Tube boost + overdrive running off a 9 volt battery

[Pigyboy]

Hard to tell much from the pics. If it was me I would take it apart and start over being very careful to check the layout. I can see you may have some issues with solder joints and trying to wire it all up with the socket pins gives lots of chance for error.

[zambo]

and put c1 back in. It stops the dc voltage from reaching your instrument. This happens more with low voltage tube projects for some reason. Scratchy volume pot is one of the symptoms of it.

[Freekmagnet]

and put c1 back in. It stops the dc voltage from reaching your instrument. This happens more with low voltage tube projects for some reason. Scratchy volume pot is one of the symptoms of it.

I'll check it out for sure. Thanks for the suggestions. I guess I'm going to have to just pull all the wires out and do it again. 

[bassmannate]

I tried building one of these about a year ago and it sounded great with a battery but when I used a regulated power supply, it was just too noisy. Not sure if it was my soldering causing the noise or not. I was wondering if anyone had any thoughts on getting a pcb mounted socket and putting it all together on a piece of perfboard instead of soldering multiple components into the same hole? I loved the sound I got with a battery but was discouraged when I couldn't track down the source of my buzz.

[zambo]

sounds like it was a bad power supply experience. I use a 1spot power supply with great results and no hum. dane elctro 200ma power supplys work as well. I think even boss supplys work but i dont use them so i dont know from personal experience. If you look back in this thread Renegadrian has posted a vero board layout several times and it seems to work quite well. I bet its on the schematics and layouts page to. A cap from positive to negative on the dc input and a 7812 from ratshack helps things out as well. Hope this helps and keep building!G

[bassmannate]

sounds like it was a bad power supply experience. I use a 1spot power supply with great results and no hum. dane elctro 200ma power supplys work as well. I think even boss supplys work but i dont use them so i dont know from personal experience. If you look back in this thread Renegadrian has posted a vero board layout several times and it seems to work quite well. I bet its on the schematics and layouts page to. A cap from positive to negative on the dc input and a 7812 from ratshack helps things out as well. Hope this helps and keep building!G

Yeah, It's a 12v 1spot supply. It's more of a hiss than a buzz. I've tried a cap across the dc input and it reduces it some but it's still there. I'll have to try the 7812 as it sounds like an easier mod than I previously thought. Nice to know I can get it locally instead of ordering from yet another supplier (have to order the socket from a tube supplier)

I saw the vero board layout when I was rummaging through the forum. I forgot that was there! I have an extra piece of perfboard laying around so That's what I'll probably use this time around.

[lofty]

Hey guys, i was looking at the pics from Freekmagnat. Please correct me if i'm wrong.Isn't a Elco with 1000UF not a bit much? Doesn't it cut of the signal?
I am new at this stuff and just build one of these. It works ands sounds ok, just getting a little hiss.

[kaalaraab]

Finally, it worked! It really boosts up with a lot of gain, but some issues, a was thinking to skip it and start with the no-tone version, but I'm here primarily to learn, so I'll try to fix them.

Issues:

- A pretty loud hum.
- The led doesn't light up.
- The sound is a little bassy.
- The sound is less overdrived than I wish,
- The tube lights up much more than expected, I'm afraid I have voltage issues.




Ideas:

- For the hum, integrate the Renegadrian idea with the 7812 regulator, and check out the ground bus.



-For led, just check out the wiring and the led itself.

- For the basst sound, change the capacitors value, I know That the no-tone version deals with this problem, but I want to make this version sound good.

- For the overdrive, I'll will experiment with other tubes: 12au7 and 12at7 of several brands. I'm using a new EH 12au7

- For the tube light, I'm going to post voltages, hopping somebody check them out, maybe the 7812 will fix it.

Thanks to you all, specially Rick and Renegadrian which contributions were must helpful to me.

[Harold]

I've also buit the ValveCaster and experimented with it for a while but I'm stuck now... 

I didn't like the saturated gain it gave me so I changed R2 to 100K, lowered C1 to 22nF, added the SWTC2 tone control and stuck a Tillmann FET Preamp in front of it. Nice! But this could be better!

Yesterday, I made a voltage booster to get voltages up to 80 volts from my 12 volt input (Cioks Double Jack). This gave an enormous volume boost to the Chinese 12AU7 but also increased the dense, saturated gain it already had at 12v. I then tried a 12AX7: insane amount of volume and gain, up to a fat distorted fuzz. Not really what I was hoping for


How do I decrease that saturated gain? Should I try to get a better 12AU7? Or maybe try a 12AT7?

[Renegadrian]

- For the hum, integrate the Renegadrian idea with the 7812 regulator, and check out the ground bus.

It seems to help a lot, easy fix should be...

- For the bass sound, change the capacitors value, I know That the no-tone version deals with this problem, but I want to make this version sound good.

I myself find the Valvy a little on the bass side - tweak the input cap and it should be less bassy.

- For the overdrive, I'll will experiment with other tubes: 12au7 and 12at7 of several brands. I'm using a new EH 12au7

The first one I made has the same tube of yours, yes not a distortion for sure but a good overdrive.

- For the tube light, I'm going to post voltages, hopping somebody check them out, maybe the 7812 will fix it.

Simply check pins 4 and 5, they should read +-12V

Thanks to you all, specially Rick and Renegadrian which contributions were must helpful to me.

Glad if I can help you somehow!!!

[Renegadrian]

@Harold: are you after a cleaner boost!? It shouldn't be that difficult to get with some fiddling I believe...

[Harold]

@Harold: are you after a cleaner boost!? It shouldn't be that difficult to get with some fiddling I believe...

I'm looking for a mild overdrive that's not overrsaturated and not overcompressed. I'd like to use it to push my old JCM800/JMP MV amps into high(er) gain terrritory for which I now use a Taiwanese black Ross Distortion (MXR Dist+ clone with Silicium diodes), but I'd like to explore the possibility of an all-tube signal clipping path.  

Current mods:
* Tillman Preamp to boost input signal and clarity
* C1: 22nF
* R2: 100k
* EDIT: SWTC2 tone control

I'm going to breadboard the ValveCaster and fiddle with the caps and resistors some more. I already got the advice to lower C2 to 2-22nF and maybe add a cathode resistor(/pot) between pin 8 and ground to finetune the gain a bit more, next to lowering C1 to 1nF...

[kaalaraab]

Glad you got the problems resolved!   
Did you place the 100uF across the +/- of the power leads?

put a 100uF cap across the DC jack (positive leg to positive rail, neg. leg to neg. rail), then, instead of connecting the positive rail directly to the circuit, connect it to the regulator's pin1, ground to pin2, and the circuit to pin3. Then screw it on the enclosure. It is a 7812.

The caps legs are soldered directly to the dc jack lugs...

Quick question, if I ground pin2, then screw it on the enclosure, due that the terminal 4 of 7812 is conected to pin 2, it wouldn't create a ground loop?

[zambo]

@ Harold..if you are after a cleaner boost the adition of a 1meg pot between stages is good. It creates a pre and post type circuite. So after c2 put a 1 meg pot. do away with r4 as the 1m pot is your reference to ground for pin 7 now. You should be able to limit the amount of signal going into stage 2 now. put another 50 k pot from pin 8 to ground just like the gain pot of pin 3. Assuming this is all on a bread board. Tweak to taste then start measuring things like the resistance of the gain pots. You can replace them with fixed resistors if desired. Let stand 5 minutes and serve warm with beer..Good luck, hope that helps. G

[kaalaraab]

Done!!   I'm so happy that finally, after 3 months of trying with tree or four proyects, and a little painful curve or learning   I manage to assamble one DIY, and not any DIY, this rocks. I'm still wating for some tubes to arrive for try them all, and tomorrow in the studio I'm going to try my valve with diferent amps, guitars and bass, and configurations with other pedals. I'll try to record samples for you all, Thanks for the help, this tread has been enlighting.



The led lit up when I realize my confusion, I was using a 470k res   instead of a 4.7k, at the end, I'm using a 1k resistor.

I change the 47nF in cap for a 22nF, bassy sound fixed.  



This fixed the hum problem, well, here in Mexico City the electical current is very fluctating, but at least, my valvecaster doesn't make a hum any louder than my Cooltron Big Ben.



Here it is, my first son  

Thank you all, spetially Rick and Rnegadrian, and everybody working on this proyect.

Next: Twincaster!!

[kaalaraab]

Here's mine, running at 12 volts:

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

These are my readings:

Pin 1: 3.21v
Pin 2: -0.35v
Pin 3: 0.00v
Pin 4: 0.00v
Pin 5: 12.05v
Pin 6: 1.84v ??
Pin 7: -0.08v ??
Pin 8: 0.00v
Pin 9: 5.95v

Is there a problem on pins 6 and 7, or those are normal readings?

[zambo]

seems like pin 6 should be getting more voltage than that. I know a lot of people have posted voltages throughout the forum thread. You might look back a few pages on here to find out. I dont have a digital voltage meter so i cant measure to help you. Pin 6 seems low to me though.

[kaalaraab]

seems like pin 6 should be getting more voltage than that. I know a lot of people have posted voltages throughout the forum thread. You might look back a few pages on here to find out. I dont have a digital voltage meter so i cant measure to help you. Pin 6 seems low to me though.

Yes, I think that too, what could be the problem? Could C3 or R3 (100k) being sucking the voltage?

[Harold]

Assuming this is all on a bread board.

...

Let stand 5 minutes and serve warm with beer..Good luck, hope that helps. G

Hi G,

I've just received a package containing all components to create another ValveCaster, this time on my breadboard. I got a lot of tips to unsaturate the valvecaster and I'm hoping I can try the first ones out this weekend...


This is the voltage booster I've used for feeding the plates:

[kaalaraab]

seems like pin 6 should be getting more voltage than that. I know a lot of people have posted voltages throughout the forum thread. You might look back a few pages on here to find out. I don't have a digital voltage meter so i cant measure to help you. Pin 6 seems low to me though.

OK, pin 6 still reads 2.00V. Here's where my theoretical knowledge is pretty lame. What happens if I change the value of R3 (100K)? Will that generate a problem with C3 or tone pot? And finally, do I need increase or decrease the value of R3 to give more voltage to pin 6?