Dirtbag Troubles

[jubal81]

I know it's the simple things that always get me.
I don't think I can see any barrier between the backs of your pots and the board. Maybe something is grounding out on the pots ...

[Scruffie]

Little test for ya, try swapping the BBD positions and see if the first remains clean.

I just say this cause I once had a 3208 that distorted like hell, something to rule out.

Then post voltages and check all your values in that area.

Try with a strat or something too just to rule out your pickups overdriving things (I doubt it but it's always good to rule stuff out).

[tenwatt]

I know it's the simple things that always get me.
I don't think I can see any barrier between the backs of your pots and the board. Maybe something is grounding out on the pots ...

I do have double sided tape between the pots and the PCB.

Little test for ya, try swapping the BBD positions and see if the first remains clean.

I just say this cause I once had a 3208 that distorted like hell, something to rule out.

Then post voltages and check all your values in that area.

Try with a strat or something too just to rule out your pickups overdriving things (I doubt it but it's always good to rule stuff out).

Neither BBD gets completely clean.  The both have a bit of a fuzziness to them.  IC5 is just much worse.  I swapped them out and the results seemed to be the same.  I used a Tele and got the same results.

I'm also noticing a whine in the last half of the turn of the "Delay" pot.

Voltages

IC4
1.8mV
4.72V
6.58V
6.58V
7.94V
5.96V
4.72V
8.2V

IC5
1.8mV
4.72V
6.49V
6.49V
7.94V
5.91V
4.72V
8.2V

Delay Pot
4.72
4.65
4.65

[madbean]

Signal seems a bit hot coming off pins 3&4 of each BBD. I'll need to get some voltages from mine for comparison.

One possible solution to reduce distortion is to reduce the signal input to the BBD's even further. This is untested but here are a couple of ideas:

Temporarily disconnect R18 to see if the overload LED is having an influence on noise.
Increase R21 to 100k and reduce C14 to 3n3.
Lower R11 and R12 down to 33k.

Also, do you have the two GAIN trimmers turned all the way down?

[tenwatt]

Also, do you have the two GAIN trimmers turned all the way down?

Yup.  Gain both gain Trimmers are all the way counter-clockwise.  I don't have all the parts you recomended so I'll have to order them and get back with you.

What about the "Delay" pot?  Do the voltages seem right there?  That whine has me wondering if maybe I have a bad joint somewhere.  Should I try reflowing the pins of the pot?

*EDIT* I was looking over the circuit this morning before work (cleaning between solder joints and checking for sold joints) and noticed tht IC2 and IC9 weren't pressed all the way down into their sockets.  I didn't have time before work to test it again, and I don't know if that has anything to do with anything, but I thought I'd share.

[LaceSensor]

disappointingly mine is behaving the same way.
v3205, jumpers are correct. Both delay chips sound distorted as hell.
At some points in the bias travel, I get no signal too.

Hopefully there is a fix for this.

[Scruffie]

disappointingly mine is behaving the same way.
v3205, jumpers are correct. Both delay chips sound distorted as hell.
At some points in the bias travel, I get no signal too.

Hopefully there is a fix for this.

Well no signal with the blend on fully wet would be normal when twisting the bias control, BBDs only work within bias.

@tenwatt
IC4
1.8mV
4.72V
6.58V
6.58V
7.94V
5.96V
4.72V
8.2V

Pins 2 & 6 should be the same voltage for a 50% duty cycle square wave, these are rather different... something wrong between your clock & bbds.

Your ground (Pin 1) shouldn't have voltage on it... being ground and all.

Pin 5 is a littleee off (D2 should drop about 0.6v to make Vdd 14/15th of Vgg) but it shouldn't hurt I don't think...

Keep looking, hopefully pushing down IC2 & 9 has solved your issues.

[LaceSensor]

ill have to do my voltages later.

For now colour me gutted 

[LaceSensor]

just to add mine is doing all the same as Tenwatts, almost to a tee, apart from my volume control seems to work fine.

Even does the whine at high delay settings.

im a bit cautious to start unsoldering parts on the board mostly cos Im a bit rubbish at it.

[Scruffie]

just to add mine is doing all the same as Tenwatts, almost to a tee, apart from my volume control seems to work fine.

Even does the whine at high delay settings.

im a bit cautious to start unsoldering parts on the board mostly cos Im a bit rubbish at it.

You're probably just pushing too much delay out the pedal (perhaps your 2 x 120pF caps = more than 240pF?) and introducing clock whine at the high delay settings.

I read about the measurements of many original Deluxe Memory Mans delay time, 400mS was an average, 550mS might be a little bit of an overstatement.

No need to start unsoldering yet! Post the voltages up and lets have a look.

[tenwatt]

just to add mine is doing all the same as Tenwatts, almost to a tee, apart from my volume control seems to work fine.

My volume works now too.  My ONLY problems are the distorted BBDs and the whine in my "Delay" pot.

Thanx for looking at that stuff, Scruffie.  I'll be checking things out as soon as I get home.

[LaceSensor]

just to add mine is doing all the same as Tenwatts, almost to a tee, apart from my volume control seems to work fine.

Even does the whine at high delay settings.

im a bit cautious to start unsoldering parts on the board mostly cos Im a bit rubbish at it.

You're probably just pushing too much delay out the pedal (perhaps your 2 x 120pF caps = more than 240pF?) and introducing clock whine at the high delay settings.

I read about the measurements of many original Deluxe Memory Mans delay time, 400mS was an average, 550mS might be a little bit of an overstatement.

No need to start unsoldering yet! Post the voltages up and lets have a look.

Sounds reasonable, hopefully.
So, to be clear, if that 240 is LOWER than 240 it could potentially be a good thing, but would give lower delay times (i dont care so long as they sound nice, 300ms is plenty for me). BUT if its over 240pF itll potentially give rise to shit sound.

[Scruffie]

just to add mine is doing all the same as Tenwatts, almost to a tee, apart from my volume control seems to work fine.

Even does the whine at high delay settings.

im a bit cautious to start unsoldering parts on the board mostly cos Im a bit rubbish at it.

You're probably just pushing too much delay out the pedal (perhaps your 2 x 120pF caps = more than 240pF?) and introducing clock whine at the high delay settings.

I read about the measurements of many original Deluxe Memory Mans delay time, 400mS was an average, 550mS might be a little bit of an overstatement.

No need to start unsoldering yet! Post the voltages up and lets have a look.

Sounds reasonable, hopefully.
So, to be clear, if that 240 is LOWER than 240 it could potentially be a good thing, but would give lower delay times (i dont care so long as they sound nice, 300ms is plenty for me). BUT if its over 240pF itll potentially give rise to shit sound.

That's about the long and the short of it.

The 5k6 resistor, Delay pot & 240pF all contribute to the delay time, push the clock too much (i.e. more delay) it'll become audible.

The lower the delay time the better the bandwidth too so your 300mS would be cleaner than your 500mS.

[LaceSensor]

why dont I just drop a 220pF in there or something then?

My DMM wont read capacitance. Worth a shot or am I dreaming?

Doing voltage now...

[Scruffie]

why dont I just drop a 220pF in there or something then?

My DMM wont read capacitance. Worth a shot or am I dreaming?

Doing voltage now...

Yeah may as well, it still might be too high a value though (Ceramics at 20+/-% Tollerance means that could be up to 266pF).