tube amps

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TMFK

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looking for a CHEAP tube amp, preferably under 50 dollars i can restore as a first prodject. Also i have a RCA superheterodyne radio with a 50c5 output tube, and 14gt8 preamp. Its only 2 watts, but hey its a perfect beginners prodject, and I really would like to build a small tube amplifier out of it if at all possible. The radio works great! all tubes work perfectly, and the radio is more sensitive than some others i own, mabye cuz its a superhet? anyways, Also one prob; I think the output tranny is junk, because the responce rolls off below 60-80 hz or so, it doesnt get much bass at all, even when I hook it up to one of my marantz sp1200s. Is the tranny made to cut off low end so as not to hurt the 2 watt alnico 4 inch mounted in the radio?

any help would be great, thanks~!

TMFK~ :D
 
The tranny was most likely designed around what it was being used for. I don't imagine there was much call for 40 Hz to come out of a radio of that type. Making a tranny that will pass either very high or very low frequencies (much less both) is more costly and not very useful in that situation. I would look on Ebay for broken guitar amps, if that is what you are looking for. As far as tube stereo amps go, I don't think you will find anything for $50.
 
ahh Im sorry, I should have made myself more clear lol. I don't particulary need stereo, I just want a mono amp. The radio it came out of was mono, so I dont care. I have looked on ebay, sadly i havent found anything for under 50 dollars...much less shipping costs at least that much! :(

also what is the responce of my tube into useable power at what db? I know its pretty low power, they say 2.5 watts is a bit optimistic.. but have made 1 transistor amps that make some nice full range sound before.. couldnt be more than 300mw output:p but anyways..Also I have the rest of the tube lineup here for you guys: 50c5, 14gt8, 19hr6 ,17c9,12be6,12au6 .
 
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I couldn't find out about the 5OC5 per se, but from what I know about tubes the frequency response is going to be dependent more on the preamp circuit and output transformer than the power tube. The audio band should be well within the usable power range of just about any power tube.
 
sweet

sweet! I did not know that peice of info, I know most modern 1-2 watt ic amps dont have a very good freq. resp. , usually dropping off the useable spectrum around 100 hz or so. I did find online (useing a google search) that the 50c5 is around 2.5 watts (max) 1.5 nominal..2 mabye if your lucky with your voltage, and the freq resp is 10hz-30khz I think. So do you think the usable spectrum goes down to at least 30 hz? That would be nice. Anyways, you said something about the preamp also haveing to do with freq resp, could my 14gT8 have some sort of limiter to prevent from hurting the cheap speaker in the radio? Is it a low pass cut off cap in the circuitry, or is it a cheap tranny? heres a link to what my radio used to look like

http://www.chalkhillmedia.org/images/RCA AM-FM Clock.jpg

although i have it taken apart right now to put it in a custom built box.. ok so any of the other tubes it has be used in an amp or no? heres a picture btw of what I have so far, altho I need to find 4 new 7pin chassis mount tube sockets, and 2 new 9 pin chassis mount sockets, as my tube sockets are pcb mount and will not mount to metal :( :(

Tube radio/amp case, not finished.

not bad for a 16 year old eh? :p Its not done, but Im getting there!

thanks for all the help guys, anything else would be greatly appreciated! :D

TMFK~
 
I think you are headed in the right direction. 16, eh? We could have a future entrepreneur on our hands! Remember, several high profile amp manufacturers got their start doing exactly what you are doing. They kept at it til it sounded great TO THEMSELVES. Fortunately for them, others wanted one too. Keep up the good work!
 
Be Careful! amps and radios using 50C5's often had no isolation transformer.
these units were made this way to save money. I've recently bought several vintage record players and one old movie projector amp that all use that same circuit sometimes called a hot chassis I even heard one guy call them rubber sneaker amps because if you become the path to earth(ground) via your guitar strings you could get zapped big time ..even killed .they can be modified and the transformer is cheap.You can find out a lot about these amps online also it could be used as a tube preamp by wiring resistors to the speaker output wires. Gerald weber of kendrick amps has written about this trick
any tube amp can be used this way .Bottom line don't give up if you don't see a power transformer in that unit it's a widowmaker but many people are moding these old amps also if it does not have a polarized power plug that is another clue you can flip the plug over to correct polarity .If you put a transformer in it you can then add a three prong polarized plug.
who knows it may sound great keep chasing tone.
Nortone
 
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I'm sure the OP has moved onto bigger and better things by now.

What gives nortone? First post and you're resurrecting a thread that's been dead for over 5 years... ??
 
Wow, I gotta be honest with you havent been here in ages...but I've been a long time member of Audiokarma, DIYaudio, and a long time lurker of Metroamps, the amp garage, 18 watt, etc etc.

I've got 5 amps for sale in a local shop, and have restored too many to count. One happens to be a Harmony H303A widowmaker....I installed an isolation tranny in it when I did a full restoration.

I've built far too many tube amps to count by now, and restored numerous antique radios and done several hi-fi amps and restorations. Yes, I'm the dude that lurks thrifts and CL snatching up anything with tubes in it to restore, reuse, save, or recycle.

I forgot this thread existed! But yes, I'm 22 now and getting ready to open my own business full time building my own three lines of guitar amps: Blues series amps, Hotrod series amps (beefed up versions of the blues series with more gain for heavier rock,) and a line with some ultra-high gain amps. All my amplifiers are extremely quiet recording amps with metal resistors, high quality caps, and star grounding, extensively developed layouts to minimise noise and RFI/EMI interference and maxmimize tone. I make sure my amps sound amazing to me, and I can make them produce the most amazing soulful tones with any of my many guitars , before I show them off to other musicians...then I realize they sound much more amazing to them than they do to me. :)

It may be slow going, and I wish my website were finished but sadly it is not, but be looking for Getchell Amplifiers (TM) in the next several years.

Yes, I have moved on to bigger and better things now and thanks for all the replies.
God Bless.

Some examples..
https://sites.google.com/site/getchellbluesboy/
https://sites.google.com/site/arvin160ttableradio/
https://sites.google.com/site/philcoa801chairside/
 
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