The Big Bad Stone Thread

[Scruffie]

Post any Completed Builds, Sound Samples, Questions, Ideas, Info, Mods, Notes, Working Voltages, Debugging Questions for the Bad Stone Phaser PCBs Here!

Here is the purchasing thread and also all the information currently available on the ordering page (Re-Drawn Schematic, PCB Layout, BOM, Original Bad Stone Phaser Graphic & Mod Ideas)

- http://www.diystompboxes.com/smfforum/index.php?topic=87281.0
&
- http://www.digitaldestruct.com/BadStone.html

[B Tremblay]

Some notes on my Bad Stone build.

The Feedback pot could possibly be replaced with a switch as there little perceptible change through the pot rotation.  I tried linear and audio tapers, as well as smaller values, but none provided more "in-between" settings.  The output stage is a different than other phasers and I think that it may be worthwhile to examine more closely.  Perhaps an improvement could be made in terms of mixing of shifted/dry signal and output volume.

The Rate pot should be a reverse audio taper for the best spread over the rotation.  R40 can be changed to 27k if you prefer to not have the ludicrous maximum speed, but that's how the original operates.

A 4069 can be used in place of the 4049 (using the pinout module), but I found the sweep width and tone a bit lackluster compared to the 4049.

I socketed the phaser section 47n caps, mostly because I don't have any 47n on hand and want to put them in later.  I have 56n caps in those sockets at the moment and it sounds good.  I didn't use the LPB-1.  I omitted the Color switch, hardwiring it to phaser mode.

[Scruffie]

Interesting... is the Feedback Pot the same on your actual unit rotation wise? Also what Tapers were in the original as that's never specified on the schematics and i've never seen a clear enough gut shot, was it originally a Reverse Log taper for Rate?

When you hardwired to Phaser mode, did you jumper or leave the switch pads unjumpered? Just so i'm sure.

[Pigyboy]

Have yet to start my build yet and am just posting so I get linked to all the replies

[B Tremblay]

Interesting... is the Feedback Pot the same on your actual unit rotation wise? Also what Tapers were in the original as that's never specified on the schematics and i've never seen a clear enough gut shot, was it originally a Reverse Log taper for Rate?

When you hardwired to Phaser mode, did you jumper or leave the switch pads unjumpered? Just so i'm sure.

Yes, my original Bad Stone exhibits the same all-or-nothing Feedback action and the Rate pot has all its speed increase in the last 25% of rotation.  The unmarked pots in my original seem to be linears.  I tested linear, audio, and reverse audio for the Rate in my new build - reverse audio was the clear winner.

I ran a wire across the board for Phaser mode hardwiring.

I've done a cursory comparison of my original with the schematic included on the order page and everything seems to match so far.  However, there seems to be no input or output caps!  Since I've always babied the original, I haven't noticed any switch pop.  I plan to take some higher resolution photos of the board and will also measure voltages.

[B Tremblay]

Setup: Tele bridge pup - Bad Stone - Ampeg Rocket II - mic - mixer - MacBook

Due to the different tapers of my original and the new build, I set the controls to maximum Blend and minimum Rate, which -should- be pretty close between the two.  Keep in mind that I have 56n caps in the phase shift stages.  I recorded a clip with the 4069 to illustrate the tonal difference with the 4049.

original Bad Stone

new Bad Stone

new Bad Stone with 4069

[Scruffie]

Nice Clips! Cheers for recording them 

The New Bad Stone sounds exactly the same to me as the old, which is a good thing and I can certainly hear what you mean about the 4069 version, still works fine though which is the main thing, just a different tone, which some people might like.

[B Tremblay]

I'm glad the clips convey what I'm hearing.

I updated the home-wrecker.com Bad Stone page with higher resolution photos of the board: http://home-wrecker.com/badstone.html

I did so because after taking those photos and comparing them to the schematic for the new build, I did find some differences.

- As previously mentioned, there are no input or output caps in the original.
- Also previously mentioned, my original uses two batteries.  The mono input jack sleeve connects to chassis ground (Vref) and the output jack sleeve lug is unconnected.
- There is a 33u cap from +9V to chassis ground (Vref).  This was suggested here and I reckon that it's inclusion would cure the squeal I hear when powering up with the circuit engaged.
- R49 is not present in my original and there is no spot on the board for it.  I plan to try removing it from my build and will observe the result.
- R54 is also not present and I do not believe it is necessary as it parallels R39 and it is therefore redundant.
- Q1 in my original either has a reverse pinout or it is PNP.  The markings are illegible.
- My unit uses the same board as the Manual Shift units, based on empty pads for SW2.
- I have no idea why C13 is mounted on the bottom when there is a spot for it to be mounted normally.
- pin 13 of IC5 is connected to pin 14 in the original.  Shouldn't matter, since pin 13 of both the 4009 and 4049 has no internal connection.

[coi2001]

Here is my build of the bad stone. Worked right off the bat. I used panasonic caps throughout. The booster at the end is not in yet. Hard to desolder the components if you make a mistake, I guess is the double sided plating. Sounds exactly like the clips. Thank you for developing and sharing this nice project.
Costantino

Pics posted at: http://freestompboxes.org/viewtopic.php?f=17&t=10645&p=119045#p119045

[Skruffyhound]

     Well it's working. I've just finished fiddling with it for tonight. I haven't got quite the same depth of sweep that we can hear in the clips.
Like Mr Tremblay I tried a whole range of different pots for the feedback but to no avail. What's interesting is that just when the feedback really cuts in and things get interesting then I get a lot of jet plane swoosh that is unrelated to the input and doesn't really seem to carry the signal. I will be looking into that tomorrow.
     I used the UBE version of the 4049 and Panasonic metal film for everything except the larger uF values. The tant was also switched to metal film and it measured 1.64 uF, although it was still warm after I soldered two smaller caps together to make it. Otherwise everything was totally anally stock as usual.
     There are some very sweet sounds available, thanks for the boards guys. I'll let you know if I get to the bottom of the sweep issue. I'm intending to do some "Hammer" mods to this too.

       - Aston

[Scruffie]

Cheers for the Write up Skruffy.

In the Toppopiccione project page he says "I used 1% tolerance resistors for the phasing section (R12 to R20, R23, R24, R32 to R35) and 0.047uF capacitors with the slightest difference of value." I wonder if he did this because of problems with Depth, might be worth an investiagtion...

I wonder if the Feedback pot might be more effective in the manual mode? Anyone tried adding the control? Also how does it react in Phase compared to vibrato? Exactly the same or are there some differences?

Seems like an interesting build this one though that's gunna need some further exploration, but overall a pleasing sound is had by all (my futurlec order should arrive finally next week so I can actually hear this damn thing in person!)

When I get all my electronics out of storage, might be one for the breadboard to see about mods and improvements to the original, but i'm glad this original effect is back out there now!

[Skruffyhound]

Ok,I got busy with other projects and just now got to have a play with this again.
After switching out the 4049UBE for an obsolete RCA 4049AE I happened to have and changing one of the opamps I was suspicious about, I got two slight improvements.
I fiddled about with ferrite beads for fun and changed the feedback pot again, and somewhere in this process I figured out that I should give it a hotter signal. Huge improvement. I stuck a Boss GE7 in front with the level full up and everything flat, about 3db boost I think from memory. Much more action and greatly improved S/N ratio. The treble end was carrying much better than the bass so I used the EQ to beef the bass up and again it improved significantly. I swapped out my SG with a Tele and now it was really cooking.
   There's lots more I want to do to this in terms of mods (may end up using the LPB on the front end with a filter), but just those changes produced some great sounds. I could get nice Wah sounds by timing the sweeps, and a whole range of pretty rhythm patterns alternating between chords and damped strings.
   Next I'll change out C13 for a tant. Then I want work on getting the bass frequencies to sweep better.
Thanks again. -Aston
     

[malrock75]

Hi There,
Just wondering if anyone would know off hand if replacing the 2N5088 with a 2N5089 would make any difference. I have some left over from a previous project.

Thanks.

[Scruffie]

Hi There,
Just wondering if anyone would know off hand if replacing the 2N5088 with a 2N5089 would make any difference. I have some left over from a previous project.

Thanks.

That'll be fine, if not better, that transistor is for the LFO and needs higher gains to get it running 

[malrock75]

Thanks scruffie!

[Scruffie]

Thought this thread might be handy for anyone planning to make the Manual Pot an Expressionable Control That didn't know how -

http://www.diystompboxes.com/smfforum/index.php?topic=79442.0

[B Tremblay]

I finally spent some time with the Manual control and the expression pedal option.

The good news is I was able to crudely control the shift with a rocker pedal.  The bad news?  To enable Manual mode, I had to cut a trace.

I had to cut a trace because the PCB connects SW2A and SW2B (the two miniature pads).  Therefore, the LFO is always engaged.  Adding a Manual pot as detailed in the mod notes will result in a sort of LFO depth control.  I cut the trace adjacent to the miniature pad at R36-R42 junction (I'll post a photo if anyone needs one).

With a 100k pot, the rotation produces one cycle of the LFO.  There is some "overlap" at the extremes, as a new cycle begins.  I think that some added resistance will produce a range of low to high as the footpedal is rocked.  I plan to do some more experimenting.

[Scruffie]

I finally spent some time with the Manual control and the expression pedal option.

The good news is I was able to crudely control the shift with a rocker pedal.  The bad news?  To enable Manual mode, I had to cut a trace.

I had to cut a trace because the PCB connects SW2A and SW2B (the two miniature pads).  Therefore, the LFO is always engaged.  Adding a Manual pot as detailed in the mod notes will result in a sort of LFO depth control.  I cut the trace adjacent to the miniature pad at R36-R42 junction (I'll post a photo if anyone needs one).

With a 100k pot, the rotation produces one cycle of the LFO.  There is some "overlap" at the extremes, as a new cycle begins.  I think that some added resistance will produce a range of low to high as the footpedal is rocked.  I plan to do some more experimenting.

Well, it was added on at the last second without testing as a sorta, why not (Hence the weirdly placed tiny pads) so I suppose it could be worse! Bit of a shame none the less.

However, i'm looking at the schematic... and i'm looking at the layout... and it looks right to me? Maybe the mod document is wrong, i'm gunna have to investigate further when the PCB is to hand.

Did you have to cut the track on the bottom of the board leading up to C10? If I'm right in how you've done it, there woulda had to have been a jumper to avoid the problem... I suppose this is because it's based off the version before the Manual Control I got it wrong, well I hope no one is annoyed by that, but, that's what happened, it was a last second addition and clearly I didn't do it quite right   but atleast there's an easy fix now.

What's the LFO 'depth control' like by the way? A useful mod? I'll change the mod documents if so as that sounds kinda interesting in itself actually.

Did you add the 27k resistor when you put the 100k pot in for the manual control? I assume that's there for the purpose of the pots cycle.

EDIT:
While we're here, has anyone found a good tap off point for a LFO LED?

[B Tremblay]

Well, it was added on at the last second without testing as a sorta, why not (Hence the weirdly placed tiny pads) so I suppose it could be worse! Bit of a shame none the less.

However, i'm looking at the schematic... and i'm looking at the layout... and it looks right to me? Maybe the mod document is wrong, i'm gunna have to investigate further when the PCB is to hand.

Did you have to cut the track on the bottom of the board leading up to C10? If I'm right in how you've done it, there woulda had to have been a jumper to avoid the problem... I suppose this is because it's based off the version before the Manual Control I got it wrong, well I hope no one is annoyed by that, but, that's what happened, it was a last second addition and clearly I didn't do it quite right   but atleast there's an easy fix now.

What's the LFO 'depth control' like by the way? A useful mod? I'll change the mod documents if so as that sounds kinda interesting in itself actually.

Did you add the 27k resistor when you put the 100k pot in for the manual control? I assume that's there for the purpose of the pots cycle.

EDIT:
While we're here, has anyone found a good tap off point for a LFO LED?

Yes, I cut the trace between the mini-pad and C10.  Here's a photo:


I didn't test out the depth control too much, but it may be useful to some.  You would be able to dial in just a shimmer, which is nice with higher speeds.  A case could be made for hardwiring the feeedback to maximum and making the depth a panel pot instead.

Yes, I have the 27k resistor in place.

[malrock75]

Hi Guys,

I have a problem with my badstone build, namely it doesn't work..

When I engage the effect I get no signal. I am using the volume adjust circuit and an electro cap in place of the tant. (1.5uF)

Here are my voltages

Battery=8.84v
IC1
1- 4.13    5- 1.74
2- 4.14    6- 4.9
3- 4.13    7- 5.34
4- 0       8- 6.13

IC2
1- 4.05    5- 4.20
2- 4.15    6- 4.20
3- 4.10    7- 4.20
4-    0     8- 6.11

IC3
1- 4.19    5- 4.08
2- 4.1      6- 4.10
3- 4.12    7- 4.02
4- 0       8- 6.09

IC4
1- 4.18    5- 4.07
2- 4.09    6- 4.09
3- 4.11    7- 4.00
4- 0.00    8- 6.07

IC5
1- 5.47        9- 5.46
2- 4.11       10- 4.09
3- 5.47       11- 5.40
4- 4.06       12- 4.05
5- 5.46       13- 5.45
6- 4.05       14- 5.45
7- 5.46       15- 4 - 4.03
8- 4.08       16- 5.45

IC6
1- 4.85           8- 4.33
2- 3.99-4.02    9- 4.01
3- 4.01-4.03    10- 4
4- 6.03           11- 0.00
5- 3.73           12- 4.35
6- 3.74-3.86    13- 3.51
7- 3.85-4.05   14- 4.73

Some of the readings were fluctuating so I wrote down what I could see.
If anyone can see anything from these readings I would really like a point in the right direction.

Please excuse the noobiness.

Thanks Mal.