Author Topic: Tube boost + overdrive running off a 9 volt battery  (Read 1599955 times)

rankot

Re: Tube boost + overdrive running off a 9 volt battery
« Reply #3660 on: February 11, 2017, 12:23:31 PM »
I will try to make this kind of power supply for my Valvecaster: I plan to use 9V supply, then to make 2x 6V for heater using two of 78L06 (very cheap and providing just enough power for one half of heater), and I will push 9V to 40V using MC34063A charge pump. Any thoughts about this idea?

 :icon_mrgreen:

« Last Edit: February 11, 2017, 12:26:33 PM by rankot »
Ampegulator, Bassballs, Bazz Fuss, Bearhug Compressor, Bronx Cheer, Clean Sweep, Demeter Compulator, Electra Distortion, Engineer's Thumb, Hybrid Fuzz, Orange Squeezer, ProCo Rat, Ross Compressor, Valvecaster, 6J6, SFT 2, Ugly Face, more to come...

PaulBass

Re: Tube boost + overdrive running off a 9 volt battery
« Reply #3661 on: February 12, 2017, 04:37:35 PM »
I've used all types of voltages but you really hear its full potential when you're at 36v and above. at 50v the sound is killer

suncrush

Re: Tube boost + overdrive running off a 9 volt battery
« Reply #3662 on: February 12, 2017, 06:03:05 PM »
"Full potential". I get it!!!

rankot

Re: Tube boost + overdrive running off a 9 volt battery
« Reply #3663 on: February 13, 2017, 01:39:55 AM »
I've used all types of voltages but you really hear its full potential when you're at 36v and above. at 50v the sound is killer
For bass or guitar use?
Ampegulator, Bassballs, Bazz Fuss, Bearhug Compressor, Bronx Cheer, Clean Sweep, Demeter Compulator, Electra Distortion, Engineer's Thumb, Hybrid Fuzz, Orange Squeezer, ProCo Rat, Ross Compressor, Valvecaster, 6J6, SFT 2, Ugly Face, more to come...

vigilante397

Re: Tube boost + overdrive running off a 9 volt battery
« Reply #3664 on: February 13, 2017, 11:46:42 AM »
I've used all types of voltages but you really hear its full potential when you're at 36v and above. at 50v the sound is killer

Keeping the heaters regulated much lower though, of course. 8) Running a higher plate voltage will always get your more of that typical valve sound, otherwise our amps would run off 9V supplies. The whole idea behind the creation of the pedal (in my humble opinion) was not to make the best sounding tube preamp in the world, but to make something that sounds pretty darn good with what is generally considered an absurdly low plate voltage.
"I'm not sure what "serious design flaws" you see. Does it explode or poison your dog?" - PRR

http://facebook.com/sushiboxpedals

thomasha

Re: Tube boost + overdrive running off a 9 volt battery
« Reply #3665 on: February 13, 2017, 01:18:11 PM »
Using a SMPS to boost the 9v is a good idea, with very nice results in mini amplifiers.

I used a 555 to boost the voltage to 250v in a preamp using the ef184 tube.
The thing with smps is that they're very sensible to layout and components. A cheap inductor will introduce some switching noise.

But there are a lot of different configurations. With the icl7660s you can build a charge pump that would easily deliver 50v without the inductor.

At lower voltages adding a transistor to the plates also works as an improved anode resistor.

rankot

Re: Tube boost + overdrive running off a 9 volt battery
« Reply #3666 on: February 14, 2017, 03:05:12 AM »
I don't like 7660, it has very low working frequency. Inductors are not a big issue - they are small for currents needed for tubes. What do you think about using two 78L06 for powering heaters in parallel?
Ampegulator, Bassballs, Bazz Fuss, Bearhug Compressor, Bronx Cheer, Clean Sweep, Demeter Compulator, Electra Distortion, Engineer's Thumb, Hybrid Fuzz, Orange Squeezer, ProCo Rat, Ross Compressor, Valvecaster, 6J6, SFT 2, Ugly Face, more to come...

bluebunny

Re: Tube boost + overdrive running off a 9 volt battery
« Reply #3667 on: February 14, 2017, 03:10:50 AM »
I don't like 7660, it has very low working frequency.

With the icl7660s . . .

The 7660S has the high-speed boost option.
Ohm's Law - much like Coles Law, but with less cabbage...

iainpunk

Re: Tube boost + overdrive running off a 9 volt battery
« Reply #3668 on: December 19, 2017, 10:47:01 AM »
Bump

Hi guys, im new here.
I am building a hybrid amp of which the preamp is based on the valvecaster, modded and upgraded to within an inch of its life. On certain guitars it kinda farts out a bit when the gain is up, i suspect its an overload of mids hitting the tubes. The bass cut pot prevents this (cuts everything below 750hz by -3db/octave), but it also cuts out the bottom end, which makes it sound thin. Now for my question, how can i reintroduce the bass in my signal??
If we don't study the mistakes of the future, we're bound to repeat them for the first time.
-Ken M

vigilante397

Re: Tube boost + overdrive running off a 9 volt battery
« Reply #3669 on: December 19, 2017, 01:24:48 PM »
Bump

Hi guys, im new here.
I am building a hybrid amp of which the preamp is based on the valvecaster, modded and upgraded to within an inch of its life. On certain guitars it kinda farts out a bit when the gain is up, i suspect its an overload of mids hitting the tubes. The bass cut pot prevents this (cuts everything below 750hz by -3db/octave), but it also cuts out the bottom end, which makes it sound thin. Now for my question, how can i reintroduce the bass in my signal??

Welcome to the forum :)

Your question is a tricky one: "I'm taking all the bass out of my signal, how do I put it back?"

The Valvecaster is a pretty dark-voiced pedal, the fartiness you're hearing has nothing to do with what the tube is taking in, it's all going to be on the output. The 12AU7 has a pretty wide frequency response. I would recommend looking at a different tone stack for the Valvecaster stage and see if you can get the tone you're looking for. Good luck! ;D
"I'm not sure what "serious design flaws" you see. Does it explode or poison your dog?" - PRR

http://facebook.com/sushiboxpedals

iainpunk

Re: Tube boost + overdrive running off a 9 volt battery
« Reply #3670 on: December 19, 2017, 04:40:28 PM »
Bump

Hi guys, im new here.
I am building a hybrid amp of which the preamp is based on the valvecaster, modded and upgraded to within an inch of its life. On certain guitars it kinda farts out a bit when the gain is up, i suspect its an overload of mids hitting the tubes. The bass cut pot prevents this (cuts everything below 750hz by -3db/octave), but it also cuts out the bottom end, which makes it sound thin. Now for my question, how can i reintroduce the bass in my signal??

Welcome to the forum :)

Your question is a tricky one: "I'm taking all the bass out of my signal, how do I put it back?"

The Valvecaster is a pretty dark-voiced pedal, the fartiness you're hearing has nothing to do with what the tube is taking in, it's all going to be on the output. The 12AU7 has a pretty wide frequency response. I would recommend looking at a different tone stack for the Valvecaster stage and see if you can get the tone you're looking for. Good luck! ;D

Hey, i found the problems solution, the farting out was due to an abundance of low mids, so i  changed the caps and resistors i had going on in between the stages, this cuts out the farty mids a lot. Still a mid-rich sound, but not so over done and farty like it was. (If you look at a fender or marshall preamp frequency response, they both cut out a lot of mids, mine does less so). At first i wanted to keep the elaborate tone circuit i had going on in between the stages, but after minimizing and redoing everything, it sounded great. Il post a schematic for the preamp when i find a way to make them on my phone. (Any suggestions?)

Iain
If we don't study the mistakes of the future, we're bound to repeat them for the first time.
-Ken M

iainpunk

Re: Tube boost + overdrive running off a 9 volt battery
« Reply #3671 on: December 19, 2017, 05:43:06 PM »
The schematic after some simpifying the tone stack (im to lazy and frustrated with the program to make a "before" schematic). There were no tube symbols, i hope these squares are sufficient.



I left out the heater, but its supply is the same 12v supply as the rest.

Iain
If we don't study the mistakes of the future, we're bound to repeat them for the first time.
-Ken M

PRR

Re: Tube boost + overdrive running off a 9 volt battery
« Reply #3672 on: December 19, 2017, 07:39:32 PM »
"Classic" guitar input uses 12AX7 at 300V. Will take over 0.5V peak from guitar without rude noises.

ValveCaster 12AU7 at 12V, input overload may be 0.15V even 0.1V. Will overload on signals that an old Fender will pass clean.

The today-answer is to turn-down the guitar, turn-up after the ValveCaster.

But that gets you closer to Universal Hiss.

iainpunk

Re: Tube boost + overdrive running off a 9 volt battery
« Reply #3673 on: December 20, 2017, 04:53:59 AM »
"Classic" guitar input uses 12AX7 at 300V. Will take over 0.5V peak from guitar without rude noises.

ValveCaster 12AU7 at 12V, input overload may be 0.15V even 0.1V. Will overload on signals that an old Fender will pass clean.

The today-answer is to turn-down the guitar, turn-up after the ValveCaster.

But that gets you closer to Universal Hiss.

Or, you lower the gain of the first stage and put a gain control (volume pot) in between stages (instead of the awful bias control) and make the second stage higher gain, so the gain control lets you turn it clean or dirty.
If we don't study the mistakes of the future, we're bound to repeat them for the first time.
-Ken M