proposed dr. boogey layout -- seeking comments

[mr_deadmaxxx]

what can you say about this one?
are there any pros and cons in using this layout?

I wanted to board mount all the pots and use vertical trimmers for this layout. I'm pretty sure the layout is correct re the connectivity (though there may be errors as I haven't triple checked it yet), I'm just a little concerned about the proximity of the gain control to the input section.

Oh, the input is the green pad, the output is the blue pad. 

[jplebre]

From what I read on another post, I think the only problem was to fit all the caps together (too tight). That other than that was working.

[deadastronaut]

whats the deal with the trimpots lugs?...shouldnt there be a join on em...like the gaussmarkov version...?

[Scruffie]

whats the deal with the trimpots lugs?...shouldnt there be a join on em...like the gaussmarkov version...?

That's not crucial, just good practice.

[deadastronaut]

ok!...cheers!..

[jplebre]

whats the deal with the trimpots lugs?...shouldnt there be a join on em...like the gaussmarkov version...?

That's not crucial, just good practice.

What join?

[frequencycentral]

The trimpots are configured as variable resistors in the Boogie. For a variable resistor it's only necesary to use two lugs: the wiper (ie lug 2) and one of the outer lugs (ie lug 1 or 3). The unused lug can be left unconnected (as I have done). However, as Scruffie said, it's good practice to connect the unused lug to the wiper, so that if (and it's a big if IMO) the trimpot fails then there's still resistance rather than an open circuit. I personally don't buy in to this 'good practice', as IMO a misbiased Boogie (ie 100k resistance on a trimmer were the wiper to fail) would be as much use to me as a Boogie with an open circuit trimmer (ie the wiper fails and the 'unused' lug was unconnected). In both cases I'd replace the trimmer (in the very unlikely case of a trimmer failing). Hands up all those who have had to replace a failed trimmer in their Boogie.......oh, I don't see any hands.

[LaceSensor]

I built the frequency layout and it's a squeeze but it went  together fine in the end. Cap choice is more limited is all.
Thanks for the layout. Onboard pots beats space saving when its 6 pots to off board wire...

[jplebre]

The trimpots are configured as variable resistors in the Boogie. For a variable resistor it's only necesary to use two lugs: the wiper (ie lug 2) and one of the outer lugs (ie lug 1 or 3). The unused lug can be left unconnected (as I have done). However, as Scruffie said, it's good practice to connect the unused lug to the wiper, so that if (and it's a big if IMO) the trimpot fails then there's still resistance rather than an open circuit. I personally don't buy in to this 'good practice', as IMO a misbiased Boogie (ie 100k resistance on a trimmer were the wiper to fail) would be as much use to me as a Boogie with an open circuit trimmer (ie the wiper fails and the 'unused' lug was unconnected). In both cases I'd replace the trimmer (in the very unlikely case of a trimmer failing). Hands up all those who have had to replace a failed trimmer in their Boogie.......oh, I don't see any hands.

Hey Thanks a lot that makes all the sense in the world now

[mr_deadmaxxx]

@frequency central

[mr_deadmaxxx]

@frequency central
how can i print your layout on it's actual size on the pcb board?
do you have the dimensions? (if i resize your layout)

[frequencycentral]

@frequency central
how can i print your layout on it's actual size on the pcb board?
do you have the dimensions? (if i resize your layout)

Most people import DIYLC files into Publisher or Photoshop and scale it to a 0.1" (2.54mm) grid, as the pads are that distance apart. I've heard of people scaling to 47% too.

[Govmnt_Lacky]

...how can i print your layout on it's actual size on the pcb board?

Open with Paint.

Set page scale to 47 or 48%

Works like a Champ! 

[frequencycentral]

...how can i print your layout on it's actual size on the pcb board?

Open with Paint.

Set page scale to 47 or 48%

Works like a Champ! 

Paint kinda pixelates it. But it looks perfect in Publisher:

http://dl.dropbox.com/u/967492/Scale.jpg

[mr_deadmaxxx]

i noticed there's a difference between your input pulldown resistor and input capacitor to the schematic that i saw.
resistor (R3) : 1M instead of 2M
capacitor (C4) : 1uF instead of 0.1uF

that's not critical, am i right?
no big deal?

[mr_deadmaxxx]

anyways, will a J202 work instead of J201?

[jplebre]

Just looked at the datasheet for J201 and J202 just a slightly "lower" cuttoff voltage and "higher" saturation voltage.
That would just mean a higher headroom, no?

Also, higher forward voltage. Would this impact into the next stages?

[mr_deadmaxxx]

what if i used this one for tonestack?

[mr_deadmaxxx]

no reply?

[jplebre]

I'm no expert but I guess the first bit would get the impedance to match.
There's a couple of toneless dr. Boogey stack around that had to be changed to match this.

There's also some other posts of people that introduced other tone stacks.

I have the impression that regardless stack you choose, the impedance would have to be matched after the 4th J201 and the tonestack.

Also, what is the IC you have in that stack? 2 dual IC's?