Need help with "Matsumin's Valve Caster"

[S-tomas]

Hello I'm having trouble with this pedal. I don't know exactly where  is the problem.
When I turn it on the LED is lighting, but it don't make any sound from my amp.
I think problem is at the wiring, because all parts I used are new.

Here are the pics:

http://www.mediafire.com/?cloh52x51uy3g1e

Original site:
http://www.matsumin.net/diy/jisaku2/Valve_Caster/index2.html

any ideas?

[maarten]

From what I can see you are using a 9 volt battery as a power supply, right? Probably this has not enough power to provide the 150 mA you need for heating the filaments (you can check whether the battery still gives you the full 9 volts - which I doubt, if you have had it turned on for some time). Add some 20 mA for the LED and some mA for the anode; you will need a wallwart or a transformer that will give you 9 (to 12) volts after rectification (so: DC), capable of delivering 200 mA ore more. Make sure that the tube is warming up after you turn it on - maybe it will also start to glow a bit (don't know whether 9 volts is enough for that, never tried it); it probably will take a while before you will get sound each time you turn this thing on...

Maarten

[S-tomas]

OK, I used wallwart with 21V and 400mA and when I turn on that machine It start to buzzing, and tube doesn't do anything I only changed the power supply so I don't know what next

[Brossman]

hmm... it's a 9V circuit, but it might be able to run at that voltage. The tube can DEFinitely take 21V, sure.  But i dunno about the rest of the components.  If your caps were 16V, they may have blown due to your 21V P/S...Especially with 400 mA of current.  The 12a_7's like to draw 150 mA at 12.7V, and 300mA at 6.3V...

In the future, why not try a wallwart into a voltage regulator on the board?  Say, LM317 for the heaters? (use a trimpot to adjust for proper heater voltage).  Or maybe a charge pump (1044's seem to be popular) to increase the plate voltage to try for some more headroom?

In any case, check your caps. I'd add a power switch on the side, then use a footswitch to make it "standby" (bypass) or "on"

[linny1982]

there's a full thread about this pedal here http://www.diystompboxes.com/smfforum/index.php?topic=63479.0 there's a pdf somewhere to

[Mike Burgundy]

Don't hook up 21V to a 12.6V filament! No idea what the results would be but I'm thinking disastrous is definitely possible.
I'm hoping it was a typo for 12V? That'll work just fine on a 12.6V filament. We're not after hifi here.
There's bound to be something off anyway. Time to check everything one by one (power supply output ok unloaded? Fine. Now load it (hook up te filament - keep in mind what correct voltages are!) and see how it holds up. Does the filament glow? Yes? Cool. Disconnect the power, hook up the first triode stage, fire it up and see if you have amplification. Etc. Use new caps just to be sure.
It's small enough to just rebuild it step by step just to debug it.

[pigy00]

hi a also have a problem with matsumin valvecaster...i have hugely hummin in background and i dont know how to fix that ..i am using 10v 500mA AC adapter and converting circuit to DC about 9v with similar schematic like this one but with biggesr values of capacitator http://www.communica.co.za/Content/Catalog/Images/I1396186380.jpg ...also have 63v polyester and ceramic capacitators,resistors are 1/4W in valvecaster and tube is Russian 6N2P...can some body help me to fix that

[GibsonGM]

General info:  If you're running the heaters on AC or on poorly filtered DC, out in the open, you WILL have a nasty 60Hz buzz.  WILL.   I'm messing with a circuit right now, and I can tell you it's AWFUL until you start playing.  Then you can't hear it.   You take care of that later, when you box it up, by dressing the heater wires correctly.    You'll also get nasty noise if you're near a computer monitor or other source of interference.   The only way to avoid that is use good DC, or build your project into the enclosure as you go.

Now, that's assuming you have it wired correctly.   If not, you may have a ground missing somewhere, and that makes terrible noise!

Pigy, welcome to the forum, but I'm sad to say - what are you using to power your heaters?  Umm, "6"N2P heaters should be run on 6 volts only - the first number is the heater voltage.  12AX7s (one of the best tubes for this stuff) are good in that they will operate on 12V OR 6V if wired correctly for it.
https://en.wikipedia.org/wiki/6N2P

Now you need to figure out if your heaters are OK (continuity test), and how to get them to about 6.3V.   THEN you worry about the rest of the circuit.    10V isn't enough to run a voltage regulator, you need a couple of volts over that...so, about 12V wall wart will give you 9V regulated, etc. 

Do you have other transformers you can use?  You could make the 10V your 6V heater supply with a regulator, and get another to power the actual circuit.  I'd try for 12V or over, although 9V will do the job if you can get "clean power".  And if you can get a 12AX7, that would probably be easiest.

FIRST RULE of building with tubes - do NOT get frustrated. This is how you learn, and you'll do fine if you stick with it, don't give up, and just make some changes!     

[pigy00]

tnx you for helpful advices.and for sharing your knowledge with me...i dont have much expirienc in this stuff i build just one fuzz pedal and footswitch for now but i want to learn how to make al of that cool things that sound great,i found tube at my home and start to built valve caster  with this schematic http://www.beavisaudio.com/projects/ValveCaster/MatsuminValveCasterWiring.gif ...you were right when you say that noise is loosing when you play,same thing is happening to me...

is it gona help if regulate voltage with LM317 circuite i found it on this link (page 9)  http://miaudio.com/wordpress/wp-content/uploads/2013/11/12AU7-6111_Valve_Caster_Summary_Rev002.pdf

and one more question if i add that circuit whit LM317 how to connect it on tube? i gues Heater is pin 5, but where is going Vin on tube
   

   

[GibsonGM]

Hi Pigy,  You are more than welcome.   This is how we learn!

Are you still using the 6N2P tube?  If so, then you can use the LM317 to get a 6 volt supply to run the heater on.  You will have to set the 317 up to give 6V.

The heaters are pins 4 AND 5.  If you look on the .pdf you posted, same on the 317 circuit is on, you will see a nice circuit layout showing this.   Pin 4 is grounded, pin 5 goes to V+. 

I am not sure if the noise you have is due to interference or if you have 'dirty' DC powering it now....you are not running the heaters on AC?
Often, you will have noise if the circuit is not in a grounded enclosure.    More often, there is a bad or missing ground connection, though!!
See if moving and wires affects the noise....   

[pigy00]

one more time tnx you for answering on my post...

yes i still run 6N2P tube and i do not run heaters on AC i build DC circuit with 4x1n4002 diods 1000uf 10uf 1uf and 100nf capacitators and IC7809 like on the schematic in my first post,i tryed to replace 1000uf with 2200uf and...again nothing

i will look around the house to find some transformer and put it insted of adapter, buy parts that i need to build new  curcuit for 6.3v...all that till the end of the week and than see the results

[GibsonGM]

Pigy, if you could draw a schematic or other diagram showing what you are doing, that would be helpful.  I'd like to help you get the heaters set up right.   Even something hand-drawn is ok.   You might have buzzing because some other equipment is causing interference, or maybe there is a ground connection that is missing or not done well.

Also, guitar cords can often be 'bad', and cause buzzing!  Or, you accidentally use a speaker cable instead of guitar cord.  Usually it is something simple.    If you are running heaters on DC, and through a regulator, that's probably not it - the regulator will make clean power.   Putting the circuit in an enclosure will probably help very much, too!!   Can you post a sound clip of the buzz?   

You do still need to get 6.3V on the heater - you can use an LM317, or a LM7805 with a couple of diodes on the ground leg to lift it.

[Jdansti]

Is it in an enclosure yet?  If not, you could be picking up stray RF from the electrical system/devices in your home. I remember that mine hummed until it was shielded.

[GibsonGM]

Trying to see just how much 'buzz' he's getting....yah, it won't play nicely til it's enclosed.   A quick clip of the sound would help, but 1 thing at a time, we have to sort out his heater voltage first!  Or he won't have a tube to play with

[Jdansti]

Agreed!

[GibsonGM]

It's just getting over the first hurdles that are difficult - after you 'get it', how to set up your heaters and what a tube stage should look like, the rest comes pretty easily.  So hang in there, Pigy!