Whistles with a Echoplex Preamp

[JackSkellington]

Hello!
I built this:



from this page:
http://tagboardeffects.blogspot.com/2014/05/a-pair-o-preamps-echoplex-and-tillman.html

It's still out of the box and it seems work fine. It's clean, even with humbuckers.
But I got a strange issue. I got an high picth whistle with the PSU, which doesn't give me any problem with any pedal. With the battery it sound good with any noise. I tried a 100uF filter cap replacing the 47uF, but I got just a lower pitch. And it even lower with the 100uF and the 47uF in parallel, but it's always there. Too much annoying to use the circuit like this.

I'm using a 2N5457, but even the J201 give me the same problem.

These are the voltage measurements:
D: 7.39v
S: 0.22v
G: 0.00v

I need some help, please.

Thanks!

[Scruffie]

Add a small resistor in series with the 9V line.

[JackSkellington]

I'll try it.
Are the transistor voltage ok?

[JackSkellington]

I'll try it.
Are the transistor voltage ok?

Ok, I added a 47R resistor and it worked. I can't hear any difference between the battery and the PSU. I find it a bit weird because the layout is verified, and the voltage of the drain seems to me very high.
Whatever!

Thanks, Scruffle! I had planned to try the resistor trick, but a second opinion is always useful.

[JackSkellington]

Updating.

I'm testing around this circuit:
1. The 3.3k resistor controls the amount of the gain, and I'll keep that, because I like how clean is the sound.
2. The 22nF cap on the right side controls the gain and the tone. I tried some higher value, but I guess that a 2.2uF cap (electrolytic) will be enough to make the sound fat and dirty. I want to add a switch, but the only problem I have to solve is to decrease the volume while I engage the toggle switch, because the 2.2uF gives a big boost.
3. Encrease the 100k resistor in the output I can attenuate the high end, indeed I found it a bit emphasized. Maybe I keep it, anyway.
4. Using a 500k linear pot the volume increase really soon. I'm using a 500k log pot. It's better now.

And now the big problem!
I don't know how, but I hear again that high pitch whistle with the PSU, though it subtle is there. I didn't hear it since I added the 47R resistor in line on the 9v. I don't know if there was always there but I noticed just now.  I'm using a 47uF cap to the ground, and adding a second cap I can low the pitch not the volume.

A copule of thing: the circuit is open now, should I expect that this whistle will disappear after I close it into the box? Honestly, I don't expect this.
Then, when I encrease the volume amp start a loud squeal when I pass the half.

[lrgaraujo]

I've had this whistle problem with mosfet boosts before when using my switching PSU (it is a cheap one, well regulated, but badly filtered)
When I started using a linear PSU this problem stopped.

[JackSkellington]

My PSU is an old Boss (2005, maybe), and it works very well. This is the first time, I guess, that I got this prominent issue.
Anyway, after I had no luck replacing the 47R resistor with a 100R in the 9v, trying a 1N5817 diode I guess I have no whistle at all.

[lrgaraujo]

I'm happy that you've got it sorted out!

These whistling noises can be extremely annoying