A quick tube (valve) fuzz box

[JohnH]

Sorry to revive an old thread, but did you ever end up building your modded version Doc? Curious to see how it went if you did. I wouldn't mind having a crack at building this pedal myself

[DrNomis_44]

Sorry to revive an old thread, but did you ever end up building your modded version Doc? Curious to see how it went if you did. I wouldn't mind having a crack at building this pedal myself

Not yet since I've had a few things on my plate lately, but I'll start working on it next month, actually, thanks for reminding me about it.....cheers.


I managed to find a couple of spare 9-pin valve sockets complete with metal shields, one is made from Ceramic, the other one is made from Teflon, I'm going to use the Teflon one to make a 4-Knob Tube Driver pedal, the other one will be used to make a Purgatory pedal, might even do a build thread so that you can see how I went about building it.


Might need to order some spare 12AX7/ECC83 valves from Evatco soon, since I'm running out of good ones, most of the spare 12AX7/ECC83 valves I have are a bit weak in gain.

Here's the link to the Evatco website again, if you're interested in ordering stuff online from them, click on the Products List menu to see what they have in stock:

http://www.evatco.com.au/

[JohnH]

Thanks for the link! Will order some bits and pieces today and have a crack at it. If you get the time, a build thread would be great (especially for noobs like me)

[DrNomis_44]

Thanks for the link! Will order some bits and pieces today and have a crack at it. If you get the time, a build thread would be great (especially for noobs like me)

No worries at all mate, hope the link proves to be of some use to you, I may even order some more 9-pin valve sockets when I get round to ordering some new 12AX7/ECC83 valves, I'm going to be ordering some new valves for my 5 Watt Legacy amp later on this year together with a new Jensen C10Q speaker to put in my old Peavey Backstage Plus amp so I can get it back up and running, building a Purgatory pedal may be a good project to work on over the Christmas holiday season come to think of it.

I've got quite a few good projects on my "to do" list, one project that I'm pretty keen on is the restoration project on my Fender Super Twin amp, I reckon that the Fender Super Twin amp is going to be a killer piece of gear for live gigging, I've had a yarn to a local Darwin repair tech about the restoration project, he seems pretty keen to help me out with it, I also have a speaker cab build project planned for it as well.

[JohnH]

The Fender Amp sounds like a great project - you should definitely document it here on the forum.

I started getting the bits and pieces for the Purgatory Pedal today, so will have a bit of a play this weekend if I get any spare time.

Out of curiosity, what does the inverter do in this circuit? I've been reading up on them, but to be honest it completely confuses me, and I just ended up reading a lot about oscillator circuits (which was fun, but distracting)

[DrNomis_44]

The Fender Amp sounds like a great project - you should definitely document it here on the forum.

I started getting the bits and pieces for the Purgatory Pedal today, so will have a bit of a play this weekend if I get any spare time.

Out of curiosity, what does the inverter do in this circuit? I've been reading up on them, but to be honest it completely confuses me, and I just ended up reading a lot about oscillator circuits (which was fun, but distracting)

Basically, all the inverter circuit does is it takes the lower supply voltage from the plugpack adaptor and converts, or steps it up, to a higher DC voltage that the valve can use to run properly, even though a 12AX7 valve can work with voltages as low as 12V DC on it's anodes, it tends to work a lot better if the anode voltages are more in the range of 50V to say 100V, the 12AX7 valve was actually designed to operate with anode voltages up to a maximum of 300V DC, that's where it is able to produce the most voltage-gain, by gain, I mean amplification, if you run a 12AX7 at lower anode voltages, the 12AX7 tends to distort in a characteristic way earlier, of course we could replace the inverter with a 240V AC mains transformer that can supply up to 300V DC, but they tend to be a bit expensive and dangerous, using a plugpack adaptor with the inverter circuit works out to be cheaper and safer too.

[JohnH]

Basically, all the inverter circuit does is it takes the lower supply voltage from the plugpack adaptor and converts, or steps it up, to a higher DC voltage that the valve can use to run properly, even though a 12AX7 valve can work with voltages as low as 12V DC on it's anodes, it tends to work a lot better if the anode voltages are more in the range of 50V to say 100V, the 12AX7 valve was actually designed to operate with anode voltages up to a maximum of 300V DC, that's where it is able to produce the most voltage-gain, by gain, I mean amplification, if you run a 12AX7 at lower anode voltages, the 12AX7 tends to distort in a characteristic way earlier, of course we could replace the inverter with a 240V AC mains transformer that can supply up to 300V DC, but they tend to be a bit expensive and dangerous, using a plugpack adaptor with the inverter circuit works out to be cheaper and safer too.

Ah, ok, that makes sense.

[JohnH]

Got some tubes in the mail today, so am finally fully prepped to give this a go. As a heads up, I may have to ask a million dumb questions. Apologies in advance...

[JohnH]

Finally got to solder this all together today. So far... it’s not working. However, I’m reasonably confidant it’s just a bad solder join somewhere, so will attack it with fresh eyes tomorrow.

It’s been a lot of fun working on this. I’m still very new to reading schematics, and I’ve been enjoying trying to understand what’s actually happening.

[DrNomis_44]

Got some tubes in the mail today, so am finally fully prepped to give this a go. As a heads up, I may have to ask a million dumb questions. Apologies in advance...

Ah that's okay, there's no such thing as a dumb question, they are all valid in my book if the answers help.