Author Topic: 9V to +-14v  (Read 2051 times)

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njkmonty

Re: 9V to +-14v
« Reply #60 on: January 12, 2018, 01:51:16 AM »
smd doesnt bother me,, its more that im trying to cater for those who can't!

im just trying to figure out what parts i can use   !


do you think it will work? 
the  LT3467?      under load?   as everything else ive tried works great until i connect it !
also do you recommend the LT3467 or LT3467A

also  you mentioned this works upto aboout 80ma  each rail.

im not sure the correct way of measuring the chorus's amp usuage, ,   or do i measure each rail  after it goes through power section?

i  just quickly measured the amps on each rail (making sure it ran through my dmm and had it on DC amps!
results
negative rail       60-80ma    (cycling with the lfo )
positive rail       13-14 ma    (cycling with the lfo )

do you think it will work with these results?
after coming across this on the data sheet i feel a little more positive about your idea 

my dual lt1054 version in series works
should i just stick with that?
« Last Edit: January 12, 2018, 02:37:50 AM by njkmonty »

willwaush

Re: 9V to +-14v
« Reply #61 on: January 12, 2018, 06:34:50 AM »
if your dual LT1054 works and you have enough space, I guess just stick with that. I don't see the point in searching other solutions that might not work as well as the LT1054. As far as I know it's one of the few converters which doesn't give any "audio" issue.. anyway in order to measure the draw you should simply put the multimeter in between the +15 supply and the effect for the + draw and in between the -15 supply and the effect for the - draw.
If you did like so, you should have enough reliable results, even if it sounds a little strange to me that the two + and - draws differ so much... anyway, it should be no issue as long as it's under 100mA

I am really unpatient to see what you come up with, so I would just guess stick with the LT if you tested it under several supplies and situations and it turned out to work well.

njkmonty

Re: 9V to +-14v
« Reply #62 on: January 12, 2018, 06:52:07 AM »
Yes thatís how I measured. It. With my fluke dmm

armdnrdy

Re: 9V to +-14v
« Reply #63 on: January 12, 2018, 02:06:08 PM »
also do you recommend the LT3467 or LT3467A
Either one should put you well above audio range and the chance of heterodyning issues with the CE-1 mutivibrator.

also  you mentioned this works upto aboout 80ma  each rail.
I believe that was stated in the page that I previously linked, Obsolete Technology. The author stated that he has used the LT3467 successfully on circuits requiring 80ma. 

negative rail       60-80ma    (cycling with the lfo )
positive rail       13-14 ma    (cycling with the lfo )
These readings seem very lopsided. It doesn't seem that the circuit would be designed so dependent on the negative rail. There might be issues with your build.

Now...the reasons I wouldn't suggest the LT1054 for this build.
Let me start by saying that I regularly use the LT1054 as my go to IC to create a bipolar voltage in circuits that don't require too much current.
When I moved to circuits with a higher current draw...I had to move to find a different solution. The LT3467 is one of the solutions....others include center tapped AC wall transformers and bipolar DC wall transformers aren't quite as easy to find.

Your use of two (or more) charge pumps running at the nominal 20-30khz may create issues such as heterodyning with each other....and or with the CE-1 clock (multivibrator) circuit.
To alleviate the charge pump/charge pump issue...you must sync the two charge pumps but....this will not solve potential issues with the CE-1 clock.
Look to the data sheet for instructions.

If you haven't read this thread....doing so might explain a few things.
http://www.diystompboxes.com/smfforum/index.php?topic=98225.0

I suggested the LT3467 because it seemed like it would work well for this circuit. Last year I worked up a modified CE-1 build as well and...and I plan to use this power supply.


I just designed a new fuzz circuit! It almost sounds a little different than the last fifty fuzz circuits I designed! ;)

willwaush

Re: 9V to +-14v
« Reply #64 on: January 13, 2018, 09:14:17 AM »
Yes thatís how I measured. It. With my fluke dmm

What if you measure the current draw at the very first 9V input? It should be pretty much the sum of the two rails + some extra draw coming from the components in between...
Anyway, since you etched your build based on an original layout I find it hard to believe that something is going wrong, especially because the effect is working as expected.
Plus, since with your tests the LT1054 is performing well without noise issues, I don't really see the point of searching other stuff to power up the circuit. It works, it's compact and "builder-friendly". I guess that other solutions that include inductors or not so well famous to the diy community ICs wouldn't be the best way if you want to sell it as a kit. Plus, I guess that the double LT1054 is the most compact solution, excluding SMD stuff. The thing that I still find it hard to believe is how it is possible that two "parallel" LT1054 don't work while they do in series. It's really a mystery.

_________


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?





I am sorry, I didn't read your edit. This layout seems much more reasonable to me, you can have at least 100mA per rail which is a really good achievement. But, what about onboard space?

170mA is because you are using 3 pumps to get your desired voltage... LT1054 have their own draw
« Last Edit: January 13, 2018, 09:29:52 AM by willwaush »

armdnrdy

Re: 9V to +-14v
« Reply #65 on: January 14, 2018, 09:48:36 PM »
I took the liberty to contact someone who is very familiar with the CE-1 circuit....Tim Larwill of Retro-sonic.

I asked him if he recalled the current draw of the positive and negative rails of the original CE-1.

This is his reply:
"I designed for a total max of 200ma, but 50ma per rail is enough."

I understand that reply to mean...the draw is below 50ma per rail.

I still believe that there might be a problem with the build.
Just because it appears to be working correctly doesn't mean that there isn't a possible problem causing excessive current draw.

This might be the reason why the voltage sags with a single charge pump power supply.

There could be a cold solder joint somewhere...or a solder bridge.

Are you still working with the board that you forgot to flip....and treated like a surface mount build?
« Last Edit: January 14, 2018, 10:09:48 PM by armdnrdy »
I just designed a new fuzz circuit! It almost sounds a little different than the last fifty fuzz circuits I designed! ;)

njkmonty

Re: 9V to +-14v
« Reply #66 on: January 15, 2018, 06:47:29 AM »
here is some of my voltages
ive looked  over  pcb
everything sounds good, lfo and all leds seem to work fine including clipping led.  i checked to see if any electrolytic caps were shorting, but no?
voltages due to lfo obviously vary,  the setting when measuring was on vibrato fastest so i could actually get a reading
MN3002

1   +4.5
2   -5.1 ---  -6.0
3   -3.4 ---  -3.5
4   -13.25
5   -
6   -
7   -
8   -
9   -
10 -
11   -14.2
12   -6.0 ---  -6.3
13   -4.1 ---  -4.4
14   -4.1 ---  -4.4

1458  (lfo)
1 varies  -12 ---  -13
2 -
3 varies  -4.8 ---  -5.8
4  -14.21
5 -
6 -
7  varies  -0.8 ---  +0.8
8 +14.27

ic 1   Ta7135p
1 +12.21
2 -
3 -
4 -12.99
5 -11.6
6  0.1
7 -12.78

ic 3   Ta7136p

1 +12.04
2 +12.04
3 +12.04
4 -14.2
5 -12.87
6  +12.75
7 +14.27