Tube boost + overdrive running off a 9 volt battery

[Renegadrian]

Yup Dano this thread has taken off, its got me going crazy buying tubes, even better is that I'm starting to understand this stuff, and am having a lot of fun.

The only thin I notices is suppling enough amperage to the circuit for it to work right. I was using a 12volt 300ma radio shack wallwart and would get flubby sounds out of it. I switched to a 700ma power supply for work and it sounds amazing.

http://www.nj7p.org/Tube4.php?tube=6111
Heater Current ................................ 0.3 A
According to this, you need 600mA only for the heaters, am I right???

Dano, this thread is killer...Apart form the the first ones, like me,  Andrew and Kristian (krinor) I read more and more people interested in the Valvy...And the little effort in the building gives great satisfaction...You go like "WOW, i went TUBES!!!" 

[frequencycentral]

http://www.nj7p.org/Tube4.php?tube=6111
Heater Current ................................ 0.3 A
According to this, you need 600mA only for the heaters, am I right???

Hmmm Renegadrian - maybe you just solved my Subcaster problem - not enough mA! I guess the 317 must consume some mA too - I will try a more powerful power supply.

[Renegadrian]

http://www.nj7p.org/Tube4.php?tube=6111
Heater Current ................................ 0.3 A
According to this, you need 600mA only for the heaters, am I right???

Hmmm Renegadrian - maybe you just solved my Subcaster problem - not enough mA! I guess the 317 must consume some mA too - I will try a more powerful power supply.

Rick, if that's the case, glad I gave you a hint!!! 

[Berger]

Also a tip I ran a 220k resistor from the vin to pin 7 and that made a huge difference on my build as well

[Jimmy-H]

http://www.nj7p.org/Tube4.php?tube=6111
Heater Current ................................ 0.3 A
According to this, you need 600mA only for the heaters, am I right???

Hmmm Renegadrian - maybe you just solved my Subcaster problem - not enough mA! I guess the 317 must consume some mA too - I will try a more powerful power supply.

Hi there,

You don't neet the 317 with two tubes.
Just set the heaters of the two tubes in series, the current then is stil 0.3 A.
Right?

[iorr]

Hi Jimmy-H,
You need the LM317 of an IC 7812 to get a stable voltage on the heaters. Otherwhise you will shorten life of the tube(s).
I builded my Valvecaster with a wall wart 15V. and an IC7812, 100yF across the DC jack, pos.tip to pin 1 of the 7812, pin 2 to ground and pin 3 to the circuit.
Build the regulator on a heatsink.oh and connect only heater pins 4 and 5 of the tube.

Karsten

[Jimmy-H]

Hi Jimmy-H,
You need the LM317 of an IC 7812 to get a stable voltage on the heaters. Otherwise you will shorten life of the tube(s).
I builded my Valvecaster with a wall wart 15V. and an IC7812, 100uF across the DC jack, pos.tip to pin 1 of the 7812, pin 2 to ground and pin 3 to the circuit.
Build the regulator on a heatsink.oh and connect only heater pins 4 and 5 of the tube.

Karsten

Yeah, your right about that
But if u use good regulated powersupply in the first place, than you don't have to worry about that.
The only thing you have to do is remove the 47 E resistor in the supply filter of the subcaster.
Because of the low Resistance of the heaters.
Otherwise your voltage will drop

With tubes it's always important to have a good power supply to prevent hum.
I experienced that with the pepper shredder

[iorr]

yep, regulated power supply is very importent.
Builded this for my audio preamp - a little bit oversized - hahahahah



Karsten

[Woodooman]

Hello there

Sorry for a newbish question, but could anyone please tell me if i could use 6n1p russian 6v tubes for this project?

thanks

[Renegadrian]

A quick glance at its details, and I believe this wouldn't be the best choice...
1) it runs on 6v, while the main tubes used here are 12v
2) it needs 600mA on heater

[Fender56]

Hello there

Sorry for a newbish question, but could anyone please tell me if i could use 6n1p russian 6v tubes for this project?

thanks

The 6N1P are pre-amp tubes but are generally used as a low-power tube in guitar amplifier (see www.ax84.com for some examples), and requires about 250V on its plate (the heater is 6.3V). I don't know how it can behave in starved-mode, but it is not intended to (well, neither the 12AX7!). You can try it, but I doubt it will sound great.

[iorr]

Try it.
This one is similar to the 12AX7, ECC 88 or 6922. You can see them in a lot of high end audio applications. For the heater you will need a regulated 6.3V.
Karsten

[armstrom]

With tubes it's always important to have a good power supply to prevent hum.
I experienced that with the pepper shredder

Would a switching power supply be sufficient? I'm looking at this guy to power both my 25W stereo power amp and two Tubecaster preamps... http://www.mini-box.com/80w-AC-DC-Power-Adapter-12v-6-6A?sc=8&category=13

i won't bother if it will have a lot of hum.
-Matt

[Fender56]

Would a switching power supply be sufficient? I'm looking at this guy to power both my 25W stereo power amp and two Tubecaster preamps... http://www.mini-box.com/80w-AC-DC-Power-Adapter-12v-6-6A?sc=8&category=13

i won't bother if it will have a lot of hum.
-Matt

In order to reduce the hum from your power supply, you should look for a low line regulation value (about +/- 1% will be great). Higher this value, higher the risk of hum.

In your case, this value is not shown so it is hard to predict. I assume it will be fine (those kind of big adaptors are usually well regulated) but ask for the return policy, just in case!

[puretube]

A switchmode power supply rather causes "whine" than "hum", IMHO...

[frequencycentral]

Just been debugging my Subcaster - again.

I can't seem to unite the voltage regulator for the heater with the main circuit. I know the voltage regulator works fine without being connected to the main circuit.

So - I thought I'd try bypassing the voltage regulator and running the whole main circuit at 6 volts.

Result - it works. Distortion, but obviously no boost as the voltage is too low.

I drove it a little harder with my LPB-1 - excellent.

Conclusions: this circuit will work at 6 volt  -with less gain.

As i can't seem to get the two parts together, I'm going to try this to get 6v for the heater from 12v:



The opamp can be anything really - 741, 1458, 351 etc

I've used it before to creat bipolar power for opamps and OTAs.

I will post my results.

Anyone care to comment?

[iorr]

Why so difficult?
Just place a 100yF acroos the DC jack. The pos. leg to pin 1 of an IC7812, pin 2 to ground, pin 3 to the circuit. If you want you can place another elco (47yf) on pin 3. So you get a regulated/cheapy and nice filtered power supply.

Karsten

[frequencycentral]

Why so difficult?
Just place a 100yF acroos the DC jack. The pos. leg to pin 1 of an IC7812, pin 2 to ground, pin 3 to the circuit. If you want you can place another elco (47yf) on pin 3. So you get a regulated/cheapy and nice filtered power supply.

Karsten

That would give 12 volts at pin 3, the Valvecaster (12au7) heater is 12 volt - but the Subcaster (6111) heater is 6 volt - well 6.3 volt to be exact.

[SirElwood]

This is a EF86 preamp running on 12-24 volts. Should be interesting.

http://www.tg-music.com/EF86.pdf

[awitee]

hi i just built the valvecaster
it seems the volume is a bit weak, it needs to be at around 3 o clock to maintain the bypass level.. is it all this way or just mine?
and i dont think the gain is enough, i used a 100k log pot besides the 50k, is it because of this?
and i feel its too bassy what mods can i apply to it?
i used a 12au7 tube running off 9v
no problem with noise
i used a booster pedal before it, and it sound great
but as a standalone.. i dont know..
can you guys pls suggest some modifications? thx!