• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
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    the safety precautions around high voltages.

E130L PP Power Amplifier

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frentec

Member
Joined 2013
Hi All,

I'm just about to start a Push Pull Amp build using E130L Tubes, it will be a dual mono in one enclosure, output transformers are being custom built in Poland, input impedance 1.6k, phase splitters will be 6n6p's, grid v regs will be 0A2 gas tubes, the plan is for 50/60 watts into 4/8 ohms. This is my first Power Amp build, so any advice help on this would be appreciated. Everything I need is ordered, I've probably forgotten something.
 
V

v4lve lover

Member
Joined 2010
He has six now i believe i send him two in the mail, and im doing the PCB design for the phase splitter power supply and bias arrangement.


Currently we are thinking 6N6P phase splitter, long tailed pair with a two transistor current sink in the bottom, i really cant tell you the gain of this arrangement(16-20 i think) but some feedback may be needed to get the amp sensitivity right. As from what i understand he already has a preamp. According to the datasheet the E130L at 1K6 anode load and -17V negative need about 9VRMS to drive them to full output power.

Anode resistors would be around 18K with a total tail current of 20mA coupled by two 470nF caps into the 68K grid leaks connected to the bias servo.

For the bias i was thinking of using the plug in modules ive made a PCB for to set the bias, see schematic and board attached, this will need a time delay to synchronize the application of B+ and bias to the tubes.
 

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artosalo

artosalo

Member
Joined 2010
...output transformers are being custom built in Poland, input impedance 1.6k
Click to expand...

That schematic shows a special output transformer with separate UL-winding. Are you going to have such opt ?

The 6N6P LTP with E130L output stage require some 2 Vrms input voltage to get full output power. If you are building hifi-amplifier, you will need at least 10 dB... global negative feedback. That is, the drive voltage from the preamp should be some 6 Vrms or more depending of the overal gain of the 6N6P/E130L-amplifier.

Concerning the 6N6P LTP, do you want to keep it full tube LTP or do accept solid state components as CCS (tail) ?
 
F

frentec

Member
Joined 2013
UL Winding input voltage

The transformers are being made with UL winding, it was offered at no extra cost, but I may not use it, 6V in is a lot, any suggestions are welcome, it is a loosely based design. I do have a couple of ccs boards built from kk audio somewhere.
 
D

Depanatoru

Member
Joined 2006
With only 250V max on G2 ( and typical 150V ) this is not a tube for ultralinear or triode mode in push-pull , even if you want . Maybe for single-ended .
So the best option is a stabilized G2 voltage , 150V or so .
Very similar with horizontal sweep tubes , wich have low voltage G2
 
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artosalo

artosalo

Member
Joined 2010
The point where CCS is, i.e. at the cathodes of 6N6Ps has quite low impedance.
Then the demand for high dynamic impedance of the CCS does not exist.
Actually a LTP works fine even with a few kilo ohms resistor as a tail.

The idea of the CCS I suggested is that it has low noise and does not need negative supply voltage.
 
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