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Author Topic: Fiendmaster question
octa805

Posts: 13
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Post Re: Fiendmaster question
on: September 24, 2012, 19:41
Quote

hello. I have an update.

I got the LED to work. then I blew it up somehow

I cleaned up the connections, checked the schematic a ton. it works but it really fizzes out on the decay and when the tone is all the way up on the treble it barely comes through with any signal at all.

even full gain cranked it's not much above unity even at low volumes

this thing is driving me nuts

Schrodinge-
rsgoldfish

Posts: 105
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Post Re: Fiendmaster question
on: September 24, 2012, 22:41
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Ya,don't know what to tell you, I have the problem with that aggresive gating, too.

octa805

Posts: 13
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Post Re: Fiendmaster question
on: September 25, 2012, 08:14
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wahhhhhhhhhhhhhh!

bring out the wa-mbulance!!!!!!!!!

paging Dr. Gore

Schrodinge-
rsgoldfish

Posts: 105
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Post Re: Fiendmaster question
on: September 25, 2012, 09:56
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wait.... are we talking about the Dallas Rangemaster clone or the Fuzzbox? I have the gating problem with the fuzz, not the rangemaster. whoops.

Digital-
Larry

Posts: 192
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Post Re: Fiendmaster question
on: September 25, 2012, 10:22
Quote

To be clear, I'm talking about this circuit:

https://www.seymourduncan.com/tonefiend/wp-content/uploads/DIY%20Club%20Project%204%20v01.pdf

I am going to go out on a limb here (because I have not built this circuit, what follows is only theoretical) and strongly suggest that you increase the value of R3. As I calculated the DC operating point of that circuit, with R3 = 3.9K the transistor is in saturation. This means you don't get anything out at low signal levels. The DC operating point will set the balance of the clipping and thereby the even/odd harmonic balance. Try increasing it to 10k? Or put a 10k pot in series (with the wiper connected to one end) with the 3.9k - at one end you'll have what you have today, and once Q1 comes out of saturation at DC hopefully the gating behavior will stop and you can dial in what kind of harmonic tone you want. Maybe you'll even want to leave the pot in there.

The AC gain of the circuit is dependent on C3 being a low impedance at signal frequencies. Xc = 1/(6.283 * f * C), or for 22uF and 440 Hz, 16.4 ohms. The gain is then POT1/Xc, or about 10,000/16.4 = 608 assuming there is a high impedance load connected to the output. (Lower gain with lower impedance load). C3 is a polarized capacitor - make sure it's in the right way (+ should be connected to the battery's +).

octa805

Posts: 13
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Post Re: Fiendmaster question
on: September 27, 2012, 08:38
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Larry, this is probably very very helpful information but boy...........it is way over my head

Digital-
Larry

Posts: 192
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Post Re: Fiendmaster question
on: September 27, 2012, 19:53
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(Cough) sorry, not trying to make things worse...

Try a larger value for R3. I'd try 4.7k, 7.5k, 10k, 15k. I think they will all sound different. Choose the one which most rocks your world.

octa805

Posts: 13
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Post Re: Fiendmaster question
on: September 29, 2012, 10:29
Quote

thanks Larry.

farted around w/ my audio probe this morning. my connection at R3 to the socket is pretty jacked.

getting good signal strength at the socket, just not passing to R3 well

gonna try and fix that and see if that does the trick somehow

octa805

Posts: 13
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Post Re: Fiendmaster question
on: October 21, 2012, 18:05
Quote

I'm back! and I made a crappy video!

It's me trying to put the fiendmaster through it's paces so someone can tell me if it sounds reasonable or like barf. or.......reasonable barf!

Please excuse the poor cinematography, sound quality and lack of plot.

first is clean

then you look right into the blinding LED and I have both dials at noon (hardly any volume, lower than unity)

then I flip the blend over to the fatty boombatty deep end and it the volume spikes to barely above unity and sounds more like it should but still miles from my impression of Joe's video.

the other side of the blend didn't get recorded but it is tinny at best w/ low volume.

My assumption, is that at the very least my connections between the 2 ends of the tone caps is not so good.

However, maybe not? They both work, it's just the overall sound just seems weaker than expected so I'd think it has something to do with my connections either in or out? Or perhaps my germ?

Any ideas? I want this to be awesome. Thanks!

Digital-
Larry

Posts: 192
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Post Re: Fiendmaster question
on: October 23, 2012, 17:37
Quote

Well, you're right, it doesn't sound quite right, does it?

Would you go through the schematic and just list the color codes of your resistors and what value they are supposed to be? Strikes me that your LED is REALLY BRIGHT and maybe it is drawing too much current.

Do you have a voltmeter?

If so, measure the battery voltage and then also measure the voltage from battery (-) to the transistor's collector, when there is no signal going through it.

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