1953 US Navy study of tube amplifiers "declassified"

well...this is certainly a bit of an eye opener!...even though this report is over half a century old, most amps/circuits tested still very much apply today!
Cudos to Mcintosh too!

Guess  still close past  1945      times  . Caused that to be classified

I may have been an early non-military beneficiary of this study. My father bought a govt. surplus amplifier in the early 1950's. I think it was for driving motors in radar tracking systems, but may be wrong about that. He let me use it for my first audio amp. The output transformer was about a 6" cube, it had 6L6 output tubes, and a chassis made of ~16 gage plated steel. The chassis was about 8" X 14", and the amp stood about 8" high. It probably weighed around 40-50 lbs.

Unfortunately, I didn't really know what I was doing, don't even now in some cases, and never really had it set up to make the most of its capability. As I recall he said the amps were flat to 15 cycles per second, certainly far better than the speakers I scrapped out of old radios, and the cheap turntable I had at the time.

I'd really like an opportunity to have that amp again and do something worthwhile with it. My next amp was the ST70 and PAS 3X kits I assembled in the late 60s. Still have them, though upgraded.

Great post, thanks!

Yall know, if you read that report, the ghost of McCarthy will be paying you a visit!

sKiZo wrote:Yall know, if you read that report, the ghost of McCarthy will be paying you a visit!

I wondered what that loud moan was

Just imagine what his "ghost" must think of forum members using "commie" tubes and capacitors.

I can't help but believe that our secrecy contributed to the appalling quality of the Soviet recording industry. Having owned Melodiya LPs in the 70s, I can attest that they made 78s sound wonderful. A great loss....

Fascinating . . .
I wonder if the Classified (Restricted, in this case) designation was in deference to patent/copyright rules in force at the time. In other words, we'll show you our proprietary technology if you won't show it to our competitors. That would be my Occam's Razor supposition.
A bit of trivia: Where does the Navy conduct its deep-water acoustic testing? Hint: it's not off the shores of any coastal state. It's here in bloody Idaho, on Pend Oreille Lake, from a small base near the tiny town of Bayview. Submarines, the whole smash. Why? It's the deepest lake in North America.
If you want to rile Joe's ghost, try getting near that place. Or even mentioning it. woooooooooo

Deepee99,

The model sub base for accoustic testing is fascinating, especially given the French name of the lake has to do with ears. It's worth searching and reading. Thanks for mentioning it.

The report's secrecy doesn't really make sense, the amps could readily be bought and analyzed. On the other hand the hysteria over Communism led many people to go too far worrying about nuclear confrontation.

Might be a good time to rewatch Dr.Strangelove. If the ghost stops by, I'll remind it that the ghost of Margaret Chase Smith resides in Maine, quite ready to speak out again.


Regarding Melodia records, does anyone know of a source?

@Deepee Deepest lake in north America in Idaho?

I thought that was crater lake here in the beautiful state of Oregon with all the liberal tree huggers LOL

TN allen - This seems to be THE place for Melodiya vinyl - much of it appears to be vintage, not the new-issue versions which are German pressings: http://www.gemm.com/browse/labels/MELODIYA/.
deepee - when are you going to write a book? You are most entertaining!

TN Allen,
I may have misspoken about Pend Oreille's depths; apparently (according to Google) there are several other lakes deeper, but there's a trench through its bottom nobody has ever plumbed. When Lake Missoula let go after the last Ice Age it dug some pretty deep holes. Fly over western Montana, eastern Washington or northern Idaho and you can visualize the havoc it caused. Glad we weren't around for that party.
Back to Occam's Razor. If Saul Marantz could buy and dissect a Frank Macintosh rig, and vice versa, as you sensibly suggest, then so could any Russian.
There is a darker and more sinister force at work here. . .

deepee99 wrote:TN Allen,
there's a trench through its bottom nobody has ever plumbed.

Maybe it just doesn't swing that way ...

Long as we're on the subject of 78's ... recently stumbled across this site. Has some uber rare recordings. High res - 64kbps!

http://78records.cdbpdx.com/

Here's a nice selection for all you '30's swingers. Classics like Sing You Sinners and Taking My Sugar To Tea. When's the last time you gave Rudee Valle or the Harlem Hot Chocolates a listen?

http://pdx78s.cdbpdx.com/HOTW/index1.html

PS ... remember those killer one revolution out grooves that would smash your needle into the post? CLOWN SMASH!!

http://pdx78s.cdbpdx.com/Ode1/tn-800_LAbel_ODEON_5028-A_.JPG

Every now and then I see a case of coincidental humor, or perhaps deepee99 and sKiZo planned it.

deepee99 comments about an unplumbed trench, then mentions that "there is a darker and more sinister force at work here..."

And in pops sKiZo with; "Maybe it just doesn't swing that way ..."

I laughed quite a while over this, still laughing:

sKiZo, I'm feeling picked on here.
Gawd, don't ya love thread drift? Only Dark and Sinister forces can force us off topic.

There are probably deeper lakes, but what's interesting is the temperature at a certain depth is constant, which makes the speed of sound uniform for underwater acoustic testing. http://www.ss563.org/idahoss.html

The links look interesting.

I came across this link after finding the song in a pile of 78s I bought a few years ago, it's probably mildly non PC, but worth a listen: https://www.youtube.com/watch?v=T28_714ijms

deepee99 wrote:sKiZo, I'm feeling picked on here.
Gawd, don't ya love thread drift? Only Dark and Sinister forces can force us off topic.

I wasn't picking on you, I thought the exchange brilliant!

I suspect the forces needn't be too dark or too sinister to cause drift.

Although, the discussion does include McCarthy.

After looking up the submarine base at Pend Oreille, and reading that one reason it is used for sub research is the uniform temperature at a given depth, and then thinking about the implications of the speed of sound in water changing with temperature changes for sub detection, offense and defense, it makes sense that this report remained secret so long. Even though amp technology changed rapidly after 1953, interest in generating specific audio signals for underwater use would probably tell quite a bit about the direction research was to take for SONAR. With a sense of the research direction, detection and evasion research and technology could more easily be understood by our military opposition. They could then focus their own research and probably avoid expensive broader experimentation, and possible false research directions.

The speed of sound in 40F water is about 4600'/sec., nearly 1 mile/sec.? Can that be correct?
An accurate uniform signal would be critical to various measurement techniques for locating other sub movement and offensive behavior as well as determining what might be background noise.

Although the thread drifted a bit, the information on the sub research base sent me off in a direction that helped me make sense of the report, and consider sound and audio amps in a different way.