V1 and V3 differs quite a bit but they are still four stage OTA phasers. V 1 had 6 8 pin OTA with darlington followers which is now long gone obsoltete, four them was used for the phase stages and two of them was used for the LFO section. EH switched over to dual OTA's, LM13600's for V3 which is used for the four phase stages only. LFO section and the pre amp (which was a pnp/npn transistors pair in V 1) is operated by the LM324 op amp. Different component values in the phase stages, different colour switching...you get it...it differs quite a lot and while I haven't tried them side by side I assume they would sound quite different from each other.
Thank you. I see the v1 is the "all silver" enclosure, while v3 is the more regular version with big red square and white font, right? Is there any volume drop issue with this version? I think I will build the Pulsar first, and also the Jen Phase Shifter you posted a couple weeks ago, but I might give this Small Stone a try later. Thank you so much for all your layouts!
You are welcome!:-) Yes, V 1 is in the old school silver box. V3 is pretty similar to current version I believe. But there is also a version 2 but I cant find the layout for it at the moment. This version was produced from 1978 into early 80's and is the first version with the red square and white font. It is pretty similar to V 1 but it using one OTA chip and four transistors in the LFO section. Will upload it once I find it.
No, it isn't verified yet. And the CLR is related to your LED. Use a smaller value for a brighter light and a larger value for a dimmer light. Usually between 1-10k.
Thanks for the answer, Tom. Is any of the previous Stone's are verified do you know? I want to start one, preferably one that's a clone of v3 or v4, but I don't want to waste my time for nothing.
I don't blame you. It's a pretty huge build. I'm fairly certain that they haven't been verified as of yet. But there are some variations on the SS that have been verified. I think the Bad Stone and the Earthquaker Grand Orbiter have been verified. They may be more interesting anyway. I seem to recall the Tagboardeffects blog having a verified EHX phaser. Check them out.
The LED would stay on even when the pedal was disengaged. You would add an indicator LED to your switch off-board. If you disconnect the - LED connection from the board and wire it instead to your switch, the LED will only pulse when the circuit is engaged (acting as an indicator). So you could eliminate the second LED. The switch annotated above is the function switch not the activation switch.
Ok will do accordingly. I plan to start this project but I'm a bit skeptical as its still remains unverified.. Wish I'd known on which schematics this is based.
I believe this layout based on this schematic, only difference is the different outs used here of the LM324. Just doing the proof-reading to confirm everything is ok.
Yeah, that can make it confusing to trace everything out. I'm sure the layout would be a total mess if he didn't use alternate sides of the chip though.
Well, I bit the bullet and did that, and its precisely the same. Only difference I saw is the 100ohm resistor whereas its 100k on the schematics -the one going to IC2's 16th lug after 2 series of diodes- and the 18k resistor in the schematics is actually 16k in the layout.
Okay i finished today and as expected, didnt work again :icon_lol: :icon_lol:
I really dont have any idea what to do, as i already confirmed with the schematics from 1980. I am adding the pictures. There are 2 things caught my attention that, 1mf is non Polar in schematic whereas its vice versa in the layout. The Opposite goes for 220n as well, polarized in schematics but non in layout. Opamps are used differently in the layout and i wrote them what is what.
I looked at the schematic briefly this morning and couldn't see anything wrong either. I looked around for a fabricated PCB and was surprised to find little to nothing. I thought PPCB or Madbean would have one. Nope.
Make sure your tracks are scrapped and clean and check for bad joints and misplaced leads. If it still doesn't work, you can throw it at the wall. Hehe
After fixing the direction of d3(was in opposite, what a lame mistake) it started working instantly. Only thing is with a1m pot, its like a drone, so damn fast, i had better results with b2m pot, also increased the 220n cap to 470n, but even on slowest setting, it goes as if its around %80 of rate.
Best option i found so far is using a polar 10uf for 220n, and adding a 30k resistor in series to b2m pots any lug cuts the drone effect on fastest setting. But there should be an easier solution for this i think?
I read somewhere else that others were having a similar issue. But I'm not sure of the cause. Some versions include a VR value at 500k. I'm not sure where it would be placed but maybe in place of the 270k connected to switch 2? Maybe try socketing it and try a few values. Or if you have a 500k trimmer, try to stick it in there and dial in the optimal voltage. Maybe worth a shot.
1- I've tried several pots between 220k to 2m A and B types. With the current configuration, none seemed act expectedly, on fastest setting it was a real drone on all whereas the slowest wasnt slow enough for even B2M.
2- I've played with the 220n non-polar between W11-Z11, as it seemed to be responsible for the lfo speed, and I found the sweet spot with 22uf polar cap (positive side on W11), and used a 1m linear pot with it as it seemed to react better than A1M (I don't have any C taper and I can't find it in Turkey).
3- I used a 18k resistor between S5-S8 instead of 16k as I couldnt find it either. And for 15k's, I've used 8.2k + 6.8k resistors in series, wasn't in stock also. I'm not sure what does that 18k resistor is responsible, but 2k wouldn't be a big deal for any case.. Right? :)
4- Used 12v Zener, as I read somewhere that using 9.1v causes ticking or something like that, so I stayed on the safer side.
So, with the change of mentioned cap to 22uf and using a Linear 1M pot, it sounds quite acceptable and this can be marked as confirmed like that.
If there are any suggestions for arranging the LFO, please let me know.
update : changed the zener to 9.1v, no audible change but its safer I see.
One thing I may complain is the pot's response. Even tho I used a B taper, it acts like an A, nearly 1/4 of it seems not responsive at all (on the slower side of the rate) then it increases supposedly. I think there's some sort of resistance blocking it initially, or using a C taper is a must (even tho I tried A1M both straight & reverse, it's the same)
Another side-note that if you connect the rate led's positive to AA row between 4.7k and IC's 7th leg (which is the LFO), you'll get a nice, pulsating LED, but you'll need a rather lower resistor maybe 2.2k at most.
A recent side note that, if you have LFO ticking; do the following;
1- Connect a cap between 100n to 1uf between V19/Y19(gnd) 2- If you still hear a lfo whining on bypass, ground the input, there are various schematics on the internet for input grounded true bypass scenario.
Thank you, I love EHX pedals!
ReplyDeleteWhat are the differences between v1 and v3 of the Small Stone?
V1 and V3 differs quite a bit but they are still four stage OTA phasers. V 1 had 6 8 pin OTA with darlington followers which is now long gone obsoltete, four them was used for the phase stages and two of them was used for the LFO section. EH switched over to dual OTA's, LM13600's for V3 which is used for the four phase stages only. LFO section and the pre amp (which was a pnp/npn transistors pair in V 1) is operated by the LM324 op amp.
DeleteDifferent component values in the phase stages, different colour switching...you get it...it differs quite a lot and while I haven't tried them side by side I assume they would sound quite different from each other.
Thank you. I see the v1 is the "all silver" enclosure, while v3 is the more regular version with big red square and white font, right?
ReplyDeleteIs there any volume drop issue with this version?
I think I will build the Pulsar first, and also the Jen Phase Shifter you posted a couple weeks ago, but I might give this Small Stone a try later. Thank you so much for all your layouts!
You are welcome!:-)
DeleteYes, V 1 is in the old school silver box.
V3 is pretty similar to current version I believe.
But there is also a version 2 but I cant find the layout for it at the moment. This version was produced from 1978 into early 80's and is the first version with the red square and white font.
It is pretty similar to V 1 but it using one OTA chip and four transistors in the LFO section.
Will upload it once I find it.
And then we have the Bad Stone....
Ok, After a quick search :
ReplyDelete- V1 : "all steel" design;
- V2 : orange rounded font + black rectangle;
- V3 (&V?) : white text on red square.
Many useful informations on this site :
https://crawlsbackward.blogspot.com/2010/10/version-1-v1-small-stone-mods-and.html
and here as well (in french) :
https://www.bruynooghe.fr/post/2019/11/09/Comment-am%C3%A9liorer-la-qualit%C3%A9-de-la-Small-Stone-mk3
You beat me to it!
DeleteThanks for the links!
Is this confirmed by anyone?
ReplyDeleteAnd may I ask what's the CLR resistor?
ReplyDeleteCurrent limiting reisistor for the bypass LED, usually between 1K and 10K. Check below for more info:
Deletehttps://www.madbeanpedals.com/forum/index.php?topic=25477.0
No, it isn't verified yet. And the CLR is related to your LED. Use a smaller value for a brighter light and a larger value for a dimmer light. Usually between 1-10k.
ReplyDeleteHaha
DeleteAre you thinking what I'm thinking..lol
DeleteThanks for the answer, Tom. Is any of the previous Stone's are verified do you know? I want to start one, preferably one that's a clone of v3 or v4, but I don't want to waste my time for nothing.
DeleteI don't blame you. It's a pretty huge build. I'm fairly certain that they haven't been verified as of yet. But there are some variations on the SS that have been verified. I think the Bad Stone and the Earthquaker Grand Orbiter have been verified. They may be more interesting anyway. I seem to recall the Tagboardeffects blog having a verified EHX phaser. Check them out.
DeleteYou're right, seems the one in here verified by some. I'll check the parts locally if they're all obtainable.
Deletehttps://4.bp.blogspot.com/-5HKNaDG7LXM/Wr9AMzXumHI/AAAAAAAABws/1aVyrny1oIsReEFY6hBlKW54O50QoIv_wCLcBGAs/s1600/SmallStone.png
May I also ask on which schematics is this based upon? I may perform a proof-tracing, as I have plenty of free time at work nowadays lol
DeleteThis comment has been removed by the author.
DeleteGot a quick question for Rate Led.
ReplyDeleteIs it only active when the pedal is on, or its always blinking?
I'll build this pedal with a true bypass switch.
The LED would stay on even when the pedal was disengaged. You would add an indicator LED to your switch off-board. If you disconnect the - LED connection from the board and wire it instead to your switch, the LED will only pulse when the circuit is engaged (acting as an indicator). So you could eliminate the second LED. The switch annotated above is the function switch not the activation switch.
DeleteOk will do accordingly. I plan to start this project but I'm a bit skeptical as its still remains unverified.. Wish I'd known on which schematics this is based.
Delete14
ReplyDelete25
36
If there is no noted connection to a pot, you can leave it disconnected completely.
Cheers Tom, thanks!
ReplyDeleteI believe this layout based on this schematic, only difference is the different outs used here of the LM324. Just doing the proof-reading to confirm everything is ok.
https://www.freestompboxes.org/download/file.php?id=26559&mode=view
Yeah, that can make it confusing to trace everything out. I'm sure the layout would be a total mess if he didn't use alternate sides of the chip though.
ReplyDeleteWell, I bit the bullet and did that, and its precisely the same. Only difference I saw is the 100ohm resistor whereas its 100k on the schematics -the one going to IC2's 16th lug after 2 series of diodes- and the 18k resistor in the schematics is actually 16k in the layout.
ReplyDeleteOkay i finished today and as expected, didnt work again :icon_lol: :icon_lol:
ReplyDeleteI really dont have any idea what to do, as i already confirmed with the schematics from 1980. I am adding the pictures. There are 2 things caught my attention that, 1mf is non Polar in schematic whereas its vice versa in the layout. The Opposite goes for 220n as well, polarized in schematics but non in layout. Opamps are used differently in the layout and i wrote them what is what.
Below are the measurements for pins.
Lm324
1 2.85
2 2.86
3 2.52
4 8.96
5 2.85
6 6.89
7 0.65
8 7.45
9 0.93
10 4.67
11 0
12 1.96
13 1.96
14 1.96
And both lm13600 ics have same voltages on each of their pins as below.
1 0.75
2 3.44
3 2.84
4 2.81
5 0.08
6 0
7 0.1
8 1.4 (1.25 on 2nd)
9 1.12 (1.4 on 2nd)
10 0.07
11 8.94
12 0.07
13 2.81
14 2.83
15 3.45
16 0.76
That sucks. Don't give up yet. I found this slightly clearer schematic on GGG.
Deletehttps://generalguitargadgets.com/wp-content/uploads/ggg_smallstj_sc.pdf
This is based on ca3080s, i dont know how to match pin to pin with 324 and 13600s.
DeleteHowever i found this layout which is a bit different, check the 47n between 1 and 4 pins of 324.
https://www.freestompboxes.org/viewtopic.php?p=252068#p252068
Oh wow, I didn't even see that. I know how frustrating it is when a circuit doesn't work. I have several that I have failed to get started for months.
DeleteI looked at the schematic briefly this morning and couldn't see anything wrong either. I looked around for a fabricated PCB and was surprised to find little to nothing. I thought PPCB or Madbean would have one. Nope.
DeleteMake sure your tracks are scrapped and clean and check for bad joints and misplaced leads. If it still doesn't work, you can throw it at the wall. Hehe
After fixing the direction of d3(was in opposite, what a lame mistake) it started working instantly. Only thing is with a1m pot, its like a drone, so damn fast, i had better results with b2m pot, also increased the 220n cap to 470n, but even on slowest setting, it goes as if its around %80 of rate.
DeleteAny suggestions to slow this thing to its normal?
Best option i found so far is using a polar 10uf for 220n, and adding a 30k resistor in series to b2m pots any lug cuts the drone effect on fastest setting. But there should be an easier solution for this i think?
DeleteI read somewhere else that others were having a similar issue. But I'm not sure of the cause. Some versions include a VR value at 500k. I'm not sure where it would be placed but maybe in place of the 270k connected to switch 2? Maybe try socketing it and try a few values. Or if you have a 500k trimmer, try to stick it in there and dial in the optimal voltage. Maybe worth a shot.
DeleteI can call this confirmed with below side-notes..
ReplyDelete1- I've tried several pots between 220k to 2m A and B types. With the current configuration, none seemed act expectedly, on fastest setting it was a real drone on all whereas the slowest wasnt slow enough for even B2M.
2- I've played with the 220n non-polar between W11-Z11, as it seemed to be responsible for the lfo speed, and I found the sweet spot with 22uf polar cap (positive side on W11), and used a 1m linear pot with it as it seemed to react better than A1M (I don't have any C taper and I can't find it in Turkey).
3- I used a 18k resistor between S5-S8 instead of 16k as I couldnt find it either. And for 15k's, I've used 8.2k + 6.8k resistors in series, wasn't in stock also. I'm not sure what does that 18k resistor is responsible, but 2k wouldn't be a big deal for any case.. Right? :)
4- Used 12v Zener, as I read somewhere that using 9.1v causes ticking or something like that, so I stayed on the safer side.
So, with the change of mentioned cap to 22uf and using a Linear 1M pot, it sounds quite acceptable and this can be marked as confirmed like that.
If there are any suggestions for arranging the LFO, please let me know.
update : changed the zener to 9.1v, no audible change but its safer I see.
ReplyDeleteOne thing I may complain is the pot's response. Even tho I used a B taper, it acts like an A, nearly 1/4 of it seems not responsive at all (on the slower side of the rate) then it increases supposedly. I think there's some sort of resistance blocking it initially, or using a C taper is a must (even tho I tried A1M both straight & reverse, it's the same)
Another side-note that if you connect the rate led's positive to AA row between 4.7k and IC's 7th leg (which is the LFO), you'll get a nice, pulsating LED, but you'll need a rather lower resistor maybe 2.2k at most.
ReplyDeleteThis comment has been removed by the author.
ReplyDeleteThis comment has been removed by the author.
ReplyDeleteA recent side note that, if you have LFO ticking; do the following;
ReplyDelete1- Connect a cap between 100n to 1uf between V19/Y19(gnd)
2- If you still hear a lfo whining on bypass, ground the input, there are various schematics on the internet for input grounded true bypass scenario.