Author Topic: Pushing some pedals with 18v  (Read 3692 times)

JebemMajke

Pushing some pedals with 18v
« on: February 10, 2015, 05:30:05 PM »
For some time now i am running some pedals, designed for 9v ( ts type ods, ibanez wh 10 wah, and so on ) with 18v.

Next in line is a clone of mad professor's stone gray. 4049 inside with tl061 ( in my case, in the original it is tl051 ).

After reading this datasheet, http://www.nxp.com/documents/data_sheet/HEF4049B.pdf it seams that 4049 doesn't mind 18v. But again, maybe i am wrong. Any advice?

mth5044

Re: Pushing some pedals with 18v
« Reply #1 on: February 10, 2015, 05:55:19 PM »
Are you using a HEF4049x or CD4049x? Never seen an HEF, but here is the TI datasheet:

http://www.ti.com/lit/ds/symlink/cd4050b.pdf

TI says 20V max, HEF says 15V.

JebemMajke

Re: Pushing some pedals with 18v
« Reply #2 on: February 10, 2015, 07:10:36 PM »
I have STM 4049 available, and it says like =0,5 to 22

Here is a datasheet, so you can check yourself.

http://www.mikroprinc.com/index.php?page=shop.getfile&file_id=4533&product_id=4063&option=com_virtuemart&Itemid=8


mth5044

Re: Pushing some pedals with 18v
« Reply #3 on: February 10, 2015, 07:27:45 PM »
Looks like that one is 22V max. Usually you can trust a datasheet.

plexi12000

Re: Pushing some pedals with 18v
« Reply #4 on: February 10, 2015, 08:15:30 PM »
hey -- so do you like 18v's?  what pedals are you using it with? 

PRR

Re: Pushing some pedals with 18v
« Reply #5 on: February 11, 2015, 12:02:40 AM »
If run Digital at low to medium speed, CMOS power consumption is very low.

If run LINEAR, held near half-supply, CMOS power demand is HIGH.

This sheet does not show the current curve. However it is specced Typical 12mA for Vdd=15V, Vo=13.5V. If it is just 12ma for Vo=7.5V then this is 15V*0.012A= 0.18 Watts per inverter. Six inverters is over 1 Watt. Limits are 0.1W per unverter and 0.2W per chip.

If the current is already 12mA for a mere 15V-13.5V= 1.5V drop, it is likely to be much higher for a 7.5V (mid-rail) level.

You also have 18V instead of 15V.

You have a good chance of frying the chip.

However the chip is super-cheap. Socket it and fry away.

What are you hoping to gain by super-sizing the supply? Your next stage can only take so-much before it clips all-to-heck. And distortion will go down as supply goes up. Many people prefer CMOS distorters with hefty dropping resistors to hold them down near 3V-5V across the rails, with maybe a clean boost at the end if you really need to blow-up the next stage's input.
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PRR

Re: Pushing some pedals with 18v
« Reply #6 on: February 11, 2015, 12:11:57 AM »
me> ... the chip is super-cheap.

25.08 Din, whatever that comes to. (about 2-bits american, 0.23 USD-- a Dinar is about a US cent these days.)

However it is NOT clear that Mikro Princ is selling HEF4049B. While they link to an HEF data-sheet, the only promise is "4049" and that it comes from ST. ST may make other "4049" types, including low-volt types.

If you have handled these and know they are HEF, then never mind me.
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JebemMajke

Re: Pushing some pedals with 18v
« Reply #7 on: February 11, 2015, 05:16:07 AM »
My guitar is down tuned to G, with heavy strings and active pickup. It easily distorts. I am looking for more clarity in the sound, but with heavy distortion as well.

Stone gray already has a really good clarity, though i use it as a booster in front of f a dirty amp. I think that it could benefit from 18v.


Yes i like 18v, i like 24 v even more, it gives that nice clarity to everything, there is a bit less distortion, but i don't really need my wah to distort, or bbe sonic stomp, zen drive and other ts type od-s have enough distortion, and besides i like how they push the amp, and not for their own distortion amount.

So 18 v pedals ( aka those that i am using with 18v )
All diy

ibanez wh10 ( wah wah ), suhr riot ( modified, has a full tonestack and some caps are changed for a bit more bass ), BBE Sonic Stomp, Zendrive, Boiling point, another-ts-type-pedal-but-a-bit-modded ( not completed yet ), Also i am building  pigtronix philisophers tone ( which i plan to use with 18 v ) and diy fet based od. I was thinking of a p2399 delay being pushed with a 18v, for more clarity, but i think that it would require a big heatsink for that 7805.

So far that is it.

anchovie

Re: Pushing some pedals with 18v
« Reply #8 on: February 12, 2015, 07:13:57 AM »
I was thinking of a p2399 delay being pushed with a 18v, for more clarity, but i think that it would require a big heatsink for that 7805.

You won't gain any extra clarity - that 7805 is supplying the 5V for the chip including it's internal op-amps which aren't even rail-to-rail, so the actual headroom is about 3.5V peak-to-peak.
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R.G.

Re: Pushing some pedals with 18v
« Reply #9 on: February 12, 2015, 11:23:08 AM »
It seems a shame that the "mod" of running pedals at twice their designed power supply voltage is so popular.

I guess I should be OK with that, as it makes a better market for selling more pedals to replace the ones that die from this "mod".

But it still seems like a shame.
R.G.

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