# Sea Horse Mods



## Chuck D. Bones

As requested, here are the mods I performed on my Sea Horse to increase the delay, increase the SHAPE range, improve the filtering, change the LFO speed range and one or two other things.   It does everything that the Sea Horse and Dark Rift do, but with better filtering.  These mods assume you are building on the revised Sea Horse board, dated 01-06-20.  That board has the LFO tick fix built-in.  You can perform all mods or any combination; one does not depend on the others.  Here's a hi-res photo of my modded board for guidance on parts placement.  Note: this was the previous rev board, so one or two parts may have moved.





*Delay Mod*
This mod extends the max delay time out to about 660ms (DEPTH set at zero).  Optional.
Change ANIM pot from B2K to B50K.  It's now called TIME.  NOTE: Maxing both TIME & DEPTH can cause glitching in the delay chip, it's normal.  Back off a little on one or both and the glitching goes away.
Delete R11.
Add a 33K resistor from ANIM-1 to DEPTH-2.
Change R7 from 2.2K to 1.5K. 

*Filter Mod*
This mod re-tunes the input anti-alias filter (LPF1) and routes the delayed signal thru the output filter (LPF2).  Recommended.
Change C7 from 1uF to 10uF.
Change C17 from 100pF to 220pF.
Add a 6.8nF cap from the right-hand side of R3 to the right-hand side of R33 (verify that the  right-hand side of R33 is ground, I don't have the latest board). 
Change R4 from 33K to 22K.
Delete R13 and C15.
Connect a wire from C15- pad to DIM-3.
Change R14-R18 from 10K to 47K (I used 51K, but either will work, just make them all the same).

*Feedback Mod*
This mod limits the signal amplitude when FEEDBACK (DIM) is maxed and the delay goes into self-oscillation.  These diodes are built-in on the Dark Rift. Recommended.
Add 1N4148 diodes back-to-back from DIM-1 to DIM-2.

*LFO Rate Mod*
This mod changes the LFO speed range to 0.1Hz - 10Hz and improves the RATE control sweep.  The slower rates are desirable when using longer delay settings.
Change R25 from 10K to 22K.
Delete R22 & R23.
Change R26 & R27 from 10K to 33K.
Change R34 & R35 from 100K to 10K.
Change C20 to 1uF film.

*LFO SHAPE Mod*
This mod extends the SHAPE range further into the square wave territory, allowing more abrupt sweeps and stronger pitch shifting when SHAPE is maxed.  
Totally optional.
Change SHAPE pot from A100K to A250K.


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## Dan M

Thank you for taking the time to post this, and for calling out the “recommended” changes.


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## Cvoxdog

Hi Chuck, I took a chance and tried all your mods eve n though I have the newest version sea horse. It works but I noticed that the dimension knob doesn’t do anything. That should control the repeats right? I’ve been only getting one repeat. Any tips?


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## Chuck D. Bones

Start with visual inspection.  You're looking for a bad solder joint, missing or wrong value part. Focus on the DIM pot, R9 & C10. If that doesn't reveal the problem, review the Build Docs and mod descriptions, then visually verify that all mods were performed correctly. 

If that doesn't solve the problem, then start a thread in Troubleshooting.  Post detailed pictures of both sides of the board.  If you're good with reading schematics and have an audio probe, then check the various points along the feedback path.


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## Cvoxdog

Thanks for the reply, I’ll take a look!


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## Cvoxdog

Ok you are very smart and I am not. It was r9. I originally noticed that I missed that resistor after I boxed it all up and then just soldered it in with it boxed up. I thought the connection was good but after I just took it apart I noticed one leg was not attached! Now the pedal does what it’s supposed to and is more fun. Definitely recommend these mods to anyone building this!


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## ADAOCE

Boneyard edition board candidate?


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## Chuck D. Bones

Cvoxdog said:


> Ok you are very smart and I am not. It was r9. I originally noticed that I missed that resistor after I boxed it all up and then just soldered it in with it boxed up. I thought the connection was good but after I just took it apart I noticed one leg was not attached! Now the pedal does what it’s supposed to and is more fun. Definitely recommend these mods to anyone building this!


Cool!  Glad you found it so quickly.  Missing solder joints happens to all of us.  Visual Inspection is the #1 troubleshooting tool!  One thing I've started doing is shining a bright light thru a soldered board and looking for holes where solder should be.  I do this last thing before installing the pots.


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## chongmagic

Chuck D. Bones said:


> Cool!  Glad you found it so quickly.  Missing solder joints happens to all of us.  Visual Inspection is the #1 troubleshooting tool!  One thing I've started doing is shining a bright light thru a soldered board and looking for holes where solder should be.  I do this last thing before installing the pots.



Great idea, I actually finished a pedal a few days ago and it wasn't working correctly. It was bothering me and I couldn't get it out of my head. All of a sudden, I thought I probably missed a solder joint. Next morning I checked and voila it was the issue.


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## Cvoxdog

I hate to be the problem guy but I noticed after I hooked it up a louder amp that I’m getting the dreaded lfo tick but only when the pedal is bypassed. This is the newest version board so it should have the lfo fix built in. I tried moving the in out and jack wires and tried touching a 10nf cap on pins of ic4 without any luck other than being able to short out the lfo completely. I desoldered one leg of c19 to see if that would help and it sounds like that has to stay in. Any ideas as to other things I can try?


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## zgrav

do you get the noise when the seahorse is moved to a different place in your effects chain (assuming there is another spot)?  Does the noise go away if the seahorse is the last thing before your amp?  You could try shielding the wires going to and from the jacks to the footswitch.  only attach the shield to the ground on the jacks.


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## Cvoxdog

Is there a good link for shielded wire I could buy?


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## zgrav

Here is a *possibility* from an ebay seller.  Probably a safer purchase than an out-of-production transistor.  : ^ )


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## Cvoxdog

Thanks for the link. I actually just got some Russian transistors and diodes from eBay today. Took 3 months! I wasn’t sure if they were ever coming. For the sea horse, I added a 100r resistor in series with a 220uf cap from the power supply and the negative end to ground. I think it decreased the noise compared to before. Shielded cables would probably do the rest.


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## teal

Hi Chuck,
I have a little question:
What does the Filter Mod do with the sound?
I have built a Sea Horse (without the mods, because I see them yet) and it has too much white noise in the wet signal for my taste.
Is the filter mod reducing the noise in the signal too?


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## Chuck D. Bones

The filter mod reduces some of the quantization and aliasing noise in the wet signal.  It won't cure a noisy PT3299.  I'm told some chips are noisier than others.  Long delay settings are noisier, that's the nature of the beast.  The dry signal is not filtered.


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## teal

Thanks.
I will give it a shot!
I have also a little whistling oszillation in the wet signal if I don't play anything.
If I play it turns into noise.
Hope it becomes a little better with the mod!


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## Chuck D. Bones

If your PT2399 is in a socket, try changing to a different chip and see if the noise changes.  If you're using a power adapter, try a different one or a battery.  The whistling noise you describe is not normal; don't expect the filter mod to fix it.


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## teal

You were right it was the chip.
Bought a bunch of PT2399 and with one of it there were no noises on the effect anymore.


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## teal

I tried the Delay Mod and I realize that I would like to prefer a shorter delay time but still a longer one than in the original sea horse built.  
Do I have to change some of restistors again or can I only change the pot from 50K into let's say 10K?
I don't really know what the resistors are for in this mod.


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## Chuck D. Bones

How much max delay do you want?  In other words, what is the max setting you use now with the B50K pot?  From that we can decide if you want to replace it with a 5K, 10K or 25K pot.  We only want to do this once because replacing pots is hard on the board.

Changing R7 & R11 make the DEPTH control work better and not interact so much with the TIME control.


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## teal

The pedal starts to have an old vinyls kind of noisefloor with animate (and delay mod 50K) between 8 and 9 o'clock.
I did all your mods, so the delayed signal is filtered.
I wish to have as less noise as possible, so it is not the length of the delay in the first place that I want to change.
The delay still sounds more pleasant than the one on the Dark Rift. The Dark Rift sounded too cold and gloomy for my taste.
But I feel it still can have a little more warmth than it has now and less noise.
Would it be possible to tweak the filter a little more to achieve that?


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## teal

What impact have the capacitors on the sound?
I see you use different ones than provided.
In my kit from Musikding there are a lot of electrolyte capacitors and C5 and C6 are ceramics on my pcb. Maybe I should change them into better ones like you did


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## Chuck D. Bones

teal said:


> The pedal starts to have an old vinyls kind of noisefloor with animate (and delay mod 50K) between 8 and 9 o'clock.
> I did all your mods, so the delayed signal is filtered.
> I wish to have as less noise as possible, so it is not the length of the delay in the first place that I want to change.
> The delay still sounds more pleasant than the one on the Dark Rift. The Dark Rift sounded too cold and gloomy for my taste.
> But I feel it still can have a little more warmth than it has now and less noise.
> Would it be possible to tweak the filter a little more to achieve that?


If I understand correctly, you are only interested in chorus, reverb & vibrato tones.  If that's the case, then B5K is what you want for the TIME (ANIMATE) pot.

I have the filters set to be pretty neutral.  You could open up the bandwidth a bit since you are using less delay, but more filter bandwidth means more noise.  You might be better off using a pedal after the Sea Horse to tweak the tone.  If what you're after is a low noise delay, then an FV-1 board will be more to your liking.  Try the Octagon.



teal said:


> What impact have the capacitors on the sound?
> I see you use different ones than provided.
> In my kit from Musikding there are a lot of electrolyte capacitors and C5 and C6 are ceramics on my pcb. Maybe I should change them into better ones like you did


Film caps are better than ceramic.  You could change C5 & C6 to film, but you might not hear the difference.


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## teal

Chuck D. Bones said:


> If I understand correctly, you are only interested in chorus, reverb & vibrato tones. If that's the case, then B5K is what you want for the TIME (ANIMATE) pot.



Then B5K might be the deal for my pedal! I will try that.
I'm excited about the F V1 Delays. I purchased a kit for the Hydra Delay some days ago.


Chuck D. Bones said:


> Film caps are better than ceramic. You could change C5 & C6 to film, but you might not hear the difference.



I put some different capacitors on the LPF2 (C6) of the PT2399 Chip and it seems to be a point where it has a lot impact on high cut frequencies and the noise related to the modulation.
The higher the value of the capacitor, the more high frequencies are cut.
I compared the LPF2 stages of different delays with each other.
The Sea Horse has 470pF on LPF2.
The Faux Delay has 1nF on that stage and the Blue Delay 2,2nF.
In my ears the Faux and the Blue still sound really great with longer delay settings.
Of course they sound more like an alalogue style Pedal. But that's what I think the PT2399 is best in


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## Chuck D. Bones

That'll work.  C5 is one of two capacitors that tunes the input filter LPF1.  The 6.8nF cap that I add in my filter mod is the 2nd cap. R3-R5 also influence the filter's tuning.  Adding the 6.8nF cap changes LPF1 from a 1st-order filter to a 2nd-order filter.  Higher-order filters have a sharper cutoff, i.e. they attenuate more of the unwanted signal above the cutoff freq.  C6 is one of two capacitors that tunes the output filter LPF2.  C11 is the other cap.  I did not feel the need to retune LPF2.  

With time-sample systems, filtering is a trade between bandwidth and noise.  Let too much high-freq content in and it gets aliased, which sounds dissonant & noisy.  The output from a sampled system contains quantization noise and sampling images that are also dissonant & noisy.  Filtering reduces that unwanted crap.  The filtering requirements are dependent on sample rate, which in the case of most delays is variable.  Filtering that sounds good with short delay settings may not sound good at longer delay settings.

Analog delays (BBDs) are also time-sampled and benefit from the same filtering.  Tape delays use filtering on the input and output to reduce tape hiss.  The filtering, or lack thereof, contributes to the characteristic voice of the various delays.

I mentioned the FV-1 earlier.  Like the PT2399, it is a digital sampled system.  What makes the FV-1 so much clearer (more bandwidth and lower noise) is its higher sampling rate and resolution.


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## teal

That are very usefull informations!
Would be great having a Sea Horse based on a FV-1 one day 

Now if my pedal does not have the very long delay settings anymore, I think it can get rid of the ultra slow Rate mod settings and becoming a little bit faster again.
Is it enough to change C20 from 1uF to a lower capacitor, let's say 0,68uF?


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## Chuck D. Bones

Or go back to the original 470nF. At some point, it's "good enough."


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## teal

So true, but Rate was too fast for me in the original and not slow enough. I will try a way of the middle kind of thing 
It's good to know now which part it is!

I checked out the pedal with the bass too and it works great in any frequency now.
The original was only really responsive in high notes, that was very strange some times, especially with the bass.

But it also was an advantage that the effect reacted on how you attack the strings and the created overtones.
I wished to have a way of the middle there too, but I don't know which parts are responsible.
I guess it has to do with the filter mod? You mentioned before that I can open up the bandwidth if I'm only using shorter delay times.


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## teal

I tried it out: 5K pot works really great for animate, if you like to maximise the delay time without increasing noise, but 10K pot is still good.

R7 can easily be turned down to 1K, if you like to have a drier chorus sound (less echo) with animate set to zero and also increased reverb sound with the Dimension knob in that setting. Less than 1K are not recommended, because the PT2399 can make problems then


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