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MeterMeter

Thursday, August 21, 2008

6AU6A Pentode













6AU6 Application Data

Class Va Vg2 Ia Ig2 Ra S Rk
Pentode 100 100 5.0 2.1 500,000 3.9 150
Pentode 250 125 7.6 3.0 1,500,000 4.5 100
Pentode 250 150 10.6 4.3 1,000,000 5.2 68
Triode connected 250
12.2
7,500 4.8 330


Vh Ih VaMax Vg2Max VhkMax PaMax Pg2Max Cgk Cak Cga Notes
6.3 0.3 350 330 200 3.5 0.75 5.5 5.0 0.0035 Pg2 = 0.75W for Vg2 <>


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6AN8A Triode Pentode

















This is an original RCA 6AN8A Medium-Mu Triode Sharp-Cutoff Pentode Electronic Tube. A collector's special vacuum tube. This tube useable in VHF television and FM receivers. Naturally a Medium-Mu triode can be used for many other special purpose circuits like oscillators and RF amplifiers. Excellent for those antique radio or television restoration projects or to set up a private vacuum tube museum. It is NOS tube - New Old Stock, unused, boxed, and kept for all these years in mint condition.

Features:

6AN8A Radiotron Electron Tube
• Mfg: RCA
• Class A amplifier
• Heater: 6.3 V, 0.3 A
• Plate: 125/150 Vmax - Triode/Pentode
• Plate Current: 12.5/15 mAmax - Triode/Pentode
• Base: 9-pin miniature, all glass
• High quality Made in USA
• Tube Collector's Special
• This tube come out of a old but working Tektronic oscilloscope

Notes:


• Only two available
• Price: $30 a pairs
• Add $6 for S/H within continental US

Please send email me at : tubescrazy@yahoo.com

Thursday, August 7, 2008

Build your own HD antenna




Few months ago Time Wagner cable company had raised the price on my cable bill from $30 to $60 a month and I tried to reasonable with them but no luck the price stay and there is nothing I can do so I cancel my service. Time like this $60 a month is a lot of money for my family. But I need the basic TV channels for the family. Searching on the internet I found out there are quite number of people making their own I antenna. I stumble across the hanger antenna on metacafe.
Follow the instruction I build my hanger antenna, I am so amazing with the hanger antenna I got 46 digital channels and most of the channels are super clear. But I am not happy with the look of the antenna so I started to create a better version of the hanger antenna. I found some copper tape at my work cut about six 12'' x 1' , spent only one hour on saturday morning I made my HD antenna with this antenna I got 60 digital channels with super picure quality. I am so happy I can watch digital channels for free.
Here are some pictures of the HD antenna. Any question please feel free to email me at : allpixles63@yahoo.com.


Coat hanger antenna with this I got 46 digital channels
hanger 2

hanger 1


Copper tape antenna on card board with this I got 60 digital channels
Copper 1

copper 2


And here are the two antenna
hanger and copper

hanger and copper 2

Update After moved down to Westminster re-scan my TV I got up to 103 channels wow!
As promise I have the complete drawing of HD antenna here for anyone want to DIY enjoy. Thanks for stop by my blog.

Chinh Le.

Thursday, July 31, 2008

My First Tube Amplifier

My First Tube Amplifier

I have been fascinating about tube amplifier for years, and now I wanted to build one on my own. I have been research on the web for a kit with decent price tag. The K12G Stereo kit from S5 Electronics was my choice. The kit sell for $156 plus $10 shipping, I felt this kit is right for the beginner like me. Order the kit I did, it came few days later in a small box very well pack.

The kit rather simple I liked it but it came with a piece of wood, this does not look very attractive, again I did some more research on the web and I came across these two site: http://diyaudioprojects.com/Tubes/K-12M/K-12M.htm (Mark Houston) and http://www.siteswithstyle.com/VoltSecond/K-12M_AMP/K-12M_Push_Pull.html , learned form these two men I also purchase an aluminum chassis form Angela Instruments http://www.angela.com/catalog/chassis/Chassis.html . Got the chassis I painted with several coat of black and final with two coat of clear, and I still felt that I have to follow these two men advice about some modification for the kit. I ordered 6 new .22mf capacitors film and foil type, new fuse holder, chassis mount power jack, switch form Parts Express. The pilot lamp, RCA terminal, mounting screws from the local hobby stores. It took me two whole weeks to complete this amp because this is my first tube amp I ever build so I wanted to put extra worked to make it nice and perfect. I end up installed all the parts on the bottom of PC board, accept the 4’s ceramic sockets and the bridge rectifier. Here the picture.

Finished the amp it is time to power up and listen. My first impression was this 8Watts amp sound very loud with volume about half way. I have been heard that tube amp with couple watts sound very loud with high efficiency speaker but to my surprised my amp also sound very loud with a normal speakers.

I did not have a high efficiency speakers but with a Polk audio towel speakers the mid and the high frequency sound very clear and very clean, but bass were not there I don’t know why may be because I hooked up my CD player straight to the amp no tone control what so ever. Or any body read this have any suggestion please e-mail me. I plan to build a tone control circuit on a later day. For now I am happy with my DIY tube amp, enjoy the crispy sound of the simple tube amp until my next tube project. My next project will be a 300B amplifier.

And here the picture of finished amp. Ooooh !!!, the glow of the tube amplifier such a beauty of the past.



PC top

PC bottom

Case

assembly 3

assembly 2

assembly1

complete