Tube boost + overdrive running off a 9 volt battery

[Mfouch]

yah i've been trying to run at 12volts but haven't had any luck I think i need new 12 volt wall wart any idea of the MA it should run at ?

[zambo]

with no voltage multiplier i have run one on a 200 ma. I think its a cheap dan electro one. What is the prob with the one you have? Noisey or motorboating stuff?

[Mfouch]

just plugged it in and theres just a high pitch squeal have a 12 volt dc

[zambo]

what schematic did you use and what tube are you using?

[Mfouch]

The matsumi valvecaster with 12au7 its the one from the start of this thread.

[zambo]

got any boss 9 volt tip neg adaptors around?

[Mfouch]

Nope but ill get one thanks again

[Dongle]

Sorry - done...

[MikeH]

Hi guys!
Why is C3 an electrolytic cap? Can you also use ceramics or films for this?
Thanks!
Dongle

C3 is electrolytic because 1uF caps most often come in that sort of package.  But you could use any 1uF cap you have.  Actually doesn't even need to be 1uF, you could try all kinds of values in there to get different sounds.  I'd say anything 0.001uF to 10uF.

[Dongle]

Thanks! I just found that out... Thats why I changed the post. Sorry, that I did not manage before I posted...

Best regards!

[lofty]

This is a great project, i just finished this and worked on the second try ( switched two wires which turned it into a radio when i touched ground  ).
It is my first project and i'm very happy with it.
The sound still is a bit grainy for my taste. I run it on 12V with a National 12au7a German made tube. The only mod i did was to put a 22nF cap on c1 to make it humbucker "friendly" and used a dptd footswitch for true by-pass.
Are there any other builders who use this little monster on humbuckers?

[zambo]

yep!  tons of us! Glad you had success on your first build! Congratulations

[Dongle]

Finally I exchanged C1 and 2 with 3nF - now I also like the sound! Not so undefined bass anymore...
But still I will try to raise the voltage... Just orderd two LR8s.. I am going to try implementing a potentiometer to control anode voltage on the fly. So I can easily hear, if it makes a different or not.
I will see...

[Freekmagnet]

Hi

I'm trying to put a little valvecaster together, but to no avail. I'm getting really weird voltages and I can't seem to figure it out. Maybe some one could point me in the right direction. Here are my voltages @12.6v:

pin 1: .5v
pin 2: 12.6v
pin 3: 6.5v
pin 4: 12.6v
pin 5: 0
pin 6: 1v
pin 7: 12.6v
pin 8: 12.6v

It seems like my power is coming in through the ground, but I can't seem to figure out why. Am I correct in my assessment? Any suggestions?

Thanks!

[Freekmagnet]

OK. I realized that I was measuring my voltages backwards - whoops!

The 12au7 lights up, but I get nada. No sound, just hiss. Here's my updated pin voltages:

pin 1: 2.8v
pin 2: 0v
pin 3: .8v
pin 4: .8v
pin 5: 12.6v
pin 6: 6.5v
pin 7: .2v
pin 8: .8v
pin 9: 7.6v

Help!

[frequencycentral]

Here's mine from a working unit with gain at maximum. Yours are not that far off the mark. Cheack all connection, resistor values and off board wiring (!). As yours are close to good I'd suspect the off board wiring.

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

[MikeH]

OK. I realized that I was measuring my voltages backwards - whoops!

The 12au7 lights up, but I get nada. No sound, just hiss. Here's my updated pin voltages:

pin 1: 2.8v
pin 2: 0v
pin 3: .8v
pin 4: .8v
pin 5: 12.6v
pin 6: 6.5v
pin 7: .2v
pin 8: .8v
pin 9: 7.6v

Help!

If the polarity of your wallwart is backwards the heaters will still light up, but you will get no amplification, fyi.  Not the likeliest problem, but something to check none the less.

[Freekmagnet]

OK. I realized that I was measuring my voltages backwards - whoops!

The 12au7 lights up, but I get nada. No sound, just hiss. Here's my updated pin voltages:

pin 1: 2.8v
pin 2: 0v
pin 3: .8v
pin 4: .8v
pin 5: 12.6v
pin 6: 6.5v
pin 7: .2v
pin 8: .8v
pin 9: 7.6v

Help!

If the polarity of your wallwart is backwards the heaters will still light up, but you will get no amplification, fyi.  Not the likeliest problem, but something to check none the less.

Thanks. I tried flipping the power input leads, but still no go. I tested the polarity of the power and it seems to be correct. I have another wall wart, but that one doesn't seem to be any different. I built a little voltage regulator, so I might try putting a pair of 9 volt batteries together and see what happens.

[Pigyboy]

Tried different tubes yet? I don't think you should be getting any voltage on pin 4. I have built lots of these and they usually fire right up. What do you have it built on? Post some detailed pictures and let us have look. I have also wired it up with using either pin 4 or 5 being the hot and it works both ways. Check the tube and be sure it is good.
Chris

[Freekmagnet]

Unfortunately, I don't have any other tubes laying around. I live out in the middle of nowhere, so I'd have to order any extras. The tube is a new EHX 12au7.

I can post some photos. Here's a link to the layout I used for the rectifier:

http://www.tube-town.net/diy/lov/lov03-bananabooster-eng.html

Just ignore the top layout. I made my own on perf based on the schem posted on Beavis Audio. Here's my layout and photos. I omitted C1 deliberately - I play bass. Maybe that's why it doesn't work! Anyway, excuse the mess - I'm in trouble shooting mode.

Thanks.