Project 27- quick schematic question

[DeadSpeaker]

hi, on the Project 27 preamp http://sound.westhost.com/project27.htm there are 2 15+ and 15- locations. Do the two 15+ places connect to each other? Note 2 states "2 - Opamp supply pins must be bypassed to earth with 100nF caps (preferably ceramic) as close as possible to the opamp itself. " Does this mean that I am to use a capacitor between the supply pins and ground. Do they also connect to the other 15+/- areas?

Also, there are a lot of lines that cross each other with out any indication of a junction. An example is C2 to R5. Are R3 R4 and C1 connected at that junction. My guess would be yes, but I'm not taking any chances on a project of this scale.

[Stuey]

Why don't you email Rod Elliot? He's usually happy to help.

[Stuart Easson]

In no particular order:

Unless you are building something very special from a super-fi perspective, all the +15v and -15v lines will end up at the same place, probably a regulated power supply. If you were making a PCB you'd probably only have a single point at which +15v were connected or if the regulators were on the same board, generated. In this case, with Rods PCB the resistors and zeners are the regulators.

The connections on the schematics are clearly marked with a dot. So anytime two wires cross without a dot means they are passing but not connected. Beware of mistakes, Rod is only human, there is a small chance the schematic could have drawing errors. Unless you are on a really small budget I'd recommend buying Rods PCB. It's not that expensive, and the amount of effort you are going to end up putting into making your own will not be worth it with a project of even this modest complexity.

The caps mentioned should be from each supply rail to ground. Thus for each IC you would have a pair of caps, which are ultimately connected to the single +15v line, the single -15v line and the single ground. The decoupling caps will give each IC a slightly better supply, and a better chance of stable operation.

HTH

Stuart

[DeadSpeaker]

You know what, I might just buy those boards. They are about 50 bucks plus shipping to the US. I want this amp to sound as best as it can. I recently finished a guitar pedal that had taken me a very long time to debug due to wires snapping off the board and bad joints on the perfboard. I'd rather spend the money and get the hard part finished. Thanks for the advice.

[Stuey]

Sorry, Dead. I thought you'd already bought them, hence my comment.

Cheers

Stuey