DOD Analog Delay 680 - Power Supply Question

[joinpobob]

Hi,

So I love my DOD 680 Analog Delay. Great tone, awesome tape-like delay. It is old and kinda beat-up. In the interest of the pedals longevity, I have been contemplating a cap job - like on a tube amp. Atmittedly, this sounds kinda stupid, we are only dealing with 15v here, so the filter / EL caps likely don't have that much wear on them. Any comments on doing so?

I have also been thinking about replacing the power supply (AC input with a tranny) with a standard 9V input. I would need to add a voltage doubler (e.g., LT1054, MAX1044), but that's not hard. I don't really care wither way, but the intention was that a 9V DC input was "safer" (to the circuit) than the current AC-tranny configuration. Is that true, or are they the same to the circuit?

Thanks!


http://www.dirk-hendrik.com/temp/dod680.gif

[Govmnt_Lacky]

The glaring question here is.... Why switch power inputs??

If the transformer setup is working, GO WITH IT!! 

The "Fix it 'til it's broke" warning definitely applies here. Don't wake the dragon if he is sound asleep.

The dragon being that precious SAD4096 chip. If that goes bad, you will spend about 25 years and a couple hundred bucks finding a replacement!!!

[joinpobob]

Thanks for the input.

I agree, the only goal here is to protect the SAD4096 chip. 

Currently, the tranny is working fine (knock on wood). My concern is that the tranny and caps are old. If the tranny goes / or the caps go bad, wouldn't that potentially lead to the SAD chip blowing?

My thought was to replace the tranny with a 9V supply and the EL caps with new ones. This would hopefully, give the power section another 25 years of new life.

So, question rephrased, does anyone know of any steps to protect the SAD chip in the circuit?

[Govmnt_Lacky]

IMHO... your chances of damaging the SAD chip by tinkering with the working circuit are HIGHER than the chances of the transformer going bad and leading to the same result. 

[joinpobob]

Point taken.

Thanks!