New layout needs verification (Dragonfly's Blue Plate Special)

[svstee]

How does it look? My first real Vero layout, I know its not the most efficient use of space, but does the circuit work? I replaced the trimmer with a fixed resistor, other than that no changes from the schematic, found here:
http://aronnelson.com/gallery/main.php/v/DRAGONFLY-LAYOUTS_0/album87/BLUE+PLATE+SPECIAL_001.GIF.html

Thanks all!

[Jered]

  Your going to want that trimmer. Without it the circuit might not bias correctly. A circuit not biased properly has the potential to sound pretty bad.

[svstee]

True. I mostly just wanted to practice doing layouts, though. Aside from that, any problems?

Edit: Just found one myself. Input was one off, needed to be row d instead of e. Modified version:

[GREEN FUZ]

Other than the missing 47uf from emitter to ground, it looks fine

[Dragonfly]

DEFINITELY use the trim pot, and as GF said, the 47uf bypass cap

[svstee]

Updated version:

Added the cap I forgot, added a transistor switch and made the bias control external. Shrunk down the size a little and got all the components in the correct order. Any problems?
Edit: And I just now saw that I spelled "toggle" wrong...

[Dragonfly]

If you are going to make the bias pot external, you'd be better off using a 25k pot in series with a 56k resistor (estimated values - breadboard to see what the proper bias resistance is and then use your pot + resistor combo )

Oh, and C5 will probably fit better in the layout if you move it to the right about 6 holes

[svstee]

Forgive my electrical noobhood, but what is the advantage of doing it that way? And as for C5, did you mean left?

[kurtlives]

Left is the only way to go...five holes to the right and your in space Lots of room to the left under C3.

The resistor in series with the pot allows you from "going" to low. Guess you would be biasing to cutoff? The resistor basically allows the pots travel to have lots of usable sounds.

If you just had a 100K pot you might get no sound from 0 - 56K. Then from 56K> you would get sound and variation. The resistor just allows the pot to be more useful. Resistor prevents from too low of a resistance. Like said though breadboard to find the proper value resistor, germanium transistors are not created equal.

[svstee]

I kinda figured he meant left...

The resistor in series with the pot allows you from "going" to low. Guess you would be biasing to cutoff? The resistor basically allows the pots travel to have lots of usable sounds.

If you just had a 100K pot you might get no sound from 0 - 56K. Then from 56K> you would get sound and variation. The resistor just allows the pot to be more useful. Resistor prevents from too low of a resistance. Like said though breadboard to find the proper value resistor, germanium transistors are not created equal.

But what about a Si NPN? The switch will select either Ge or Si transistors, so even if I don't use half the range with one I may need it for the other.

[kurtlives]

You ll have to find a value that works pretty well for both then. Better that than a value that works great for one side but total crap for the other.

In my experiences I have found that Ge transistors have a wider "bias range". Maybe I am crazy...

[svstee]

Alright, thanks!

[Renegadrian]

See if this one's correct...Trimpot and 47µF cap.