The AM Forum
March 28, 2024, 11:12:45 AM *
Welcome, Guest. Please login or register.

Login with username, password and session length
 
   Home   Help Calendar Links Staff List Gallery Login Register  
Pages: [1] 2 ... 4   Go Down
  Print  
Author Topic: The Hammarlund SP-10: A true Historical Relic has arrived  (Read 44204 times)
0 Members and 1 Guest are viewing this topic.
N6YW
Contributing
Member
*
Offline Offline

Posts: 461


WWW
« on: November 22, 2014, 02:00:49 AM »

Greetings once again from Venice.
The Hammarlund SP-10 was an integral product that redefined Hammarlund as a leader in communication receiver design in 1936, the year of it's unveiling. It was in production for just a short period of time of which the SP-100 took it's place. Very few examples of this fine receiver exist, and I am proud to say that
I am now the owner of one such example. It's complete with the rack mount power supply. It has the variable IF gain, the variable crystal filter and of course, that beautiful black box look. The problems it has
is what I would call, the curse of CQ magazine "modification" articles on how to "improve" something that was so prevalent after WWII. This example is unfortunately a victim of attempted hellification of an otherwise brilliant design. I have to remove two very seriously bad modifications that resulted in the use of 7 pin miniature tube substitutions. Fortunately, these mods can be removed with the old 6 pin sockets reinstalled and wired to original stock form using the correct materials and lead dress. I have every reason to believe that this wonderful receiver will back to it's original form and function in under 3 months.
The cosmetics are fine and even though there are some scuffs here and there, it's in remarkably great shape considering it's age. I spent 6 hours installing replacement driver and output transformers that were shot, so I could hear if it worked. Well, it didn't work as far as RF was concerned but I did hook up an iPod to it so I could play some Joe Walsh through the output stage! The 6F6's drove  the speaker nicely.
The original output transformer leaked it's PCB laden contents all over the place, so it will be baked to remove and properly dispose of the offensive guts in order to save the very rare transformer cover.
A modern replacement transformer will be "potted" inside the old cover so I can maintain the look of the original. The steps needed to make this fine receiver work again will be worth it. To me, it's a once in a lifetime chance to own, restore and use something that many have never seen, used or touched.
So, if anyone has any parts from an SP-10, SP-100 in whole or part, please let me know. This will be part of an article I plan to submit to Electric Radio in the coming year.
Thanks for reading.
73 de Billy N6YW


* SP10 front.jpg (210.74 KB, 1000x584 - viewed 903 times.)

* SP10 inside.jpg (187.76 KB, 1000x942 - viewed 805 times.)

* SP10 power supply.jpg (136.78 KB, 1000x644 - viewed 764 times.)
Logged

"Life is too short for QRP"
KX5JT
Contributing
Member
*
Offline Offline

Posts: 1954


John-O-Phonic


« Reply #1 on: November 22, 2014, 04:24:07 AM »

What an awesome radio.  I like the separate supply.  Joe would be proud to know his music is being honored with a hollow-state analog piece of history.  I look forward to hearing about your progress on the restoration.

Congratulations!
Logged

AMI#1684
KA0HCP
Contributing
Member
*
Offline Offline

Posts: 1188



« Reply #2 on: November 22, 2014, 04:29:35 AM »

Sharp looking radio!  I"m sure you will have the insides just as spiffy in short order.  Congratulations.  b.
Logged

New callsign KA0HCP, ex-KB4QAA.  Relocated to Kansas in April 2019.
W3RSW
Contributing
Member
*
Offline Offline

Posts: 3308


Rick & "Roosevelt"


« Reply #3 on: November 22, 2014, 07:58:27 AM »

Very nice acquisition. Bet your very proud of it and will be more so after restoration.

I don't thing the output xformer was laden with any type of PCB oil; not sure that type of oil was even available or invented in '36.  Probably More like a bitumen impregnation. 

The driver and output xformers in later SP 200's etc. were far beefier, both black and both same sized. They were potted with decent potting compound with cardboard covers on the bottoms.
Logged

RICK  *W3RSW*
N6YW
Contributing
Member
*
Offline Offline

Posts: 461


WWW
« Reply #4 on: November 22, 2014, 09:28:46 AM »

Very nice acquisition. Bet your very proud of it and will be more so after restoration.

I don't thing the output xformer was laden with any type of PCB oil; not sure that type of oil was even available or invented in '36.  Probably More like a bitumen impregnation. 

The driver and output xformers in later SP 200's etc. were far beefier, both black and both same sized. They were potted with decent potting compound with cardboard covers on the bottoms.

I don't know what it is but it's disgusting and very very messy. Someone tried to make it work but clearly had no idea what they were doing. Thanks for the comments too. This is going to be one of my favorite projects of all time. I will of course keep you informed of it's progress. Smiley
Logged

"Life is too short for QRP"
W3RSW
Contributing
Member
*
Offline Offline

Posts: 3308


Rick & "Roosevelt"


« Reply #5 on: November 22, 2014, 10:10:39 AM »

Actually on closer inspection the footprint of both those transformers look suspect.  The driver clearly doesn't match the embossed footprint. One corner of it hangs over on an angle with no screw. Stuff I used to do in JS days to use existing holes the lazy way.

The output xfor footprint and input xfor footprint in your picture are the same, just about the size of the ones in the SP-200 where the lugs come out under the xfor's with no flange.  

I think you already have a kludged output where someone has installed an open frame transformer inside a suitable expanded aluminum case, both smaller than the original.  Then they potted it with homemade beeswax or wrong melting temp. compound.

The input xfor is obviously a kludge either added at the factory when nothing else was available for this early model or more likely added later after someone sold both really decent transformers.

I've let my SP-200 go long ago but perhaps someone will measure the footprint of their transformers and send you the results. Both originals in the 200 had expanded steel shells, same size in and out, with lugs coming out the bottom with no outboard flanges.  I'm pretty sure a set of these are what you will find is required.   Possible a museum has an original SP-10 that you can compare.

BTW yours looks more like an SP-100 with octal sockets , a host of kluges and only a few six pin tubes. The SP-100 does seem to have smaller audio transformers than the later SP-200 though.

The power supply appears to have been removed from its case and homemade mounted on the panel too.  Screw holes don't match or are open with faint marks from some previous chassis, etc.
 Very interesting pieces nonetheless.

See a SP-10 and model indentifications here:
http://www.skywaves.ar88.net/commrx/Hammarlumd/SP-10/Super-Pro_SP-10.html

Model ID chart for all Super Pro's:
http://www.skywaves.ar88.net/commrx/Hammarlumd/SP-10/Super-Pro_Data.html

edited after a little research later: This nails it . You have a 1937 SP-100X.  Look about 1/3 way down page.
http://www.radioblvd.com/hammarlund_super_pro.htm
Logged

RICK  *W3RSW*
N6YW
Contributing
Member
*
Offline Offline

Posts: 461


WWW
« Reply #6 on: November 22, 2014, 10:36:46 AM »

Actually on closer inspection the footprint of both those transformers look suspect.  The driver clearly doesn't match the embossed footprint. One corner of it hangs over on an angle with no screw. Stuff I used to do in JS days to use existing holes the lazy way.

The output xfor footprint and input xfor footprint in your picture are the same, just about the size of the ones in the SP-200 where the lugs come out under the xfor's with no flange.  

I think you already have a kludged output where someone has installed an open frame transformer inside a suitable expanded aluminum case, both smaller than the original.  Then they potted it with homemade beeswax or wrong melting temp. compound.
The input xfor is obviously a kludge either added at the factory when nothing else was available for this early model or more likely added later after someone sold both really decent transformers.

I've let my SP-200 go long ago but perhaps someone will measure the footprint of their transformers and send you the results. Both originals in the 200 had expanded steel shells, same size in and out, with lugs coming out the bottom with no outboard flanges.  I'm pretty sure a set of these are what you will find is required.   Possible a museum has an original SP-10 that you can compare.

Rick
You are quite correct. Both of the transformers you see in the photo are now removed and temp adaptor
plates have been added for using period correct non-stock transformers for interim use to get it up and running so the process can begin. My approach (was) is to allow monitoring of the radio as I go through each stage to get it operational one stage at a time. Right now, the first order of business is to make a notebook to keep track of what's stock and what needs to be returned to stock. I am sure that over time, the needed parts to make it correct will be found. The metal chassis cover needs to be completely repainted as it's the wrong color. It's ugly and because it's a table top model, that certainly needs to be addressed.
I got real lucky with the power supply though. It's right as rain and was recapped in the 70's and fortunately the original can capacitors were not removed. They are the screw on types with locking nuts and the wires of the caps exited through the bushing, which were simply cut. Sprague tubular electrolytics were installed flying lead style. That will be addressed. The plan is to open up the old cans and install new caps inside and redo the cloth wires just like stock. That will be fun and even though no one will ever see it until it's out of my hands, I figure a little extra effort will be justified.
Like the HRO radios of the day, the SP-10 & 100 enjoyed the benefit of external power supplies. This resulted in quieter operation and better performance. This is something I truly enjoy about my HRO 5TA1. It's super sensitive with a dramatically low noise floor. According to Henry Rogers, the performance of the SP-10 is truly wonderful to behold. I am looking forward to that and I hope I can muster the same amount of return on my restoration endeavor.
The way things are going, I am going to need a bigger shop. Really, my radio sickness is spreading out.
Smiley
Logged

"Life is too short for QRP"
Steve - K4HX
Administrator
Member

Offline Offline

Posts: 2722



« Reply #7 on: November 22, 2014, 10:42:16 AM »

I've owned a SP-200 and currently have a 400 but never a 10. Very cool find Billy. IMO, of the receivers made during the tube era, the SP10/200/400 are probably the best sounding for hi-fi AM use. It's heard to beat continuously variable bandwidth up to 16 kc and push-pull audio!
Logged
W3RSW
Contributing
Member
*
Offline Offline

Posts: 3308


Rick & "Roosevelt"


« Reply #8 on: November 22, 2014, 10:44:19 AM »

edited after a little research later: This nails it . You have a 1937 SP-100X.  Look about 1/3 way down page.
http://www.radioblvd.com/hammarlund_super_pro.htm

See my add'l edited remarks and referenced sites earlier while you were typing away.  Grin

Your SP100X is certainly worth the TLC your planning. Great rig.

--From above site which appears to be "the Bible" on HQ series.

Quote
1937 - SP-100 - Introduced January 1937, uses eight metal octal tubes and eight large-pin glass tubes, Sensitivity Control replaces separate RF and IF gain controls,
                            Variable coupling AVC and Detector transformers changed to fixed coupling, Selectivity control renamed Band Width, engraved scales added to
                            Sensitivity, Beat Oscillator, Band Width and Audio Gain controls
                            Fixed-coupled AVC and Detector transformers allowed the component boards to be moved from under the chassis (SP-10) to inside the transformer cans (SP-100)
                            New style small knobs with metal pointers                   
                            Audio transformers changed from potted units to vertical mount-frame types - output Z is 8 ohms
                            Paper-wax capacitors are usually Cornell-Dubilier "TIGER" brand but could be intermixed with Aerovox brand
                            Spacing rods in RF tuning unit are steel 

Someone added the larger tuning knobs later, a common practice and the semi-calibration scale marks don't seem to show up on your receiver.
Logged

RICK  *W3RSW*
Todd, KA1KAQ
Administrator
Member

Offline Offline

Posts: 4310


AMbassador


« Reply #9 on: November 22, 2014, 10:49:52 AM »

BTW yours looks more like an SP-100 with octal sockets , a host of kluges and only a few six pin tubes.

It clearly started out as a SP-10, but it has a lot more hacking than you think. The quick ways to differentiate the -10 from the -100 are the front panel (-100 has scales over the controls, -10 only has labels), and the -10 used all big pin glass tubes, no octals. This one has everything - glass big pin tubes, octals, and miniatures. Someone has swapped the tuning knobs, but that looks like the least of the problems. They also added an octal socket to the back. One nice thing I see is the then-optional crystal filter installed. This became standard on the SP-100.

The remaining audio transformer is correct, IIRC it's the 600 ohm sealed version. They also used an open frame variation for 8 ohm(?) output, or at least something considerably lower than 600. My -10 has the sealed type, -100 has open frame. And as you said Rick, the goo under the remaining transformer isn't oil but tar. Probably it was hooked to an improper load for some length of time and started the fry off.

Power supply appears to be hacked as well, tube swaps, chassis chops and so on. Something to keep in mind is that the SP-10 used a slightly lower B+ than the -100 or -200 models. With all the hacks in place there's no way to know for sure and it might not matter, but if the goal is to return everything as close to stock as possible, it becomes important. Check the serial number on the receiver (stamped into the back apron) against the one on the supply (looks like it might be under the power connector hack) and see if they're close. Quite often they became separated and some later owner just located a supply for a -200 and hooked it up. If it's the original supply, it's really a shame it got hacked but that's what you did back then. You updated your rig, you didn't have $$$ to go buy another in most cases.

I know there are at least two other list members who have SP-10s. Steve/W8TOW has one with matching supply he got at Dayton some years back in nice shape and I'm pretty sure Dennis/W7TFO has one as well. Mine is sans supply and needs a good clean up (looks far worse than it is) but it's untouched otherwise. I'll post a couple shots of the grubby innards for comparison along with the SP-100 front panel with its scales.

Probably the best place for info is Henry Rogers' site:

http://www.radioblvd.com/hammarlund_super_pro.htm

Excellent technical and historical information including serial number tracking.

It's definitely an interesting rig, the most advanced and best you could buy back in the day. The only other thing that came close was the HRO, out a year earlier. Henry provides good comparison data on his pages as well.




* SP10_B4_F.JPG (451.37 KB, 1600x1200 - viewed 744 times.)

* SP10_B4_Bk.JPG (367.57 KB, 1600x1200 - viewed 650 times.)

* SP10_B4.JPG (417.81 KB, 1600x1200 - viewed 655 times.)
Logged

known as The Voice of Vermont in a previous life
Todd, KA1KAQ
Administrator
Member

Offline Offline

Posts: 4310


AMbassador


« Reply #10 on: November 22, 2014, 10:54:42 AM »

Looks like a few of us were typing at the same time.

Here's a side shot of the audio section along with the SP-100 showing the difference in the front panels and correct tuning knobs (fairly common and easy to find).

Good luck with it. I've gotta go haul branches and brush to the landfill, woohoo.  Roll Eyes


* SP10_B4_R.JPG (350.4 KB, 1200x1600 - viewed 664 times.)

* SP100_Frt.JPG (400.87 KB, 1200x1600 - viewed 628 times.)

* SP100_FrtL.JPG (316.5 KB, 1600x1200 - viewed 698 times.)
Logged

known as The Voice of Vermont in a previous life
Steve - K4HX
Administrator
Member

Offline Offline

Posts: 2722



« Reply #11 on: November 22, 2014, 10:54:48 AM »

I want one of those SP-150s!
Logged
Todd, KA1KAQ
Administrator
Member

Offline Offline

Posts: 4310


AMbassador


« Reply #12 on: November 22, 2014, 10:58:55 AM »

Here ya go!

This Jensen 15" speaker is the one you want to hook to a Super Pro. JHP-51 or -52. They sound great.


* SP-150_1.jpg (90.85 KB, 480x640 - viewed 613 times.)

* SP-150_9.jpg (268.43 KB, 1280x960 - viewed 616 times.)

* SP-150_16.jpg (67.85 KB, 640x480 - viewed 538 times.)
Logged

known as The Voice of Vermont in a previous life
Todd, KA1KAQ
Administrator
Member

Offline Offline

Posts: 4310


AMbassador


« Reply #13 on: November 22, 2014, 11:07:03 AM »

I forgot to add, aside from the front panel and tubes, another way you can tell your radio is indeed a SP-10 is the pair of cans with thumbscrew adjustments on top. These were removed for the -100 as it was a PITA to remove the cover to reset them. Henry covers this on his page, too.

Those 6F6s were originally 47s.....

Logged

known as The Voice of Vermont in a previous life
W3RSW
Contributing
Member
*
Offline Offline

Posts: 3308


Rick & "Roosevelt"


« Reply #14 on: November 22, 2014, 11:16:46 AM »

Perhaps the whole front panel is a hack too then?  because I think the crystal mounting board looks original from the rear complete with missing shield cover holes and faint shield markings.  "Selectivity" instead of "Bandwidth" also matches the SP-100X notes too.
See the notes on the site we mentioned.

Someone must have had great fun in the day.  Grin
Logged

RICK  *W3RSW*
N6YW
Contributing
Member
*
Offline Offline

Posts: 461


WWW
« Reply #15 on: November 22, 2014, 11:17:13 AM »

Todd
Mine is a bit of a mongrel, but it is a later serial number according to Henry. He wrote me back after Gary and I submitted photos of my radio. I think mine falls under the category of a CQ magazine modified "special". Thanks for your photos and input. I feel better now that I posted the project here as a sort of landing for information acquisition. Perhaps this resource (here) will yield more information and possibly some parts. According to my research, this SP-10 came stock with the variable crystal filter as it's a later version kind of a crossover to the sp-100. There is one thing that clearly marks mine as an SP-10...
The meter is the plate current type as found on the SP-10. Later models used meters with the more familiar S unit scaling. This type of meter is apparently very difficult to find so I hope mine works!
This will be a challenge worthy of the sport.
I plan on reinstalling the #42 output tubes of which it's clearly evident by the holes in the chassis that mine is an SP-10. Several sockets were replaced with newer Octal style types.
Logged

"Life is too short for QRP"
W3RSW
Contributing
Member
*
Offline Offline

Posts: 3308


Rick & "Roosevelt"


« Reply #16 on: November 22, 2014, 11:33:44 AM »

What exactly is your chassis serial number? 
--following from site above.
Quote
Year to Serial Number Table

         SN Range        Year           Models

         1 to 1000 ........... 1936.......SP-10, PS

         1000 to 3000.......1937.......SP-100, PS

         3000 to 3800.......1938.......SP-100, PS, HQ-120X

         3800 to 5000.......1939.......SP-100, SP-200, PS, HQ-120X

        5000 to 8500........1940.......SP-200, PS, HQ-120X

        8500 to 10000......1941.......SP-200, PS, HQ-120X

      10000 to 14500......1942.......SP-200, BC series, PS, Mil HQ-120

      14500 to 19000......1943.......SP-200, BC series, PS, Mil HQ-120

      19000 to 25500......1944.......SP-200, BC series, PS, Mil HQ-120

      25500 to 30000+....1945.......SP-200, BC series, PS, Mil HQ-120
Logged

RICK  *W3RSW*
Todd, KA1KAQ
Administrator
Member

Offline Offline

Posts: 4310


AMbassador


« Reply #17 on: November 22, 2014, 12:20:44 PM »

Perhaps the whole front panel is a hack too then?  because I think the crystal mounting board looks original from the rear complete with missing shield cover holes and faint shield markings.  "Selectivity" instead of "Bandwidth" also matches the SP-100X notes too.

The 2nd receiver I posted with 'Bandwidth' in place of Selectivity is the SP-100, Rick. The first, SP-10, matches Billy's perfectly if you don't count the paint chips on mine.  Grin That's basically a quick 'from a distance' way to spot the difference at a hamfest or such. 100 has numbered scales over the knobs, too.

The crystal filter is correct, it was originally offered as an option on the SP-10 so that's no surprise. Mine doesn't have it and a friend who has a couple 10s only has the filter on one. My understanding is that it either became standard equipment late in the run of -10s or early in -100 production.

The 0-5 tuning meter was actually used through 100 production as well. It changed with the advent of the 200 series, maybe even late in the 100 line, with the illuminated S meter. Another meter change I discussed with Henry relates to the enclosing of the meter adjusting screw. Early meters had all glass, later ones had a small metal surround holding the screw in place.

It's definitely a great receiver to restore as much as you're content with doing, Billy. They made a lot of SPs and as a result, many ended up hacked. I have two pre-war 200SX models here that have been hacked, but the chassis are pretty clean as are the beautiful wrinkle black panels. Wartime versions went to smooth paint I'm sure for ease of painting maintenance/re-lettering. The pre-war panels were engraved through the paint exposing the shiny aluminum. Someday I need to decide which one to keep and restore, and send the other down the road.

Back then if you had a Super Pro, you had something. Even post-war, many used Command sets or if they were lucky, a BC-348. I'm sure they weren't cheap, so as improvements came along it was much more cost-effective to 'incorporate' them than to buy a new receiver (that might not work as well as the SP). So as nasty as some of it seems to us now from a historical perspective, it's all part of the history. Even my SP-100 has a couple modifications, fat pin to octal conversions. Someone blasted a hole in front to move the headphones from the rear apron too, but I already reversed that. Just need to fill the hole.

And yes.....the audio output used 42s, not 47s. Need.....more.....coffee before typing.

Got another load of brush to move, couldn't resist checking back. Really love the old Super Pros, and I always hold W3JN, K4HX, and WD8BIL responsible for contributing to my delinquency in that respect. 
Logged

known as The Voice of Vermont in a previous life
W3GMS
Contributing
Member
*
Offline Offline

Posts: 3063



« Reply #18 on: November 22, 2014, 12:43:20 PM »

I want one of those SP-150s!

Steve,

What version SP did I provide pony express service for?  It was the one from Dee-W4PNT (sk). 

Joe, GMS
Logged

Simplicity is the Elegance of Design---W3GMS
N6YW
Contributing
Member
*
Offline Offline

Posts: 461


WWW
« Reply #19 on: November 22, 2014, 12:44:08 PM »

Rick & Todd...
This is turning into an excellent thread.
My serial number is #996. As to the hack jobs, yes. An unfortunate sidebar to Ham Radio but in some cases actually benefited us along the way by inspiring future engineers who helped to develop new technology. I am trying my best to keep it positive, Hi. It is sickening in retrospect that so many radios were hacked, many of which can never be brought back. Up until now, I have never seen an SP-10 or at least recognized one at a swap fest or online. I know that I am now on the constant lookout for these including the 100.
I really can't imagine what it must have been like to be around back then, at over 200 dollars, the SP-10 must have been out of reach for most people. Kind of like the common middle class Ham of today wishing they could afford a $10.000+ radio currently being offered. But then, we know better don't we?
Logged

"Life is too short for QRP"
Steve - K4HX
Administrator
Member

Offline Offline

Posts: 2722



« Reply #20 on: November 22, 2014, 01:07:05 PM »

It was The Derb that turned me on to the prewar receivers, especially the silver dial Hallis and the Super Pros. He had a SX-11 with a Magic Eye. Cool is the rule.




Really love the old Super Pros, and I always hold W3JN, K4HX, and WD8BIL responsible for contributing to my delinquency in that respect. 
Logged
N6YW
Contributing
Member
*
Offline Offline

Posts: 461


WWW
« Reply #21 on: November 22, 2014, 01:20:27 PM »

Steve
It doesn't get much cooler than that. Beautiful!
Logged

"Life is too short for QRP"
Steve - K4HX
Administrator
Member

Offline Offline

Posts: 2722



« Reply #22 on: November 22, 2014, 02:13:41 PM »

Always fun giving signal reports like, "You're closing the eye three-quarters of the way OM!"
Logged
k6hsg
Member

Offline Offline

Posts: 66


« Reply #23 on: November 22, 2014, 02:15:09 PM »

I have three SP's. two 100's and a 200'
The serials are 1937, 3255 and 16116.
16116 is a 1943 civilian unit.  Not sure how rare it would be?
I have started replacing capacitors in 1937.  When I bought it it sort of worked but I discovered a wax puddle on the lower cover plate.  I have started on the job of replacing all of the capacitors.
I can take some pictures if anyone is interested.
73, John
Logged

John,  K6HSG  Tucson, Arizona
W3RSW
Contributing
Member
*
Offline Offline

Posts: 3308


Rick & "Roosevelt"


« Reply #24 on: November 22, 2014, 04:26:09 PM »

Billy, looks like Todd and your ser.  no.   ID it as a late SP10.

If you can obtain a good set of AF transformers which most output tubes work into well enough,  I think I'd replace a few caps and stuff just enough to getting the CQ mods and rest of receiver working FB, enjoy it for awhile while girding up and obtaining parts for the complete restoration.

There will be a ton of work going back to the six pin variation.  Btw I have Five or six , six pin ceramic sockets I'd picked up at cowboy Gathersburg several years ago. Your welcome to them if you want to do the full restoration.

Looks like wire hanging off IF cans may have been rerouted underneath for the min. Tubes, etc. Hope the IF cans haven't been partially bypassed, etc.
Logged

RICK  *W3RSW*
Pages: [1] 2 ... 4   Go Up
  Print  
 
Jump to:  

AMfone - Dedicated to Amplitude Modulation on the Amateur Radio Bands
 AMfone © 2001-2015
Powered by SMF 1.1.21 | SMF © 2015, Simple Machines
Page created in 0.07 seconds with 19 queries.