6CK4 PP Amp
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 15th March 2003, 12:27 AM #1 diyAudio Member   Join Date: Jul 2002 Location: Baltimore, Maryland, USA 6CK4 PP Amp I'm looking for some help in building a PP amp using the 6CK4. If someone has any hints or info, I would certainly appreciate some guidance what kind of load line, etc. Tks, Jack T.
 15th March 2003, 02:01 AM #2 diyAudio Member     Join Date: Jan 2003 Location: Milwaukee, WI Hmm...neat tube , I want some!! Sorta like 6W6 I guess... anywho... For class A1: maybe 200V supply, 50mA bias (-20V grid, 400 ohms per tube if cathode bias) = 10W dissipation (I'm sure you could push 15W Pd, vertical deflection is tough so it's going to be a hearty tube). Loadline. Go up to the zero-bias curve and choose a point.. approx. double current (i.e. 100mA) is typical. That seems a little shallow so I'll say 125mA, which happens at 100V. The flipside of the point occurs at -40V, twice the bias voltage, about 5mA/255V. Thus Imax and Imin are 124 and 5mA respectively; Io (operating) is 50mA; Vmax is 257, Vo is 200, and Vmin is 100V. The slope of the loadline is the resistance, (Vmax-Vmin)/(Imax-Imin), or about 1.3k. You can also calculate distortion, based on: Code: ``` Imax + Imin ------------- - Io 2 2nd H % = -------------------- * 100 Imax - Imin``` Which can be simplified (algebraically speaking ) to: Code: `2nd H % = 50(Imax^2 - Imin^2) + 100Io(Imin - Imax)` (That assumes my logic unit is still working.. it tends to get faulty with sleepiness... ) Anyway. That comes to 12%, but I just remembered that 2nd H is canceled in PP amps so you can ignore it Have fun. Wonder how many responses popped in while I typed this...(when I started there were none )... Tim
diyAudio Member

Join Date: Jan 2003
Location: Milwaukee, WI
Forgot the graph I prepared..

The loadline shown is SE. For PP, each tube needs to see that - so 1.3k per half (either side of the CT). So the anode-to-anode load must be four times, or 5.2k (you needn't be so exact, a 4 or 6k would work about the same ).

Now, this is where I keep forgetting things... Do the tubes act in series, hence a-a = 4*single Rl? Or do they act in parallel, giving a-a nearer 1x? Or somewhere inbetween, say one tube is half cutoff (half Gm or Rp, take your pick) and the load is suddenly on a single tube!

Tim
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 15th March 2003, 02:23 AM #4 diyAudio Member   Join Date: Feb 2002 Location: Michigan how about a schematic? Scroll down this page for one idea. http://hollowstate.netfirms.com/DIY_files/proto.htm here is another http://tinpan.fortunecity.com/saints...er/6ck4-pp.gif http://tinpan.fortunecity.com/saints...mer/index.html Something to start with anyway. Cheers Craig Ryder __________________ Ryder Any fool can ask more questions than seven sages can answer.
 15th March 2003, 03:09 AM #5 diyAudio Member     Join Date: Jan 2003 Location: Milwaukee, WI I don't recommend the second one.. 100uF on a 5U4 is liable to pop it, hearty though the tube is! That guy was probably going from his junk pile, but if you must do it like that, use a lower voltage transformer or choke input. Tim
 15th March 2003, 04:00 AM #6 diyAudio Member   Join Date: Jul 2002 Location: Baltimore, Maryland, USA 6CK4 PP Amp So many with so much information, so quickly. Do you guys have lives? What more could I ask for? Thanks so very much. I'll put pencil to tongue and go from there! Tks a mil, Jack T.
diyAudio Member

Join Date: Jan 2003
Location: Milwaukee, WI
Re: 6CK4 PP Amp

Quote:
 Originally posted by Jack Thomas So many with so much information, so quickly. Do you guys have lives?
No..

frugal-phile(tm)
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Join Date: Oct 2001
Location: Victoria, BC, NA, Sol III
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Quote:
 Originally posted by Sch3mat1c Now, this is where I keep forgetting things... Do the tubes act in series, hence a-a = 4*single Rl? Or do they act in parallel, giving a-a nearer 1x?
I tried to follow a thread on the JoeList on this subject -- seemed like a thousand posts -- and there seemed to be perfectly valid arguments for both cases -- over my head at the moment.

dave
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6CK4

Hi,

Quote:
 Do you guys have lives?
We all sold our souls to DIY...no live, no pay...just helping out the newBs....maybe a small statue...if you insist.

Cheers,

/This may be an idea for the "Policies thread"...oh well we'll see ...
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Frank

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Join Date: Jan 2003
Location: Near London. UK
Statue

Quote:
 Originally posted by fdegrove ...maybe a small statue...if you insist...
What did you have in mind? How about a 1950s communist-style statue of our worker hero striding boldly forward with soldering iron held proudly aloft?
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