+9v to +18v charge pump Help!

[Lost_soul]

i am planning on building a Timmy and wanted to add an internal charge pump to take +9v and outputs +18v to the circuit.
i was wondering if there is a schematic for that.

also i won't be using a battery or the Ring connecter on the jacks but i will use a psu instead.

Thank you!

[GGBB]

What charge pump are you using? The datasheet will usually have the schematic for a standard voltage doubler.

[GibsonGM]

I don't know of any 'stand alone' schematic for the timmy w/charge pump at 18V, but I would think you can just take any 'approved' charge pump schematic, and connect the output of it to your power and grounds, and bias network, for the Timmy.  As long as your parts are rated for more than 18V (caps...the opamp is ok at 18V) you should be all set!   

[Lost_soul]

What charge pump are you using? The datasheet will usually have the schematic for a standard voltage doubler.

The charge pumps i have available here are the Max1044 (SMD version which i can solder to an adapter to make it DIP8)

And i have the ICL7660 Dip8 (without the s at the end)

Idk what i am gonna use yet, but maybe the Max1044 as i hear it has no whine to it.

I found this one:


And i read that it has the transistor for the jack ring connection so to act normal if you use a battery (which i will not be using)

Also i am not sure it the charge pump grounds should connect to circuit ground and to the power jack ground or it's something diffrent.

[Lost_soul]

I don't know of any 'stand alone' schematic for the timmy w/charge pump at 18V, but I would think you can just take any 'approved' charge pump schematic, and connect the output of it to your power and grounds, and bias network, for the Timmy.  As long as your parts are rated for more than 18V (caps...the opamp is ok at 18V) you should be all set!   

Yes that's what i was intending to do. But i am not sure if the charge pump ground should be connected to circuit ground or not.

[antonis]

Lots of outputs...



You can see signal and power grounds difference..
You shouldn't mix charge pump and signal currents elsewhere than power jack negative..

[GGBB]

https://www.analog.com/media/en/technical-documentation/data-sheets/ICL7660-MAX1044.pdf

Figure 9.

[Mark Hammer]

Not that it will make much, or even any, sonic difference, the pair of 1N4001 series diodes, that Antonis shows, will subtract a bit over 1V (maybe 1.2V, depending on individual diodes) from the derived +18V.  This will also be true if one uses 1N914/4148 as well.  So the circuit shown will provide about 16.8-17V.  When a pair of equal-value resistors are used to derive a Vref from it, the Vref will be around 8.4 to 8.5V. 

The "benefit" is that, where a standard guitar signal can often only be amplified 35-50x before it runs out of headroom and produced clipping within the op-amp used, this higher supply voltage will permit more clean amplification of the signal before introducing clipping.

But here is the qualifier.  If the higher supply voltage is being used for a circuit like a Tube Screamer, or anything else using diodes in the feedback loop, the higher supply voltage will yield much less benefit.  Diodes in the feedback loop will prevent the amplified signal from ever exceeding about +/-600mv (well below the maximum swing of the op-amp with +9V power).  If it is a circuit like the Distortion+, where diodes to ground are located on the output of the op-amp, then the op-amp is permitted to amplify, cleanly, as much as the supply voltage allows.

Bottom line, there are contexts in which a higher supply voltage can provide audible benefit, and some contexts where it is wasted effort.

[GGBB]

Not that it will make much, or even any, sonic difference, the pair of 1N4001 series diodes, that Antonis shows, will subtract a bit over 1V (maybe 1.2V, depending on individual diodes) from the derived +18V.  This will also be true if one uses 1N914/4148 as well.  So the circuit shown will provide about 16.8-17V.

As noted in the datasheet, Schottky diodes are recommended - e.g. 1N5817 - to minimize the voltage loss. But I also agree that there's not much benefit to using +18V with a Timmy.

[Lost_soul]

what is the diffrence between the one antonis posted and the one Gord T. posted?

is it that the latter doesn't use the 1st pin which is the booster pin?
and would that make a diffrence?

also from what Mark said, the timmy won't sound any diffrent on +18v because of the FB loop diodes. i understand that but i wanted to try to impply a charge pump in a project and i really wanna make a timmy sooo....

[Lost_soul]

Lots of outputs...



You can see signal and power grounds difference..
You shouldn't mix charge pump and signal currents elsewhere than power jack negative..

thank you antonis!
but do i connect the 100uf power filter cap and the polarity protection diode to +9v like in the picture or to 18v?

my guess would be +9v as that's where power comes in to the circuit right.

[antonis]

my guess would be +9v as that's where power comes in to the circuit right.

  

[GGBB]

what is the diffrence between the one antonis posted and the one Gord T. posted?

One is far simpler and accomplishes what you need. The one Antonis posted does things you don't actually need (-9V, +4.5V). But they could be used if you wanted to change the Timmy circuit a bit. Also, Antonis's circit is actually for the LT1054 - I'm not sure if that will work with the MAX1044/ICL7660 but it might.

The simplest way to do this without changing anything in the Timmy is to use Figure 9 from the datasheet and use the +18V output to power the Timmy without any changes in place of the normal +9V supply.

If you want to get more sophisticated, you could use the charge pump to provide the Timmy with both Vin (+18V) and Vbias (+9V) with Antonis's circuit excluding the -9V and +4.5V bits. In the Timmy you would need to remove the Vbias supply divider and connect the charge pump's +9V output appropriately.

Or you could do something even more advanced and run the Timmy from a dual supply using the charge pump to provide -9V (datasheet figure 5). If that interests you, it requires a minor change to some of the Timmy's grounds in addition to removal of it's Vbias supply divider.

[antonis]

Also, as Gord and Mark well pointed out, charge pump series diodes voltage dropout should be the minimun obtainable..
(at least, from good design practice viewpoint..)

[antonis]

Or you could do something even more advanced and run the Timmy from a dual supply using the charge pump to provide -9V (datasheet figure 5).

Why not at +18V/-9V with Vbias at +4.5V..??

@My dear Doctor: I presume you do undestand that we're partially joking about supply wider margins..
As Mark said above, for a single pair of feedback diodes there shouldn't be any audible difference between +/- 4.5V or +/-9V or +/- 13.5V swing..
Meaning, if diodes total voltage drop is significantly lower than half of supply margins swing, don't bother with exact supply value..

[Lost_soul]

Or you could do something even more advanced and run the Timmy from a dual supply using the charge pump to provide -9V (datasheet figure 5).

Why not at +18V/-9V with Vbias at +4.5V..??

@My dear Doctor: I presume you do undestand that we're partially joking about supply wider margins..
As Mark said above, for a single pair of feedback diodes there shouldn't be any audible difference between +/- 4.5V or +/-9V or +/- 13.5V swing..
Meaning, if diodes total voltage drop is significantly lower than half of supply margins swing, don't bother with exact supply value..

No problem antonis, i know you like to joke with me

What made me though that there would be a difference is from what i saw of people's opinion online about the timmy, also i saw that AM king of tone which has 4 diodes in the FB loop also had a charge pump internally so would always be at 18v and people like it. But i guess i was wrong.

I actually have the timmy on my breadboard. I might test it myself to see but from what you guys said. It's not gonna change.

[drdn0]

Instead of a charge pump, have you considered using a DC-DC converter? Something like the Recom xx09D series will give you isolated +/- 9v out from a 9v supply, switch at 30-88khz and only need a couple of components to be EMI compliant (if you're concerned about it). With bipolar power you can ditch the voltage divider, and simplifies PCB layout somewhat (as you no longer need Vbias + ground).

You can also use a MeanWell N78 series in negative voltage mode that don't require any external components to meet EMI regulations, but you're getting pretty close to the lower input voltage range (8v for a -9v out).

[Matthew Sanford]

You could always run Timmy on 9v then follow up with an op amp on 18v and a lotta gain, cause...well, you tell him Ella

[GGBB]

What made me though that there would be a difference is from what i saw of people's opinion online about the timmy, also i saw that AM king of tone which has 4 diodes in the FB loop also had a charge pump internally so would always be at 18v and people like it. But i guess i was wrong.

KoT has a charge pump? I don't think so but I could be wrong. I've never spotted one in gut shots e.g. https://medias.audiofanzine.com/images/normal/analog-man-king-of-tone-4154118.jpg or in schematics (which are not inerrant). Is it hidden somewhere?

KoT and Timmy share the quad feedback diode setup but otherwise are quite different - especially tonally. In the Timmy, the diode clipping happens in the first gain stage. In the KoT its in the second gain stage. Timmy can be much more neutral sounding ("transparent") but also has more tonal options with the bass and treble controls. KoT has it's own specific tonal signature. The tone and presence controls give you some control over top end and upper mids, but it always cuts some lows for a mid push sound - very nice IMO. I like the Timmy too but I wouldn't compare the two - they are different beasts doing different things tonally.

Both the Timmy and a variation of the Bluesbreaker/KoT I call Notorious OD are on my board - in fact they are together in a dual overdrive pedal I built. They complement each other nicely and make for a versatile partnership. Lately, though, I've been preferring the Mostortion over the Timmy, but the Notorious has been my main OD for a long time now.

[Mark Hammer]

You could always run Timmy on 9v then follow up with an op amp on 18v and a lotta gain, cause...well, you tell him Ella

Took me a moment to get the joke....but I like it.