Building the Meat Sphere

[idy]

I added a switch so the blend control could either blend the filtered effect with the signal out of the input buffer (stock) or the signal from the return. It sounded kind of funny blending a fuzzed filtered sound with a clean signal, I liked the "phasey" setting available with the blend on clean sounds so I thought...

I pulled up leg one of the "blend" control, the clean input. The leg of the pot went to the middle of a switch. The hole on the board went to one throw, and the return jack tip went to the other.

It works as I expected BUT:  when I set the mode to Bandpass I get feedback/oscillating when the color knob is turned up even a bit. That is a feedback control... If I play I get crazy siren like whoops and screeches, very loud

This only happens when the fuzz box is engaged. With the fuzz bypassed everything is OK.

Any ideas? Can I fix this?

[idy]

I realize that now the input and output (plus filter) of my fuzz are lug one and three of a 10k pot.  Maybe this is not such a great idea.... But it's an improvement on the settings where it works.

[Taylor]

Yeah, that behavior makes sense with it connected that way. It's sort of turning the blend knob into a parallel feedback path, with as you say a fairly low value resistance (the 10k pot) sort of in parallel with the colour pot. You could try adding a buffer on the return input?

[idy]

Thanks. Opamp buffer between return jack and switch. Problem solved. Anybody who wants to mod the blend control can do this.

[Granny Gremlin]

I've been trying to wrap my head around all the (sometimes conflicting - e.g. whether the color pot mod/fix is to jumper pins 1&2 or 2&3.... turns out it's 1&2) info in this thread so I just wanted to run some stuff by y'all to make sure I have my head wrapped around it correctly

1) Moog mod
It was stated that the switch (populated with resistor and extra cap/resistor in parallel) should be connected in place of the 10K resistor that connects UIA pin2 to U1C pin8.  Also stated that if by chance one connects it in place of the 10K connecting U1A pins 1 and 2 it will also work, but weirdly.  Then there was this post (http://www.diystompboxes.com/smfforum/index.php?topic=92894.msg994479#msg994479) showing the place one person connected it (and although I see that their switch wiring was wrong, as mentioned in the next post) nobody payed any attention to where the switch leads were going to on the PCB.  Based on tracing the PCB I think it is going to the wrong place, but I wanted confirmation; my take on it:



2) Bypass wiring mod (maintains fx loop in bypass mode vs stock wiring)
Taylor mentioned that it can be done with a 4P2T stomp (which exist - Tayda has them for $4.50; same price at Bitches).  In this post (http://www.diystompboxes.com/smfforum/index.php?topic=92894.msg988513#msg988513) is a diagram showing the use of of a (fictional?) 5P2T to do this and (in the post before) wondering how it would be possible with a 4P2T.  Somebody suggested the LED wiring was superfluous (it isn't). What is superfluous is switching the send/return jack connections from PCB to I/O jacks at the bypass switch because there's no need... I think ... Anyway, just  wanted to post my idea for this for other brains to confirm (and then I'm sure this will help a lot of people out):



Thanks guys.

[markusw]

I've been trying to wrap my head around all the (sometimes conflicting - e.g. whether the color pot mod/fix is to jumper pins 1&2 or 2&3.... turns out it's 1&2) info in this thread so I just wanted to run some stuff by y'all to make sure I have my head wrapped around it correctly

1) Moog mod
It was stated that the switch (populated with resistor and extra cap/resistor in parallel) should be connected in place of the 10K resistor that connects UIA pin2 to U1C pin8.  Also stated that if by chance one connects it in place of the 10K connecting U1A pins 1 and 2 it will also work, but weirdly.  Then there was this post (http://www.diystompboxes.com/smfforum/index.php?topic=92894.msg994479#msg994479) showing the place one person connected it (and although I see that their switch wiring was wrong, as mentioned in the next post) nobody payed any attention to where the switch leads were going to on the PCB.  Based on tracing the PCB I think it is going to the wrong place, but I wanted confirmation; my take on it:




Thanks guys.

For the colour mod you connect the wiper to the lug connected to the 1k5. 

As indicated in this post
http://www.diystompboxes.com/smfforum/index.php?topic=92894.msg810973#msg810973
it's the top 10k resistor that connects UIA pin2 to U1C pin8 not the one you indicated in green.
Sorry for the late reply.

Regards,
Markus

[Granny Gremlin]

No worries I been busy and haven't had time to move much on this.  So if that's not the right spot (I traced it, but had to guess a bit as it's a dbl-sided PCB and I had it populated already so some bits were blocked from view)- when you say top one, you mean the one just below the swicth; above the one with red leads in the pic?  I'll try tracing again.

[idy]

I can't hear any difference with the moog switch. I have read and re-read the thread and don't think there is a lot of explanation/verification on it. One guy simulated it and liked what it did for his bass, maybe I missed something. Q gets lets as frequency goes up, right? Only affects some settings of LP/BP/HP?
I have yet to hear a difference. Have tried only guitars, but both solid body and electro-acoustic.
So I guess I should ask: Anybody out there hear a real difference on this mod?
I did try it wrong a few times, had to rewire the switch, have looked at the various illustrations and schematic.

But oh how useful is the switch that allows you to blend in either the send or the return with the filtered effect! (buffered it must be.)

[markusw]

No worries I been busy and haven't had time to move much on this.  So if that's not the right spot (I traced it, but had to guess a bit as it's a dbl-sided PCB and I had it populated already so some bits were blocked from view)- when you say top one, you mean the one just below the swicth; above the one with red leads in the pic?  I'll try tracing again.

Exactly, it's the one below the switch above the one with red leads in the pic.

[markusw]

I can't hear any difference with the moog switch. I have read and re-read the thread and don't think there is a lot of explanation/verification on it. One guy simulated it and liked what it did for his bass, maybe I missed something. Q gets lets as frequency goes up, right? Only affects some settings of LP/BP/HP?
I have yet to hear a difference. Have tried only guitars, but both solid body and electro-acoustic.
So I guess I should ask: Anybody out there hear a real difference on this mod?
I did try it wrong a few times, had to rewire the switch, have looked at the various illustrations and schematic.

But oh how useful is the switch that allows you to blend in either the send or the return with the filtered effect! (buffered it must be.)

With the "Moog switch" the resonance is dependent on the frequency, at lower frequencies there is less resonance than at higher frequencies.
Therefore, it tames the resonance at low frequencies.
The difference between "Meatball" and "Moog" mode is most obvious if the filter range is set lowest and intensity is also set to low.
In "Meatball" mode the low frequencies can become rather unpredictable.   
The difference is clearly more obvious with my bass guitar than with my Telecaster. With bass guitar for me it's an essential mod, in fact I never use my Meatsphere in "Meatball" mode.
Since I always use LP mode I can not really comment on HP or BP. 

[Granny Gremlin]

Thanks.

[idy]

Thanks Marcusw
I'll have to try it with bass.

[DrKoester]

Hey group - i built this project about 3 years ago for my brother and I'm finally building one for myself. 

Unfortunately I don't have many notes or pics from my first go and I can't recall how the rotary switches are oriented on the board.  'Range' and 'Up/Down' have the A, B, and C labeled on the board but it doesn't correspond to the lettered logs on my switches (which are Alpha from Small Bear).

Sorry if this has already been clarified somewhere else - I couldn't find it in this thread.

Thanks in advance for your help!

Update: found the answer herehttp://www.diystompboxes.com/smfforum/index.php?topic=104025.msg930003#msg930003

[chemosis]

i have the same problem and ive built 2. the first one had hardly any sensitivity and no real wah sound. very sublte light effect only and now it dosent work at all. it just creates a loud white noise sound. now my second one also just creates white noise and ive even resolder most components and took the stomp switch out of the equation and tried different IC's and im getting to the point where i just want to pay someone to trouble shoot these 2 meatspheres for me

[DrKoester]

My previous build used the VTLs which I thought sounded decent but I've been swayed by previous posts to use the LDRs.   think I understand the LED/LDR but if someone can confirm for me that'd be great. 

Use one of these green LEDs: http://smallbear-electronics.mybigcommerce.com/led-t-1-3-4-5mm-diffused/
The '+' mark is on the board is for the positive leg of the LED, negative goes in the hole directly below.

Use a LDR like this: http://smallbear-electronics.mybigcommerce.com/photocells-cds-5mm-diameter/
Which is ideal? PN 8104 that has the 2M dark resistance?

Also, does the LED need to 'face' the LDR with any particular orientation to provide the greatest light or is that inconsequential since it is diffused?

Thanks in advance, Tom

[Taylor]

My previous build used the VTLs which I thought sounded decent but I've been swayed by previous posts to use the LDRs.   think I understand the LED/LDR but if someone can confirm for me that'd be great. 

Use one of these green LEDs: http://smallbear-electronics.mybigcommerce.com/led-t-1-3-4-5mm-diffused/
The '+' mark is on the board is for the positive leg of the LED, negative goes in the hole directly below.

With the board right side up so you can read the text: yes, the LED's positive leg (anode) go to the pad marked with the +.
The LED's negative leg (cathode) goes to the pad directly to the left of the one with the +.
The LDR goes into the two pads below the box reading "VTL5C3," and it doesn't matter which way around it goes in.

Use a LDR like this: http://smallbear-electronics.mybigcommerce.com/photocells-cds-5mm-diameter/
Which is ideal? PN 8104 that has the 2M dark resistance?

None of these have the same range of resistance as the 5c3, but that may be what other people liked about the response. I guess the closest one is 9200 - the others all have less range, which would keep the frequency sweep within a smaller area - may be more expressive and less quacky, to use vague sound terms. 

Also, does the LED need to 'face' the LDR with any particular orientation to provide the greatest light or is that inconsequential since it is diffused?

Thanks in advance, Tom

You'll want to point the LED at the face of the LDR, put them right up against each other, and the results would be better if you wrap some black heat shrink around them to isolate them. Here's a relevant thread, seems a good idea to use a piece of a drinking straw or similar before the heat shrink to keep it from getting in the way of light transmission:

http://www.diystompboxes.com/smfforum/index.php?topic=103184.15

[Fine Mechanics]

Hi Taylor. I'm still somewhat stuck with my build. When engaged the unit passes signal but the filter is fixed despite the fact that the LED flashes in line with the attack and decay settings.. Otherwise, all controls seem to be working as expected.

Any ideas why the filter sweep wouldn't be working despite the fact that the LED shows that there's clearly an envelope opening and closing?

Many thanks as always for your assistance.

[Taylor]

I would guess the problem lies with your optocouplers, since you say the envelope generator and audio sections are both working - it must be the part connecting them that's giving you trouble.

Double-check the datasheet for the optocoupler you used to make sure you've got the LED part on top, resistor part on the bottom, and that the positive LED lead is in the right (as in not left) pad.  All directions are with the labeled side of the board facing you, text the correct way up.

[Fine Mechanics]

Taylor, thanks so much for the help. My optocouplers were wired incorrectly. The unit now works and sounds great. After rewiring the optos the LED now seems to have stopped working, so further troubleshooting to be done, but great to finally be 99% of the way there on this one at last!

[Carl James]

  This is my first time in a forum. So please forgive me for being a noob. I love my meat sphere! I just ordered a few more pcbs. But I just can't get the effects loop to work. It just goes silent with the blend clockwise. What did I wire wrong?
   Oh great. I can't figure out how to even upload an image. This is nothing like texting?
    I'm using stereo cliff jacks. They fit very nicely. But I can't figure out what I'm doing wrong? Could someone maybe help me out here? I'm sorry I'm so dumb with this forum stuff. I've just been stuck for 2 weeks and don't know what else to do.
   Thanks guys.