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Topics - PhiloB

Pages: [1] 2 3 ... 9
1
Open Discussion / Switch to swap pots in op-amp feedback *pop*
« on: August 05, 2018, 08:21:09 PM »
I have a friend that wants a simple pedal to set 2 different vol/gain levels and provide a buffer.  I thought a simple approach would be to use an op-amp and vary the feedback resistor.  I decided to lay it out as below in hopes to keep the impedance low on output.  He wants the max volume to be unity gain.  My problem is there is pop when I switch between pots.  I suspect DC build up.  I tried using "pull-down" resistors either side of the pots with no luck.  Do I need to use 2 separate sides of the op-amp and switch between op-amps?  Or can I utilize the current layout and deal with the DC?  Thanks for any help.

2
Open Discussion / General Op-Amp question
« on: February 04, 2018, 07:51:36 AM »
I built a basic op-amp overdrive last night and got very low output but everything sounded and functioned well otherwise.  I decided to use my audio probe to see where the output dropped and discovered there was no audio at PIN 6 (JRC4558) and very low output at PIN 7.  I decided it was probably the resistor in the negative feedback loop and found out I had some 1k resistors in my 22k bag.  Problem solved.
But now I'm confused as to why I don't get audio with my probe at the input (PIN 6) but I do at the output (PIN 7).  Can someone help me understand why I can't "hear" the signal at PIN6?
To keep it Madbean, here is a similar schematic:

3
Open Discussion / Ernie Ball as a AB panning pedal
« on: August 22, 2017, 10:13:46 AM »
I have a guy who wants to split his guitar signal coming off his board.  He wants to be able to direct his signal either to his acoustic amp or electric amp.  He also wants to be able to blend the two. 
I've never done this but I am concerned about volume when at the 50/50 mark on the pan.  Each amp would only receive 50% of the signal.  Wouldn't the perceived volume in the audience be significantly less with only 1/2 signal to each amp.  Not to mention changes in tone from the amps themselves.
Is there a better approach than just a simple Pan from one amp to another?


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4
Build Reports / Lost Cosmonaut (Total Recall)
« on: July 28, 2017, 08:14:53 PM »
It's been a while since I built a Madbean project and I've been eyeing this one a while.  Had a guy in town post he was interested in building one and might need some guidance.  So we decided to go in together and do up some nice boxes.
Madbean did a bang up job!! Fit perfectly in the 125BB.  Used the Xvive chip with no issues.  Biased by ear and sounds awesome.  I had a vintage DMM on my bench back in April for repair and this one certainly seems less noisy-but still noisy in the repeats:)
I did have an issue with the regulator.  The voltages were all wrong.  It was like I was getting -30v to ground.  I checked all my solder joints and polarity on components.  I had taken a great deal of time and effort to line up the regulator up with the silkscreen and have it laying flat on the PCB.   I lifted the regulator off the PCB just barely and all voltages were corrected.  I built a second board and it had the same issue.  As soon as I lifted the board a bit voltages are good.  Is this a fluke?  Was voltage jumping from the input tab to the ground plane on the PCB through the hole in the PCB?  Sounds crazy but both circuits work perfectly with them just slightly of the board.
Anyway, sounds great.  Incredible planning on Madbeans part...there was like a 1mm clearance around the PCB and enclosure.
Used Inkscape to do up the artwork and had PedalPartsPlus do the printing.  If their printing had been off just a little, things wouldn't have fit. 
Had a lot of fun/challenge in building this circuit.  Now to have fun playing!!


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5
General Questions / Total Recall Compander Question
« on: July 21, 2017, 06:29:28 AM »
I built the Total Recall (plan to do a build report soon) and it is a superb project.  Kudos to Mr. Madbean:)
I have a question about the compander.  I was unable to find the NE570 at Smallbear so I ordered the "equivalent" Coolaudio V571D.  Any draw back here?  I'm hearing a decent amount of hiss that accompanies the repeats and disappears when the repeats fade which I assume is a result of the work the compander is doing.  Is it worth pursuing the original NE570 chip or will it have a similar noise level?

Thanks!


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6
General Questions / Total Recall Resistor value
« on: July 07, 2017, 09:41:45 PM »
I'm preparing to build the Total Recall.  The BOM calls for a 24k3 and 33k2.  I thought I had ordered carbon film resistors (5%) of the values 24k and 33k and planned on finding values close.  Apparently I didn't do a good job of ordering.  Looking at the schematic though, R23 and R24 don't look too critical if I use a 24k and 33k (1% Metal Film) Resistor.  Looks like they are responsible for setting gain and rc filter for IC3.  I only ask because those values are so specific.  Want to make sure I'm not missing something!
Thanks,
Phillip


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7
General Questions / HSS Strat - suggestion for the "H"
« on: May 25, 2017, 07:44:51 AM »
I picked up a used $150 LTD St-203 (Strat) because the pickups sounded really great and the neck was equally nice.  Problem is, I already own a Strat with Sunday Handwound pickups that sounds great (but different).
For versatility, I'm thinking about replacing the bridge with a humbucker.  The neck and middle measure right at 6.0k resistance.
I've watched video after video on YouTube.
Here is what I think I want....
1. A pickup that will compliment the neck and middle eq wise (not sound out of place).  From my research, all I've been able to determine is that the stock pickups are Alnico - I suspect Alnico ii based on the sound.  Again they are around 6.0k
2. 4 conductor wire so I can wire position 2 with a single coil of the humbucker and get the traditional strat quack.
3.  Low out put humbucker (ill wire the bridge position to be a full humbucker - not coil split.) By low output I just mean that volume wise, I don't want a big jump in output when going from neck to bridge. 
4. Being a budget guitar, I don't care to drop a lot of money on a pickup.  I'd love to pick one up for between 50-75 but that's not hard and fast.  If there is something that costs more but well worth the investment I'd entertain it.

I respect the collective opinion of Madbean forum.

Phillip


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8
General Questions / 'Clickless' Bypass circuit that doesn't loose signal
« on: October 10, 2016, 06:30:17 AM »
Anyone have a project out there that allows use of a momentary switch that doesn't drop audio?  My brief searches turn up complaints about signal loss when depressed.


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9
Open Discussion / NGD - sorta
« on: March 19, 2016, 11:20:29 AM »
I've been wanting an offset body guitar for a while.  A squier Jagmaster came up on Craigslist and guy took a volume pedal and a little cash for it.  I had a nice neck (roasted maple with compound radius), Gibson 490r/t pickups and a Callaham bridge from a previous build that was not in use.  Didn't realize the original tremolo was a 2 point until I got it and it is an odd size (not typical USA strat distance apart).  So I decided to DIY the bridge.  The original bridge plate seemed of equal quality/weight as the Callaham and the string spacing was the same so I broke out the router and made room the full size trem block!
The result is probably the most comfortable guitar I have.  The neck is fat (like I like'm).  The ebony fretboard feels really nice.  Compound radius makes for low action.  Alnico ii pups make for a clear and beautiful tone.  And the bridge is solid and stays in tune despite abusing the vibrato.  I'm a huge strat fan but loving this guitar atm.
I plan on replacing the tuning pegs for Grover staggered locking tuners (they'll fit the current holes and I can be rid of the red knobs!!) and I want to try my hand at Reranch spraying and change the color.  What color should I go with?


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10
Introductions / Long time no see
« on: March 11, 2016, 08:58:49 AM »
Hey folks.  I rarely use my laptop for Madbean and Tapatalk for my phone stopped working for this forum for many months (although I think I may have been the only one with issue??)
So, I've basically been out of the loop.  Tried the Tapatalk this morning and I could view threads again!!  Now I don't have to look at stupid Facebook when I'm on the toilet anymore!!!
Look forward to seeing you around:)
Phillip


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11
Open Discussion / Master's in Ignorance from Big Dummy U
« on: May 10, 2015, 07:09:50 PM »
So I received my honorary Master's Degree from Big Dummy University today.
I built a 1776 Multiplex+modulation+RDD.  Sounds REALLY nice.  I decided to play it for a while and decide what mods I want to do (playing with ramp speed and such) before boxing it up.
So today I just wanted to play it.  I patched the testing rig into my pedal board so I could try it out with my dirt pedals.
Played it for about 5 minutes and really enjoyed it.  Then I decided to try a different mode on the delay but couldn't get the Delay 1 head to engage- been playing in EP-3 mode.  Then start playing with the mix and feedback knobs and they made no difference!!  Turns out none of my controls work!  I'm hearing delay+modulation+reverb but NONE of the controls work!! How could this be:(
Well, turns out I had forgotten that the last time I played had not been with the testing rig.  My Hamlet+ delay was engaged with modulation and the reverb on my amp was turned up pretty high.  THE TESTING RIG WAS IN BYPASS.
Guess what, it worked fine once I turned it on:/
I love the combo BTW.  Way to go Josh.

Proof that it works:)

http://soundcloud.com/resuggan/multiplex-with-modulation-rdd

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12
Open Discussion / Attention to detail - {video}
« on: May 05, 2015, 11:07:32 AM »
Came across the this video today.  The amount of care and precision that goes into this blew my mind and challenged my attitude and approach to pedal building.
Hopefully some of you will enjoy this as much as I did.
http://www.facebook.com/marcospereira1010/videos/877509138981816/




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13
Open Discussion / Humbucker Polarity Question
« on: May 04, 2015, 08:27:06 PM »
I'm working on a HH strat.  In fact it is close to being done.  I have the adjustable pole pieces on the neck pickup closest to the headstock and the adjustable pole pieces of the bridge pup closest to the bridge. 
In the middle position of the switch with both pups full volume I get a thin, out of phase sound.  Both pickups are Gibson, 490r/t. I bought them used.
When I drop a magnet on them,  the neck pickup attracts at the adjustable pole pieces. the bridge attracts at the fixed pole pieces.
I am assuming I need to spin the magnet around on one of the pickups.  I'm double checking here because I'll have to remove the cover that I just secured with silicon when adding the cover:(. Hate to go through all that if I'm mistaken!

Thanks,
Phillip

Poor photo:


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14
So a guy in town bought 8 Klons and was doing a Shootout.  He had bought a GrindCustoms build off CL (I had built one for an acquaintance who decided to get out of music and sold off all his gear).
So, he advertised it on Facebook and I decided to attend.  I was the only one to attend:)
He had a KTR, Mythical Od, Arc Effects, Soul Food, JHS Soul Food, Hinson Klon, Grind Customs and one other I can't remember currently.
I sat at the back of the room and took notes as he played each one with similar settings (originally we went through all 8 set as a relatively clean boost through a Morgan amp).
I picked 1 and 8 as top.  They were both quite unique from the rest of the pack.  Ultimately 8 won out because I preferred the break up a little better.
Turns out I picked the GrindCustoms Chimarae as best sounding.  KTR was second with the rest paleing in comparison.
All this really means is that:
1. I prefer Rej's Od circuit
2.  There is someone out there willing to buy 8 Klon Klones!
That it might be of interest to some.

BTW, I used the I go off the BYOC thread to pick components and values for the Chimaera.


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15
Open Discussion / Octave up
« on: May 02, 2015, 09:38:47 AM »
Don't know if it's been discussed:
http://www.bigfootengineering.com/octave.html

Seems pretty cool.

Any similar effects out there?


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