• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

6l6gc SET, my first DIY

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It works! I can hardley believe it, now that I have it working with the Schematic below, does anyone have some seggestions, I used Musicaps for the coupling caps, however my 1000uf is just some bargain piece-o-junk. Please post some seggestions on how to improve either the fidelity or, or the power, which right now is about 1.5wpc

I plan to buy Edcor Output transformers with a center tap so I can hook it up as a Pentode eventually
 

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I have an amplifier on my Tubelab breadboard that has almost exactly the same schematic. I am currently using a 12AT7 for a driver. I am using the Edcor transformer and UL mode. I find better sound at 430 volts B+ using a 5K load. I also needed a bypass cap on the driver cathode to get enough gain. I have not measured the power yet, but it is way louder than my 2 watt 45 amp.
 
In other words, hook up the output Transformer as 5k primary and an 8 ohm secondary? then use a higher B+ voltage to accomidate for the extra resistance

how soon are you going to have the schematic posted on your website? I would love to take a gander at that
 
I will have the schematic done in a week or so. I have been tweaking on this amp on and off over the past few weeks. It evolved from the 6AV5 experiments that were done several months ago. I have 2 diferent designs of this amp. The simple one (very similar to yours) and a more complex design similar to the TubelabSE. I haven't drawn a schematic for either one yet, but I did a PC board for the simple one. It is not built yet.

For most SE amps and many P-P amps you will get more power as the load impedance decreases (to a point). You will get lower distortion and a higher damping factor and a generally tighter sound with a higher load impedance. In general UL mode gives more power than triode with higher distortion and poorer damping factor. I tried several combinations using a variable power supply, before settling on 5K UL with 430 volts. Current was set at 65 mA. All of this was done with low cost Shuguang 6L6GC, coke bottle shape. Different tubes may yield different results.
 
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