Lab Rat Low Volume Output

[ThatDude]

Does the Lab Rat have a lower volume output than the original Rat Circuit? I have to turn the volume almost all the way up to get about unity volume output. Compared to my builds of original Rat circuits it definitely has less volume on the output. I am not sure if that the way Lab Rat circuit is, or if I something is not right with my build.

 

[SamuelG]

I haven’t built one but what you’re experiencing doesn’t sound right.
Your soldering looks good but has your input jack, ground solder flowed properly?
Also, might be worth swapping tubes to check that’s not the issue

 

[ThatDude]

I haven’t built one but what you’re experiencing doesn’t sound right.
Your soldering looks good but has your input jack, ground solder flowed properly?
Also, might be worth swapping tubes to check that’s not the issue

Thanks @SamuelG. I’ll check the ground of the input jack and swap tube and see if that fixes it. I’ll report back.

 

[Tassieviking]

Just dusted of my 50year old CRO and with all knobs on 12 o'clock I had the same out as in, with the volume on full I more then doubled the output signal. I like my old CRO with a real cathode ray tube in it.

edit: I just noticed all the dust at the bottom of the screen in the pic, it has been a long time since I used it.

 

[ThatDude]

Just dusted of my 50year old CRO and with all knobs on 12 o'clock I had the same out as in, with the volume on full I more then doubled the output signal. I like my old CRO with a real cathode ray tube in it.

edit: I just noticed all the dust at the bottom of the screen in the pic, it has been a long time since I used it.

Thanks @Tassieviking. Sounds like it’s something in my build. I am going to look into it. I don’t remember the output being that low always. Something probably needs fixing.

 

[RobinMallard]

One thing you may want to check is that the ends of C15 or C16 isn’t grounding on the bottom of the pot.

These pots have metal on the bottom that goes to ground, so if the legs are a bit long signal could go to ground.

 

[ThatDude]

Closing the loop here, I just got around to taking a look at this. The culprit was the tube. The output volume jumped up after swapping the tube. Thanks everyone for the input!

 

[ThatDude]

Re-hashing this thread. I had another tube wear down prematurely. I measured some voltages and it seems like the tube might be getting starved of power and getting damaged. I am measuring 8.89v across pins 4 and 5 of the tube, it seems like the voltage is not getting stepped up to 12v in the circuit. I measured across the circuit and seem to be getting 244v for the B+ line where needed but I am consistently getting 8.8-8.9v on the heater power output. I measure 11.9v when I run the pedal at 12v though. Is this pedal supposed to run off 12v or 9v? I am using a Cioks DC7 for the power supply. I have version 1.1 (12/2023) of the PCB. Thanks in advance.

 

[ThatDude]

Reading up on this, it sounds like 9v across the heater is the way this is designed. Any recommendations of places I should check to see why tubes would be wearing down in a matter of a few hours of playing time? The pedal is not dead, but there is definitely a volume drop.