9V to +-14v

[njkmonty]

i might source some 78L15's and give it a go
if one rail is 40ma and the  other is -40ma    does that mean its a total of 80ma current draw?

also if hypothetically, (will measure it again)  my peak current drawer is say 82ma,   is a 100ma  max component have adequate  head room?

[rankot]

But if you already use 2 pcs of LT1054, you don't need 7815 at all, you can arrange them like this:



LTspice shows that output is +15.4/-13.4 V for 100mA load on both rails, which is maximum output of a single LT1054.

[njkmonty]

i see and just tweak load resistors to taste?

[njkmonty]

ok ive finished breadboarding the last dual LT1054 schematic from Rankot

I actually got the lfo to work (i didnt plug the ce 1  sonically , as  ive found if the voltages are in the correct range the throbing lfo etc works good)

however i had to make some adjustments
in order to get the circuit providing as close to 14v on both rails, i had to omit Rload2 as without it it was only producing -12.5v  (under load)
Rload1  i found that a 200 r resistor worked best ,
however .....

the Rload1 resistor was getting extremely hot!
i put in a 1/2 w resistor  and it was getting very hot too

i disconnected to prevent any issues,  and came to the conclusion that even though the led was throbbing   the volatges were only ideal on the Positive rail, and the hot resistor really worried me that it was going to fail if left on,
and that

my original dual lt1054 plus regulator worked fine without these issues

any comments or thoughts would be happy to hear!

[Phoenix]

in order to get the circuit providing as close to 14v on both rails, i had to omit Rload2 as without it it was only producing -12.5v  (under load)
Rload1  i found that a 200 r resistor worked best ,
however .....

the Rload1 resistor was getting extremely hot!
i put in a 1/2 w resistor  and it was getting very hot too

Rload is not a component you need to include, it is a stand-in for the circuit in simulation, a resistor that will draw a current approximately the same as the circuit will. This simplifies simulation so you don't have to model the entire circuit and bog down your computer with simulating the entire thing (because all we want to know is that the power supply works, not that the CE1 circuit works).

[njkmonty]

oh!
(embarrased!)

[rankot]

 

Of course, remove Rload resistors from breadboard!

And without them, most probably the first one schematic will work (using only one LT1054).

[njkmonty]

ok here is results

using Rankot's single lt1054  (minus the Rload)  didn't work , it measure properly but under load dropped dramatically

using Rankot's Dual lt1054 (minus Rlaods 1 & 2    )    provided greater than 15v on the + rail and only 12.4 on negative, when connected , it was enough to make the led come on but wouldn't throb with lfo

im happy to pursue my other 2 x surge pump layout plus regulator  which has tested well,  my only questions now are, ..

since ive mashed together different layouts i was wondering if a few components may be removed or reduced in value?

particularly    the 15v zener diode

and 5 x 220uf caps?

surely some of these can be reduced or removed?

[amz-fx]

The 15v zener is over-voltage protection for IC7. If you know that you will never connect more than 15v to it, then leave out the zener.

You need the 220u caps.

Diodes D29 - D32 are not needed and are part of the problem.

The input voltage from IC7 will sag and is too close to the low limit on the LM7815 for me, so I would use a low dropout regulator like the LM2940. You might get by with the LM7815 but it is close.

Delete D27 too.



regards, Jack

[njkmonty]

Thank you for replying!

most schematics involving the zener ive come across have only come from madbean layouts!
so i wasn't sure how important it may be!  ive got some room on my layout in that area , so i will just leave it in

i currently have the layout shown previously working on my clone,  using the regular regulator!, but will buy some of the LM2940ct-15 soon
however regarding the 3 diodes on each rail after ic 8  are more like pads to add and remove diodes for taste
to get mine in the working 14v   i need  3 diodes in series on the +  side,   and only 2 on the negative.
unless there is another way (with minimal, easily sourced parts to drop that .75-1 volt  from 15 down to 14 ,  then i was going to stick with the diodes as they seem to be working!
something like this?



i went out and remove some of the items and found now after updating it , it seems good after removing some of the advised diodes
currently  1 diode on the +
and no diodes on the negative rail  (once load is connected , seems good! )
i also increased all 5 caps to 220uf

[lietuvis]

Hi I had success powering that4301 compressor with this inexpencive dcdc converter, its a 3W dual 15V. And output voltage can be adjusted with resistors. It might work for your circuit, here it is on ebay :
https://www.ebay.co.uk/itm/15V-Positive-Negative-Dual-DC-DC-Step-up-Boost-Converter-Module-3-3V-5V-12V/172763714588?hash=item283985141c:g:1~YAAOSwzx9Zw6Mw

[nickbungus]

That seems nice and clean.  Thanks

How do you adjust the voltages with resistors?

[lietuvis]

the only chip I could think of is this XL6007
http://www.ksmcu.com/pdf/XL6007%20datasheet.pdf
there is two resistors to adjust feedback, look in datasheet. I did not need to adjust voltage for my application.
or it is possibility to use 14V zeners.
BTW the chip i figuring out is from here also on ebay its can be seen on images :
https://www.ebay.co.uk/itm/Positive-Negative-Dual-Output-Power-DC-Step-up-Boost-Converter-Module-5V-15V-VD/253246459737?ssPageName=STRK%3AMEBIDX%3AIT&var=552368949139&_trksid=p2060353.m1438.l2649

[rankot]

I can't understand why you make 18V with LT1054, then regulate that down to 15V, and then use that same voltage for inverting? It means that you are limited to total maximum output of first LT1054, which is 100mA, and your circuit obviously doesn't use more.

You may try this circuit, too:


If you experience voltage drop under load, you may try to remove regulation part of a circuit (transistors and zeners).

[willwaush]

I can't understand why you make 18V with LT1054, then regulate that down to 15V, and then use that same voltage for inverting? It means that you are limited to total maximum output of first LT1054, which is 100mA, and your circuit obviously doesn't use more.

You may try this circuit, too:


If you experience voltage drop under load, you may try to remove regulation part of a circuit (transistors and zeners).

I do agree with you. I think it would be best to separate the two LT1054, since when you cascade them not only you are limited to the first IC 100mA, but you are adding a load of some mA to the first IC coming from the second...
It seems really strange that your schematic wasn't working properly with two separate LT1054... maybe the negative doubler configuration doesn't provide enough voltage on its own? Is it worth maybe a second try? I have found as well a datasheet which shows how to get +2*9v and -2*9V with two LT1054... this should work I think!




Anyway, if you guys really want to be limited to the 100mA from the first IC, there is a Bipolar Supply doubler schematic floating around. I can try to build it, but I wouldn't know how to test it under load.





PS: if the CE-1 mA request is under 100mA I wouldn't think about it too much and use the first working schematic 

[rankot]

XL6007 is actually very cheap - you can buy 10 for some 2 USD.
https://www.aliexpress.com/item/5pcs-lot-XL6007E1-SOP-8/32820416393.html

[nickbungus]

I'm very interested in using the MC34063A.  Its DIP, can invert and step up and ticks all the boxes.

I found this calculator online which allows you to key in your input voltage, desired output voltage etc and then it gives you the schematic and BOM.



I'm just a bit confused what I should be setting the Vripple and Fmin parameters to, if we intend to use it for the CE-1?  I take it Vripple is output ripple, but I dont know what that is!

Anyone willing to give me an explanation and some guidance, it would be most appreciated

[rankot]

I've tried MC34063A in one of my pedals as a high voltage generator (35V) and it was too noisy. I replaced it with Schmitt trigger step up which was very nice.

F_min is oscillating frequency of MC34063A, it shall be at least 25kHz for audio applications (but it may be safer to push it to 50).

V_ripple is acceptable voltage ripple of your output voltage.

[njkmonty]

ive been playing around with many layouts and could not get 2 x surge pumps under load to give +/-  14v  (in parallel mode)   the negative rail    would always only get to about -12.5

so i had a crack at 3 chips!

the following schematic i used got both rails on +/- 14     under load and seem to work fine,

i didnt hear any noise when playing the chorus,  and appeared just the same as my 2 x lt1054   in series layout that worked for me,

i guess this allows each surge pump to handle the amps better?

also since the chips max can handle is 100ma,  then i can use a smaller regulator  T0-92 package, which is also 100ma rated.

i measured the Dc amps being used on circuit straight out of the (9V Boss power supply and this chorus seems to draw about 170ma?

would love to hear others thoughts / comments



i also purchased some of the following to test aswell ......
https://www.ebay.co.uk/itm/Positive-Negative-Dual-Output-Power-DC-Step-up-Boost-Converter-Module-5V-15V-VD/253246459737?ssPageName=STRK%3AMEBIDX%3AIT&var=552368949139&_trksid=p2060353.m1438.l2649

[armdnrdy]

Hi I had success powering that4301 compressor with this inexpencive dcdc converter, its a 3W dual 15V. And output voltage can be adjusted with resistors. It might work for your circuit, here it is on ebay :
https://www.ebay.co.uk/itm/15V-Positive-Negative-Dual-DC-DC-Step-up-Boost-Converter-Module-3-3V-5V-12V/172763714588?hash=item283985141c:g:1~YAAOSwzx9Zw6Mw

Unless you know exactly which IC you are dealing with here....I wouldn't chance it.
I punched on the ebay link and read something about 20ma.
There is no way of knowing what frequency this supply runs at either.
Most things aren't bothered by audio frequencies...but the things we build...are.
I know that the guys are searching for a through hole component that fits all of their needs but...the market does not support that.
I had searched for quite a while and came up empty.
The LT3467 DC/DC converter runs at an ample frequency, supplies ample current, and supplies the proper voltage.
Downfall...it's SMD. Have you considered using the LT3467 with other through hole components to make up the supply?
If one's soldering skills lacks the ability to solder a single six leg, surface mount IC...they might want to consider a different hobby.