Egnater Tweaker 40 Head not working as it should

[PARTYM]

Hello fellow music lovers! This is my first post here and I'm hoping one of you kind and knowledgeable people can help me diagnose my amp fault.

So my Egnater Tweaker 40 Head is producing VERY low volume on both channels (gain needs to be up full and master around 11 o'clock position before I get an audible sound, and even then it is REALLY quiet. I have taken out the valves (2 x 6l6gc and 3 x 12AX7) and they look ok, all glowing and when tested with a multimeter it confirmed they are powering up ok, and I have tried tapping on them with a pencil when powered on and no obvious crazy sounds there. I have tried plugging straight into the effects return and although I do get a louder signal when I do this, it is only when I strum hard and is only for the initial attack sound plus it is very distorted. I know these amps are notorious for having transformer issues but I have one of the newer versions where the old dodgy transformers are apparently no longer in use. I have tried all the other obvious signal chain possibilities (cables, guitar, speaker, speaker cable etc) and these variables are all working fine. Please help! Thanks!

[DrGonz78]

Sure yes don't immediately think the problem is the transformer as it will be last on the list usually. Do you have another working amp that has a preamp out? If you do then take that amps preamp out (or effects Send) into the Egnater effects return, sound good or bad? Then take the Egnater's effects send into the other amp's power amp in (effects return) and how did that sound? What we want is to divide and conquer to check if the problem is the Egnater's preamp section or power amp section. I only have the power amp schematic for the Egnater 40 and it is now posted. Do you have a multimeter for checking voltages and resistance? How comfortable do you feel working on the inside of this amp while it is powered on?

[J M Fahey]

Try to lift the left leg of R51 or the left leg of C39 and inject signal there.
You might need around 1 V RMS or maybe somewhat more because you are going *straight* into the power amp, and check you can drive it to full power.

IF possible, you have a good OT and power amp in general.
If not , try the OT with RG Keenīs tester or replace it with another push pull OT, even a 15W one, if you have a spare one available, just to confirm/discard it as a suspect.

[PARTYM]

Thanks for the information and help guys! I thought I would go with the most simple possible fixes first to just rule then out. I replaced the 12AX7s and no change, got a pair of 6l6gc's coming tomorrow so I'll try them then. I have a multimeter and a little experience with electronics but probably not enough to comfortably work on the amp with the power on. I don't have another head that I can try the effects loop change over with but I will see if I can borrow one to try that. Honestly, thanks loads for the suggestions. The annoying thing is I haven't even played live with this head yet, only at low volumes at home.

[g1]

What kind of volume do you get if you plug your guitar into the FX return jack?

[PARTYM]

I have also now tried a new set of 6l6s but still the same problem. Plugging the guitar into the fx return jack doesn't give me proper volume. It makes like a crackle type noise when I strum hard for the attack but no lasting tone, just the initial attack of the strum.

[g1]

There is a 1 ohm resistor, R12 in series with the fuse F1. At each end of this resistor are test points TP1 and TP2.
Can you measure the DC voltage with one probe connected to each of those test points. It should be something less than 200millivolts range.