the 455J versions. Replaced all the 6AL6s with solid state diodes, and modified the power supply as well.
Went thru 2 more A - 4s before I purchased a NICE, like new condition Serial Number 42XX A - 4. By now I had the 200 Hz crystal filter, 500 Hz, 800 Hz, 1500 Hz, 2100 Hz, 3100 Hz, and the 6000 Hz Mechanical Filters. After looking closer at the VCZ mods, I was not impressed. Besides, COLLINS had gone thru many mods, and circuit improvement by the # 4000 releases. My diode changes reduced the thermianic heating ( watts ) by about 25 %.
Realigned, stability great, resettabily near perfect.
My ham life was very much graced by my wife's tolerance of my hobby. Thus I was able to run this beautiful A - 4 in parallel with several KWM - 2s,a 75S - 3, a 75S - 3B, a Yaesu FT -901 DM, and later a TS 930. Who was the winner ? On CW the FT 901 DM audio was beautiful. Sensitivity, Selectivity 75A - 4. I had all the best of the MECHANICAL FILTERS, and the RECEIVER WAS ALIGNED to spec.
You DSP lovers, that A - 4 of mine, with todays 40 year old technology could equal or even out perform most modern rigs. I had the 200 Hz Crystal filter, the 500, and 800 hz filters for CW , and for SSB the 1.5, 2.1, or 3.1 Khz Mechanical JEWELS of filters. Sensitivity around 0.10 uvolt, so ?
Talk about notch filters, passband tuning, noise blankers - the WATERS Q Multiplier in my 75S - 1 was just as good as those in the 2000 vintage radios.
If you have the Dollars, best 75 A - 4s came out of CANADA, production runs with Serial Numbers over 5000. See one get it.
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WB6YZZ
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Rating: 5/5
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Feb 10, 2007 15:28
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Better than expected!
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Time owned: 0 to 3 months
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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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WY6K
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Rating: 5/5
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Jan 9, 2007 20:11
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Best of its era
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Time owned: more than 12 months
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I am fortunate enough to have two fully restored 75A-4s, both of which were restored by Howard Mills, who did an exceptional job. I was a ham when this radio ruled the airwaves and was in awe of it after I was able to compare it to my SX101 - there was no comparison. It is still head and shoulders above the other receivers of that era - the SX101, HQ170, NC303, etc.
But you must remember that the design goals were stability, sensitivity, and selectivity - roughly in that order. The 75A-4 was the first truly stable receiver I ever experienced, it was, and is, amazingly stable for a non-synthesized rig. It made all the other recievers of that era look like toys. You could actually depend on the markings on the dial to be correct and repeatable. On most other rigs, the markings were just approximate and not necessarily the same from day to day.
It is still one of the most sensitive radios I have. Only the R390A seems better. It consistently hears everything my IC756PRO hears.
The selectivity is clearly not what you get with a modern rig but is more than adequate for everything but serious contesting or the most difficult dxing conditions. Of course, you don't get effective noise reduction or bells and whistles.
The audio is fine in both my rigs, although some manual gain distribution management is required (sometimes you have to turn the RF gain down a bit) and you don't want to drive the audio stage too hard. I use a 312B-4 speaker. I can also tell some difference between the two rigs.
The 75A4 was really made to introduce SSB to the amateur community. While many improvements were made in later rigs, especially in the S-line (which are surely better SSB rigs), the 75A-4 performs well enough on SSB. Correctly setting the Passband Tuning yields excellent results, even on weak signals.
This receiver is great fun and one of my favorites. If I'm serious about DXing, I turn on the 756PRO. But if I just feel like listening to see what's going on, I turn on either a 75A'4 or a 75S-3. Get one of these radios if you want a wonderful nostalgic experience, or if you just like the sound of tube radios of this era (especially Collins). Don't get one thinking it is going to beat your ICOM or Ten Tec. But if you are considering radios from that era, there is no way to go wrong with the 75A-4. It's the Rolls Royce of that era.
I would happily pay $3000 (in 2007) for a Howard Mills restored 75A-4. I'd pay $1500 for one in excellent, but not restored, condition. And maybe $1000 for one that needs work.
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K6JPA
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Rating: 5/5
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Oct 22, 2006 21:47
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Elegant Classy Lady
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Time owned: more than 12 months
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I was fortunate enough to find a fully restored example for sale several years ago and purchased to to complete a full "Gold Dust" set. Although not used as much as my newer rigs, it still brings a smile to my face to watch this old girl light up and bring the airwaves to life. It's not really fair to compare her to my newer receivers. Frankly, even with their computer controlled, digitally processed DSP wizardry, they simply lack the kick in the rear fun factor of pulling in and listening to a weak station using skill, and not simply relying on microprocessors.
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N4KH
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Rating: 5/5
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Mar 16, 2006 19:45
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Great vintage receiver
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Time owned: more than 12 months
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This is a great vintage receiver, but they sure are big. Mine had the optional noise blanker module in the back. I don't understand some of the negative comments from other reviewers. I can only conclude that their receiver had some problems that needed correcting. Yes, there are some good mods that improve performance and you do have to nurse these things on a little like any vintage rig. Unfortunately, I sold mine to help fund other equipment purchases.
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G8AQN
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Rating: 5/5
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Jul 20, 2005 08:19
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Great quality & performance
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Time owned: 3 to 6 months
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I have read a number of reviews regarding the 75A-4 some good to excellent & some bad, however I would like to add my bit regarding this great receiver.
I bought mine on the German Ebay site, with caution I might add, due to the fact that it had been modified somewhat,the seller stated that he had modified it with SSB as his main interest, he had replaced the mixer stages with 7360 balanced mixer/modulator valves which were popular back in the 60/70's, as per W2QWS's suggestions in QST dated July 1964, plus he had changed the AGC for fast attack & slow decay times, he also relaced L27 IF tuned cicuit with a 3.1KHz. Collins mechanical filter for use as a noise roofing filter, the same type as is used in the receiver selectivity stages.
When it arrived the 75A-4 was in very good clean condition, with no signs of black staining under the chassis as is evident with a lot of use, I was very surprised at the quality of the workmanship done during the modifcations & replacement of parts obviously done by a professional wireman, after the usual visual & safty checks I switched the radio on, & "WOW" what a performer, there were no cross mod. & blocking problems as some of the reviews suggest even on 80Mtrs in the evening when the band is crowded, & good sensitivity with low noise level, the stability of the oscillator is superb, I measured 200c/s drift from switch on in the first quarter of an hour, with minimal drift of 150c/s during the day.
I promptly ordered a 6 & 9KHz. filter from Electric Radio for AM use, these arrived a few days latter & were fitted, the 9Khz. filter replaced the 3.1 KHz filter that was fitted in place of L27, the 6Khz. filter was installed in it's usual holder.
I must admit that the audio on the 75A-4 did sound a bit strange, it had very "edgy" sort of sound, I tried a number of metal cased speakers of all sizes with no difference in sound, I was beginning to get a bit frusterated so I decided to tackle the audio stages, this turned out to be a red herring & a waste of time, in desperation I tried a 1930's extension speaker which was fitted in a wooden cabinet, & beleive it or not, the 75A now sounds great, so try it!!
As regards to SSB performance, it is not fair to compare it to the modern receivers, after all the 75A-4 was produced in the early days of SSB , so come on, I don't know of any other receiver as good as this from this era.
I know that the purist & collector ( I am one of them) believe in the original design, but my 75A-4 is superb & I have no intentions at this stage to reverse the modifications, I use mine regulaly on the 40 & 80Mtrs AM nets.it's a great receiver as it is. If one comes along at the right price in original condition then I may buy it if only to compare it with my modified one.
I would not part with my 75A-4 for anything.
73's
Tony G8AQN
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K1YPB
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Rating: 5/5
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Dec 2, 2004 13:25
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Excellent Receiver - Keeping in mind what it is and its vintage
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Time owned: more than 12 months
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I am a proud owner of a 74A4 manufactured in March 1955. It is in excellent shape with all the filters, and works pretty good.
In reading all the reports I can agree with a lot of the opinions offered. I think that considering what this receiver is, and when it was designed and the technology at the time, this receiver is pretty much (or was) "state of the art" Ever since I was a kid (got my ticket in 1962) I desired to own one of these extraordinary receivers. I was finally able to obtain an excellent condition unit a few years back.
It really is not fair to compare this to say... a TS2000 (which I also have). The new digital DSP rigs run circles around these old boat anchors. But... out of respect of what these receivers represent, they still do a very respectable job receiving signals through the QRM. Good filters in combination of a properly operating PBT, along with knowing how to set the other controls in conjunction to what you are receiving renders some still pretty respectable performance. And it is still kind of nice (nostalgic) to see the tubes glow, and enjoy the sights, sounds and smells of a tube powered radio. In our modern adjustment free radio environment of today we are pretty used to pushing a function button and having the DSP or whatever so to speak automatically take care of the function. These older rigs took a little "balancing of the controls" to make the difference between exceptional performance and marginal performance. Quite often that performance was resultant of the operator's skills in that regard, rather than the rig not working properly (ie complaining about crowded band performance while the RF gain control is set at full gain, or maybe the wrong agc time constant selected.
In fairness, I give the 75A4 a "5" from a 1950's 60's evaluation vantage point. From todays vantage point... maybe a "4". I think it all needs to be kept in perspective.
Dan
K1YPB
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K7NG
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Rating: 4/5
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Dec 1, 2004 17:01
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Good, not great
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Time owned: more than 12 months
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I owned a (used) 75A-4 for about 20 years. During that period I had occasion to use it in several different setups. I must say that the audio quality is second to none. Compared to receivers of similar vintage I can't think of any (except for maybe the R-390A)that perform any better in terms of selectivity or sensitivity. But if you were to compare the 'A-4 to a modern receiver, I think you'd find that the newer rig actually outperforms the old 75A-4 in almost every specification. Though the 455-kHz mechanical filters were (and are) the best in existence, the filter blowby, reciprocal mixing due to oscillator noise, high noise figure of the front end and mixers, etc. make the 75A4 second rate today. But if you like the look and feel of the A-4, and enjoy the sounds that come out of it, and aren't trying to win a big-time contest, you can't beat it.
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W2XS
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Rating: 3/5
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Dec 1, 2004 12:44
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The Drakes are better
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Time owned: more than 12 months
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I once did a side-by-side comparison of the 75A4 and the Drake 2B. I was interested in CW QSK performance - receiver overloading, AVC action, and clean sound with good QSK with an external T/R switch. (QSK is the ability to hear in-between the dots and dashes even at high speeds). To make a long story short, I sold the 75A4 and kept the Drake 2B.
These days, I prefer the general-coverage boat anchors for SWL and AM BCB listening, and any Drake R4x receiver for boat anchor ham operating.
Then again, the 75A4 is very impressive looking, has a great dial, and was the first receiver with the incredible feature of passband tuning.
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