zenith2134
Addicted Member
Hello, I want to build a tube audio amplifier from many tubes that I have, from radios and tv sets. Can someone tell me where to start?
DIY Tube amp
- Thread starter zenith2134
- Start date
Nick_the_'Nole
Super Member
I think the first thing you should do is search the forums for examples, figure out what kind of thing you want to build. It might help to know what sort of tubes you're thinking of using as well...
zenith2134
Addicted Member
Tube Types
Hey man, I've got these types, but would like to know which ones are for audio: 12AT7, 35C5, 12BA6, 6AU6, 6AL5, 6V6, 6CB6A, 6AV6, 6AG5, 12AT6, 12BE6, 6AU6A. I am not too familiar with tube type numbers, can someone guide me please?
Hey man, I've got these types, but would like to know which ones are for audio: 12AT7, 35C5, 12BA6, 6AU6, 6AL5, 6V6, 6CB6A, 6AV6, 6AG5, 12AT6, 12BE6, 6AU6A. I am not too familiar with tube type numbers, can someone guide me please?
zenith2134
Addicted Member
Also: 5V4, 5U4, 5U4GA, 6K6, 1B5.
Nick_the_'Nole
Super Member
Well, the 6V6 is a power tube, that'd make a good amp if you've got a few of 'em (and those kinds of amps are fairly common so it's easy to find examples and schematics). The 6AU6A can be used as a driver for the 6V6 (check here for an example). The 6AV6 I believe *can* be used as a driver tube as well if you hook up the triode section... IIRC the triode section is very similar to the commonly used 12AX7. It would be somewhat of an odd design for a first project, though. The 12AT7 is also a driver tube, but it's rarely used in hifi applications because it's somewhat ill suited for the task. It's used in a lot of Marshall guitar amps, though. I believe the 12AT6 is similar, but again it's prolly not a very good choice for a hifi amp. The 35C5 is a power tube, but it's low power (maybe 1 watt or so output) and it's designed for use in amps without power transformers, thus making a hot chassis. It'd be easy to design an amp with that one, but you prolly wouldn't be satisfied with the end result, and it can be dangerous working with a hot chassis. The 5U4's are rectifiers, the 5V4 is a better rectifier IMO. I have no idea what the 1B5 is. Most of the rest of those are either IF or RF amp tubes, designed for radio and TV tuner sections.
Now... out of all those, for a first amp, I'd prolly recommend the 6K6 if you have enough of 'em. It's a rather unothodox design, but it would be pretty simple to wire up and I think it would sound quite good. Use the triode section as the driver and the pentode section as the power amp. No need for separate driver tubes. Check this out, it's not exactly what I'm thinking about, but maybe one of the more experienced tube builders could help you with a design.
Edit: BTW, is it at all strange/sad that I'm 20 and I knew all those tube types off the top of my head? :saywhat:
Now... out of all those, for a first amp, I'd prolly recommend the 6K6 if you have enough of 'em. It's a rather unothodox design, but it would be pretty simple to wire up and I think it would sound quite good. Use the triode section as the driver and the pentode section as the power amp. No need for separate driver tubes. Check this out, it's not exactly what I'm thinking about, but maybe one of the more experienced tube builders could help you with a design.
Edit: BTW, is it at all strange/sad that I'm 20 and I knew all those tube types off the top of my head? :saywhat:
zenith2134
Addicted Member
Thanks
Those links helped me alot, as did your intelligence on tubes. Now, I've got only two 6V6's, one 6K6, and four 6AU6A's. What can I build with what I've got, I'm so excited about this lol.
Those links helped me alot, as did your intelligence on tubes. Now, I've got only two 6V6's, one 6K6, and four 6AU6A's. What can I build with what I've got, I'm so excited about this lol.
Thatch_Ear
Addicted Member
You could build a nice SE amp with 2 6V6s using a 6AU6 per channel as the signal amplifier. Both of those tubes are good and also easy to get.
Your going to need a good schematic to go by, something of a tried and true nature, I have a Magnavox console 6V6 amp but it's a PP, try www.triodeel.com and look in schematics and see if there is one in there for 6V6 SE.
Nick_the_'Nole
Super Member
With two 6v6's, you could do a single ended amp, give you about 7w/channel, running the 6au6's as drivers (although I'm not sure if those are gonna have satisfactory gain for what you want). I can't find a schematic that specifically does that, so I'm gonna pass that one off to the other tube guys. Or, since you'll end up spending some money on the transformers and such anyway, you could always buy more 6V6's (they're cheap and easy to find), get a quad of 'em and do a push-pull setup modelled after the [very sweet] old Magnavox console amps. It really depends on how much power you're looking for and how much money you want to spend. Maybe once you decide what you wanna do you can move over to the Tube forum and ask for schematic ideas there.
Do you have a tube tester available to make sure those tubes are actually good? If you want to just use your existing tubes that should prolly be the starting point.
Do you have a tube tester available to make sure those tubes are actually good? If you want to just use your existing tubes that should prolly be the starting point.
mhardy6647
Lunatic Member
Don't tell Doc Bottlehead that! He and Paul Joppa used the 12AT7 as the driver in the Paramour SE 2A3 amp kits.
zenith2134
Addicted Member
Hey guys thanks for the replies. I searched through that sight and found some useful tube data, and no I don't have a tester but assume the tubes are good because they were pulled from an RCA tv chassis with a burnt flyback-- but still lit after that, the 6V6's are both RCA tubes, and the 6AU6A's are all Sylvania. I have alot of parts such as small to medium output xformers, and 7wpc is fine for this project, so any other suggestions to get me off the ground?
zenith2134
Addicted Member
Magnavox Console
Oh i forgot-- I passed up a magnavox console with 6V6's once for $50 at a yard sale, and it worked! (not well, but it wouldve been a nice restoration) believe that
Oh i forgot-- I passed up a magnavox console with 6V6's once for $50 at a yard sale, and it worked! (not well, but it wouldve been a nice restoration) believe that
Mike Stehr
Poverty Audio
That would have been worth 50 bucks.....
The SET amp I have uses a Television PS transformer, 6AU4 damper tubes used in Televisions, and the 6EA7 driver tubes were used in Televisions.
The SET amp I have uses a Television PS transformer, 6AU4 damper tubes used in Televisions, and the 6EA7 driver tubes were used in Televisions.
Nick_the_'Nole
Super Member
Hm, I hadn't ever seen a 12AT7 as a driver except in guitar amps, always understood that it would end up overly bright with low gain when used in hi-fi. Learn something every day I guess...
Maybe I was thinking about circuits designed for 12AX7's, where you can use the 12AT7 but with less than satisfactory results. Is that correct?
Yeah, sucks you didn't know to nab that console, that'd've made a great first tube amp. Those Magnavoxes are sort of underdogs nowadays but they sound great. I have a Magnavox SE 6BQ5 amp that I need to put back in service once I can find (build?) some more efficient speakers- Fostex BLH's, here I come!
Anyway, back OT, I guess all there is now is to find a schematic that uses 6V6's and 6AU6's. Where to find one, I have no idea, somebody else can prolly come up with something that'll work tho. Then it's just checking through, see if you have a couple OPT's and a power tranny that'll work, and puttin the thing together...
Maybe I was thinking about circuits designed for 12AX7's, where you can use the 12AT7 but with less than satisfactory results. Is that correct?
Yeah, sucks you didn't know to nab that console, that'd've made a great first tube amp. Those Magnavoxes are sort of underdogs nowadays but they sound great. I have a Magnavox SE 6BQ5 amp that I need to put back in service once I can find (build?) some more efficient speakers- Fostex BLH's, here I come!
Anyway, back OT, I guess all there is now is to find a schematic that uses 6V6's and 6AU6's. Where to find one, I have no idea, somebody else can prolly come up with something that'll work tho. Then it's just checking through, see if you have a couple OPT's and a power tranny that'll work, and puttin the thing together...
Chad Hauris
Super Member
Has anyone made an audio amp using TV tubes and parts...I have been thinking about this. You could use a horizontal output tube like a 33GY7 as an audio output and rectifier, use a 17JZ8 vertical output as a driver and output, use a vertical output transformer for audio, etc.
mhardy6647
Lunatic Member
Aren't the 6EM7's and some of the other tubes folks use in spud amps old TV tubes?
http://www.the-planet.org/6EM7.html
Can't see much added value to using series-string tubes (except maybe low price) as you'd still want an isolating power supply in this day and age.
Now I COULD imagine someone using color TV sweep tubes (e.g., 6JE6/6LQ6 and its ilk) as outputs... just like some of the cheaper old RF linear amplifiers did.
http://www.the-planet.org/6EM7.html
Can't see much added value to using series-string tubes (except maybe low price) as you'd still want an isolating power supply in this day and age.
Now I COULD imagine someone using color TV sweep tubes (e.g., 6JE6/6LQ6 and its ilk) as outputs... just like some of the cheaper old RF linear amplifiers did.
Mike Stehr
Poverty Audio
6EA7 can drive itself, it's a rather linear tube.
Here's a writeup of the 6EA7 with bridged Allied IT driving 45/46/2A3/300B.....
""Yes, I looked at the low frequency response and it was excellent. It can
swing a PP signal of a couple hundred volts PP at 20, or 30 Hz at low
distortion. I forget exactly, 200 V PP at 30 Hz for sure and 100 V PP at 20
Hz, or maybe better. The response is dead flat from below 20 Hz to several
hundred kHz w/o overshoot, or ringing. Distortion at a hundred volts PP
is -55 dB 2nd harmonic declining about 15 dB per successive harmonic (with
an RCA brand 6EA7).
The low end frequency response is forced by the very low plate resistance of
the 6EA7. Of course, a mismatched driving impedance makes the IT tend to
ring rather severely, but the bridging cap acts as a low impedance at high
frequencies coupling the secondary to the low plate resistance, which very
effectively swamps the secondary ringing. And that is about the sum total
of it.
I have found it to sound very good, though there are other good driver
circuits as well. This one is cheap and easy, and works very well with all
the advantages of IT coupling w/o the normal expense associated with good
ITs.""
Here's a writeup of the 6EA7 with bridged Allied IT driving 45/46/2A3/300B.....
""Yes, I looked at the low frequency response and it was excellent. It can
swing a PP signal of a couple hundred volts PP at 20, or 30 Hz at low
distortion. I forget exactly, 200 V PP at 30 Hz for sure and 100 V PP at 20
Hz, or maybe better. The response is dead flat from below 20 Hz to several
hundred kHz w/o overshoot, or ringing. Distortion at a hundred volts PP
is -55 dB 2nd harmonic declining about 15 dB per successive harmonic (with
an RCA brand 6EA7).
The low end frequency response is forced by the very low plate resistance of
the 6EA7. Of course, a mismatched driving impedance makes the IT tend to
ring rather severely, but the bridging cap acts as a low impedance at high
frequencies coupling the secondary to the low plate resistance, which very
effectively swamps the secondary ringing. And that is about the sum total
of it.
I have found it to sound very good, though there are other good driver
circuits as well. This one is cheap and easy, and works very well with all
the advantages of IT coupling w/o the normal expense associated with good
ITs.""
