Building the Meat Sphere

[BetterOffShred]

Got it going, works pretty good, as stated in the previous 27 pages of information there are some settings where it just doesn't do anything.   I tried a bunch of Small Bear vactrols, and they all worked, but it didn't sound that great.  I had a couple 5537's (2M dark) with red 5mm diffused I rolled for other projects and threw those in there, they sounded way better.  After reading the rest of this I'm going to roll some 5528's (1M dark) with 5mm Green diffused when I get home and try those as well.   I am using a LM1458 from Small Bear and it works great, but I am going to try the 5532 since reports indicate it may even be better.   I haven't done the colour mod, but that's happening, and I'm also going to do the Moog Mod.

EDIT:  I wasn't indicating that the Small Bear products are to blame, Steve's stuff is top notch. I think the circuit just sounds better with the response from the rollies.   

A ways back a Dude mentions that you can run a lead from the intensity pot to the middle lug on the Time pot on some delays and get some envelope controlled delay pitch divebombs, so I may wire up a lead and run that out to a 1/8 jack on the back or something for future implementation. 

Did anyone try LM358's in this yet? I read a few pages back that it may be a suitable replacement due to voltage swing characteristics etc. 

I used the EBay enclosure, from the same seller who sells many great amp chassis, I have the Vibrochamp version.  It's high quality AF though I did have to goose every hole to fit my stuff.  The 4 selector holes I had to go way bigger, and then got some Chrome Vanity washers to hide the oversized holes.   I'll post a pic as soon as I finish the paint job.  I may add an expression jack to the back for control of the intensity pot as mentioned a few times as well.   

It's a bananas circuit for sure, the sweep down with the right settings sounds like some kind of seismic charge going off .. lots of house rattling goodness, maybe the Moog mod will tame this a hair, though it's pretty cool if your cab can handle the sub frequencies.   Mine bumps like Dr. Dre's Impala

-Brett

[BetterOffShred]

5528's and green diffused 5mm, NE5532, are definitely staying in my build.  It really sprang to life with those guys.  All the knobs are way more responsive.  I have yet to do the other two mods so that's all for now. 

[1878]

Hello Everyone.

Need a bit of help here if possible. I plugged in my Meat Sphere a couple of days ago but it was as dead as disco. No sound of any sort, no LED lighting up, nothing. I opened it up and the two 6n8 caps look a little blown.

I'll swap them out soon, but would there be any reason why these two caps have blown other than the fact that they may have been a defective batch etc?

Thanks in advance...

[duck_arse]

.... the two 6n8 caps look a little blown.

look blown how? they [I'm assuming] look to me like stacked-film types with heatshrink covers. I'm not sure heatshrinking that type cap is a good idea, either. if only those cpas "were blown", the other ranges should still werk, surely.

voltages. you know the drill.

[1878]

Blown as in, they didn't look like that when they went in there.

Not a problem. I'll get some voltages & check them against what peeps have posted here.

[Govmnt_Lacky]

Hello Everyone.

Need a bit of help here if possible. I plugged in my Meat Sphere a couple of days ago but it was as dead as disco. No sound of any sort, no LED lighting up, nothing. I opened it up and the two 6n8 caps look a little blown.

I'll swap them out soon, but would there be any reason why these two caps have blown other than the fact that they may have been a defective batch etc?

Thanks in advance...

Could be wrong but, I believe those caps only adjust the envelope. Even if they were blown I do not see how it would cause the whole pedal to be dead. I would start looking at power and grounds. Are you sure the polarity of your PS matches with the wiring of the pedal? Blown protection diodes??

[theehman]

After having this PCB sitting around for a few years I finally got round to finishing it up this weekend.  I've got it working OK, but only in one position of the up/down switch.  I assume UP is working as the LED turns on with the envelope.  In the DOWN position the LED turns on and I can see it go out with the envelope, but there's no signal.  Anyone else run across this problem or have recommendations for a fix?

[BetterOffShred]

Knob position is very important in this build and it definitely has spots where it makes no noise.   So you may want to twiddle there. 

This is a verified board as well, other than a few component changes mine worked first try.  That is to say check your build closely.  I always take a close picture of the board  before I populate it so if I have to go back and look closely it's a lot easier.

Let us know  

[theehman]

While I have no doubts about the PCB quality, I have been over the PCB and corrected a few components (bought populated from another member).  I removed the Vactrols and used 2 green diffused LEDs and jumpered the photocell pads with wires.  Still no signal when in DOWN position.

[BetterOffShred]

Are you certain you used the right type/compatible rotaries?  What opamp did you use?  Mine didn't work super great with a few I tried, but the NE5532 definitely worked awesome.  I used 5528 LDR from eBay. 

[theehman]

Are you certain you used the right type/compatible rotaries?  What opamp did you use?  Mine didn't work super great with a few I tried, but the NE5532 definitely worked awesome.  I used 5528 LDR from eBay.

They look like the correct ones.  They're Alpha and were already installed.  I'm using an MC1458.  I tried a JRC1458 first but I haven't seen any difference.  It had Vactrol VTL5C3 in it when I got it.  I've temporarily removed them and put green LEDs in so I can see the envelope action.

[BetterOffShred]

I don't think it'll work at all with the LDR slot jumpered.   You may want to source the 5528s before any further troubleshooting.  I could be wrong,  but LDRs never go to zero ohms. 

[Govmnt_Lacky]

The original Meatball used 2M dark LDRs and diffused Green LEDs.

You definitely need the LDRs in place for the circuit to work properly.

[vigilante397]

My plan is to read everyone else's posts and see all the issues get sorted out before I stuff my board. Had it sitting around for about a year now

[theehman]

Are these the correct photocells?

https://www.ebay.com/itm/10x-Photo-Light-Sensitive-Resistor-Photoresistor-photocell-cell-5mm-GL5528-DIY/251320127568?hash=item3a83d8d050:g:O0wAAMXQiFxSC2ou

[Govmnt_Lacky]

Are these the correct photocells?

https://www.ebay.com/itm/10x-Photo-Light-Sensitive-Resistor-Photoresistor-photocell-cell-5mm-GL5528-DIY/251320127568?hash=item3a83d8d050:g:O0wAAMXQiFxSC2ou

You could try them however, they only have a 1M dark resistance. The original used 2M dark. You will probably lose quite a bit of the sweep.

I would go with these:

http://www.ebay.com/itm/5-PCs-Photoresistor-GL5537-2-LDR-Photo-Resistors-Light-Dependent-Resistor/161090106076?hash=item2581b7f2dc:g:958AAOSw2GlXG~~~:sc:USPSFirstClass!20636!US!-1

See if they can do combined shipping for 10 pieces

[BetterOffShred]

I bought 2 sets that came with 5508 5516 5528 5537 5539 five if each. They have worked in everything I've tried. 

I read that the 1M worked great elsewhere in this thread but now I want to try the 2M ..  It's easy enough to make another pair with heatshrink.   

I may try it tomorrow after work and report back.   

[theehman]

Just wanted to thank everyone for their patience and support with me while I was troubleshooting my build.  I ended up using the green LEDs and the GL5537 suggested by Govmnt_Lacky and they sound great!
As to what my problem was, let's just say I should not have used one of the external led pads as a grounding point.

[Govmnt_Lacky]

Just wanted to thank everyone for their patience and support with me while I was troubleshooting my build.  I ended up using the green LEDs and the GL5537 suggested by Govmnt_Lacky and they sound great!
As to what my problem was, let's just say I should not have used one of the external led pads as a grounding point.

Good to hear Ron. Funny, after you posted I remembered a similar problem I had with a Meatball build. Turned out the red LED was grounding to edge of a Tayda bezel (Yes... their plastic silver bezels do conduct) and I was seeing the same problem.

[theehman]

And here's my completed pedal.  I'll probably change the label to say Meat Sphere instead.