Easydrive woes..static in the attic.

janus · February 07, 2006, 01:45:41 PM

Hello,
Built an easydrive on perfboard and it works but the noise is out of control. I checked all my grounds 10 times nothing seems to clear it up.As far as components in the circuit to be grounded there are 3 (680ohm resistor, 22uf cap, .01uf cap) I'm using a 2n5088 with an hfe-585. the noise isn't a hum so much as just like a constant loud static almost like hyper hot sounding. can hear the guitar and it sounds good but when you stop playing the static rages. I'm wondering if this sounds like a bad solder somewhere? If so is there a way to use a DMM to check the solders they all look pretty good but I could be wrong. Or it could be something different.am using no pots right now just straight out to mono jacks.. I used all the parts listed on the schematic put 2 33k in a series on the + battery hookup. The only questionable thing is the grounded .01uf cap between the 220k resistors I used a cap that was mustard yellow and square and shiny with the number/letters 103j a5 and am asuming it is a mylar I bought a bag full of stuff a long time ago and didn't label them. I'm really new to this so I'm wondering if I put a electrolytic in there and didn't know it and that's making it go apeshit. any help or suggestions appreciated.
Thanks,
Brian

AdamB · February 07, 2006, 02:03:54 PM

Hey,

I just built the easy drive a day or two ago. I built it with the exact same components except that the transistor is a 2N5089. I think the 5089 is the low noise version of the 5088, so that might be a help. Mines in a thin plastic box and has no noise problems at all. It sounds pretty cool, tho I've found it sounds really good when it's either driving or being driven by a high gain fuzz (like the rocket I also just built).

EDIT: Heres my thread on the easydrive: http://www.elixant.com/~stompbox/smfforum/index.php?topic=41667.0

-Adam

johngreene · February 07, 2006, 02:21:11 PM

When you say static, do you mean hiss? or snappy poppy kind of static. Frying bacon kind of static?

--john

janus · February 07, 2006, 02:59:37 PM

yes like frying alot of bacon. but more constant like when you plug a mic into a board and crank the gain and hear all the noise cause the mic is so hot.

phaeton · February 07, 2006, 03:25:03 PM

I recently built one also (on breadboard). I also used a 2N5089 and it was pretty noise-free. In fact, mine amplified fine but it didn't seem to distort at all.

Nonetheless, the transistor could be the ticket. Try a 2N5089 if you've got one, or anything else if you don't.

puretube · February 07, 2006, 04:01:55 PM

tried a big cap (>10µF, electrolytic) from +9V to ground?
and wiggling the battery-snap?

AdamB · February 07, 2006, 04:19:30 PM

Yea, when I first built mine it was more of a booster than a distortion, I replaced the 680k (mine was actually a 620 as thats the closest I could find) with a 10k and it gave me much more gain to play with.

-Adam

johngreene · February 07, 2006, 04:20:44 PM

Is the noise still there when you turn down the guitar volume?

--john

janus · February 07, 2006, 05:01:41 PM

Is the noise still there when you turn down the guitar volume?

Yes it's there all the time....it's constant. I added a 250k pot on the front and back of the circuit and it did nothing except turn the bacon from quiet to loud.

puretube · February 07, 2006, 05:06:06 PM

QuoteI replaced the 680k

pinout?

janus · February 07, 2006, 05:08:51 PM

Yea, when I first built mine it was more of a booster than a distortion, I replaced the 680k (mine was actually a 620 as thats the closest I could find) with a 10k and it gave me much more gain to play with.

I'm really trying to learn all the theory and reasoning behind circuits. I was wondering why you just don't connect the emitter straight to ground. What is the purpose of the 680k resister and the 22uf cap from the emitter to ground?. Is that to slow current down before it gets there? what would happen if you bypassed it and just connected the emitter to ground?

Joecool85 · February 07, 2006, 05:15:19 PM

If you bypass the resistor/cap combo, you get even more gain.

puretube · February 07, 2006, 05:30:05 PM

one more time: 680k ?

janus · February 07, 2006, 05:31:45 PM

sorry ohm. at least on my build.

puretube · February 07, 2006, 05:39:14 PM

QuoteI replaced the 680k (mine was actually a 620 as thats the closest I could find) with a 10k and...

so the 10k was 10 Ohm, accordingly?

AdamB · February 07, 2006, 07:10:00 PM

Sorry, typo.

-Adam

Paul Perry (Frostwave) · February 07, 2006, 08:19:00 PM

If the 22uF is reversed, dried out, or leaky, you could get a frying noise.

Joecool85 · February 08, 2006, 07:23:56 AM

Here is a solution, bypass the cap and resistor, go straight to ground. If you get sound, that was your problem. Worst case you don't like the tone/too much gain, and then you throw in a new cap and a potentiometer.

janus · February 08, 2006, 11:26:10 AM

thans for all the suggestions! I will get to it tonight. here is a stupid question the negative of the cap goes to ground ..right? That's what I read but it's like a new language to me.
thanks again,
Brian

Joecool85 · February 08, 2006, 11:54:14 AM

yes, the negative of the cap goes to ground. But like I said, a quick check is to bypass the cap and resistor and run the leg of the transistor straight to ground. It should give tons of gain. In fact, the only down side is that some people don't like the tone.

News:

Easydrive woes..static in the attic.