flintlock flanger -- reducing the clock whine as low as possible

[ulysses]

hi all,

just wondering what LT1054 you are using in the flintlock flanger??

the first one i tried had a really bad noise coming thru as a whine as the lfo sweep went thru (cant remember the brand as i binned it). the second one i tried was branded TI and much quieter, but now i'd like to get to much closer to 0.

ive got a ti branded lt1054 that says "TI(logo) 66L VFD LT1054CP" -- i guess it could be fake? or not the most ideal 1054?? ive seen there are 'analog devices' 1054 chips that are twice the price of the TI 1054 -- any chance this AD chip will be quieter?

alternately, can the charge pump be removed all together if we use the 3207? does the FF lose it's magic with the 3207?

cheers

[danfrank]

Here, read this:

https://www.madbeanpedals.com/forum/index.php?topic=31768.0

The problem is that the internal frequency of the LT1054 is too high and therefore interfering with the BBD clock frequency.
Don't throw away your LT1054s, they are still good and can be used with other projects!
The charge pump frequency needs to be lowered for the Flintlock.

[Betty Wont]

Here, read this:

https://www.madbeanpedals.com/forum/index.php?topic=31768.0

The problem is that the internal frequency of the LT1054 is too high and therefore interfering with the BBD clock frequency.
Don't throw away your LT1054s, they are still good and can be used with other projects!
The charge pump frequency needs to be lowered for the Flintlock.

Cool, thank you for this. I tried to build a couple of Flintlocks that I ended up scrapping because of this. I might try another because I'd really like one of these. 

[danfrank]

If worst comes to worst (is that the saying?) Just feed the board with 18volts, that's the quietest solution. But I've fixed mine with a 33pf cap from pin 7 to ground. If you have a high impedance frequency meter/counter you can measure the internal clock frequency at pin 2 of the charge pump

[ulysses]

thanks for your replies

i didnt have a 33pf on my desk, but i did have a 27pf so i tried that, and it is a bit quiter, but it's still there.

i have an 18v psu from an old shaver -- when i remove the 1054 from the socket and plug in the 18 volts i get a really loud "meeerrrrrrr" so somethings not right -- maybe the 18v psu is rubbish. what brand psu do you guys like for 18v?

do i need to pull any other components from the baord if im going to use 18v?

cheers!

[danfrank]

For 18 volts, just remove the charge pump, the 2 diodes in series offer protection and a slight voltage drop.
You can go up to 40-50pf for that capacitor, there's no set value. Basically you want enough to lower the frequency to around 18-20kHz for the charge pump.

As for my 18 volt supply, yeah, I kind of cheat... It's a lab supply, ultra regulated. Lol!
If you have the room in your box, you can add 2200-4700uf filter capacitor to the DC input jack. That along with the on board regulator should do the trick to keep hum to a minimum. A lot of those wall wart power supplies have 4 diodes to convert to DC but don't even bother with a filter cap in them.

[ulysses]

For 18 volts, just remove the charge pump, the 2 diodes in series offer protection and a slight voltage drop.

yeah awesome thanks for that -- yeah i thought that was right just to remove the 1054 looking at the schem, but wondering why it made an awful noise -- must have been the shitty power supply i was using.

i rigged up 2x 9v batteries to make an 18v plug and very happy to see absolutely no whine. now i just have to find a power supply that can give me clean 18v

thx again for you help

cheers