So... I did something dumb... but well intended.

[Capt Beaver]

 I have a Speaker Cranker and wanted a bit more drive... so I removed the 2n 3904 a40 transistor and replaced it with a OC75...thinking it would kick it into a higher gain. Kinda wanted to get it closer to an amazing Lovepedal 50 I have had for years. It did nothing...

I know... I don't know what I'm doing... BUT I tried!  

Can I get a transistor that will work in this circuit and have a tad more grit?

PS... You can make fun of me here I can take it!  


Mitch

[peterg]

try a 2n5088 or 2n5089

[thelonious]

Using an OC75 would have two issues. First, it is PNP instead of NPN, so the polarity is backward compared to a 3904. Second, it is a germanium transistor instead of silicon, so the biasing will be different. Unless you want to change other components and possibly have to hack the circuit board, you should try a higher gain silicon NPN transistor than the 2N3904. Try a 2N5088, or for even higher gain, a 2N5089. Double check the pinout when you try a different transistor.
___
Edit: oops, peterg beat me to it!

[Tony Forestiere]

try a 2n5088 or 2n5089

And be sure of the pin outs. Data Sheets are cool.

*edit* oops. tristan beat me to it!

[Capt Beaver]

Thanks for the advice and wisdom....  I sure need it!

[Quackzed]

is this it? if so you could try shorting one of the orange diodes...(probably..its an educated guess) alligator clip each side of one of the diodes together... well one of em will kill output to zero, but either of the other two will add more distortion along with less volume when shorted... , less than unity i'd think...
heres a thread...http://www.diystompboxes.com/smfforum/index.php?topic=101384.0

[Capt Beaver]

is this it? if so you could try shorting one of the orange diodes...(probably..its an educated guess) alligator clip each side of one of the diodes together... well one of em will kill output to zero, but either of the other two will add more distortion along with less volume when shorted... , less than unity i'd think...
heres a thread...http://www.diystompboxes.com/smfforum/index.php?topic=101384.0

That's her... I'll order some new trannies today. Thank you to all...

Mitch

[peterg]

I suggest using a socket so you can try out the transistors.

[midwayfair]

Changing the transistor in this pedal will do very little. A single transistor can only amplify so much and will not distort much. A germanium transistor will also be LOWER gain.

Look up the schematic for the pedal and you'll see that it's a single transistor followed by a few diodes. The diodes are doing all the heavy lifting for the distortion. They're silicon diodes and they clip at .6V on one side and 1.2V (two diodes in a row) on the other side. You can essentially double the amount of distortion you get by replacing those diodes with Schottky diodes such as BAT41. You'll lose a lot of output this way, though. You could also use germanium diodes instead of the Schottky diodes, but it won't sound that different. Germanium diodes, unlike a germanium transistor, will actually make a difference here. (A germanium transistor will actually have far LESS gain and a lot more noise, even if you rebias it correctly by changing basically all of the resistors in the circuit.)

I would really suggest just using a different pedal instead of heavily modifying this one. It's made to do one thing well, which is add a little distortion and keep a relatively constant level of volume.

You can also use a booster in front of it instead of modifying it. Anything will do.

[bool]

If you want to squeeze a bit more gain from this one, you can try the following:

1) replace the 330R resistor with something smaller, like 100R

2) replace the 2.2Meg resistor with a bigger one, like 3.3 or 3.9Meg

3) use a higher gain Si transistor as already suggested

(all these will change bias a bit, but that shouldn't prevent the pedal from working)

4) with above mods you will most likely have to reduce the input cap. value to something like 47 or 68nF.


IMHO you are better off reverting your pedal to stock, and build a "clone" with above mods incorporated. ymmv

[thelonious]

You can essentially double the amount of distortion you get by replacing those diodes with Schottky diodes such as BAT41. You'll lose a lot of output this way, though.

Assuming Capt doesn't mind the lower output, your germanium diode idea would provide a cool change of flavor.

Changing the transistor in this pedal will do very little.

If changing the transistor raises the signal voltage hitting the diodes, wouldn't that provide the same result (without losing output volume) that lowering the clipping threshold provides? If the transistor doesn't run out of headroom, that is.

If you want to squeeze a bit more gain from this one, you can try the following:

1) replace the 330R resistor with something smaller, like 100R

Easy and effective!

[stm]

Raising the gain is as simple as bypassing the 330 ohm resistor with a 10uF electrolytic capacitor (bypassing means placing the capacitor in parallel with the resistor, also known as piggybacking.)

No need to rebias.

[P.D.]  If you want a flat frequency gain boost you should consider a 47uF capacitor; on the other hand, a smaller capacitor around 4.7uF will give you a sort of treble boost effect.  Finally, if the overall boost is more than you need, you can limit the gain increase by adding a resistor in seriues with the capacitor, perhaps in the range of 47 to 470 ohms.  A 1k pot could serve as a simple gain control.

[Capt Beaver]

You can essentially double the amount of distortion you get by replacing those diodes with Schottky diodes such as BAT41. You'll lose a lot of output this way, though.

Assuming Capt doesn't mind the lower output, your germanium diode idea would provide a cool change of flavor.

Changing the transistor in this pedal will do very little.

If changing the transistor raises the signal voltage hitting the diodes, wouldn't that provide the same result (without losing output volume) that lowering the clipping threshold provides? If the transistor doesn't run out of headroom, that is.

If you want to squeeze a bit more gain from this one, you can try the following:

1) replace the 330R resistor with something smaller, like 100R

Easy and effective!

The parts in this thing are SO small... I'm gonna try a different tranny just because I have to replace the one in it now and order a stock one also...

I was thinking it would be a simple mod to get in the "50" ballpark... I only have one 50 left in the stable and it's my go to pedal at every gig... I don't take the Gainster pedal out when I sit in very often... the 50 can get me my tone with most amps I sit in with.

Good plan.... bad brain!

[Capt Beaver]

https://fbcdn-sphotos-f-a.akamaihd.net/hphotos-ak-xfp1/v/t1.0-9/p180x540/10987692_10205212543745414_2054255163540568035_n.jpg?oh=58b4c9368e654203a2f094d9b7ad1143&oe=557A6669&__gda__=1431261840_34be0be18ab0e31ed23a8a107f951eb4


This is my 74 Boogie Larry Rodgers built for me and my pedal platform... The SC works well but I just wanted a tad more grind... not much


https://fbcdn-sphotos-g-a.akamaihd.net/hphotos-ak-xfa1/v/t1.0-9/10403476_10205212545825466_8431581811678668576_n.jpg?oh=8ff59acec93adce1446e265b598f1647&oe=5578738C&__gda__=1434142305_3200580099e4018added743efd5a2f3b