tube glow

[John Roman]

I've been following Corndogs  recent completion of a modified  Dynaco ST 35. I've always wanted to try out a decent push-pull design and find this may just be the ticket. I do want to build something that stretches my understanding of these type of amps.  Honestly it won't take much "stretching" but I'm intrigued by the notion that building something of my own design will increase the satisfaction factor.  "My own design" is not quite accurate, more like an amalgamation of some existing designs just for fun. I've always thought that not enough focus  has been brought to the overall look of the tubes themselves. A design that sounds good is most important but something that really displays the beauty of the tubes. The light they emit in the dark would also be a key design factor. I enjoy this aspect of vacuum tubes very much and although there are many beautiful designs when it comes to the base/cabinet and overall look I think I'd like to experiment more with light. I'm sure different tubes can supply varying degrees of illumination so what I need is a clever way to test several tube types to expose  their emission pattern. A test fixture of sorts to begin looking at several possible tubes and extrapolate an amp design from that. Thanks Corndog for your contribution of the ST-35 design. Perhaps this will lead to something fun!
Regards,
John

[2wo]

To light up a tube, just to see. All you need is a socket and 6V. A battery will do and with a few clip leeds, you don't even need the socket. If you want to look at VR tubes or Mercury rectifiers, That would be harder. To explore some other light ideas have a look at the "Red Light District" project over at DIYaudio. Also consider, you can mount an LED in the center hole of a tube socket to shine up into a tube if that is what you are looking for...John         

[RayP]

Take a look at the video of the Dowdy Lama's GM70 amps for some ideas of the colours you can achieve.



Here's a photo of an amp with blue LEDs shining up thru the socket.
http://db.audioasylum.com/mhtml/m.html?forum=tubediy&n=190082&highlight=829B&search_url=%2Fcgi%2Fsearch.mpl%3Fauthor%3DEric%2520B%26user_id%3D8388%26forum%3DALL%26sortRank%3DNone%26sort%3Ddate%26sortOrder%3DDESC

And if you really want pulsating light, take a look at one of my light bulb amps.
http://829b.com/6v6lumiere.aspx
The light bulbs change brightness level along with the music as the music gets louder. Essentially I use the bulbs as resistors in a parafeed arrangement. They are not linear resistors however but close enough for my listening pleasure and I do prefer their sound to ordinary power resistors.

ray

[John Roman]

Thanks guy's,
I really appreciate the help, and the links. I thought this notion may be a little "out there" and wasn't sure if I'd get any response. I'm inclined to build an EL84 based amp along the lines of a Dynaco STC-35. I saw Corndog71's recent effort and really liked what he has done. It appears to be a relatively simple design with room for some refinements as he has accomplished. If you should have any ideas regarding a similar design please let me know. And thanks again for the help!
John

[Paul Joppa]

If you are feeling exotic, you might look into an 801A p-p amp. It would operate in Class B, but with a similar level of feedback to that needed by the EL84 it might be low enough distortion. It has tungsten filaments, which are much brighter than the usual oxide filaments. The data sheet includes an operating point with only 400 volts, not much greater than EL84 type amps.

[corndog71]

For the record my pics are a little overexposed to accentuate the light of the tubes.  Although they do still look impressive in the dark.  Thanks for the kind words.