Tube boost + overdrive running off a 9 volt battery

[pazuzu]

hello people. i recently built a valvecaster. (single tube). i thought i had it working but apparently i don't after hearing some sound clips. i am only getting a gain boost over about 8 out of 10 on the gain knob, and the signal completely drops off lower than 5. i thought the circuit was just weird but apparently it should be almost transparent at gain 0.

the only problem i can see is maybe the gain pot, it's a futurlec panel mount, and it has a wiper swish. i have some proper pots from smallbear but no 50k. could i sub a different value to test this?

or if this is a common problem please let me know what i am doing wrong.

thanks, joe.

[Jule553648]

How to bypass this pedal?

Can I use 2pdt and just bypass from one input jack to another?

[pazuzu]

yes.

[ianchad]

Hi all,
I found this site and thread just over a month ago.
I followed the schematic posted at the start and 'breadboarded' the circuit.
It sounds amazing. it adds warmth and a little crunch to my solid state bass rig but in front of my Ampmaker WF55 it sounds fantastic.
So I'd just like to say thanks to all the contributors who have made this possible.
Next thing is to experiment with different anode resistances as suggested in the thread and then box it all up.

[PaulBass]

just got all the parts and ready to build! All I have to do first read through 102 pages of this thread   

[zambo]

pazuzu you can use almost any pot i think but i would stick to like 100k . I use that one all the time. no problems.

[Astronaurt]

actually, I've got my own minor problem with the circuit. it's all breadboarded and whatnot with stock parts from the normal Valvecaster scheme, and I'm running it off of 12V regulated DC from my power brick. The problem is that the gain pot doesn't give me all that much Gain! There's only the tiniest bit of overdrive when the Gain pot is turned all the way up. I'm alligator-clipping all the pots into the circuit, so I thought that mayhaps that they were introducing some resistance in there that might be limiting voltage to the Cathode on the first tube, but that seems like a pretty hokey answer there. I'm looking to buy a Multimeter ASAP for this and other projects, so I can't give voltages right now, but by any chance could anyone give me the voltage and Current values that SHOULD be between the connection from Tube 1's cathode to ground for the both extremes of the pot at values of 0Ω and 50KΩ?

alternatively I was thinking of modding this thing with a Tillman boost or a MOSFET booster (parts on the way! ) in front of it and adding some Cathode Bypass caps to one or both stages, and that should hopefully give me shittons more gain and overdrive. WHICH IS WHAT I WANTZ!!!

[kaalaraab]

Pin 1: 3.02v
Pin 2: -0.518v
Pin 3: 0.00v
Pin 4: 0.00v
Pin 5: 11.97v
Pin 6: 8.21v
Pin 7: -1.285v
Pin 8: 0.00v
Pin 9: 5.91v

DC power in is reading 11.99v.

Gain at maximum.

Edit: My gain pot is 100K not 50K.

Hi, Astronaurt. Here are the voltages taken and shared by Rick earlier in this tread.

I think the resistance must be between 0 and 50k in any way

I've been trying with Omega from runoffgroove.com http://runoffgroove.com/omega.html In front of my valvy switching it with a second 3pdt, it sounds great.

[zambo]

@ Astronuart- This thing doesnt give all that much distortion. It does provide enough boost to overdrive the input of an amp though. So while it wont really be a distortion pedal, It will knock a valve jr or a blues jr or something of that nature into the next level of OMG distortion. If you want a distortion pedal then yeah, the tillman boost is a good one to put in front of it i hear or an sho. I just run one into the other using three of them but really, there are better design for distortion. This is nice for what it does though..my 2 cents, G 

[pazuzu]

pazuzu you can use almost any pot i think but i would stick to like 100k . I use that one all the time. no problems.

thanks, i am going to try it tomorrow than. thanks to the guy who quoted the voltages on the pinout. i will test that tomorrow as well.

[PaulBass]

Sorry about that! Actually I've found that there's no noise with the battery now but a hum with one regulated power supply and an enormous hiss with another supposedly regulated supply!! Can't believe there's so much variation out there! Sorry for messing up the thread.........

when using power supplies, whether regulated or not, I always connect a 1 or 2 ohm 3 watt resistor in series and a large electrolytic to ground (i.e. 1,000uF) to the power line. It acts like a filter

[pazuzu]

in between the power in and the fx board?

[PaulBass]

in between the power in and the fx board?

at the point after the power hits the board. the values aren't critical. the resistor just has to be at least 3 watts and can be from 1 to 5 ohms. usually a 1000uF should work but I would use a higher cap value if using higher voltages.

[pazuzu]

oh ok i see, resistor between the v+ and the board and then the cap run off the same junction to ground. could this clean up some of the back ground noise on the valvecaster in theory?

[PaulBass]

oh ok i see, resistor between the v+ and the board and then the cap run off the same junction to ground. could this clean up some of the back ground noise on the valvecaster in theory?

it works well for me. YMMV though. noise comes from a lot of sources like house wiring, electric motors, dimmers, compact fluorescent bulbs, neighbor's invisible fence, etc.

[pazuzu]

yep. my house was built in the 40's...so, yeah. the wires are solid copper with cloth insulation. 

[BarnyardBill]

Here's version 0.4 - removed unnecessary strips and optimized it again, tone now working the right way.
Should work...
Next is the MVT redrawn by me, it displays better in this layout...Credit obviously to the makers of the previous schem and layout...




BTW, sorry for my ignorance...what is a SHO?! 

Also, I know that there's ORMAN Tube Driver that's working on 9-12V, I found some good layout I'd be posting here...

Hello,

I am new here, but I have a question about your layout.

What does it mean when you say "cut track under C1"? 

And just so I am sure, all of the 'to ground' wires need to connect to each other some way or another right?

sorry for the noob questions, but this is only my 2nd build.

And as far as I can tell, all of the caps are non-directional.  If I already have these capacitors, but they are directional, which way should they be going?

I only ask b/c I went to the Radio Shack and all they had were electrolytic caps in those values.

Most of all, thanks for the layout, I can't wait to get started on it.

-Bill

[deadastronaut]

HI, WELCOME.

cut under c1 means that the copper under the c1 capacitor has to be cut..so there is a gap in the copper trace..

electrolytic capacitors have a grey side on the diagram..this is the negative side...

on the valvecaster there are no electrolytics...so your ok with straight forward caps ok...

yep all grounds to each other...

with the marsha there is one electrolytic cap..all others are normal ok...

elecrtrolytic caps come in 'uf' values meaning micro farad..

other caps uf/nf/pf...but not polarized ok..not positive and negative....

good luck.

[BarnyardBill]

HI, WELCOME.

cut under c1 means that the copper under the c1 capacitor has to be cut..so there is a gap in the copper trace..

electrolytic capacitors have a grey side on the diagram..this is the negative side...

on the valvecaster there are no electrolytics...so your ok with straight forward caps ok...

yep all grounds to each other...

with the marsha there is one electrolytic cap..all others are normal ok...

elecrtrolytic caps come in 'uf' values meaning micro farad..

other caps uf/nf/pf...but not polarized ok..not positive and negative....

good luck.

Ok, so if I am using a generic perfboard, then it shouldn't matter right. 

This is my favorite type of layout.  What software is it?  My first project had the same type of layout software.

[deadastronaut]

perfboard yep...thats ok. i thought you were using veroboard..(copper clad on one side)

the software for making these layouts is called diy layout creator..

its free to download. from bancika, there are 2 versions...version 1 is what has been used on those layouts ...great bit of software!..

http://diy-fever.com/software/