Improving a Boss CE-1 Power Supply?

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Hi,

First post here at diyAudio. Looking for help with a replication of the 70's Boss CE-1 chorus pedal, as I have only a fair knowledge of electronics. It seems like the only way to get that big, vintage tone is to either spend $350-500 for a beat-up unit off eBay or build it yourself.

Here's the only schematic I could find:

http://www.freeinfosociety.com/electronics/schemview.php?id=119

I realize there are many obstacles provided by this circuit, but for now I'm focusing on the power supply. Everything runs off +/- 13 volts and +/- 14 volts DC, at least I think that's what it says. I'm assuming I need to stick with those voltages too(might change the gain or headroom?).

If a faithful reproduction of the original tone is the goal, would it be best to seek out those obsolete(?) power transistors or can I replace them with something like voltage regulators?

I understand I have a lot to learn so absolutely any help is greatly greatly appreciated. :)

Thanks, Jake
 
Have you looked at the newer Boss CE-2 schematic?

Tonepad.com is an excellent resource for this stuff. They also offer PCBs for cheap.

The CE-1 uses the MN3002, a 512 Stage chip, whereas the CE-2 uses the MN3007 or
MN3207 which offers 1024 stages for longer delays. (the MN3207 is basically the same
chip as the MN3002 but can be run as low as 3 volts, which would greatly reduce the
complexity of trying to clone the CE-1's powersupply.)

Also, check out the Small Clone Chorus, which uses much simpler clock than either
of the other two.

Of course you could also pick out the best features of the three and roll your own,
DYI style.
 
Thanks for the replies. I've looked at the CE-2, Small Clone, Ibanez CS-9, and the Boss DC-series chorus pedals. I find it hard to describe what it is about the CE-1, but the others just can't get there tonally. Even the Retro-sonic Chorus Ensemble, which claims to be the only circuit that uses the original MN3002 chip, seems lacking to me.

I think a big part of what made the CE-1 so great was its funky input-loading thing. The input impedance seen with those vintage transistors and the optional Mic Preamp section changes the way the guitar interacts with it (frequency response, gain) in a pleasing way.

A few more questions:

For the 15V zener diode, will a 1/2 watt power rating and 200mW current rating suffice?

What would you guys recommend for the transformer as far as current?
 
They apparently use a 34vct secondary to achieve 23.7v per leg after the bridge.
A substitute transformer might require some resistor tweeking.
Watch the 16v caps if you use a higher voltage transformer.

100 ma transformer ought to be plenty.
200mW diode should be ok.

Have you thought about using super regs to increase the PSRR to lower the noise?
 
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