@cybercow
Forum Replies Created
-
Posts
-
mybud – I agree completely. Between Robbie and Ray, the compositional skills and note-for-note articulations are quite underrated. I was amazed to learn years ago how Ray used a Fender Bass Rhodes keyboard for the bass lines. It never occurred to me, (before learning that fact), from where the bass was coming. I assumed they simply had a hired bass player.
mybud – thank you for the kind words.
And yes, you’re right. The first chord progression is from “You’re Lost Little Girl” by the Doors.
And here’s my latest rendition of the dual chorus . . . .
On this one, I added Rate LED indicators. I sunk them just below the surface of the waterslide so they shine from beneath the waterslide. I like the white enclosure and blue theme labeling better than the purple.
Sure. The switch is a 4PDT On-On-On toggle switch.
In these next two photos, you can see where the sync switch ties in between the middle lug (#2) of the Depth (B10K) pots. (Note the yellow & green wires.)
“And you won’t read that book again because the ending’s just too hard to take.”
RIP Gordon> And thanks for all the great tunes.
Two identical builds with pre-verified component values and they both suffer the same high output problem? That is a conundrum! To me tho, that sounds like a win. As long as the controls still exact their influence on the sound as they ought, I’d leave ’em as they are.
But if getting the volume down is important . . . . . . Regardless of the R3 & R4 values, I would focus on that afterburner section with the JFET. I would argue that the 22µF cap adds a considerable boost (and dirties up the signal significantly) and could be pulled temporarily to see how the pedal performs (volume-wise). Pretty sure it will sound a bit less “dirty” with that 22µF cap removed, but it might provide another clue to the high output issue.
I also wonder about the JFET itself. I didn’t see which specific JFET was used. And even if it is the stock value of a J113, I’d suggest swapping it and reset the bias trimmer. If it’s NOT a genuine J113, what did you use in its stead please?
If TR1 is already set to it’s minimum position, the WF mod will have no effect. Have you adjusted TR1 for a correct setting of “near-infinite-repeats when the Repeats pot is set to max?
The WF mod should only need two wires to facilitate. The added stomp should be a normally-open, momentary-on type.
What is the resistor value installed for “R-A”?
If TR1 is already set to it’s minimum position, the WF mod will have no effect. Have you adjusted TR1 for a correct setting of “near-infinite-repeats when the Repeats pot is set to max?
The 2N7000 devices are just for hard clipping. The circuit will work with or without them. It will simply be louder and cleaner without the 2N7000s. D1 is just part of the hard clipping configuration to provide asymmetric clipping. Just make sure it’s oriented properly. If it’s not, it just won’t clip right, but the signal should not be dying out like that if the diode is backwards. Dbl-check that orientation.
As for the dying out, it sounds to me like a cap on the PS line is failing. Do three fast voltage measurements.
First, check the 9v supply at the DC jack when you first power it up. Then measure it again when the signal dies out as demonstrated in your video. Write those down. Both measurements should be about 9v.
Second, check the VB supply (4.5v) at the junction of R12, R13 & C10 when you first power it up. Then measure again when the signal dies. Write those down. Both measurements should be about 4.5v.
Finally, measure the DC voltage between ground and pin 8 of the IC when you first power it up. Then measure again when the signal dies. Write those down. Both measurements should be about 9v.
If the 9v dies out in any of the 9v measurements, remove the IC and test the voltages again. There will be no guitar signal to hear, but the voltage testing without the IC will indicate the IC is bad if the 9v stays at 9v for longer than it take for the signal to die. I’d say about a minute or two between measuring without the chip.
With the chip in and the 9v supply line dies after a minute, C9 may be the culprit.
If the VB (4.5v) supply line dies out after a minute or so, it is likely that C10 is bad. If not, check that R3 is indeed a 470K resistor.
Let us know how that goes.
If those are germanium BJTs, the leakage must be very close to zero in order for voltage measured biasing to work well. Most Ge BJTs have some leakage to them and the Burns Buzz Around fuzz circuit needs Q2 to have some leakage to get “that sound”. I’ve built a few of these circuits and always got the best results when the gain of each BJT is greater than the BJT before it and set the bias by ear. I used the following formula the up-cascading gains on the BJTs:
Q1 Gain: 40 to 60. Q2 Gain: 70 to 90. Q3 Gain: 110 to 140
And as Billy points out, socketed trannies can be problematic if they do not seat firmly. (Strong emphasis on “firmly”.)
Good luck!
Please go back re-read the build document carefully. If you follow that doc to the letter, you will find success. Using a TL071 instead of an LM308 or OP07 might be a problem. The second issue is that R7 AND the trimpot are both in place. Can’t tell what value trimpot you have in there. (Again, that bit is in the build doc.)
And please double & triple-check ALL the grounds.
Looking good Barry. Glad to learn things health wise are turning around for you. Thanks for the update.
If all the grounds involved are common, there is no need to switch the ground wires and a SPDT On-On toggle would do fine.
And whether SPDT or DPDT, anticipate a “pop” when switching the voltage.
