RAT Distortion

[north99]

Hi all !

Yesterday I just built my RAT from the tonepad layout. All good upon I put the battery on it. I start it and the amp just sounded like hell. It was a low sound/output, a muddy distortion and (i think) some buzz. The DPDT bypass works. I have checked my soldering points, they were all good. Some sugestions?

[nguitar12]

Hi all !

Yesterday I just built my RAT from the tonepad layout. All good upon I put the battery on it. I start it and the amp just sounded like hell. It was a low sound/output, a muddy distortion and (i think) some buzz. The DPDT bypass works. I have checked my soldering points, they were all good. Some sugestions?

This is pretty frustrated but I have to say that if you know nothing of electronic (like me). There are almost nothing you can do when the build doesn't work. All you can do is make sure there no short or break in the circuit. Otherwise you have to rebuild everything. You may also measure the pin voltage and see if someone here can help you on this. But trust me don't hold your breath on this. I have repeated this procedure over and over again and many of my builds end up threw into the bin.

[nocentelli]

Hi all !

Yesterday I just built my RAT from the tonepad layout. All good upon I put the battery on it. I start it and the amp just sounded like hell. It was a low sound/output, a muddy distortion and (i think) some buzz. The DPDT bypass works. I have checked my soldering points, they were all good. Some sugestions?

This is pretty frustrated but I have to say that if you know nothing of electronic (like me). There are almost nothing you can do when the build doesn't work. All you can do is make sure there no short or break in the circuit. Otherwise you have to rebuild everything. You may also measure the pin voltage and see if someone here can help you on this. But trust me don't hold your breath on this. I have repeated this procedure over and over again and many of my builds end up threw into the bin.

Everyone has builds that don't work, and there can't be many builders who haven't failed to track down a fault in a build and eventually just junked it. However, if your builds are regularly failing, that's called systematic error and suggests there is something faulty with building procedure. This could be questionable soldering, or regularly misinterpreting build instructions, misreading parts values etc.

After a few early failures, I stopped just blindly building other people's vero layouts and either designed my own, or started to go over the layout with the schematic laid next to it so I could trace the layout to check a) it was actually a viable working representation of the schematic, and b) that I understood why the parts were placed as they were. This leads to far fewer populating mistakes, e.g. putting in a 100u electro instead of a 100p ceramic: This would be a million times bigger than required required, but is easy to do if you don't know why you're putting it in that spot.

Breadboarding the circuit first will mean you can be certain the parts you have actually work before you commit them to solder; building a bypass looper test box to try out circuits before you box them will mean you can be certain the switch and hardware wiring is not the cause of any fault.

[garcho]

There are countless ways to err. You have to put effort into your post to get any response. Take pictures. Take voltages. Post a link to your layout/schem. Read the post at the top of the forum about "what to do when it doesn't work", etc.

[north99]

I have used the 2N3904 transistor instead of 2N5458... After some research, i think it's wrong... Can I use the BF245C instead of 2N5458?

[Groovenut]

I have used the 2N3904 transistor instead of 2N5458... After some research, i think it's wrong... Can I use the BF245C instead of 2N5458?

2N5458 is a JFET. 2N3904 is a BJT. These two parts are not interchangeable in this circuit without some changes. The BF245C should function fine as a replacement buffer for the 2N5484 without any circuit changes.

[GibsonGM]

There are countless ways to err. You have to put effort into your post to get any response. Take pictures. Take voltages. Post a link to your layout/schem. Read the post at the top of the forum about "what to do when it doesn't work", etc.

Yup ^      The trouble with Vero     Yeah, we can get away with building some things blindly, and often they work if we solder well and follow the directions.  But "kind of an understanding" of what's going on, and some handiness with a meter, go a LONG way in making things work, or work again if they've failed.   

[duck_arse]

another reason builds fail is datasheets. people swap a 2N3904 for a 2N5458 because they haven't checked their datasheets for the parts correct pinout. doing so shows they are different things. and swapping a BF245C for a 2N5458 won't work either, unless the builder has checked the relevants to see that the BF has a diff gate location to the 2N.

a BF245B would be a closer spec part.

[nocentelli]

2N5457 also works great in a Rat.

[deadastronaut]

I have used the 2N3904 transistor instead of 2N5458... After some research, i think it's wrong... Can I use the BF245C instead of 2N5458?

those 3 legged little buggers may look the same.....but they are very different beasts..

 

[Fp-www.Tonepad.com]

You'll pick up on transistor substitutions, cases like these are what make diy a learning experience. And obviously there ARE ways to sub a bjt for a fet, but you'd have to redo the biasing and make sure the pinout of the part is right.

[LightSoundGeometry]

I have been stumped lately with around 12 to the bin, but the last two worked and I think it might be a clean NEW tip, and solder.
BUT
I am sure it was a few errors along the way , and I am glad it happened because it forced me to breadboard a little bit and follow the schematic. I actually had my "aha" moment over the weekend..but now I am stuck again. I cannot move the breadboard to my own vero matrix . I can see it sort of..I can see my + and my ground rail but still getting confused when say 4-5 parts connect and make a run...if that makes any sense lol

well anyways, I have slowed down and working on the board along with pencil and paper to form my pathway through the layout..up until this point I was just copying other veros from t he web and not really learning too much until I hit some problems.

Sometimes I think its the materials ..I always test each piece before populating it. I think new tips are very important and sometimes a bad solder ratio can lead to problems

its kind of refreshing to hear others run into very similar problems I do lol 

[north99]

Ok, new info. I've replaced the 2N5458 with a BF245C transistor, they look equivalent. The problem is that i have some noise, and when im trying to "0000", 1 note is hearing well and the other one is "dropping", its not hearing at all. I dont know what to say...

[Cozybuilder]

As ducky mentioned above, check your pinout.
Looking at the transistor legs down, flat facing you, the pinouts are:
 2N5458: DSG
 BF245C: GSD