EHX - Holy Stain

Ice-9 · Post by **Ice-9** » 17 Mar 2011, 22:58

I can't edit my posts

It was meant to say remove the resistor R18 circled in RED

After the resistor follow the trace down under the FV-1 chip to the two pins on the chip that are connected together, the bit circled in GREEN now this track needs to be cut seperating the two pin of the chip (20 and 21). Even after cutting the track between the two pins we can still reverse the mo if needed by placing a blob of solder between the two pins on the chip . (nothing in these mods can't be put back to standard)

Next a wire from the top pad of the removed resistor need to soldered from there to pin 20 ( the lower pin in the white trace) This just reconects the pot to its original control pin.

Adding the second pot now is just as easy. Using 100k linear pot solder one end to the 3.3v and the other end to gnd or just conect each end to the ends of the pot that I have put the white trace on. The centre pin on the pot then goes to the other end of the R18 pad ( bottom pad R18)

If any of this is confusing just ask and i can answer every question, this second picture with the mod done should make it clear.

culturejam · Post by **culturejam** » 18 Mar 2011, 02:27

I noticed that reverb creeps in on the tremolo and thought it was odd. So you're saying that as you go higher with the speed on chorus and flanger, the reverb also creeps in like in the tremolo?

I have a Rev A board, by the way.

I think I'm going to do the first mod only at first, and then consider doing the control pot mod. There's not a ton of room on this thing for drilling.

By the way, if you could put together a through-hole version of just the modulation side of this thing (minus the FV-1, of course), that would rule.

Ice-9 · Post by **Ice-9** » 18 Mar 2011, 10:20

culturejam wrote:I noticed that reverb creeps in on the tremolo and thought it was odd. So you're saying that as you go higher with the speed on chorus and flanger, the reverb also creeps in like in the tremolo?

I have a Rev A board, by the way.

I think I'm going to do the first mod only at first, and then consider doing the control pot mod. There's not a ton of room on this thing for drilling.

By the way, if you could put together a through-hole version of just the modulation side of this thing (minus the FV-1, of course), that would rule.

Yes, there isn't much room for putting an extra pot on the enclosure without spoiling the decal. I considered putting the pot on the side of the enclosure. although both mods could be done individually, having both done makes the unit work the way it should have worked in the first place.

The only part of the schematic I haven't bothered to draw is the fuzz, the rest is complete. All the modulation effects are done in code in the FV-1.

culturejam · Post by **culturejam** » 18 Mar 2011, 18:08

Got the switch installed and working. I think I will end up doing the extra control pot mod as well.

By the way, I notice that in the clean pre amp setting, I'm still getting some clipping if I strum pretty hard, regardless of which effect type I'm using. Is this normal?

Ice-9 · Post by **Ice-9** » 18 Mar 2011, 21:41

culturejam wrote:Got the switch installed and working. I think I will end up doing the extra control pot mod as well.

By the way, I notice that in the clean pre amp setting, I'm still getting some clipping if I strum pretty hard, regardless of which effect type I'm using. Is this normal?

Glad you got the switch installed ok, easy mod to do isn't it. Yes my pedal also had some clipping on the clean setting when played hard, so i guess that is normal.

Ice-9 · Post by **Ice-9** » 18 Mar 2011, 21:50

Oh by the way I mentioned an FV-1 project I was working on in an earlier post, here are a couple pos pics of how far I have got so far. I wanted it to be a bit of a modular thing and in these pictures the programs are selected using a 8 or 16 position data pot, which when i do other addons could be replaced with a footswitch board similar to the wat the Holy stain selects programs.There is also an external Eeprom on board for additional programs which I also have plans to make an add on board that could use a smartcard reader so you basically could have a library of effects on a credit card size smartcart that you just plug in and I have some more ideas also. For the time being though i was just working on getting the main effect correct. I know a little off topic but what the heck.

culturejam · Post by **culturejam** » 19 Mar 2011, 04:48

Damn that's cool.

culturejam · Post by **culturejam** » 19 Mar 2011, 16:48

Just did the control pot mod.

Now the new pot acts as the speed control, and the Amount control is now doing nothing. And there is still reverb.

I think the issue is that in your picture, there is a resistor off lug 2 of the new pot. But this is not mentioned in the text description of the mod, so I left it out. I'm assuming I should add this resistor? I can't see the value from the photo, but it looks like it might be 15K?

Thanks

Ice-9 · Post by **Ice-9** » 19 Mar 2011, 18:30

culturejam wrote:Just did the control pot mod.

Now the new pot acts as the speed control, and the Amount control is now doing nothing. And there is still reverb.

I think the issue is that in your picture, there is a resistor off lug 2 of the new pot. But this is not mentioned in the text description of the mod, so I left it out. I'm assuming I should add this resistor? I can't see the value from the photo, but it looks like it might be 15K?

Thanks

I had a 10k resistor there but there is no need for it at all. the pots are connected one end to 3.3v the other end to gnd and the centre to the control pin all it does is put a dv voltage on the pin.

I would suggest using a meter to trace where each pot centre connection goes to. ie which pin on the fv-1 also you dont need to lift any pins for the pot mot . The pin lift is only for the switch mod.
Maybe if you could post a close up photo of your modded board and i will try check it.

culturejam · Post by **culturejam** » 19 Mar 2011, 19:31

Ice-9 wrote:also you dont need to lift any pins for the pot mot . The pin lift is only for the switch mod.

Whoops!

That's the problem. I'll fix that. Thanks

culturejam · Post by **culturejam** » 19 Mar 2011, 20:35

Yep, that was it.

Now in the Tremolo, Chorus, and Flanger modes, the reverb can be adjusted from zero to moderately hall-ish. The pot doesn't seem to have any effect in the reverb-only modes or the pitch shift modes.

So the new pot becomes LFO speed, while the "Amount" pot becomes the reverb control.

Very good work, Ice9!

Please note: I did not do the "artwork" on the pedal.

Ice-9 · Post by **Ice-9** » 19 Mar 2011, 23:46

culturejam wrote:Yep, that was it.

Now in the Tremolo, Chorus, and Flanger modes, the reverb can be adjusted from zero to moderately hall-ish. The pot doesn't seem to have any effect in the reverb-only modes or the pitch shift modes.

So the new pot becomes LFO speed, while the "Amount" pot becomes the reverb control.

Very good work, Ice9!

In the reverb only modes the pot should control reverb time, and the second pot should control a HF filter on the reverb, I can hardly hear any difference on the HF filter control.

I glad you got it all sorted.

On one of the pitch shift program The FV-1 data sheet says only one pot is in use and it coontrols , well, pitch shift.
On the second pitch shift program the second pot controls the echo delay time, but as the 3rd pot isn't there (I didn't do the 3rd pot mod) the echo level is set to off so it won't make any difference what the echo delay pot is set at as you won't hear the echo.

I didn't bother doing the 3rd pot mod as on most of the patches it just controls the level of the effects except the reverb level.

The 3rd pot mod is still very easy to do do and all thats needed is another 100K pot with the outside lugs to the same points as the the other pot. (3.3v and gnd) You need to lift pin 22 in the same way as the extra program mod, and soder the pot centre connection direct to pin 22. I don't really think it's worth the bother for the 3rd pot to be honest though.

Ice-9 · Post by **Ice-9** » 19 Mar 2011, 23:48

Here is a link to the FV-1 data sheet, page four give a list of the eight internal programs and what each pot does to each patch.

http://www.spinsemi.com/Products/datash ... 1/FV-1.pdf

contrcf · Post by **contrcf** » 23 Nov 2011, 21:56

Hi guys, I’m new here, and I was looking at your mods and they look great, unfortunately my Holy Stain got damaged before even trying, and I’ve track it down to the U4 but since it got burned I cant get a hold of the part number. Could some one help me out and send me the U4 part number so I can buy it and change it.

Thanks in advance.

Ice-9 · Post by **Ice-9** » 24 Nov 2011, 09:40

I don't have my Holy Stain anymore but I have just had a look at the pictures I posted and U4 is just a dual opamp, anything will do for example a TL072.Maybe someone that still has there pedal could give you the exact opamp markings but i would just throw in a TL072 or similar opamp.

Tan85 · Post by **Tan85** » 07 Apr 2012, 09:06

I think that this pedal eat the tone horribly. I had replaced 1mkf smd ceramic condensers (....emm...by the sound way) for metallized propylene caps by scheme and it sounds MUCH BETTER. This is totally another fuzz !
Im a kind of man, who hear the difference between caps

Can anybody tell me - where there is "analog distortion stage" - is it Q1-Q2, Q3- Q4?
I can't understand also what D7-D8 diodes do above the COLOR pot?

I want to replace all the f***ing ceramic caps in audio part, but for now Im out of the low-voltage caps =)

Ice-9 · Post by **Ice-9** » 07 Apr 2012, 12:07

Tan85 wrote:I think that this pedal eat the tone horribly. I had replaced 1mkf smd ceramic condensers (....emm...by the sound way) for metallized propylene caps by scheme and it sounds MUCH BETTER. This is totally another fuzz !
Im a kind of man, who hear the difference between caps

Can anybody tell me - where there is "analog distortion stage" - is it Q1-Q2, Q3- Q4?
I can't understand also what D7-D8 diodes do above the COLOR pot?

I want to replace all the f***ing ceramic caps in audio part, but for now Im out of the low-voltage caps =)

I don't have the pedal anymore, and i never traced the fuzz part of the circuit as it sounded awful anyway.

So from looking back at the pictures in this thread it looks like D7-D8 are connected to the colour switch so they will be switched in and out of the fuzz circuit. So they will be clipping diodes.

Tan85 · Post by **Tan85** » 08 Apr 2012, 10:46

Ice-9, can you send me scheme from second page in a good quality - i can't see clearly details №. Thx!
Can you tell me a good sounding fuzz with clipping diodes in your opinion? I never played this effect before! (Just tube amps and preams)
I have a litte soviet germanium transistors, if it useful in this case.

I see FV-1 has 24bit ADC-DAC and operational bitrate of 32 bit (!?). So, it looks like to be the best bargain... I hope good mod can help.

ClevelandRocker · Post by **ClevelandRocker** » 06 Nov 2012, 19:15

Tank you Ice-9 for putting this post up!! I just got a Holy Stain and it has a nasty 60hz buzz to it, even when the effects are off and the sound is "clean". A university instructor suggested I replace all the capacitors with higher farad components. If I replace ALL the non surface mount caps with higher rated components, that would not fry other parts of the circuit, correct?

Ice-9 · Post by **Ice-9** » 07 Nov 2012, 10:58

ClevelandRocker wrote:Tank you Ice-9 for putting this post up!! I just got a Holy Stain and it has a nasty 60hz buzz to it, even when the effects are off and the sound is "clean". A university instructor suggested I replace all the capacitors with higher farad components. If I replace ALL the non surface mount caps with higher rated components, that would not fry other parts of the circuit, correct?

Replaceing the caps with higher voltage caps will not do any harm to other components, but before replacing any caps I would look eslewhere for any problems. (The power filtering caps are next to the psu socket). Also check the electro caps visually for swelling on the top of the can. The problem is more than likely tracable to psu problems though.
If you have the pedal connected to other pedals in a chain and use the same DC adapter to power the pedal, then maybe try powering the pedal using a seperate psu. See if you have any hum when only this pedal is connected to the guitar and amp.

EHX - Holy Stain [schematic]