freestompboxes.org

papercutnoise wrote:this is what I came up with based on the descritions on her site and given that it's of a similar design to some of her other pedals....

Any comments are appreciated.

It's a two transistor circuit.

From the Etsy page:

Karaoke Party

INPUT - IN1
GROUND - GND (either one)
9volt + - 9v (either one)
OUTPUT - OUT

3.3m resistor from middle of Q1 to IN1

R1 - jumper
R2 - 2.2M (red red green)
R3 - 10K (brown black orange)

C1 - .1uF (104)
C3 - .1uF (104)

Q2 - MPSA18 (same orientation as Q1 screen print)

Emphasis is mine

IvIark wrote:

think this is not wrong at all, if u remove Q2 it should work any way!!

I'll create a poor PCB based on IVIark desing and let you know what happen.

also i'll use Q2 with another transistor just to try....

cheers.

Steven_M wrote:

papercutnoise wrote:this is what I came up with based on the descritions on her site and given that it's of a similar design to some of her other pedals....

Any comments are appreciated.

It's a two transistor circuit.

From the Etsy page:

Karaoke Party

INPUT - IN1
GROUND - GND (either one)
9volt + - 9v (either one)
OUTPUT - OUT

3.3m resistor from middle of Q1 to IN1

R1 - jumper
R2 - 2.2M (red red green)
R3 - 10K (brown black orange)

C1 - .1uF (104)
C3 - .1uF (104)

Q2 - MPSA18 (same orientation as Q1 screen print)

Emphasis is mine

I'm not convinced to be honest, on every other description on her Etsy page she clearly states Q1 AND Q2 if they are used. I think what she means by the "3.3m resistor to middle of Q1" is that one end of the resistor goes into the middle hole of the Q1 on the PCB, the other 2 holes are left empty. I may be wrong, but given that her directions always clearly state the type of transistor used in each position, and also every circuit she has with 2 mpsa18s sound absolutely mental, I definitely think it's a 1 transistor circuit. That said, given the sound of the circuit, I would have expected there to be 2 transistors in there too! Hopefully someone will be able to track down some guts shots for us anyway to clear it up

thats what i think too

It sounds a though there is way too much gain on tap for this to be a one transistor pedal.

Steven_M wrote:It sounds a though there is way too much gain on tap for this to be a one transistor pedal.

Having said that!

Look at this thread:

https://www.freestompboxes.org/viewtopic ... 33&t=11525

Two of the same booster PCB's in the same box! Maybe I AM smoking crack.

Steven_M wrote:It sounds a though there is way too much gain on tap for this to be a one transistor pedal.

Yeah I totally get what you're saying, when I listen to the pedal I think the exact same thing. Just a thought, but the mpsa18 is a pretty high gain transistor as it's a darlington transistor, maybe one would be enough to give the drive the Karaoke Party needs? As I said before, guts shots may be the only way we'll be able to properly work it out

ever hear of the bazz fuss?

teej212 wrote:ever hear of the bazz fuss?

Of course, but the diode is doing a lot of the work there.

Anyone manage to track down any more info on this? Been trying to find gut shots online but no luck so far. Dying to build two of these into one pedal!!

Some developments on this over on the Devi Ever forums. jjthechemist worked out the following schematic from which I them made a stripboard layout. Putting them here as they may be of some use to somebody. Please note the direction of the Transistor may be incorrect so best to socket it and see which direction gives the desired results. It is currently unverified!

Colour me embarrassed. Here is the official Devi Ever schematic for the Karaoke Party: It is one transistor after all!

As drawn...



POP

Hides-His-Eyes wrote:As drawn...



POP

That's what I thought. What is that 2.2M resistor doing aside from stopping the input cap from blocking DC?

Limiting the current flowing into the input jack, of course.