# Two Rock Mayer Preamp Pedal - Tube not heating



## cgmason1986 (Aug 14, 2021)

I just tried my first venture into a tube pedal - saw Peace Hill FX post some amazing stuff and wanting to give it a shot. I found the layout on AmpGarage for the whole amp and just cut out the preamp section of it. The first noticeable issue is that there is no sound - tube isn't heating. I checked and have 6V on the heater pins. I'm just not really sure what to check with a tube build. Pics attached. Maybe something wrong with the way I drew my layout? I'm pretty confident I followed it correctly. Note in the pics there is 1 wire from pin 1 to the mid-boost circuit missing that I have since put in.


----------



## Flying (Aug 15, 2021)

You say you have 6V on the heater filaments, I just want to check that the 6v is between pins 4 and 9, in your diagram you only have a conection going to pin 9 there is nothing connected to pins 4&5, i.e. nothing to complete the circuit.


----------



## JamieJ (Aug 15, 2021)

I have nothing to offer you @cgmason1986 in terms of troubleshooting help other than to say I hope you get this working because it looks cool AF 😎 

P2P looks awesome.


----------



## cgmason1986 (Aug 15, 2021)

Flying said:


> You say you have 6V on the heater filaments, I just want to check that the 6v is between pins 4 and 9, in your diagram you only have a conection going to pin 9 there is nothing connected to pins 4&5, i.e. nothing to complete the circuit.



Thanks for the response. I actually have the 6VDC connected to pin 4, in 4 and 5 are jumped, and then a lead from 5 to 9. Do I also need to add a ground connection from pin 9? I just tried to search around for how to connect heater filaments, looks like a confusingly large number of different ways out there for 12V, 6VAC, 6VDC, and I'm having trouble just getting a firm grasp on this. From what I can tell though you don't need the twisted wires for a 6VDC wires since there's no AC hum to cancel. Other than that I'm lost.


----------



## Flying (Aug 15, 2021)

If I've understood you correctly 4, 5 and 9 are all connected together?

If so this is wrong, your 6v to pins 4&5 is correct.

Pin 9 will need to be connected to somewhere else, I'm guessing ground. But sometimes filament heaters come off a transformer winding with a center tap, and it's the centre tap that goes to ground.

What is the box in your diagram that's providing the HV and Heater power?


----------



## Flying (Aug 15, 2021)

Cool project by the way... Tempting


----------



## cgmason1986 (Aug 15, 2021)

Flying said:


> If I've understood you correctly 4, 5 and 9 are all connected together?
> 
> If so this is wrong, your 6v to pins 4&5 is correct.
> 
> ...



Oh yea I know now that it's 100% wrong lol. Yes they're all connected together.  The box is a 12V to 250V(ish) power supply - with separate regulated 6V DC output for heater filaments:


			https://frogpedals.com/index.php/product/frog-smps-high-voltage-power-supply/


----------



## cgmason1986 (Aug 15, 2021)

Flying said:


> Cool project by the way... Tempting


Thanks! I thought it would be an easier/less expensive way to start getting into tube amps.


----------



## Flying (Aug 15, 2021)

Okay, it looks like you just need to disconnect pin 9 from pins 4&5 and connect pin 9 to ground, which is the solder tab next to the 6v output on the SMPS board.


----------



## cgmason1986 (Aug 15, 2021)

Flying said:


> Okay, it looks like you just need to disconnect pin 9 from pins 4&5 and connect pin 9 to ground, which is the solder tab next to the 6v output on the SMPS board.


Gave that a shot - Somehow threw off all my voltages? Not getting any 6V from the pad, pin 1 and 6 only reading about 50V and not responsive to the power supply trimmer. Switched it back to the wrong wiring and all the voltages are back to normal. Maybe pin 9 should connect to 6V and 4 and 5 should connect to ground?

*EDIT* - Nope same thing. It seems like if 4 and 5 aren't connected to 9 I get voltage problems. Also my socket has a center pin that's not connected to anything - Thought maybe that was something for another kind of wiring - is that something I need to connect somewhere?


----------



## Barry (Aug 15, 2021)

Maybe post the schematic you took it from


----------



## fig (Aug 15, 2021)

I see the problem here. You forgot to put the pcb in. 😁

Looks great! I look forward to hearing you rock it!


----------



## cgmason1986 (Aug 15, 2021)

Barry said:


> Maybe post the schematic you took it from


Good call. I basically used this schematic with some minor value changes. I bubbled the part that I used.

*EDIT* no idea what happened - didn't change anything but now it seems to be working?? Maybe there was a short somewhere? We'll see after I button it all up. Thank you so much for all your help on this, and sorry for sending you on a wild goose chase.


----------



## Flying (Aug 15, 2021)

That's great, hope it sounds good.


----------



## Feral Feline (Aug 16, 2021)

This Mayer project is way cool. 

I wouldn't have the knowledge let alone balls to attack a project like this, I've gone the easy route and got a MadBean Uber Tuber and similar, ie somebody else who's far more knowledgeable than I has already done the hard&dirty work.

That ghost problem happened to me with my 5E3 build's input jacks. After fixing some known problems with them, they still weren't working quite right. Took them out to inspect them, couldn't find fault so put them back in and _voila_, they worked properly.


The P2P here is beautiful to behold.


----------



## Barry (Aug 16, 2021)

Beautiful work, glad you got it working!


----------



## JamieJ (Aug 16, 2021)

cgmason1986 said:


> Good call. I basically used this schematic with some minor value changes. I bubbled the part that I used.
> 
> *EDIT* no idea what happened - didn't change anything but now it seems to be working?? Maybe there was a short somewhere? We'll see after I button it all up. Thank you so much for all your help on this, and sorry for sending you on a wild goose chase.


We NEED a sound clip for this! Glad it’s working!


----------



## Flying (Aug 16, 2021)

With this being a genuine PreAmp, can it be used as a pedal into the front end of an amp, or do you feed it into the return of an amps effects loop?


----------



## Stickman393 (Aug 17, 2021)

So fresh.  So clean.


----------



## cgmason1986 (Sep 9, 2021)

Flying said:


> With this being a genuine PreAmp, can it be used as a pedal into the front end of an amp, or do you feed it into the return of an amps effects loop?


Sorry for the delayed response. I've done both ways with good results, but into the return of the effects loop is how I primarily use it.


----------



## cgmason1986 (Aug 14, 2021)

I just tried my first venture into a tube pedal - saw Peace Hill FX post some amazing stuff and wanting to give it a shot. I found the layout on AmpGarage for the whole amp and just cut out the preamp section of it. The first noticeable issue is that there is no sound - tube isn't heating. I checked and have 6V on the heater pins. I'm just not really sure what to check with a tube build. Pics attached. Maybe something wrong with the way I drew my layout? I'm pretty confident I followed it correctly. Note in the pics there is 1 wire from pin 1 to the mid-boost circuit missing that I have since put in.


----------



## JamieJ (Sep 9, 2021)

As @Feral Feline has said this is an amazing project but I don’t have the balls to have a go at this. The p2p is insane. I’m sure loads of people would love to build this if there was a PCB.

I would love to see a build report of this and to hear how it sounds.
Great work @cgmason1986


----------



## cgmason1986 (Sep 9, 2021)

JamieJ said:


> As @Feral Feline has said this is an amazing project but I don’t have the balls to have a go at this. The p2p is insane. I’m sure loads of people would love to build this if there was a PCB.
> 
> I would love to see a build report of this and to hear how it sounds.
> Great work @cgmason1986


Thank you! I forgot to update this after I was finished. I threw up a build report and included link to some pics and a demo.


----------

