9v /12v Tube Driver Veroboard / 100% Complete + JFET Version

[finkfloyd]

Hi, Im a bit stuck on the below layout, As you can see it isnt' yet complete
I have included Jack Ormans schematic, with additional component / pot / valve numberings for reference.

I am stuck at the point of how do I read the valve pins, have I commented them correctly? If so where is pin 9 connect to?
   Also I am correct in thinking that the opamp , vcc+ goes to + power and vcc - to ground?

The valve will be mounted offboard, probably onto a socket.

Cheers you input most appreciated

EDIT : NEWER LAYOUT AT THE BOTTOM

[JimRayden]

Viewed from the bottom of the tube:

http://tdsl.duncanamps.com/show.php?des=12AX7

Also I am correct in thinking that the opamp , vcc+ goes to + power and vcc - to ground?

Quite correct.

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Jimbo

[finkfloyd]

Hi Jim,

Thanks for the help

Now the opamp part is correct, as you can see ive added the valve pinout diagram myself, and numberings to the original schemetic which didnt have any markings

I just need to know if that looks correct, and where Pin 9 goes, I suspect it goes to ground.

It has a funny way of splitting the valve into 2 parts

[JimRayden]

Just let number 9 hang there. You use both filaments in series for 12 volts, the centre tap is not needed.

Edit: Let me note that grounding pin 9 would result in the both ends of one filament being grounded and the other filament getting all 12V. And that's not too comfortable for the tube.

-----------
Jimbo

[finkfloyd]

Hi

Thanks for the help, So the pinout looks ok to you?

I will get on with finishing it, space is running low on the board but only a few components left (i know the layout is a bit of a mess & not space friendly) But it shall hopefully work

[finkfloyd]

Here is the newer 3 knob 9volt tube driver layout, 100% done although not verified, I'm still waiting for a tube socket.

Although all but one wire is confusing me(from the dpdt  to R8), look at the schematic, the vero layout should work.

Update: Slightly newer & neater layout with the diagnol jumper removed and useless cut track, fixed R9(22k to ground), was missing.

NOTES:

Neater, newer and fixed layout!

I've been through this circuit component by component with my eyes, and cannot see any mistakes, I will let you know when ive built it, Or if someone else wants a try, tell us how it sounds!

I thought I would share this as it is apparently a great sounding pedal as used by Dave Gilmour, and Eric Johnson & I've never seen a Vero or Perf Layout!

On the plus side it is also a none potentially lethal tube project.

<IMAGE REMOVED> LOOK FURTHER DOWN.

[finkfloyd]

You can see Mr BK Butlers patent for this circuit here : http://freepatentsonline.com/5022305.html

Tube overdrive pedal operable using low voltage DC battery eliminator
Document: United States Patent 5022305

Abstract: The distortion pedal for electric guitar and other electronic musical instruments employs vacuum tube circuitry operated by low voltage "battery eliminator" DC power supply. A pull-up resistor biasing circuit on the vacuum tube grid improves input and output impedance and circuit headroom while providing good control over the harmonic content and sustain.

[finkfloyd]

Ive just created this fet version , it is unverified and untested, so try it at your own risk, any comments welcome,

I have put 100K resistors for both "drain" connections, but i guess that it could be anything around that value, I couldnt fit trimpots on the layout.

Re-checked, fixed R17, This one should be OK!

<Image Removed>

[finkfloyd]

280 + views and no comment?

Anyway.... I shall verify this myself tommorow, when my parts arrive! so there 

[George Giblet]

I suppose there's been so many JFET <-> Tube subs that it's not new any more.

It's awkward trying to read the vero layout.  The lack of schematic makes it difficult to check the layout because there's your intentions aren't clear.

All I can say is it seems to have mistakes.

- the source of Q1 goes to the +ve rail
- the source of Q2 hits opamp pin 5.
- the ground rail on C1, C2 hits C3
- R5 looks shorted by the links.

Lot's of errors?   Too many cuts missing?

[finkfloyd]

Theres a schematic above that jfet one, read it and you shall see that its correct. although yeah they could be an error or 2 though


- the source of Q1 goes to the +ve rail your right, it needs a cut track just after r15.
the ground rail on C1, C2 hits C3 - it is supposed to, refer to the above schematic for cross reference
R5 looks shorted by the links. It looks OK to me.


Its  abit late here, 351 ill look tommorow, im first building the tube version

[George Giblet]

I'm still not convinced.  When I trace over it I just can't make it match the tube schematic.  I keep seeing missing cuts.

Take the link to the left R5, the one between C1 and C2.  It's shorting R5.  There should be a cut between C4 -ve and R4.

The +ve rail track which starts at R4 then hits R13, R14, and R15, which is fair enough, but then it hits Q1's source which should be ground.
Then it connects to the long ground link on column 32.  So perhaps the track between R15 and this long ground link needs to be cut. That cut will remove the +ve/gnd short and get Q1-s to ground.

[finkfloyd]

I'm still not convinced.  When I trace over it I just can't make it match the tube schematic.  I keep seeing missing cuts.

Take the link to the left R5, the one between C1 and C2.  It's shorting R5.  There should be a cut between C4 -ve and R4.

The +ve rail track which starts at R4 then hits R13, R14, and R15, which is fair enough, but then it hits Q1's source which should be ground.
Then it connects to the long ground link on column 32.  So perhaps the track between R15 and this long ground link needs to be cut. That cut will remove the +ve/gnd short and get Q1-s to ground.

The 2 links left of R5 , 1 actually isnt needed, and it isnt shorting r5, look at it again, its grounded like it should be.
But yeah it needs 1 cut track added, so source of q1 can reach ground 2 and not touch + rail.


But thanks for taking the time to look at it.

[George Giblet]

One thing I forgot to mention.  That circuit is for tubes at low plate voltages and as a result it uses weird biasing which just worn work for JFETs.  The resistor R14 is part of this, you should connect this to ground (or a small DC voltage like 1V) instead of +ve.  You can also play around with the bypassed source resistors and the drain resistors to getthe proper biasing for the JFETs.

Good luck with it.

[RLBJR65]

Nice project. Much appreciated! These layouts are a bit time consuming but get much easier the more you do.

George is right look at strip 4 and 5 (from top down) They are both grounded. You have a jumper in the 3rd hole conecting the 2 strips also there is one in the 11th hole that connects them shorting R5 and C3 also you are grounding R4 it should be Vr. If you move D1, C1 and C3 bottom leads down 1 strip you can remove those 2 jumpers (3 and 11) looks like that will fix it.

One other thing I noticed you need a jumper between pin 1 and pin 2 of the opamp. If you are using a socket you can run a jumper wire under the IC and move the trace cuts over 1 hole to the right.

Nice work keep it up!
Richard

[finkfloyd]

Hi, Just woke up , and appreciate your taking the time to help me!

Well my new tube + other stuff arrived , but no tube sockets yet, which means I cannot build till monday, presuming they arrive on monday.

I have fixed the tube version now I think.

I've added a cut track 7 down left 6 across to prevent it touching pin 2 of the opamp
I've also extended legs of D1, C1 and C2 to go to ground directly and removed the 2 jumpers,
I have now adjusted the opamp part, and moved the jumpers so you can see where they are going easier.

Please have a look to see if you see anything else.

Here's the updated layout




Would you agree this is now correct?

[finkfloyd]

And now heres the FET Version with corrections, the main trouble once this is built will be biasing the FETs, without trimpots, this circuit is entirly experimental.

[spudulike]

Thats an awful lot of vero ?

[finkfloyd]

Thats an awful lot of vero ?

Hi, Not really, it s about the same size as the phase 45 I think, I havent got a 1590BB at hand, but it would most likely fit both ways
It is a first major vero project for me, but considering the amount of wiring for the Tube etc.. it isnt that big, and especially when its sat in my hand.

But feel free on making it smaller, If you think you can Ive never seen any tube circuit layouts on vero personally in my time of being addicted to this hobby.

Anyway I need to wait for a socket, hopefully when i wake up the post has been, Then Ill report back with the news on whether it works or not, and hopefully with a soundclip.

[RLBJR65]

The vero I have has about 10 holes / strips per inch so your looking at about 1 1/2" by 3 1/2". I would have to take a much closer look at your layout. You could probably shrink it down a bit there would be a lot more trace cuts though.

Not sure of the fet version, I think you will need to use trimmers on the drain.
Look at some of the amp sims at ROG, http://runoffgroove.com/eighteen.html,  http://runoffgroove.com/englishchannel.html, http://runoffgroove.com/fetzervalve.html, http://runoffgroove.com/flipster.html or here is one of Marty's I did a layout for http://aronnelson.com/gallery/Richard-Boop-RLBJR65/London2Step, and a sim of Doug Hammonds  FireFly http://aronnelson.com/gallery/Richard-Boop-RLBJR65/FireFly_Pedal
Fets are not just drop in replacements they require different biasing than tubes. Trim pots make it much easier to adjust but they take up a lot of space on vero.