TS808 Build Issue - No Sound

[Ncuab]

I'm building a TS808 with the clipping option and I'm not getting any sound.  I'm able to trace my sound all the way to transistor Q2 and the 100R resistor attached to the E leg of Q2.  I even used my multimeter to check continuity from transistor Q2 to the output and I get continuity so I have no idea why I'm not getting any sound.

Here are some pics:

[Ncuab]

Oops, I forgot the tone knob.

[induction]

I haven't found any build errors in the pictures (so far). But continuity between Q2 emitter and output suggests a shorted output cap (10u). That cap should prevent continuity there. Set your DMM to DC volts and measure between the output node and ground. It should read close to 0V. If the output cap is shorted it will read much higher (somewhere around 4.5V). Measuring across the output cap will be the opposite: you should read about 4.5V, but if the cap is shorted it will read close to 0V.

[MOPO]

Hello,

At home laTS808 (with clipping switch) works fine but at the modes, there is a big drop in volume when one switches the mode of 1N4148 diodes.

If you solved your problem can you tell me if you have the same thing?

@ +

[Bugsi]

What transistors did you use?
The TS808 schematic calls for 2N3904, but they're just buffers, and any decent low-noise transistor will work, with 2SC1815 being a common replacement.

2N3904 and 2SC1815 have a different pinout.  

2N3904 is EBC, nad 2SC1815 is ECB.  The stripboard layouts are set up for EBC.  If you use a transistor that is ECB, you have to twist the right-most legs so they fit in the other's position.  (reading the pins left-to-right with the flat facing you.)

Since you socketed your transistors, if that's your problem you have an easy fix.

Good luck!

[Silver Blues]

I believe the 2SC1815 was the original spec component. The 3904 are called for because they are a more commonly available part number.

[Travis]

For anyone looking for 2SC1815, check eBay. You can get them for under $0.02 each without hardly searching at all

[Muadzin]

MOPO wrote

Hello,

At home laTS808 (with clipping switch) works fine but at the modes, there is a big drop in volume when one switches the mode of 1N4148 diodes.

If you solved your problem can you tell me if you have the same thing?

@ +

The clipping switch has three settings, 1N4148's, diode lift and LED's. The last two make for a massive boost in volume compared to the 1N4148 setting, which is the stock and thus normal sound if you hadn't included the mod. So to me it sounds like everything sounds like it should.

On a side note, you should keep in mind that the human ear/mind loves loud volume. When given two identical pieces of music, but one is louder then the other, then the human brain thinks that the louder version sounds better. The music industry knows this and thus mixes its music to sound as loud as possible, to the point of killing all dynamics. Apply this to a diode switch on a dirt pedal and the same thing will happen. More of us will like the louder setting, even though the softer setting may be less compressed. Or as in your case think there is something wrong with the softer setting.

[Bugsi]

Silver Blues wrote

I believe the 2SC1815 was the original spec component. The 3904 are called for because they are a more commonly available part number.

Either way, the stripboard layout is set up for the 3904 pinout, so if you're using transistors that are ECB instead of the EBC that the board is set up for, your circuit isn't going to work unless you bend the transistor leads to swap their position.  If the build is otherwise done correctly, I suspect this might be the problem.

2SC1815 is available at taydaelectronics for $0.03.

[Silver Blues]

Yes exactly.