Lovepedal Purple Plexi Help

[canman]

Hey guys,

My uncle is having me build him a two-in-one pedal, and one of the circuits he wants is the Purple Plexi 800, so I built it from this layout: http://tagboardeffects.blogspot.com/2011/02/lovepedal-purple-plexi-800.html. 

I just got the board all populated and tested the circuit.  Everything works as it should, but I know it isn't right.  It just doesn't sound open and super crunchy like the videos all demonstrate.  I didn't replace any values on the layout, and the sound I'm getting is just weird.  It doesn't sound like a cranked Marshall, it sounds almost fuzz-ish.  The frequency knob functions as it should, and the gain and volume knobs both work, but the sound is really thick and muddy, even with the frequency knob dimed. 

What confuses me even further is when I'm on the bridge pickup, it's extremely muddy.  When I switch to the neck pickup, it actually gets less muddy...    Every other pedal I use does the opposite of this!!  Has anyone ever encountered that before?  Maybe it's just how my pickups react to this circuit, but it just doesn't seem right.

Anyways, is this thing supposed to sound like it's covered in mud and then wrapped in a blanket?  If so, I'm telling my uncle we're doing a different circuit, haha. 

Oh by the way, I have a few different LM386 chips that I ran through...one didn't work, but I've got a couple that get the circuit working and they both sound the same. 

I'll post voltages tomorrow, but I at least wanted to get this up tonight and see what you guys thought.

Thanks!

[pappasmurfsharem]

Hey guys,

My uncle is having me build him a two-in-one pedal, and one of the circuits he wants is the Purple Plexi 800, so I built it from this layout: http://tagboardeffects.blogspot.com/2011/02/lovepedal-purple-plexi-800.html.  

I just got the board all populated and tested the circuit.  Everything works as it should, but I know it isn't right.  It just doesn't sound open and super crunchy like the videos all demonstrate.  I didn't replace any values on the layout, and the sound I'm getting is just weird.  It doesn't sound like a cranked Marshall, it sounds almost fuzz-ish.  The frequency knob functions as it should, and the gain and volume knobs both work, but the sound is really thick and muddy, even with the frequency knob dimed.  

What confuses me even further is when I'm on the bridge pickup, it's extremely muddy.  When I switch to the neck pickup, it actually gets less muddy...    Every other pedal I use does the opposite of this!!  Has anyone ever encountered that before?  Maybe it's just how my pickups react to this circuit, but it just doesn't seem right.

Anyways, is this thing supposed to sound like it's covered in mud and then wrapped in a blanket?  If so, I'm telling my uncle we're doing a different circuit, haha.  

Oh by the way, I have a few different LM386 chips that I ran through...one didn't work, but I've got a couple that get the circuit working and they both sound the same.  

I'll post voltages tomorrow, but I at least wanted to get this up tonight and see what you guys thought.

Thanks!

Are you certain of the cap values used? Are your 4n7's actually 47n or 470n?

[canman]

Here are the voltages for the LM386:

1: 1.41
2: 0
3: 0
4: 0
5: 7.38
6: 8.48
7: 4.36
8: 1.4

As far as the cap values go, I'm fairly certain I used the correct values (4.7n, 100n, 47u)...the 4.7n caps are little guys, I don't think 47n caps would be this small.  Could be wrong though!

[gjcamann]

canman? Are you a proctologist?   

I've never been able to get a PP (or Smashdrive or any other variant) working to my liking. Every few months I try again and still just a bunch of fizzyness.  It all depends on taking an LM386 and trying to get it to do something it isn't designed to do. There is a big difference in the chip variants, the -3 and -4 each sound quite different. If you're looking for a simple marshal sound you may want to try the Rust Driver. But again they're both such simple circuits you can't expect too great of things from either. The COT50 may be a better bet.

You may want to look at the COT50 or Les Luis, which are both easy, great sounding and very easy to tweak.

[canman]

So I'm building this and a Sweet Honey overdrive for my uncle, got the Sweet Honey working first try.  Great circuit. 

I'm open to trying a different circuit, the problem is that I only really have some TL072's (maybe one or two TL074) and some 2n5088's to work with.  Any solid mid-higher gain distortion/overdrive circuits that you guys know of that could utilize these components?

[nocentelli]

You could try out a rustdriver with the TL072, it's a decent sound for a simple circuit, and supposed to be Marshall-ish. I would add a 1M pot instead of the 470k in the feedback loop so you've got a gain control. I wouldn't bother with the tone cap switch, just put a small cap to ground before the volume pot, value to taste (maybe 1n to 4n7) depending on how bright you like it. I have also used a 50k pot as a variable resistor instead of the output resistor leading the tone cap so it works as a simple treble roll-off in front of the volume pot.

[canman]

I just found the Ross Distortion, I may give that one a try...simple circuit, sounds cool...just gotta figure out how to put a tone control in there!

[jimilee]

The one I built sounded like this and all the you tube videos I've heard sound this way too. Built it for a buddy, he loves it.

[canman]

Built the Ross distortion, sounds good!

However...it's driving me nuts that I can't get this circuit to sound right!  I'm using the LM386L, I've read people have had mixed results with the 386L...some are successful, others aren't.  So I'm inclined to believe I've screwed up somewhere in the circuit, except I can't find where.  Do my voltages look OK?  I'm wondering if pin 3 should be 0, since it's an audio amp instead of a dual opamp?

Any ideas?

[pappasmurfsharem]

Built the Ross distortion, sounds good!

However...it's driving me nuts that I can't get this circuit to sound right!  I'm using the LM386L, I've read people have had mixed results with the 386L...some are successful, others aren't.  So I'm inclined to believe I've screwed up somewhere in the circuit, except I can't find where.  Do my voltages look OK?  I'm wondering if pin 3 should be 0, since it's an audio amp instead of a dual opamp?

Any ideas?

what are you running it into?

[gjcamann]

So I'm building this and a Sweet Honey overdrive for my uncle, got the Sweet Honey working first try.  Great circuit. 

I'm open to trying a different circuit, the problem is that I only really have some TL072's (maybe one or two TL074) and some 2n5088's to work with.  Any solid mid-higher gain distortion/overdrive circuits that you guys know of that could utilize these components?

You can use 2N5088's for the COT50 and Les Luis.

[canman]

what are you running it into?

Do you mean what amp am I running it into?  I'm running my guitar into the purple plexi into my egnater tweaker 15.