Tube boost + overdrive running off a 9 volt battery

[sundgist]

I assumed the same when I used 100k for gain.
Turns out that max gain is when the pot is at least resistance. Mine seemed to be clean for half the pots travel.
Instead of changing the pot I've put a 82k resistor in parallel with it, making 47k. This gives me clean with a fair bit of headroom and also gives a bit of antilog taper which spreads the gain out a bit.
There's quite a range of gain in the last bit of the pots travel. If I need more clean headroom I can always switch a 47k resistor in series.

[jaki54321]

If you want, you can increase the gain of the pedal by adding a higher value potentiometer. Change it from B50K to idk, maybe even A1M! 1M audio.

That won't increase the gain. Rather it will make for a cleaner boost. 1M is far too high though. 100k would be fine. But neither will increase the gain. Though a cathode bypass cap might.

Really? I always heard it will up the gain... hmm... maybe ill give the 100K pot a try. is it worth it?

http://www.diystompboxes.com/pedals/tubedummy.html

"The cathode resistor along with the Plate resistor control the gain of the tube stage. Typical values are anywhere from 100 ohms to 10K. Smaller values = more gain."

A 100k gain pot will allow for cleaner boost, well worth it.

So... Small Value puts more gain? I like the way my valvecaster sounds right now but Im not afraid to experiment... I also thought if you lowered the input cap(C1) it will reduce bass, one person put it down to .022uF and said he loved it. Any suggestions on tonal improvements? lol

[ultran8]

all hail vavlecaster. so i used xicon caps in mine that r 630v . im runnin a 12ax7 in it and luve it . renagadrian mentioned he tried it but to bassy . with a 12au7 ,it was nothin but clean . soooo would the 630v caps have a say on drive and gain?

[sundgist]

soooo would the 630v caps have a say on drive and gain?

I had a 12ax7 in mine sounding good with the stock values. Went for slightly lower gain 12at7 in the end (sounded better to my ears at full gain).
I doubt the voltage rating of the caps would have any influence.
I lowered the input cap to 10nF and the one between the triodes to 22nF to take some bass away. Depends on taste, amp, valve(maybe?).

[Kazha]

Hi everyone
i'm total noob and this was my first attempt to build stompbox in sum i failed  . I'm getting no sound just buzz was hoping for some hints were did i get wrong.
Used this schematics without switch

With 9v 1A  adaptor
only difference is that the tube is soviet 6N1P(perhaps that's the problem?) checked connections several times everything seems ok
Voltages for pins are as follows
1: 3,2
2: 1,2
3: 0
4: 0,1
5: 8,8
6: 6,2
7: 6,2
8, 0
if necessary i can post some pics
sorry for bad english
P.S. will try to make another one with tube 6N2P(12AX7 equivalent)

[jaki54321]

Hi everyone
i'm total noob and this was my first attempt to build stompbox in sum i failed   . I'm getting no sound just buzz was hoping for some hints were did i get wrong.
Used this schematics without switch

With 9v 1A  adaptor
only difference is that the tube is soviet 6N1P(perhaps that's the problem?) checked connections several times everything seems ok
Voltages for pins are as follows
1: 3,2
2: 1,2
3: 0
4: 0,1
5: 8,8
6: 6,2
7: 6,2
8, 0
if necessary i can post some pics
sorry for bad english
P.S. will try to make another one with tube 6N2P(12AX7 equivalent)

Whoa man... Ok i looked up some data on a 6N1P tube and um it says it runs on 6.3 volts! idk if this data is correct but it is, i think your putting too much voltage in the tube. I am no professional, but I think thats y it may not be working.

Try a 12AU7, 12AT7, or 12AX7, jus about any tube that can run on atleast 9 volts will be ok, take a look at these data sheets, jus open them up an look at the voltage requirements/limits.

http://www.drtube.com/tubedata.htm

Every tube will sound different, not jus by type, but by company as well, try Eurotubes.com

[Kazha]

can't buy them enywhere localy so went for soviet tubes
will have to order some 12AU7 todey from ebay then
thanks jaki just have to wait now

[jaki54321]

can't buy them enywhere localy so went for soviet tubes
will have to order some 12AU7 todey from ebay then
thanks jaki just have to wait now

ok. also did you build this layout without the switch?

[Kazha]

can't buy them enywhere localy so went for soviet tubes
will have to order some 12AU7 todey from ebay then
thanks jaki just have to wait now

ok. also did you build this layout without the switch?

Yes without (don't have it jet) did that just to test if everything is ok
cos i had some concerns about the tubes and they came true
don't know what to do with them now though  , but they came very cheap and theres probably some project out there,
where i could put them in, in future.

in few days 12AU7 will be in my hands and ill wrap it up

[spud]

One thing to keep in mind about the 6n1p and similar types is that heater wiring is different - different pin out and different voltages.  It is a true 6v (6.3v really) tube not a 12v tube like the 12--7s that can be run at 6v (parallel).  Pin 9 on the 6n1p isn't even used - it goes to a shield that is between the 2 triode sections.  So if you want to use them, you may need to rewire the heaters and probably drop the voltage down to the 6.3v or so - at least under 7v.  I don't have the spec sheets in front of me so I'm writing this from memory.  I'll look at the schematic you posted. 

Ok - Just looked at the schematic, apparently you aren't using pin 9 at all so that's cool.  You are running 5 at +8.8 v so that is too high.  You might try re-wiring it so that R3 hangs off pin 5 with 9v coming in and just jumper pin 5 to 6 - that way both will get 6.2v.  Pin 4 is ground so that's ok. 

Should work - hope this is of some help -

Jim

[jaki54321]

can't buy them enywhere localy so went for soviet tubes
will have to order some 12AU7 todey from ebay then
thanks jaki just have to wait now

ok. also did you build this layout without the switch?

Yes without (don't have it jet) did that just to test if everything is ok
cos i had some concerns about the tubes and they came true
don't know what to do with them now though  , but they came very cheap and theres probably some project out there,
where i could put them in, in future.

in few days 12AU7 will be in my hands and ill wrap it up

Thats good. Spud is probably right. Im not a pro but you can give his idea a try. it may jus work...

[Kazha]

One thing to keep in mind about the 6n1p and similar types is that heater wiring is different - different pin out and different voltages.  It is a true 6v (6.3v really) tube not a 12v tube like the 12--7s that can be run at 6v (parallel).  Pin 9 on the 6n1p isn't even used - it goes to a shield that is between the 2 triode sections.  So if you want to use them, you may need to rewire the heaters and probably drop the voltage down to the 6.3v or so - at least under 7v.  I don't have the spec sheets in front of me so I'm writing this from memory.  I'll look at the schematic you posted. 

Ok - Just looked at the schematic, apparently you aren't using pin 9 at all so that's cool.  You are running 5 at +8.8 v so that is too high.  You might try re-wiring it so that R3 hangs off pin 5 with 9v coming in and just jumper pin 5 to 6 - that way both will get 6.2v.  Pin 4 is ground so that's ok. 

Should work - hope this is of some help -

Jim

Thanks for an idea but nothing happens tube isn't even lightening up or getting hotter  voltage goes down to 0 at the moment when it is connected to pin 5

[jaki54321]

One thing to keep in mind about the 6n1p and similar types is that heater wiring is different - different pin out and different voltages.  It is a true 6v (6.3v really) tube not a 12v tube like the 12--7s that can be run at 6v (parallel).  Pin 9 on the 6n1p isn't even used - it goes to a shield that is between the 2 triode sections.  So if you want to use them, you may need to rewire the heaters and probably drop the voltage down to the 6.3v or so - at least under 7v.  I don't have the spec sheets in front of me so I'm writing this from memory.  I'll look at the schematic you posted.  

Ok - Just looked at the schematic, apparently you aren't using pin 9 at all so that's cool.  You are running 5 at +8.8 v so that is too high.  You might try re-wiring it so that R3 hangs off pin 5 with 9v coming in and just jumper pin 5 to 6 - that way both will get 6.2v.  Pin 4 is ground so that's ok.  

Should work - hope this is of some help -

Jim

Thanks for an idea but nothing happens tube isn't even lightening up or getting hotter   voltage goes down to 0 at the moment when it is connected to pin 5

Id jus wait for the 12AU7 and give it a try. Oh since you did wire the pedal without the switch, make sure it is connected like this:



i think this is one sheet u did follow tho

[Kazha]

Received tube today, not much to say my clumsiness made my day really bad i  broke it
at least finished up proco rat that worked
probably gonna try to figure out how to make it work with 6n1p if anyone has some more ideas i would kindly appreciate it

[pleiades]

So I built the a box based on the schematic I posted earlier.  I left out the "warmth" control for now just because I figured it was ambitious enough building a circuit with 3 dual triodes for my first valve circuit.

First impressions on the sound are: UNBELIEVABLE.  Playing it through the clean channel on my Egnater Rebel it sounds like a cranked Laney stack... totally awesome.

The only problem is a persistent high-pitched whine/hum.  I messed around with my grounding scheme to no avail, so I figure it must be the caps ringing or some behavior of the 12AU7s that I am not aware of.  Has anyone had similar problems and/or have any ideas?

[jaki54321]

Received tube today, not much to say my clumsiness made my day really bad i  broke it
at least finished up proco rat that worked
probably gonna try to figure out how to make it work with 6n1p if anyone has some more ideas i would kindly appreciate it

Oh no! I am soo sorry that happened to you! Im clumsy too so i kno how it feels to break a tube, i buried mine in my backyard and it grew more tubes(Sarcasm lol)

I looked over the datasheets. I think what you should do is get a 6v DC wall wart and have it run the same way as u have the connections now.

have pin 5 running to the positive rail of the DC jack and pin 4 to ground. Use the sleeve of the input jack as ground. if it still doesnt work, have pin 4 run to positive and pin 5 to ground. If it still doesnt work let me kno an ill see if i can come up with something.

[Kazha]

Everything works now  re soldered everything and took 6v DC sound thou isn't good (cos of tube probably) and there is no boost actually clean is louder why that is I don't know same thing is on proco rat But I'm happy that it works gonna find cool knobs and post some pics when i'll have a time

P.S. Thanks for help

[sundgist]

I've just added the vibracaster tremolo to my build. A worthy addition to anyones valvecaster.

Here's a verified stripboard layout for just the addon LFO.



8k2 resistor should be changed to 47k if yours runs on 12v. Mine is at 21v and I've used 27k here. Changes the range of tremolocity. 

Full post here including flashing rate LED. http://www.diystompboxes.com/smfforum/index.php?topic=70160.msg718098#msg718098

[zambo]

    Re: Tube boost + overdrive running off a 9 volt battery
« Reply #1734 on: July 11, 2010, 02:23:15 PM »   

--------------------------------------------------------------------------------

So I built the a box based on the schematic I posted earlier.  I left out the "warmth" control for now just because I figured it was ambitious enough building a circuit with 3 dual triodes for my first valve circuit.

First impressions on the sound are: UNBELIEVABLE.  Playing it through the clean channel on my Egnater Rebel it sounds like a cranked Laney stack... totally awesome.

The only problem is a persistent high-pitched whine/hum.  I messed around with my grounding scheme to no avail, so I figure it must be the caps ringing or some behavior of the 12AU7s that I am not aware of.  Has anyone had similar problems and/or have any ideas?


sounds like a layout issue..picking up rf or not using sheilded wire in the signal path. Also running a pedal with a buffer in front of it helps with the whine. I have built a bunch of these three tube versions and the only one that doesnt whine as much is the one i built in a huge enclosure. Try putting a buffered chorus in front of it. it doesnt have to be turned on even. hope this helps. cheers, Zambo

[jrmcgrath13]

Hi,

I have a question that I'm hoping somebody can help me out with (probably Renegadrian).  So, here's my question: based on the circuit below, in theory, do I need to run the ground from the input sleeve via individual wires to tube pin 4, volume 1, and 3pdt 5, or can I just instead run a single wire from the input sleeve to, say 3pdt 5, then from there to volume 1, then to tube pin 4 and have it do the same thing?  I'm building a single enclosure with three vlavecasters in it with a fourth master 3pdt on/off, and I'd really save me a lot of wire mess if I can just do the grounding like this instead of running a separate wire out to each solder point from the input sleeve.  Thanks for the help in advance.  =]

-Jr