Could you use a TV as a guitar amp?

[MiloCroton]

Forgive me if this question is naive. But I was thinking, traditional TV's are a whopping great cathode ray tube. Would it be technically possible to use one for audio signal amplification? Just for fun, even if it didnt work so well?

[teleamp]

The CRT would not work for audio, but, the TV has an audio amp so, anything (sort of) is possible.

[jh45gun]

[StephaninMelb]

too much MTV

...a guy won a Darwin award by installing a rocket engine in a car. What remained were skid marks and a black spot on the side of a hill

Are you asking if you can convert an old tube TV audio amplifier section into a guitar amp? The answer is you could but that a TV is so full of video circuits it would be a nightmare to perform operation to cut out the video function. Due to the time & amount of study involved it aint worth the effort. An experienced electronics hobbyist could possibly salvage "some parts" out of an old TV to build a guitar amp.

[MiloCroton]

Originally Posted by teleamp

The CRT would not work for audio, but, the TV has an audio amp so, anything (sort of) is possible.

I know nothing about electronics, ive heard audio vacuum tubes described as "just like the tube in your television" which got me thinking.

There are millions of CRT's lying in landfill around the world. Could they be put to use somehow?

[StephaninMelb]

TVs were full of many tubes to handle functions such as UHF frequencies, VHF frequencies, and all the cathode ray tube functions, etc. As a result lots of unusual types were used in TVs (relative to common types used in guitar amps). It was also common to use Compactron tubes, which were like 2 to 3 older style tubes packed into a smaller tube. You can use these to build amps, but they are a challenge and you end up not using all of a tubes capability. While a few hobbyist might muck around for a project it is not worth it on a large scale. If these tubes had any great value you'd see the whole dump covered with people digging as if they were truffles.

[TeleTim911]

I know a guy that did that, but it was a tube chassis. Worked pretty well as a bass amp.

But you have to be careful, even SS TV's can have quite a charge built up in the caps.

[boldaslove71]

Alex Lifeson does in his recent live rig ;)

[StephaninMelb]

Old televisions with glass picture tubes (seems strange to say this!) required a high voltage supply to operate. A transformer known as a flyback transformer steps up the AC (alternating current) used in the horizontal oscillator circuit to provide 20,000 to 50,000 VDC to the picture tube. The high voltage travels through a highly insulated cable with a wire clip on the end (known as the anode) and is attached to the side of the glass picture tube via a hole in the rear of the tube. A high-voltage capacitor is attached to or built into the flyback transformer.

If you look at the tv flyback schematic, the divider (for screen and focus) are tapped from the middle winding before the output diode. Due to this design, when a tv is switch off the high voltage from the picture tube (infact picture tube is a large capacitor) can't be discharge because of the output diode preventing the current from flowing to the divider. Thus the high voltage remains in the tube and can only be discharged with a screw driver connect between the cold ground and the flyback anode. You will hear arcing sound from the spark generated when discharging the high voltage. Best for non trained people to not muck around with these things.

[jefrs]

We used to play guitar through old valve picnic box (vinyl) record players. You would disconnect the stylus/pickup plug and jack the guitar in there.

The final generation of CRT tellies had no valves besides the TV tube, but probably do have a few audio inputs on the SCART if nowhere else. I do not remember ever seeing any audio inputs on an older all-valve television.

Modern tellies do have numerous audio inputs, most are line-level. I would not like to see what happens to their pathetic little speakers if you do this. Caution.

You can generally use an aux input on a modern domestic "hi-fi" amp (the CD player) that has suitable speakers. Keep the volume down as it is easy to over-load, hi-fi speakers are fragile and low efficiency and thus nowhere as loud as guitar speakers, so temptation to turn the volume up. Results usually disappointing anyway.
I do use a Denon hi-fi as studio monitor, but it feeds a pair of 80W 12-in guitar speakers (ext cabs), not ideal but robust.

Your PC speakers may have an aux input. Again try not to blow them up.

[Justinvs]

I wonder what sort of picture a guitar would produce if you could convert the signal from the pickups to a VHF frequency?

[dsutton24]

I wonder what sort of picture a guitar would produce if you could convert the signal from the pickups to a VHF frequency?

None. The television picture was actually base band video information modulated on a vistigial sideband carrier. You'd have to convert the audio signal to a video signal (around 0 - 4.5 Mhz), add sync and color information, then modulate it to your desired channel.

Waaaay back in the mists of time I remember seeing a video color organ. It was used on a public access cable channel... basically amateur disc jockies would play their records, and this thing would create line patterns on the screen in sync with the music. I have no recollection of what it was called or how it worked.

As for using TV audio amps for guitar amps, again going way back, TV amps were great sources of parts for amps, but past the 70's or so, they didn't have transformers, and had odd tubes. Transformerless guitar amps are dangerous and generally bad news.

[telepath]

Cant answer the OP's question (other than muttering 'oooh crikey, not sure about that!') though my first 'amp' was an old 'Radiogram' Cabinet (furniture style!) with an Aux input that I cobbled together a jack adapter for.
It actually sounded OK, in my distant memory. Definitely had some kind of growly break up going on - I think it was valve / tube, but far too many moons ago ..

[StephaninMelb]

How about a TV guitar? Or convert old TVs into Fender TV Series like this Fender Bassman TV Series...

If it doesn't work out you can make a TV aquarium.

[Alamo]

Ah, Tube Radios - some sounded really good.
we had a Grundig at home and I played my first electric guitar over that. 4 Watts, three speakers. I think it would sound great by todays standards.
found the exact model

http://www.bastel-radio.de/2011/grundig3088/

[StephaninMelb]

Those Grundig Tube Radios had a really great sound. Very three dimensional sonics. I've always wanted to buy Grundig exactly like that one.


It is too bad radio is moving totally to digital and we won't be able to hear these old radios any more.

[Justinvs]

Originally Posted by StephaninMelb

It is too bad radio is moving totally to digital and we won't be able to hear these old radios any more.

I seriously hope they never mandate a switch to digital radio the way they did television. It would rob me of my favorite medium. I'm a real radio junkie, AM more than FM, but I'll even listen to shortwave when the mood strikes. But, if you live in mountanous region digital signals are completely worthless. I've checked the maps and there isn't a single HD radio station in range of where I live.

Justin

[Jimclarke100]

There's an antiques guy local to me who has a bunch of old '50s and 60's valve radio's that he's selling pretty cheap - Ecko, Bush and so forth.
Been looking at them with my modding eyes on....
Thinking in terms of doing something like Fender's new toy the Greta so's I can plug guitar, iPod and Digital Radio all in to get all that valvy goodness in the amplification.
Gotta be pretty careful with them though - some of them don't have power trannies and take the mains straight into the smoothing circuit.
Don't fancy the idea of TV circuits though - too many volts on the back of the CRT, and not too good sound.

[SamClemons]

Some of the old tube TVs had an amplifier section that was pretty much separate from the TV section and would be pretty easy to remove and setup as a guitar amplifier. Better be careful though, not worth getting killed for.

[printer2]

Just did a lower voltage single tube 5F1 Champ kind of amp with a 12AE10 (not great 1w amp), a 4W Tweed Princeton type amp with a 15CW5 which was used as a TV audio output pentode, just picked up some 12W6GT's used as a audio output in TV's or as a vertical-deflection amplifier in tv receivers (sort of a higher heater current 6V6).