R.G. here's my official ROG Ruby "What to do when it doesn't work" post.

[Hiwatt25]

Okay, here's my official "What to do when it doesn't work" post for my ruby build.

1)   This project is the ROG ruby amplifier based on Torchy's VERO layout.
2)   
3)   Now, unless I've done something wrong I followed the layout as it is represented on Torchy's layout with the exception of the 1K pot (to simplfy things)
4)   I didn't substitute any parts in fact I ordered parts just for this project and waited dutifully for them to arrive.
5)   I believe it's a positive ground circuit because the positive lead is connected to the board.  (I've connected the negative lead of the battery to the ground post on the jack)
6)   Right now, some of my guitar signal is coming through (but very distorted) and it's also picking up a local sports talk station here in Danbury.  The ruby was saying something about Terrell Owens if that helps. If I turn it up too much it begins to howl like a Dallas fan.  Coincidentally, this is the second Ruby that I've built this week and it was making the same noises.

Now for the Voltmeter stuff

Q1: Measured from the pin to the jack ground.
G = 5.21
S = 6.38
D = 8.35

IC1 (or U1):  As with the transistor, I measured from the pin to the jack ground.
P1=1.32
P2=0.00 and the radio station got louder and clearer when my probe touched the pin
P3=0.00
P4=0.00
P5=4.00
P6=8.29 and all sound stopped when my probe hit this pin
P7=4.16
P8=1.31

Okay, that's it.  Thanks all for the help thus far and a hardy hazza to R.G.

[R.G.]

Q1: Measured from the pin to the jack ground.
G = 5.21
S = 6.38
D = 8.35

Here's a problem. The schematic shows that gate as grounded by the 1.5M resistor. You measure it at +5.2V. So something is pulling the gate of the JFET up. Is your 1.5M resistor somehow shorting to +9? or to some other point?

The voltages on the amplifier chip don't look too bad. Have you checked the pinout of the actual JFET that you have against the manufacturer's datasheet?

It is possible, given the radio pickup that you're getting, that the thing is actually working, but you are picking up a huge amount of radio and that's overwhelming the amplifier.

Do this. Check out your JFET. Something is wrong there. If you have these spare parts, put a 100ohm to 1k resistor in series at the input, before it comes onto the board, and a small ceramic capcitor to ground, right across the 1.5M resistor. Also, if you have a 0.01uF to 0.1uF plastic film or ceramic cap, put it across the chip from pin 6 to pin 4.  Those changes will kill off a lot of RF.

See what you get from there.

[Hiwatt25]

Thanks again R.G.  I'll double check the jfet and make the suggested changes.  Thanks for taking the time to look over my numbers. 

[Hiwatt25]

Okay, I made the changes you suggested with some results but was still getting a good bit of sports talk.  Apparently someone named Pete Rose should have known better than to bet on baseball.

Totally flummoxed, I replaced the IC with no luck so I replaced the JFET as well (for the second time) and Voila!  I was rocking moments later when I stuck my smalley boost in front of the Ruby and wired the Ruby to an old Tannoy arena speaker I had in the garage.  Oh, and I guess you could figure out from my screen name that I'll be sticking witht the "Hiwatt" mod.

I swear I replaced the JFET once before so either I destroyed two of them or Futurlec sent me two bad ones.  I really appreciate all your time and I'm sorry that I wasted it. 

The good news is that the layout is verified and now I have two ruby's. 

Thanks again R.G. you are in charge of the planet.

[R.G.]

It's not a waste of my time. You're now a bit more knowledgeable, a bit more capable of doing your own electronics work, and a bit more likely to keep doing so.

You and other like you will buy parts and magazines with DIY articles and that will send a message to the sellers that there is a DIY market there, so they'll keep parts and information flowing. And soon the WHOLE WORLD  will be making their own electronics, and ...

... and friends, it's a movement.

I'm actually just a soldier in the guerilla war to keep electronics from being something only factories do.



Che Keen

[Hiwatt25]

Do I smell a book in the works..."Guerilla Electronics" by Ernesto R.G. Guevarra?     Thanks again. 

[petemoore]

  aaaah- >HA< !!!
  The unterior motive slips out !!!
  Good One!!! [lol].
  Nothing against super cheep mass produced items: in moderation .
  If they take over to the exclusion of all else, that IS a problem, hopefully as long as human ears can scrutinize, there will be 'Independant Electronic Experimentation and Development. Abbr. to: 'IEE' or 'IIED'
  Who Is Going to be Designing the next kool Gizmoes that time demands...if all possible components are SMT's applied to existing design boards.
  Never forget How designs often come about: You have a need, look over your boxes and sacks of parts, find what you need, and apply it !
  ...~almost that simple~...
  May DIY electronics live forever !!!

[baddayinparadise]

I now have the same problem, a lot of gain, and some radio talk. Apparently, Jeff Gordon just crashed. Is it safe to say that my JFET is also faulty? it is from radio shack, so I don't have high hopes for it. The only modding I did to it was I used a 100K pot in parallel with a 1k5 resistor for gain, since I don't have a 1k pot.

[R.G.]

Is it safe to say that my JFET is also faulty?

It's sure a good place to start.

[baddayinparadise]

I found the problem. I replaced the JFET and I had forgotten to connect the ground to the input jack.

[baddayinparadise]

now it's really quiet.  How can I fix this?

[R.G.]

Define "really quiet".

[brett]

If there's a bug, please send the voltages, like Hiwatt25 did.
An audio probe is also VERY handy. (A ruby makes an excellent audio probe amp, by the way).
Cheers

[baddayinparadise]

the amp is not as loud as the guitar itself. Also, in order to send the voltages, i would have to have a DMM, and in order for that to happen, I would have to have money. Could it just be a bad battery?

[brett]

If it's quiet and very distorted, it could easily be a battery.
Use the search function to find the place that sells cheap meters (? $5).

[R.G.]

the amp is not as loud as the guitar itself. Also, in order to send the voltages, i would have to have a DMM, and in order for that to happen, I would have to have money. Could it just be a bad battery?

Without a meter, it could be anything. Using a meter is the only way to separate out some issues other than rebuilding the whole unit, or relying on sheer chance.

Without money, you might also be able to borrow a meter, or find a new friend who also happens to have a meter and might even enjoy helping you out.