Testing 2SC1815 transistors for noise (the video surprised me)

[M23Bomber]

Hey all,

When I saw this video ,  I got confused on how he does it!!!!!

https://www.youtube.com/watch?v=D6Pvvv1H53A ( https://www.youtube.com/watch?v=D6Pvvv1H53A )

Does anyone else build effects with this level of attention as mr. Giovanetti? I was impressed and also curious.   

He is testing the 2SC1815 (the original transistor in the TS 808 buffer) because he builds "exact copies".

I have so many questions after watching the video, because I would like to do the same, does anyone have a tool that tests for audible noise in transistor when they are in stand by? Im wondering if it all transistors or other transistor will do the same .

Regards,
M.

[R.G.]

Testing devices for noise is simple if you're willing for your "measurement" to be your ears.

You set up the device in the circuit you'll be using it in (the circuit itself will add noise, and to avoid being surprised, you ought to keep that the same. Then you add to the basic circuit a reasonably low-noise amplifying stage to amplify the noise from the device and circuit up so you can hear it, then connect that to an amplifier and listen as you change out devices. Of course, you have to take some care to set up the gains and amplifier volume to be relevant and then not touch the gains to get a true relative noise perception.

I'm not sure how the youtube thing measures noise, as I didn't watch and ponder it very long. But if you want to do a more quantitative noise measurement, you set up the test circuit as above, including the post amplifier to get the noise up out of the noise floor of your measuring equipment, and note carefully the gains an such so you can correct the amplification back out of it. Then you measure the noise of just your amplifier and measurement setup all by itself, so you can subtract that noise back out of your measurements.  With all this done, you can start subbing in devices and measuring the amplified noise, correcting it back down by the amplification factor and applying various measurment techniques - peak to peak, RMS, and bandwidth limiting come to mind immediately. There's a lot of techie work to doing this right.

But you can do a listening test easily enough.

[M23Bomber]

Hey RG,

Your idea thank you

Do you have any Pcb transfer for the ts808 with the 2sc1815?

Pozdrawiam ,
Miguel

[R.G.]

Sorry - I quit making PCB transfers back in the early 2000s.  General Guitar Gadgets licensed my layout, and they sell a PCB for it.

I don't know that it's specific to the 2SC1815, as the difference between these and my favorite, the 2N5088, is only bending two leads, but it's certainly applicable.

The 2N5089 and MPSA18 are quieter yet, and designed specifically for being quiet. Of course, so was the 1815.

[M23Bomber]

I know that there are a ton of mods that can be made to the tube screamers to make them fit to any taste, but in my case its because recently I found a few 2sc1815 And thought to my self why not build a few according to the original spec. I organize a small event to build tube screamers so you can start to imagine he.

Btw I saw your post about the Octave screamer and was a nice read.

Im waiting for the parts to build it.

And what are you up to?

M.