The AM Forum

Hello all,

I am getting back to my early days of Ham Radio (1966) and now
have a DX-60 with HG-10 VFO using them on CW and AM.
For my receiver I use a IC-735 or my IC-746. They work but
seem to lack the Fidelity I seem to remember listening to back in the
60's-early 70's.

I would like to buy a receiver and have been reading several
articles but thought this forum might be best to post my
question about what should I be looking at.   

When I got my General in 1967 I had a HQ-170A which I thought was
pretty good but after reading over the last few weeks most post
say not to good for AM reception.  I used it with a Johnson transmitter
on CW and AM.

Any tips would be appreciated.

thanks
Ken
N1KK

Ken,

The HQ-170A is a good receiver for a variety of conditions but it isn't as broad as some of the vintage gear.  It is one of my favorites because it does a great job when conditions become difficult.   The Hallicrafters SX-96 family (includes 100,101,115 etc.) offer the same selectable sideband on AM capability with a little broader maximum bandwidth.

For decent conditions I really like the sound of a lot of the National receivers (NC-240-D, NC-183, 183D, HRO-50etc.) but they won't do as well as the HQ-170A when conditions really become difficult.

Look at these articles: 

http://www.amwindow.org/tech/htm/slabrxreview.htm
http://amfone.net/ECSound/JNRECS.html

My choice:  the Hammarlund SuperPro (pre-SP-600) - SP-10, SP-100, SP-200, SP-400, BC-779, BC-1004

First of all, you have to make the decision on what you want out of a receiver.

Do you want "battle conditions" selectivity, OR high fidelity.

the two usually dont go hand in hand. You and only you have to decide which is more important to you and go from there. Everything is a trade off and the two usually don't go hand in hand!

Johnny,
            One day I have to get a chance to go through my notes and spend a little time beatin on the keyboard. I have close to 10 more to add to that list...............

Ditto.

73DG

My two cents...
Depends on what you want to spend or can afford.
For me it's a toss up between a Collins R-390 or the SP-600 JX-17. I have both and I cannot imagine anything better. For fidelity, the National NC-183 and Hallicrafters SX-28 are pretty nice to listen to.
The push pull 6V6 output stage of the NC-183 is pretty hard to beat, especially when coupled to an Altec 604 Duplex (coaxial) speaker. If you want BOTH performance and fidelity, then the 390 or 600 using a line out to an outboard tube amplifier pushing a real speaker or recording monitor. After that experience, nothing else even comes close. Maybe a bit off topic, but half the battle of getting good receiving results is the choice of good monitoring. I see guys spending big bucks on equipment but skimping on monitoring equipment.
It doesn't have to be expensive either. For example, I use an inexpensive self powered two-way recording monitor that produces 75 watts of clean audio. It cleanly reproduces the audio derived from your tube receiver and if you add some equalization in that chain, then it enables you to contour the system to your set of ears.
Food for thought.

I wonder whether the size of the Dixie 60 is part of your station plan.

Some of the receivers others have mentioned are also my preference for the best quality of AM, but if you want a smaller size, consider the Hammarlund HQ110. It's about the size of a Johnson Ranger, not as deep, and probably would fit the same table top as the Heath gear you've already got.

They're also not very expensive.

I've got an HQ100A^* that I really like.  I use an external audio amp with tone controls, and a good "stereo" type loudspeaker.  The external amp is fed at a level from the Hammarlund that sounds the best from the receiver's compensated tone design. (the proportion of bass/treble varies with volume).

Also in the smaller-is-better category, the Kenwood R-1000. Solid state, 30 years old, a good example can still be found.  I have one of them too, and lately find myself using it instead of the SP600, R390 or R390A just because it's instant-on to let me check the bands.

I've paired it with an FT101EE for use up on 10 meters for now.  Great tabletop combo.

---

*disagreeing with John's review.  I don't find the audio "awful" when you set the level in the sweet spot, and the selectivity is generous to allow good quality AM signals to come through.

Larry, W8ER, has done some mods on the HQ110 to improve the audio¹

Recordings he has made of my station sounded good.

http://www.amwindow.org/tech/htm/hqaudiomods.htm (http://www.amwindow.org/tech/htm/hqaudiomods.htm)

Dif'rent strokes for different folks.  Everyone has their likes and dislikes and I readily admit to my prejudices in receivers.  The little HQs are pretty good for what they are, but I'd never use one as a main station RXer.  Too weak a front end, and the awful (to my ear, and compared to stouter receviers) audio is the icing on the cake.  And to be honest, there's no one receiver that I've ever owned or used that has ALL the features I want, or doesn't have some irritating weakness, so I'm building my own (again).

At the end of the day price/availability/personal likes determine what you end up with unless cost is no object.

Unless you custom build or modify your own.  Then, you can have both. I like the 75A-4 for its stability, dial accuracy and selectivity.  But the audio was an afterthought at best, and the stock receiver sounds like crap.  I adjusted a few coupling capacitors in the low level audio stages, pick the audio off the af gain control, and use an outboard amplifier (an old 1950s vintage monaural "hi-fi" amplifier with a pair of 6V6s), feeding a 15" broadcast studio monitor speaker and enclosure. With that, it has pretty decent audio.

I added an outboard box with additional mechanical filters to my A-4, so I can choose 300~, 3.1, 4, 6, 8 and 16 kc/s selectivity.  The stock 6 kc/s AM filter is too narrow for good quality.  OTOH, the R-390A jumps from 4 to 8 kc/s; sometimes the 4 is too narrow for condx while the 8 is too wide.  They should have included a 6 between the 4 and 8.

The R-390A sounds good if you pick the audio off the "diode load" terminal on the back of the set and run it to an outboard amp, but the thing is a PITA to tune through the frequency ranges.  I also like a slower tuning rate than the 100 kc/dial revolution.

The R-390 (non-A) sounds much smoother than the A model, due to the phase  distortion generated by the mechanical filters.  The selectivity of the L-C filters in the non-A is almost as good as that of the mechanical ones.  

Another often-overlooked receiver is the R-392.  It runs on 28 vdc, but works much like the R-390 (non-A), with L-C filters, except no 16 kc/s selectivity.  It is smaller, but the thing is ugly, yet even the stock audio sounds good with a decent speaker. You  have to provide a 28 volt DC source at several amps.

I work CW from time to time, and occasionally monitor slopbucket, so I want good solid stability.  Most of the "vintage" receivers like the Super-Pro and other Hammarlund, and Hallicrafters are lacking in that department.  The most solidly stable vintage receivers are the ones made by National: HRO series, NC-240D and NC-101 series. They take a while to warm up, but once they come to temperature, the stability is almost as good as the Collins.

I have been doing some additional reading since my post and found
folks saying the R390A might be the best receiver ever but
they said the audio was not as good as others.

It's interesting the more I read the reviews of receivers on forums
I can't find 2 reviews that both agree on a particular receiver having
the best audio for AM reception.

I had a 75S-1 given to me and I just finished cleaning it up.
other than comparing it to my IC-735 and IC-746 I am curious
how it fits into the top receivers for AM.  It sounded better
than my Icom radios on AM but doesn't come close on 15 and 10m
for sensitivity. With a old Ameco HF preamp it's not bad.

A few hear are adding external audio amps with selective frequency adjustments. I guess it helps but that would be the case with most.

So I will refine my request to what is the best receiver for AM and CW.

Ken
N1KK

Quite a few AMers up here in NE are using rice boxes that have capability of going wide on AM.  I know this is off topic, but it is an option.  I think everyone on this forum knows my bias toward the Flex radio system (I have both the Flex 5000 & the Flex 1500).

I like Don's recommendation best among the BA receivers - particularly picking the audio off before the crappy final AF stage and using a HIFI amp.  I use a SP600 with the Sherwood SE-3 for outstanding audio if I am in the BA RX mood.  The audio cant be beat - mostly because it takes care of the distortion that comes from modern high density modulation and the inability of diode detection systems to handle high mod % plus selective fading is minimized.

Oh yes, be sure to make room for a decent speaker - not those nice stock speakers that Hallicrafters, National Radio etc offer.  Of course if you can lay your hands on the Hallicrafters bass reflex speaker that would be !!GRRRREAT!!

Have fun, Al

Sort of like asking: what's the best car for day and night driving". You can ask 100 people and get a hundred different responses. Same goes for "best receiver". There is no one answer.

Well................. As they say, opinions are like that there certain part of the anatomy.............. everybody has one ;D  ;D

I could never make up my mind or allow myself to be shackled to having just 1 receiver, so I have around 15 or 16 of them................... ;D  ;D

So I guess space/size not a consideration if you're receptive (pun) to the R390 sized receiver.

The R390 sounds better than the R390A.

The SP600 sounds as good as an R390.

The Flex5000 sounds better than all of them.

Your Icom could be a very nice AM receiver with less attention than some popular 50s receivers.

Always remember that Icom spelled backwards is Moci................. ;D  ;D  ;D

Is that used as back masking on Led Zep tunes.

Slab Bacon spelled backwards is Nocab Bals
Collins spelled backwards is Snilloc
National spelled backwards is Lanoitan
Kenwood spelled backwards is Doownek

And, on and on...

This thread is progressing in very evitisop manner. I applaud all of you.
I own and use the following:
R-390
SP-600 JX-17
NC-100-XA
NC-183
75A-4
75A-3
HQ-129-X
HQ-140-XA
HQ-170
SX-28A
S-19 Sky Buddy (first childhood radio I own)
EH Scott SLR-F

My favorite one? All of them. :)

Most of the suggestions that have been made are excellent. Unfortunately most of them are expensive in the current market. I am assuming you would prefer something turn-key or plug and play. The R390(a) and Sp600, Collins 75A-4 options are great, however they are close to $1000 these days in turn key condition. $500-600 at best.

If your not willing to spend that money, I do recommend the Hammarlund HQ100 or the HQ110a. They can be had in excellent shape for about a tenth of the price of the aforementioned, and sound quite good for AM.

Another option, is an SDR of some sort. There are several by different manufacturers, other than the Flex (who do not build a receive only radio). There is one that shows up on eBay all the time sold by a fellow in Japan. It's called the Soft66LC which comes with the board and case and hooks up to your line audio whatever (stereo, powered monitors etc.) and to the antenna, and to your computer via USB. Works and sounds great and is about the size of a pack of cigarettes. Sells for about $110USD +shipping. There are others as well. The one I mention I have tried and it works great, but there are many others.

John, W2WDX

SP-600....has that flywheel on the dial that makes band excursions easy and fun...
Buy that R388 from wd4tc...(Listed on this board)....those are good receivers too

For my vintage AM ops I like my HQ-180 over my 75A4 - hands down.  Although the 75A4 does very well on SSB

However, my best AM reception is from my Flex 3000 using a set of open frame studio ear phones (AKG model K240) I typically run with a +/- 4 kHz filter but can open it up even more if conditions warrant.

To hear an AM recording thru my Flex go to this link http://w5gw.com/ham7.html and scroll down to a short recording of Darrell, WA5VGO.

I also get pretty good quality AM from my 75S-1.

I can almost answer: I have a 75S3-C, son of the 75S-1, without the optional AM mechanical filter, just an IF transformer. It's just fine on AM. I have to lie about it though because all of my friends pooh-pooh it as an AM receiver. I lie about the 75A-4 too, pretty darned nice with 9 kHz filter. I tell them I'm using one of my Nationals or Hallicrafters. Then they leave me alone.

I haven't done an A/B but I'd wager the 75S-1 is better in all regards than say the HQ-110 mentioned earlier or any of the lower end receivers -- small Nationals, Hallicrafters, Hammerlunds etc. The bigger stuff with the better audio sections -- HRO-50's, SX-42's, SX-28's will sound better but won't hear as well.

I think you'll find most of us miscreants on this board have more stuff than we can use and can say something nice about just about all of it.  I will say though, I do no like the Drake 2B on AM.

PS: Whoever it is that's giving you Collins S-line pieces? Stay on his good side.

Finding a good AM receiver can be a life long endeavor.  I'm 40 years into the search and have tried quite a few out.  One affordable choice that I don't think has been mentioned is a National NC 303.  It does a lot of thinks well and can be made to sound good with a little tunin' on the audio output stage. Besides the National, some other favorites were 75A4, R390A and Sp600 and Kenwood R-1000, which all had strengths and weakness.   

Have fun finding "it", and certainly don't limit yourself to just one.

What does the AM filter look like in a 75S-1?  At the moment I don't
know if this receiver has a AM filter.

Ken
N1KK

My rx experience is extremely limited.  I like the sound of an all analog vacuum tube signal path.  My s.s. DSP box I got during an earlier life sounds dull and antiseptic.  It is "hi-fi" with a perfectly flat response, but it also sounds lifeless.  

I'm told most NC-300/303 searchers go for the NC-303 passing on the NC-300, so it is actually a better buy, especially for AM.

I am very happy with my 75A-3.  It has the black wrinkle, the amber dial lamps, the great vintage aesthetic and audio plus the PTO stability and the 2 and 3 are much less cost than the 4 and for AM and CW ragchewing I do not believe the 4 is that important.  BUT, I have tapped the AF pot wiper out to a pair of external 2x6BQ5 amps, one on each speaker, put in two HB 6 and 9 kc ceramic filters, and solid stated the 5Y3.   With the stock 3.1 kc mechanical filter and single ended audio stage it was not a pleasurable AM rx.

I hear hams on AM using all kinds of older and newer RX's, all having a good time doing so.   The best RX is any RX you enjoy using.

My favorite is my modified 75A-4, does everything real well.  The speaker audio plays across an 8 ohm R, thru an old "Super SCAF" filter, and into a Heath AA-23 25W Hi-Fi Mono amp (P-P 7591s).  The amp drives a Hallicrafters PM-23 with the big magnet Jensen 10 inch speaker, minus the Hi-Z transformer.   Sounds super, the 75A-4 audio gain never gets above 2.... at which point I can hear it well from outside.

I also use the same setup on a HQ-170A taking audio off of the audio gain pot wiper.  Sounds great, much better than audio from the speaker out.  HQ-170's are going for bargain prices these days and are a lot of bang for the buck in addition to being a really cool old RX.  These need a while to settle down and largely quit drifiting, as I'm sure you'll recall, but what the heck, most of these delightful old radios are bit drifty. 

The OP around here is a bit drifty too but one of the joys of AM is that bit of drift doesn't matter much. ;D ;D ;D

My Elecraft K3 also works very well on AM, great audio reports and a lot of flexibility on RX.  I use it on 10M AM since my HT-37 doesn't work there.

73 Jack KZ5A

One just sold recently for over 600 bucks on Ebay. Great radio and very stable too.

Don't forget Otis spelled backwards = Sito.

strap ---  parts

This SDR looks interesting.  I would like to hear from anyone who has compared
it against the old tube receivers.   Sensitivity/selectivity/overload and quality
of AM audio

The price is certainly right.

Ken
N1KK

A NC-300, a few hours spent on replacing paper caps and some resistors (needed on most any old radio) and then doing some of the factory updates will get you into AM pretty cheap. The audio is far better than anything made by Hammarlund after the early SP's.

I have most of the ones mentioned and have 4-5 receivers available at each operating position. At least one is for the audio and others are for battle conditions. There are a few that do both quite well, NC-183D, HRO-50-1 and HRO-60.

Carl

I have a NC-300 and audio is bassy but you do mod it and it sounds pretty good I like mine but mine been opened up by joel WA3JS was N3EYR but like to get something else but i look on E-pay some go way to much for what I think they are worth I am selling my SX-99 need some tlc but does work

                                                                                               Carl KB3RDT

I did a bit more testing last night with my IC-735 and IC-746.
Using one of my old Hallicrafters speakers, I have one with a Communications/High Fidelity
switch on the front, the IC-746 sounded better than the IC-735.
The 746 stock filter is 9KHz for AM.  The IC-735 manual states 6KHz @ -6dB
18KHz @ -50dB

I came across this site for a replacement 6KHz filter for the IC-746
http://members.bellatlantic.net/~vze3rys4/6kc_filter/746_Instruct.htm
Wondering if anyone has any experience with this filter resulting
in to narrow a bandwidth for AM.

Ken

I feel like a white fly, considering that this receiver is quite rare and uncommon, but I think that the Squires-Sanders SS-IBS (or SS-1R) is (my) "the best AM receiver".

$1000 for a SP-600? There were several at NEARfest priced under $300.

Yup, I agree with N6YW on this one, except I believe the diode load output is superior to the stock audio line output for recovering the audio from these receivers. The audio transformers in the R-390 and R-390A are essentially telephone-grade, and not of the best quality if you really want to gild the lily for maximum audio performance.

To my ears, the R-390 (non-A version) sounds better than the R-390A that I also have, for the reasons discussed by others in this post. And the AM performance and audio quality of the SP-600 JX-21 and JX-28 I have rivals that of the R-390. In my station, the audio from all of these receivers is recovered from the the diode load, and fed to an outboard push-pull triode amplifier, driving a 15-inch Altec-Lansing 604C coaxial duplex speaker in a bass-reflex enclosure. I too think it does'nt get much better than that. One remaining improvement that I would like to implement one of these days is to replace the diode load connection with a synchronous detector; I think that would result in the best possible AM performance obtainable from these receivers.

I had an NC-183D years ago (like around 1973), and the audio from that thing was indeed superb, using the stock push-pull 6V6 amplifier. I loaned it to the father of a girl I was going out with in the mid-1970s (he was an aspiring ham), and when we broke up after about a year or so, her father managed to "misplace" the receiver and could'nt find it, and I never was able to get it back. Nice guy.

73,

Bruce

If you want the best functionality for the buck take W2WDX' advice and get a Softrock 66LC. Hook it to an early I.F. in your ricer. The very first I.F. would allow a nice full display of what's happening on the band but it would need to be 70 mhz or lower. I'm not familiar with the scheme in your I-calm.

People get lazy and hook to later I.F.s and lose one of the best features.

The downside is no glow in the dark and all the other cool old radio stuff. AND you need a computer.

The Softrock 66LC should also work on many an old tube receiver too.
The thing cost about what you might pay for a couple used I.F. filters.

That sez it all in a nutshell! ! ! !  ;)  ;)

If I may add a comment,  I have a Heath Mohawk, a National NC-300, a Heath SB-300 and a Hallicrafters SX-111, all of which I use on AM. 

All are "factory stock, all satisfy my needs, but none are "perfect".

I love this conversation. :)
There are some really great posts here. When I referred to using "line out" from my 390 and 600, I am referring to the diode output. My bad, I use the "line out" statement to describe my audio take off point by habit from my recording mentality. I use the diode Out.
Another point to consider here, not everyone likes to work on these old radios and finding the parts that are becoming more scare by the year.
Albeit, most of us here do enjoy tinkering and maintaining these old radios, and do it much of the time, but even a radio head like myself gets tired of it and with that I will give you my take on the current technology.

SDR platforms offer the user a monumental array of choices and features that boggle the mind.
The software being written for SDR's today allows you to virtually define what your radio does and conforms to your needs, even down to the look or "Skin" of the environment.
Many people can't get around the look and interface of this. The look, smell, feel of the knobs, the mass of steel. It's hard to accept a computer screen as a replacement for the "Real" thing. Then again, the "Virtual Radio" of today is real... very real. What I really like about SDR's is I will never have to use my soldering equipment to repair it. I may have a hard drive crash, or the operating system needs an update... the usual headaches of computing, but what you get in return is an IMMENSELY powerful set of radio tools that literally crush our beloved boat anchors in every regard (including weight) with the exception of the audio "character".
This is an area that will be debated forever, but I firmly believe that Tube audio reproduction has no peer.
It also depends on what your operating habits require. I like it all and I use all of the available things in the shack for enjoyment. Just last week, my 390 started making a noise. It bothered me, so I found the problem quickly. Bad tube. Replaced it and back to normal in a few minutes. Last month my hard drive crashed on my radio PC. It took four hours to repair including installing the operating system. Then, another 4 hours to install and configure all of the drivers and software. I cussed a lot. When I was done, all is back to normal. I can perform a full re-cap of a 75A-4 in about a day. I cussed a lot too. ;) And, for the life of me, some of the engineering mistakes that the Collins engineers made in building the 75A-4 leave me scratching my head.
Anyway, I think you get the ideas I am writing here.
Analogous to this discussion, I will leave you with the "Pro Tools" environment. A professional recording system comprised of hardware and software which includes virtual equipment and instrument "Plug in's" which are designed to capture the essence of the real, often insanely expensive hardware and instruments found in the best equipped studios of the world. Recording and mixing in the "Box" as it is referred to, has been met with a lot of pushback and much of it for good reason. To me, nothing is better than a real console with real outboard gear. It's immediate and real. I turn a knob or a fader and I get results. Well, guess what? In "The Box" I get the same results. A Neve EQ, or a Fairchild Compressor plug in can sound very convincing and work very well by comparison. At the end of the day I guess it comes down to whatever works and keeping the hobby fun and exciting, gratifying too. I love it all except lifting that @#$% SP-600!

If you have time you can make a radio sound how you like it but you get an old receiver make sure change the caps plus look at old resistors some might need changed I know my mine was made my NC-300 low in receive but I got rough with mine but it's working with helps of friends also hams Joel WA3JS Chris KB3RDU

And how much would it cost for someone in six land to go to Nearfest? And how many hours of work would the fester ones need? Unknown. I got one of those SP-600's from Nearfest and it needed about 20 hours of work, all new caps and about 20 resistors were out of value and the alignment was WAY out. And it was a four hundred dollar one, that looked new. Somebody went for me there and I was on the phone with the person making the purchase. Festers are a value yes, until you get them home, hihi!

Yup $1000 for one that is plug and play. For R390(a) even more. I've bought seven SP-600's over the past year at Festers and everyone of them needed some work, whether component replacements, and mostly alignments. I suspect this is not what the original poster wants. And I also suspect he wants something right now, not this spring or next fall.

You can buy, off the shelf, a super great receiver like the IC-R75 for under $700 or the Alinco DX-R8T for under $500. Add an outboard audio amplifier and you have a great receiver and a great sound. No need to diddle with questionable fester stuff.

Ken,

I restore old tube receivers for a living. I have a Collins 74A-2a on the bench right now along with a Hallicrafters HT-37 transmitter, and a Collins R390a in waiting. I know most of the radios mentioned here inside and out. I'm listening on an SP-600 and an HQ110a right now.

What I will tell you is the SDR is probably the best fidelity option out of the lot. Now Dave, W2VW has his SDR's mixed up. The one I referred to is the Soft66LC2, which is not a "Softrock", but instead a complete receiver with its own front end. You do not have to use another radio's I.F. stage.

Here's and image of the board for this SDR which comes full assembled and tested. It comes with a little case that you have to cut some holes in for the connectors and LED.


It has an SME antenna input, a USB port, and an audio line out. It is powered by the USB port (FYI: It doesn't seem to have the ground loop problems or RF hash problems reported on other SDR's using USB). All you need is a decent stereo audio card and you can have whatever bandwidth filters you want 22k, 6k, 9k, 25k 41k ... it just depends on the sampling rate of your sound card and its driver. I use the M-Audio Delta 44 which works amazingly well at $150. But you can use the built in soundcards as well.

Here's and image of the board in the case (less front cover). Behind it you can see the bottom part of the software, in this case its the WinRad software.


Here's a link to a YouTube video of it working. Mind you its a Japanese Ham, but you can see how it works here. The radio in the video is the version just before the 66LC2, called the 66ADD. The Soft66LC2 is the current model. Here's the link:



You can use WinRad software to control this and it is simple to use. You get a visual display of the band. and you can see the spectral display of the signal your listening to on that. I believe there is a way to use the Flexradio (PowerSDR) software but I haven't figured that out yet on this SDR. (BTW, Has anyone tried that yet with this SDR?)

You can purchase it directly from Kazunori Miura, JA7TDO at his website via PayPal. The fully assembled unit which requires only the holes in the case is $118 including shipping. The link to his site is http://zao.jp/radio/order/#soft66ad (http://zao.jp/radio/order/#soft66ad)

As far as how it sounds relative to a old tube radio, its much clearer. And since you can see the signal, you can contour the filters to match the signal your trying to receive. And you can use Synchronous Detection to help reduce fades. It's really cool. It's just not Vintage!

John, W2WDX

I have a Softrock ensemble II RX and have been thinking of plugging it into the 8.9 low if output. My issue is it has a 50ohm input and I don't understand how this input would work on w 50 ohm input. How do you interface one of these with the low 8.9mhz input which would be the front end of the input chain?

I was selling one for $300, plug and play.

The point is that most anywhere in the country where there are a reasonable number of hamsfests, you can find a SP-600 (or similar receiver) in good working order for far less than you claim. Scaring people off with incorrect or unrealistic prices is of no value to the original poster or anyone else in the market.

Sorry Steve, I understand what you are saying, but your are incorrect. The last three SP-600's that sold online sold for over $600 & some others at $900. This is not speculation or guesses on my part. It's my business. Sure he can wait for a few months and hunt around for a good deal, and maybe end up with something that works 100%. But more often than not, & I know since I purchase about 100 radios a year from Festers, most radios are NOT plug and play nor 100%.

Good for you though for offering something worthwhile at a Fester. That's the way it should be.

Watching or gauging online auction pricing is never accurate in determining actual equipment value. Auctions generally breed nonsensical bidding emotions from participants. From the seller's perspective, make it pretty, write a good convincing pitch that might tug at the heartstrings, have at least two bidders, and you're good as gold for the big payoff.

In 30 years of going to festers, I've never paid more then $150 or any receiver or transmitter, although at one local radio auction, I did bid $185 and win, a SB-102, SB-200, matching speaker, SB-610, and the SB-644 (I think) remote VFO.

I guess we disagree on what is plug and play.  ;D  There is also a big difference in sold on-line and sold at a hamfest. I find most eBay offerings a poor value when any sort of bidding occurs.

Anyway, I cannot recommend to the original poster to pay $1000 for a SP-600. As I see it, he's trying find a good receiver for AM. From the posts in this thread, it is clear that there is not anything approaching a consensus (not surprisingly). So, if he is to find out for himself, he'll need to buy a number of receivers and try them. Paying top dollar isn't the best value approach. It would be better to get a number radios in good working condition (not perfect or restored) for a lower price. If there are some he doesn't like, he can easily get his money back by selling them. If he finds one he really likes, and if so inclined, he can take the time or spend the money to resto as needed.

And since Ken specifically mentioned Fidelity, I'll third it! There are a few others out there that sound decent, like the SX-28, NC-240D, NC-183D etc, but the Super Pros (not including the 600) are at the top in my book too.

As far as SP-600 prices, $250-$500 seems about average for a decent, working unit. Original cabinet can add value if the buyer is interested in such things. It's a reasonably good receiver for what it is, and quite common. Online prices and real world(not online) prices do vary considerably. The difference is between what you are likely to find locally or at hamfests you travel to, from friends, Craigslist, etc, or buying online where you have to compete with far more parties. Doesn't mean they're worth more, just that one forum provides the possibility of higher visibility, bidding wars and so on.

And it shouldn't be any surprise that paying someone else to do your work for you would cost more. Still doesn't change the overall value beyond that example. No different than buying a car to restore or one already restored by someone else. If you have a vested interest in making money from it, you'll always support the higher selling price.

???  The last three I see in the ebay completed listings went for $250, $430, and $1656, which seems to reinforce Pete's point. 

In my experience, you have as much chance of buying something online that doesn't work as at a hamfest, despite what the seller tells you.  However repairing the thing is often its own reward.

Yes I do have some of the names mixed up  ;D

I still like to use the SDR with the ricebox as a front end even if it plays alone. Just easier for me.

Used to use a pair of R390A I.F. strips married to the ricebox too. I like cables.

"I like cables"  ;D ;D ;D ;D ;D ;D ;D ;D ;D ;D ;D ;D ;D ;D

has there ever been a program at NEARFest where you all get around 10 vintage receivers in a room and conduct an audio quality demonstration?

I'm sure there'd be no problem rounding up several of the well known AM receivers for a side by side comparison.  In my opinion that would be one hell of a program and far more interesting than someone droning along about antenna modeling software or propagation.
of course you need a test signal source but in the northeast that should not be a problem.   Have the demonstration timed to take place during an AM net.  Any ham like me who will never be able to own and try dozens of receivers would love to be able to listen to some of them side by side without having to buy them.  I bet that would be SRO.

Yep, I KNOW that SP-600 was a plug and play receiver cuz it was mine before I traded it to Steve towards an FT-1000D SS amp module. I replaced about 40 caps, aligned it and used it for 7 years - up until the swap.  Steve let it go for a very fair price. Actually the guy got quite a bargain.  

Why did I get rid of it? Replaced it with an HPSDR 160-6M rig.  No more commercial boat anchors in the shack - but plenty of homebrew BA's ...  ;)

T

Most receivers and I say most, even single ended versions, can have good fidelity provided the reproducer is capable of the frequency response.  Today a good quality reporducer for mid band is difficult to find in the 8 or 10 inch size.  That is for a reasonable price.

You can find wide range speakers between 8" to 15" inches for a reasonable price. The Jensen Mod series speakers are inexpensive. Also, Celestion makes a lower priced line of speakers that would work perfect for this application. These can be found at Antique Electronic Supply.
 A coaxial speaker would be the real game changer, and those made for car stereo systems can be had at bargain prices, and can handle the power easily. Craig's list can be useful for finding them.
I once took a 6X9" Jensen coaxial car stereo speaker and mounted it in tuned port enclosure to use with my HQ-129X. I was thrilled at the sound that issued forth. Huge difference from the stock 10" general purpose speaker that was in the Hammarlund cabinet.
Here is a real bargain. These little KLH 2-way bookshelf speakers that are found at Costco or Sams Club, are like 20 bucks each or for the pair. I don't remember which. They sound fantastic for the money and produce a rich full spectrum sound field. Go to a local second hand thrift store and you are likely to find stereo system speakers for dirt cheap. Sometimes, the foam surround on the woofers has deteriorated. Easy fix. You can buy replacement surrounds and glue them on yourself without having to recone the entire speaker.
Because I am a professional guitarist and build guitar amplifiers for a living, I use speakers that are tailored for the guitar. Well, guess what? The sound spectrum that is most desired for guitar falls right in the area where communications speakers are most useful, between 200hz to 4khz, with a useful bump in the upper mid range. This is where we get "articulation" in both speech and music. So, a guitar speaker like the Jensen Mods that I referred to is ideal for this. Wire in a tweeter with a proper crossover capacitor and you're better still. My amplifiers use the ultra sensitive Celestion Alnico Gold's and are prohibitively expensive for this application but would certainly blow your mind if hooked up to your radio set.
If you want to keep your present vintage speaker cabinets in service, then just remove the old speaker and box it up for safe keeping. Install a more efficient modern replacement and kick back and enjoy the sound.
Also worth mentioning, are the newer family of Neo Dymium magnet equipped speakers being made today. They are super efficient, plenty loud and better yet, LIGHT WEIGHT!

For example from my last post:
http://www.ebay.com/itm/Jensen-MOD8-20-20W-8-Replacement-Speaker-8-ohm-/190598575818?pt=LH_DefaultDomain_0&hash=item2c608f76ca
And here:
http://www.ebay.com/itm/KLH-970A-Main-Stereo-Speakers-/280781966529?pt=Speakers_Subwoofers&hash=item415fe8ccc1
And if you really want to go top shelf:
http://www.ebay.com/itm/Tannoy-System-1000-/160690104544?pt=Speakers_Subwoofers&hash=item2569e068e0
This Tannoy is a concentric (coaxial) two way speaker that is spectacular to listen to. It is also a time aligned speaker meaning that the tweeter and woofer are designed such, that the highs and lows arrive at the listening position at the same time. This greatly helps hearing coherence.

I generally find "high fidelity" type speakers annoying to use for listening on short wave or ham bands. Nothing like high fidelity buzzes, pops, static crashes, adjacent frequency QRM, and assorted other atmospheric garbage to rattle your teeth and nerves. I find headphones the most enjoyable plus I can monitor myself when I'm transmitting. I leave the speakers for Frank, disco, and good jazz.

Frank Zappa or Frank Sinatra?

Please excuse this old man but those bookshelf or computer speakers don't cut it for me either.  The sound is tinny and hollow.  I have one similar in a Icom SP 23 that has the filters built in.  Sound is not at all good no matter what button I push.  As for the Jensen, I didn't see the frequency response published with it.  I have looked all over for one that is good from ~ 50 to 6-7K and the prices for the only one line Jensen makes is over $100.

I can buy a case of whiskey for that amount and not care about sound.  Most reasonably priced (below $50) 8 and 10 inch speakers I have found cut off at about 4K, way too bassey for guys who use audio compression, equalizers and such.  I have an R 46 that had a bad speaker and one of my students brought me a speaker like the one on ebay.  It is not comfortable listening.

Pete,  I'm with you.  I never thought I'd use it but I often do, a Sounds Sweet speaker.  It's claim to fame? lousy high frequency response. I switch to a mid-fi (Boston Acoustics) speaker when I can but I often find myself using the Sounds Sweet. http://www.eham.net/reviews/detail/2754

PS: You know you're losing it when you read a review, agree with it and discover you wrote it.

Sinatra of course.  :D

Here my NC-300 with some mods done by WA3JS

Ya know, there is something to be said for this. (for a rare change, I actually somewhat agree with Pete) Limiting some of the high frequency response in a receiver's audio is not always a bad thing. A lot of hiss, crackle and background noise can be a bit fatiguing after a while. Limiting the highs without causing the mid bass to sound muddy can be a good thing at times.

I have an old military receiver, IIRC it is a RBS. It has very specific bandpass filters in the audio section. IT IS NOT HI-FI. But it is the quietest receiver I have ever used. You hear little or no background noise, but the incoming voice just leaps out at you. Sometimes on noisy, crappy nights, it can be a real pleasure to listen to. With all of the hiss and static filtered out of the audio, sometimes you wind up checking to see if it is still running.
I wouldn't want it as my only receiver, but sometimes it is a real pleasure to listen to. It somewhat reminds you of listening to FM.

However, Pete..........................I hate headphones and trying to listen to myself through headphones drives me NUTS! ! ! ! ! 

(http://amfone.net/Amforum/gallery/25_08_01_08_12_19_49.gif)(http://amfone.net/Amforum/gallery/25_08_01_08_12_19_49.gif)(http://amfone.net/Amforum/gallery/25_08_01_08_12_19_49.gif)(http://amfone.net/Amforum/gallery/25_08_01_08_12_19_49.gif)

How many highs could there be with an IF bandwidth of 6-8 kHz?

No need to bring the speaker into. Any cheapo speaker will be FB at 4 kHz.

Thank you for this information.
It does sound interesting and for the price it's affordable just to play
with. 
Setting the audio aside, what's the negative of this SDR.  Not comparing
it in this case to a tube radio but the technical performance against
all Ham Radios. Sensitivity, overload, selectivity, etc. 

Since you restore the oldies, how would you rate the tube receivers
you worked on

Have you ever worked on a 75S-1.  I have one, believe it or not
it was at my local dump and one of the workers gave it to me,
I cleaned it up and checked all the tubes with just an Emission checker
tube tester.  All the Tubes checked good but I noticed the sensitivity
is way down on 15 and 10m compared to my IC-735/IC-746. 
I use an Ameco PLF-2 Preamp on 15/10 and it brings it very close to the Icom's
in sensitivity.  On 80,40,20 sensitivity seem fine.
I don't know what to expect for this receiver. Could be normal for
low sensitivity on 15 and 10m.

Ken
N1KK

Always remember that receivers are like Jello, there's always room for more!

 ;D  ;D  ;D  ;D

Hi Ken, I don't have much interest in the junior Collins models like the 75S because my operating emphasis is on AM.  I have a 51S-1F that works well on 10 meters AM, and it is a nice tabletop receiver. But I wouldn't have gone out and bought it, having come my way sort of like your 75S.

So unless it's taking up space or tying up some money you could use toward one of the senior Collins models, just keep it around and use it for CW or other voice modes that it was tilted toward.

"  PS: You know you're losing it when you read a review, agree with it and discover you wrote it. "

I'd worry more when I start to disagree with myself.


klc

Speakers for what I want should be 250 C - 8 Kc.

Then just about any speaker will do.    ;D

If not, just add the right cap(s).

I put on cans only if it makes the difference between copy and no copy.

I prefer speakers, but I am in comfortable range of at least a dozen big signals from the western Great Lakes region and down south and over to Missouri and Iowa.  Nothing like a big carrier and big audio.  crank up the volume and enjoy. 

Here is some useful info on post-WWII receivers, including descriptions and photos.

http://www.radioblvd.com/Post-WWII%20Ham%20Gear.htm


Click here for a guide to the entire website (http://www.radioblvd.com/)

Hello John

I was reading your description,
"It has an SME antenna input, a USB port, and an audio line out."
What is the audio line out for if you need a sound card for the audio?

Ken
N1KK

Hi Again,

Let me first say, I'm not a fan of the Collins S-line for AM use. Collins by this time really got a SSB bias (as did many manufacturers of this period). However they are very nice for SSB.

On the Soft66, let me simplify this a bit. The audio out is to drive the software used to process the audio. There is a proprietary method used by these SDR's to process the audio called I&Q.

The audio out on the card is not meant to be for listening (while you could), it's meant to feed the software. So do not think of this output on the card as a line output or speaker output, as in a normal receiver. It is meant to be sent to software for further processing, so as to be listenable.

There is much material online about the process, so read that. (I won't bore everyone here going over this.) Suffice it to say, the specific type of audio goes into the audio card on your computer and the software processes the signal into a usable analog audio signal you can listen to. It is a broadband signal fed into the software, and it can then be manipulated and viewed as a bandpass (depending on your cards max sample rate). The software does the filtering, spectrum display, equalization, and most of the functions that allow you to tune in the signal. This is an over simplification, but gives you the idea of whats going on.

Read information on the FlexRadio site, WinRadio or anything regarding SDR receivers online and this will give you all the technicals on what's going on with I&Q and SDR in general.


John, W2WDX
 

I & Q signal processing is old hat technology, used for decades in Doppler radar, phased array radar, digital cellphones and military communications.   It is not something new that ham radio has been created for ham radio.

And also todays digital TV, both on the air and cable.

I/Q processing in ham radio receivign is as old as the GE YRS-1 DSB sync detector circa 1952, and probably older.  ANy phasing SSB xmitter also obviously does I/Q processing to reject the unwanted sideband.

Bell Labs was doing it before WW2

No bias involved, Collins focused on communications gear, not entertainment receivers. As did others. High fidelity wasn't a consideration for most folks using AM. Punchy audio was more valued to cut through the heterodynes and other noise on the bands. In fact, about midway through production of the KW-1 Collins changed the values of numerous components to restrict the audio further, just for this reason.

Many of us prefer the older sets that provide higher fidelity for AM use these days, because it's great to enjoy when you can. In the case of older tube receivers, push-pull output really does the job. Coupled with a speaker capable of covering the spectrum of frequencies, something like and early Super Pro where you can open up the IF to 16 kc on a quiet night with big signals is a thing of beauty.

On the noisy nights, I can't imagine trying to operate without the utility of the 75A-4 with its steep skirts and its passband tuning. Especially when a station cozies up next to your QSO. The trade off is - the audio leaves a lot to be desired at 6 kc as well as other limitations. As Steve points out, at narrower bandwidths, the speaker you choose matters less since it doesn't need to be HiFi. The aging process tends to take away some high frequency ability too.

I think the last P-P output tube receiver was the SX-62B, beating the HRO-60 by about a year. But the HRO-60 offers far more utility and performance for amateur use, and was probably the top of the heap for development, making it tough to beat if you can only have one receiver (and don't want to bother with external audio amps) with the best available technology of the day.

How does the Collins 75S-1 compare to some of the others mentioned
here?  As mentioned, I have one of these and if its just as good
as the HQ-170 or NC-300/303, or some of the others, then my search
has ended.  Playing with this receiver it seems OK but not what I seem
to remember my HQ-170 was in sensitivity.  I can't remember the audio
of the HQ-170A I had even through I did use it with a Johnson Ranger
back in the 60's in AM mode

Ken

Most of us know it's not new. Did I imply that? What I did say was I wasn't going to make a long description as to what it was, since many have known about for a very long time.

Sorry if my reply sounded contentious.   I was just wondering if the SDR receiver manufacturers were making it sound like they invented complex signal processing.  It is much easier in software than all the circuitry required for the hardwired methods of the past.

BUT the HRO-60 was in production as late as 1968, thats a pretty long life having started in 52.

Who was the first ham/comm set with PP outputs? National and Hammarlund both had it in 36 but consumer sets such as Scott had it in 31 in the AW-12 for example.

I'm fairly new to the board here but have been licensed a while, anywayz, I'm just getting interested in playing around with AM. I don't have any of the receivers you all have mentioned, but here's what I plan to use to receive AM.

I plan to use an Empire (Singer) NF-105 for my receiver. I'm going to mod the tuning unit and add one or two 6kc@455kc crystal filters and I've built three separate (160/80/40) bandpass filters to feed the antenna into before going into the front end. I figger that'll make an ok receiver.

Have I missed anything?

You'll have one of the more unique receivers on the bands. I used one of those very briefly about 28 years ago. I have no idea on the internals. I also used some of the old Empire antennas (loops and rods) too. These had the brown/tan crinkle finish. Cool stuff.

Very good. There's no real AGC in this thing so building that would be nice as well and I could convert the meter to a real S meter, but that'll be later on. I have two of these with most of the plug ins. Pretty cool stuff.

Hello I just picked up a Hammerlund SP-600 JX for $350.00 I didn't get it for looks but works I was like wow! smooth thanks Guys for the idea!