Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: supro66 on November 10, 2010, 12:02:41 pm
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This thing could not work :huh:
(http://i282.photobucket.com/albums/kk243/supro66/AMPS/126kd6.jpg)
6KD6 tubes need 900 volts on the plates 15 tubes :shocked:
One big Transformer
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> 6KD6 tubes need 900 volts
No... that's a maximum.
They were designed for 150V TV sets.
They will pass large current at low voltage. Over 1 Amp with 45V plate (but 160V 110mA on G2).
> 15 tubes
Yeah, and they are $40-$60 each with a steady market in radio transmitters.
I estimate it works near 200mA per tube, 3 Amps for the whole amp (which disagrees with the 150mA on the plan). Maybe 800 Watts total dissipation for ~~30 Watts output. $700 of tubes.
The suggested 6V 5A heater power would not warm two 6KD6 (2.85A each!).
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What about the 6DK6 tubes?
Source of data: http://www.nj7p.org/Tube4.php (http://www.nj7p.org/Tube4.php)
"Miniature type used as if amplifier tube in color and black-and-white television receivers. Requires miniature 7-contact socket."
Preferred Substitutes ......................... 6CB6 6CF6 6DE6
Substitutes ................................... 6BZ6 6HQ6
Heater Voltage ................................ 6.3 V
Heater Current ................................ 0.3 A
Maximum Ratings (Design Center Values): Pentode
Plate Voltage ................................. 330 V
Grid No. 2 Voltage ............................ 330 V
Plate Dissipation ............................. 2.3 W
Grid No. 2 Dissipation ........................ 0.55 W
Class A Amplifier
Plate Voltage ................................. 125 V
Grid No. 2 Voltage ............................ 125 V
Grid No. 1 Voltage Derived from
Cathode Bias Resistor ....................... 56 Ω
Plate Resistance (approx) ..................... 350K Ω
Transconductance .............................. 9800 µMho
Plate Current ................................. 12 mA
Grid No. 2 Current ............................ 3.8 mA
Class A Amplifier
Plate Voltage ................................. 300 V
Grid No. 2 Voltage ............................ 150 V
Grid No. 1 Voltage ............................ -6.5 V
Transconductance .............................. 9800 µMho
Plate Current ................................. 12 mA
Grid No. 2 Current ............................ 3.8 mA
The 6KD6 IS a different beast, and not the tube mentioned on that schem.
6KD6
"Duodecar type used as horizontal-deflection amplifier in color and bw tv receivers. Requires duodecar 12-contact socket."
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Tube Depot sell 6DK6 at $ 3.95 each
http://store.tubedepot.com/nos-6dk6.html
Kagliostro
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Tube Depot sell 6DK6 at $ 3.95 each
http://store.tubedepot.com/nos-6dk6.html
Kagliostro
I am going to get 4
I have a Yaesu FT 401-B Ham radio transceiver
There are 2-- 6KD6 tubes for the output
After I retire I plan to put a station on air again
That’s a good price
WRONG WRONG
I went and checked $50.00 for 6KD6 you had 6DK6
http://www.tubedepot.com/nos-6kd6.html
I knew that was to good to be true :cry:
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WRONG WRONG
I went and checked $50.00 for 6KD6 you had 6DK6
http://www.tubedepot.com/nos-6kd6.html
I knew that was to good to be true
Why are you interested in 6KD6? Your schematic clearly shows 6DK6.
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I think he has two different interest
one for a Transformer Less amp 6DK6
and other for 6KD6 to be used in his RF transmitter
Kagliostro
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I think he has two different interest
I guess? But the 6KD6 has nothing to do with the topic of this thread or the schematic he posted. I really think he just got the tubes mixed up in the original post.
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I think he has two different interest
one for a Transformer Less amp 6DK6
and other for 6KD6 to be used in his RF transmitter
Kagliostro
Yes you are right
I am sorry
I was looking for 6KD6 stuff
I was not paying attention
63 is a tough age for me
I wanted to see a 6KD6 schmatic
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If you are looking for 6KD6 audio schematics
Traynor YBA - 3 use similar tubes 6KG6
if I'm not wrong 6KD6 = EL519 -- 6KG6 = EL509
http://www.lynx.bc.ca/~jc/700116_YBA3_A.gif
Kagliostro
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> What about the 6DK6 tubes?
Dislexya strikes agian.
Then yeah, a bit over 10mA 2W per tube, say 200mA total, 1.6V or 1.13V RMS in 8 ohms is 0.16 Watts output from 40W plate heat and 28W of heaters.
Even if you find tubes and sockets super-cheap, is it worth the work?
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Seems like a transformerless tube power amp is possible but not practical when dealing with any sort of real power. If it was, Fender & Marshall etc. woulda been doing it already. OTOH, it's quite doable at lower power and higher impedance. My headphone amp is transformerless using 6DJ8's as White cathode followers. It sounds great and drives my cans plenty-o-loud.
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use 6AS7/6080 or 6c33 soviet.
--ISO
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> What about the 6DK6 tubes?
Dislexya strikes agian.
And I do records on air craft every day
Hours and Drawing numbers for repair parts
I have to watch my P's and Q's
I have transposed numbers like 3753 to 3573 :shocked:
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Seems like a transformerless tube power amp is possible but not practical when dealing with any sort of real power. If it was, Fender & Marshall etc. woulda been doing it already. ...
You just said a mouthful!
If we had good speakers with an impedance of 200 ohms or so, OTL amps would be more common.
However, there are folks that feel OT's have so many flaws and design problems that they must find a way to eliminate them. That is easily done with solid-state, but difficult and wasteful with tubes.