Quote from: Blacklabel on August 12, 2007, 05:00:26 AM
hi, thanks for all you help everyone but now its just blowing fuses ..so ive given up on it ..ill use the case and pots and speaker for another project...and i suggest every one bypasses the fender frontman series when buying an amp....too much trouble..but i thank every one who has helped me out....

My problem as well.  Just blows fuses.  Mine blows them instantly, so I can't even probe to check voltages in the circuit (the only diagnostic on the schematic).  Agree the Frontman series are total garbage.  I'd also advise folks to avoid them.  And I'm going to use the cab and speaker for my own project. 

Quote from: R.G. on August 09, 2007, 12:27:19 AM

Well, there are several obvious design flaws I see in the schemo.

Such as? 

Don't know.  Mine won't turn on because it blows the 500 mA fuse about as quick as a flash bulb when I try to power it up.  I know of several of these failed Frontman 15's.  I'm convinced they're truly a POS amp. 

Quote from: tonyharker on August 05, 2007, 03:06:41 PM
I have a few further questions for you:

have you any photos of your construction you can show us?

I could, but my camera takes photos that are too large to host.  I'll try to figure something out.

Quote from: tonyharker on August 05, 2007, 03:06:41 PM
What did you build the circuit on - PCB or Perfboard?

Perfoboard. 

Quote from: tonyharker on August 05, 2007, 03:06:41 PMWhat is your supply, battery or    If you are using a battery is it a good one?

Battery.  Tried more than one.  All read 8.6V or better.

Quote from: tonyharker on August 05, 2007, 03:06:41 PMWhat FET did you use and are you sure it is the right way round? 

J201.  Yes, I'm sure it's right way round.

Quote from: tonyharker on August 05, 2007, 03:06:41 PMWhat source are you using - a Guitar?

Yes, a guitar.

Quote from: tonyharker on August 05, 2007, 03:06:41 PMHave you tried feeding the input directly into the top of the volume control?

No, haven't tried that.

Quote from: tonyharker on August 05, 2007, 03:06:41 PMHave you adjusted the drain of the FET to 4.5 volts?

No.  I'll measure and see what I have.  My resistance values aren't jiving with what I think they should be.  I think I may have the variable resistor in wrong. 

Quote from: tonyharker on August 05, 2007, 03:06:41 PMSorry about the Qs but it is necessary to find out exactly what you are doing.

Tony.

It's the circuit on the ROG FAQ page as shown here:

Just worked up a Ruby with the 'Fetzer Valve' mode from ROG.  But now I can't get it to work at all.  All I get is a hum.  If I turn the volume pot down all I get is a motorboat noise.  I've retraced the components against the schematic and don't find anything wrong.  Any ideas where I should look? 

Well I took a look at my deceased 15G yesterday.  The area around the power indicator LED (designated LD3 on the schematic on the left side about midway down) appears to be slightly discolored.  I used a 9V batter to apply power directly to the LED.  Tried it both directions and it still lights.  Is this correct?

The issue I have with the amp is that it blows the 500mA fuse immediately on power up.  So I'm searching for what must be a dead short.  But to date I haven't found it. 

Did a "Noisy Cricket" as my first.  Now I'm working on a Ruby with a Fetzer Valve and Condor Cabsim.  Lot more components in the Condor, but it's all just a hobby anyway. 

I recall having seen (somewhere) a schematic to build a bipolar power supply using batteries.  Anyone know where that might be? 

Agree that SS amps need to quit trying to sound 'just like' tubers.  But that will only change if some artist comes out with a 'new' sound that's made with a SS amp.  Until that happens, most musicians will think they haven't arrived until they have a 'real' (read tube) amp.  But I believe SS amps are capable of producing a sound all their own.  I just don't think any serious musician has gone after a new sound like that.  For a different sound most will just use a tube amp with some stompboxes or perhaps a different guitar configuration/tuning.  Jack White has a different tuning for some of his songs.  David Crowder has a REALLY odd tuning.  But a SS amp could have a sound all its own.  Be neat to hear someone who really knows how to make use of one get together with someone who knows how to build what the artist wants and come up with a unique sound.  If that happens, we could see a lot of interest in SS amps. 

Well I think my issues may be due to my desire to use this amp stricly with headphones.  I didn't do anything to reduce the output, just made the circuit like it's on the page in my previous post.  I pulled out an old set of headphones I had laying around that has an inline volume control and turned the volume up on the amp with the 'grit' circuit on.  By upping the gain and volume I was able to make the amp start to distort.  And there was no hiss. 

So my question, how can I add something to cool the output to the headphones without using this ancient set I have (it is kind of cheesy).  Would the addition of a resistor in the circuit just before the phone plug do the trick?

Schematic of the Cricket is here:

http://www.beavisaudio.com/Projects/NoisyCricket/DIY/

Don't know about Beavis' friend though.  Maybe he has an FX site now? 

Anyone built the Whisker Biscuit off the Runoffgroove site?  Are the cap values for the 0.1 and .0047 caps micro-farads or nano-farads?  It doesn't say. 

Just finished my starter project.  The Noisy Cricket from the Beavis Audio site.  Finished debugging it and it works okay.  But I have a hiss in the sound.  And this circuit has a 'grit' switch, but the switch seems to make little difference other than upping the overall volume and hiss levels.  Any ideas on where to start? 

So, again citing my lack of electronics knowledge, does this provide a voltage gain?  If you ran the output of this into a power amp, would that drive a speaker and would this provide an effective control to condition the signal going into the power amp?  Or would it need another amplification stage before it would provide a useful input to a power amp? 

It does appear to have some amplification potential via the JFETs in the circuit.  I just don't know if it will provide sufficient signal boost to feed a power amp.