Low end clipping on SL 18 conversion

[JimbpGaff]

Thanks Josh

I will see if I have one and change it over or I will order one from RS.

Jim

[JimbpGaff]

The 2200uf cap has turned up now so I will hopefully change it over later.
The biasing reads 7.7 volts , I assume to raise the volts to 12 I should increase the resistor size ?
I currently have a 150r fitted .
As always , thanks Jim

[JMPGuitars]

The 2200uf cap has turned up now so I will hopefully change it over later.
The biasing reads 7.7 volts , I assume to raise the volts to 12 I should increase the resistor size ?
I currently have a 150r fitted .
As always , thanks Jim

Perhaps you should post all your voltages. 12VDC is the target for higher cathode resistor values biasing higher voltages in standard builds dealing with high wall AC. In your conversion's case, it might be a little different, so you'll need to calculate the correct bias point.

[JimbpGaff]

Ok .
Good advice.
I will check them out later.

[JimbpGaff]

I have now installed the 2200uk cap, reverted to the original tone control, fitted the sag resistor and installed the bright switch.
All works ok but the clipping is still there ( slightly ) and the overdrive is only light.
I will measure and post my voltages later.

To be honest, wiring wise, it has all got a bit messy in there now and hum has become an issue.

I feel I may have to strip it out and start a re build using the recommended layout and circuit.
If I do, would you recommend I go with a better power transformer?
Mine is the Ampmaker ( Danbury ) one with the 2 /9 / 18 watt switch option. I want to get it how I want it so I will have to dig into the savings pot.
I also have F&T filter caps - 47/22/22/22 UF - would you recommend I change the first two for a 32/32 double?
I also would need the passive loop before the phase inverter.

Thanks as always, Jim

[geoff 1965]

hello Jim,
can you post some pics with your voltages? i had a danbury PT in my lite 2 and with a 100 ohm sag got some very good tone so i wouldn't be concerned with that, looking at the schematic the first thing i would do is fit a 10-33K ohm grid resistor into pin2 of V1, did you use shielded cable for the input?

SL18preamp.jpg

regarding the effects loop i have a series passive in my lite2 but if you are going to rework the circuit the one in the downloads is best, Josh has included it in the new layouts if you want to check it out.