Tube boost + overdrive running off a 9 volt battery

[Kesh]

Trying to troubleshoot my valvecaster. I am getting a lot of gain and the volume and tone pots don't seem to do anything. I have checked the wiring a million times but can't see a problem, why might I be getting these results?

probably not grounded those two pots. which wiring diagram did you use? the pcbless layout at beavis is a bit odd as it's different to their schematic. but there's a wire from both pots to sleeve, with a cap, C4, from the tone one, which is in a different place in the schematic.

[6BQ5]

  Hello all
     I just want to thank everybody! This has been,and still is the best thread I've read(many times).
  I've built valvecasters of all types, built them into ss amps, with great results.
  Now I'm going to try the buffered/bootstrapped, going to try my own variation.
     
      Just wanted to thank all for some great info.

                                                         Steve 6BQ5

[ozzu2000]

Hi! I've just built a valvecaster, but have a few doubts about using a voltage regulator.
If I want to use a 12v wallwart, and a 7809 regulator, how should I wire it?
12v to the heaters, unregulated directly from the ww and 9v to the rest of the parts, from the regulator?
I'm guessing that the heaters aren't sensible to the noise from the ww, am I wrong?

Could I use a 18v ww with a 7812?

btw: I've already done some changes to it, removed the tone and increased r2 to 220k in order to increase output volume.

Thanks!

[Renegadrian]

if your wall wart gives out 12V stabilized regulated and filtered, you're lucky! you don't have to use a regulator at all.
just feed both the heaters and the plates with that voltage.
Valvecasters need a good regulated power supply - just try it!

[Jdansti]

What he said^; however if your wall wart is unregulated, you could have more than 12v on the heaters and damage them. If that's the case, it would be best to your the 18v supply and a 12v regulator (with filter) for the heaters and the rest of the circuit. You'll probably get more headroom doing that anyway.

[Ark Angel HFB]

Trying to troubleshoot my valvecaster. I am getting a lot of gain and the volume and tone pots don't seem to do anything. I have checked the wiring a million times but can't see a problem, why might I be getting these results?

You foul'd something up... I'd say give us some voltage readings and see what comes of it.

[ozzu2000]

The output volume of my valvecaster seems to be lower than what I expected...
When I set the volume to max, and the gain to minimum, I get an output that in only as loud as the bypassed signal.
Is this it's normal behavior? I thought the output was supposed to be stronger as this circuit is used almost as is booster purposes (see the tube town banana booster)

If I want to make the signal stronger than the one coming from the guitar I have to use a higher gain value, but then my signal get's a bit overdriven... (as expected).

And this is with the tone cap+pot removed...

running JJ 12au7, regulated 12v supply, and a strat with singles and humbuckers.

Thanks!

[Kesh]

i use a wall wart for heaters when i breadboard tubes. i just measure the voltage under load and add a resistor or diode if necessary. i haven't had any noise, but if you go over to diyaudio, they'll all talk of diode switching noise and the like. my wall wart is probably a smps.

[qtws]

New builder decloaking off the starboard bow.....

Santa brought me some 12AU7 valves and a 3PDT switch, so I built me a valvecaster as my first ever build -  Is is normal to be so stoked when a build works??  I'd have posted earlier, but I've been goosing the front end of a Marshall class5 with it and that's taken all my time over the last week.... And I have read all 150 odd pages of this thread...learned a heck of a lot about tube circuits.

I'd like to say it worked first time, but it took a reflow of a duff connection on the tube socket to get it to work.  Built on breadboard as I'm waiting for some perfboard to arrive. No tone control, 9V is ok, but 12V is definitely better.  Its loud     100uf electrolytic capacitor across + and -  rails of the regulated 12V PS seems to make it a lot quieter.

Its a bit farty in the bottom end, changing C1 to 22nf helps a bit, but it sounds a bit like a solid state amp overdriving....Its fine for low levels of boost, and pretty creamy in the mid range with a Les Paul. 

However, I didn't like the low end (and for some reason couldn't get a twincaster to work), so I dug into my tube amp book (vol4) and built something else a bit more to my taste .... (see JCM-caster thread     ).

[Jdansti]

Congratulations and welcome!!!  It's an endorphin rush when you build one and it works!  Be careful because it's addicting!  Just don't forget to play your guitar and say hi to the family now and then.

[bluebunny]

Family?  Who they??

[Ark Angel HFB]

Am I a bad person from sitting on some value changes that turn this into the best pedal I've ever played...

No really I've tested probably 60 different combinations of values.... systematically and recorded the results.

I won't let exactly what I'm doing slip but I'm telling you all there is crunchy gold to be found here.
Let me suggest the following... STRONGLY SUGGEST!!!

1. Built the valvemaster...
2. R2/R3:  (Lower values are better for me... think on it like this, if you keep the gain lower in each stage, the end result is still a lot of volume bit it is neat.)
3. R4/R5:  (higher values may be better)
4. C4/C5:  (High values worked better)

Lastly add a an EQ circuit just before the volume control... a passive one works fine. I've posted a good one in the past...

[josh1324]

I did what one of the users suggested, I forget whom, and raised the value of R1 to 2M. Could this have ruined the tube? After I changed this, there was no sound whatsoever, even after i changed the resistor back to 1M. Please help

[Ark Angel HFB]

Think you may have a problem somewhere else... but when in doubt take some voltage reading for us.

I've tried higher values than that without hurting the tube so... idk.

[josh1324]

Yes, I figured it out, it turns out my gain knob is messed and i just couldn't hear it due to the hideously low gain. I just jumpered over it for now to have maximum gain. Ill have one order a new knob soon.

I have another question though, how do I make it louder? it is noticably quiter than when the pedal is turned off. Surely it is just as simple as changing a resistor. I tried increasing the resistance from both grids to ground and that helped a little bit, now when it's on it is about 95% of the volume when the pedal is off. Could this have anything to do with me having EMG active pickups?

Thanks in advance.

[josh1324]

Yes, I figured it out, it turns out my gain knob is messed and i just couldn't hear it due to the hideously low gain. I just jumpered over it for now to have maximum gain. Ill have one order a new knob soon.

I have another question though, how do I make it louder? it is noticably quiter than when the pedal is turned off. Surely it is just as simple as changing a resistor. I tried increasing the resistance from both grids to ground and that helped a little bit, now when it's on it is about 95% of the volume when the pedal is off. Could this have anything to do with me having EMG active pickups?

Thanks in advance.

[Ark Angel HFB]

Yes, I figured it out, it turns out my gain knob is messed and i just couldn't hear it due to the hideously low gain. I just jumpered over it for now to have maximum gain. Ill have one order a new knob soon.

I have another question though, how do I make it louder? it is noticably quiter than when the pedal is turned off. Surely it is just as simple as changing a resistor. I tried increasing the resistance from both grids to ground and that helped a little bit, now when it's on it is about 95% of the volume when the pedal is off. Could this have anything to do with me having EMG active pickups?

Thanks in advance.

voltage reading bro...

Ground the black lead of your multi-meter and then touch the red lead to each pin of the tube while it is plunged in and turned on...

Also try a value of 22k for R2/R3... This pedal should give you close to 40db of boost... so if it is less than unity you got some real weirdness going on.

[josh1324]

Okay, voltage reading with black lead connected to -9 volts:
Pin 1: 8.99v
Pin 2: -0.2v
Pin 3: 0v
Pin 4: 0v
Pin 5: 9.23v
Pin 6: 8.86v
Pin 7: -0.2v
Pin 8: -0.3v
Pin 9: 0v
Or was I supposed to connect the black to an actual ground like the third prong on a plug?

[Ark Angel HFB]

Okay, voltage reading with black lead connected to -9 volts:
Pin 1: 8.99v
Pin 2: -0.2v
Pin 3: 0v
Pin 4: 0v
Pin 5: 9.23v
Pin 6: 8.86v
Pin 7: -0.2v
Pin 8: -0.3v
Pin 9: 0v
Or was I supposed to connect the black to an actual ground like the third prong on a plug?

Interesting... those seem right... ok first... Can you list the values of everything you used.

The next step in trouble shooting would be to audio prob. Take off one of your multi meter leads and jump the base of it to the tip of a guitar cable that is plugged into your amp. make sure another clip also goes from the sleeve to ground in the circuit.

Turn everything on and plug a guitar into the effect. leave the guitar in a stand btw. Turn on your amp. Strum the guitar before every prob.

Now take the other end of the muilt-meter lead and touch these places in the circuit, turn all pots all the way up. Record what sound is there...

1. The tip of the input cable (Should be the normal sound of the guitar as this bypasses the effect.)

2. Pin 2 (Should be mostly the same.)

3. Lug one, of the gain pot. (Should be very loud, if it is not loud move to Pin two and test there.)

4. Pin 7. (Should be as loud as before the gain pot...  if it isn't turn the pot the other way and retest. if still not loud but before the pot is loud, then suspect bad pot.)

5. Pin 6. (Should be crazy loud.)

6. Before and after the tone circuit.

7. Before and after the Volume pot.

If you do the above it will allow us to pin point the area of the pedal that has the problem... good luck

[josh1324]

By record, do you mean literally record it? Or just jot down roughly how loud it is?