# Hydra Questions



## joelorigo (May 28, 2022)

Having mostly built ODs and boosts, I’ve been becoming more adventurous with my building interests. I have been looking at the Hydra. As I have gathered the FV chip is hard to find right now and hard to solder? Anything else about this project that is to note?


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## lumberjack (Jun 2, 2022)

I’m an FV-1 noob and recently built my first couple pedals with that chip, including a Hydra about a week back. Awesome pedal, highly recommend - I’m new to pedals but have been soldering in amps for years, and I’d recommend watching some videos on surface mount soldering techniques first. It’s definitely doable but it’s a totally different approach than I’m used to on huge turrets/eyelets, or even 1/4 watt and 1/8 watt pcb pads. 






Can’t overstate this: you need flux, and possibly more than you’d imagine. You can see in this video the legs and pads are practically submerged in the stuff. I tried doing it without flux first and it wasn’t  pretty. Plenty of flux and good cleanup after helped a lot.

I found a batch of FV-1 at stompboxparts.com a few weeks back but they seem to be out now. Amplified Parts has them in stock though: https://www.amplifiedparts.com/products/integrated-circuit-spin-fv-1-dsp-multi-effect-reverb


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## joelorigo (Jun 2, 2022)

Thank you!

When you say flux, you mean more than a flux pen can apply? I have this one:


			https://www.amazon.com/gp/product/B008OC3VMU/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
		


And this is a total FV-1 noob question, but the  FV-1combined with the rest of the circuit makes the delay sounds? I was searching the Hydra and came across a post about programming something on a pedal with the FV-1.

EDIT; I see on the Hydra PCB page it says “Includes 24LC32A EEPROM with Hydra algorithm preloaded.” Is this what has the specific delay sounds?


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## lumberjack (Jun 2, 2022)

Again, major noob here open to being corrected, but as I understand it the FV-1 is the hardware/processor of the circuit and the EEPROM chips contain the program/software that tells the FV-1 what to do with the signal. EEPROM are a form of memory/storage chip, and they contain the algorithms specific to the effect. That’s why the different effects all need the same FV-1 but come with various different pre-programmed EEPROM chips.


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## EGRENIER (Jun 2, 2022)

lumberjack said:


> Again, major noob here open to being corrected, but as I understand it the FV-1 is the hardware/processor of the circuit and the EEPROM chips contain the program/software that tells the FV-1 what to do with the signal. EEPROM are a form of memory/storage chip, and they contain the algorithms specific to the effect. That’s why the different effects all need the same FV-1 but come with various different pre-programmed EEPROM chips.


You are correct, I'm no expert but what you describe I know... Another point is the FV-1 does come with local program if you don't feed one to it.  That's actually a troubleshooting technic I've seen here to exclude a problem with the EEPROM and confirm the FV-1 works and passes the signal.

EEPROM programing is a very niche hobby... if you're like me you buy the chip pre-loaded as provided by PedalPCB, but an EEPROM is just that a programable chip, so nothing stops you to reprogram it with different patch (Programs) and get different effects out of the FV-1.

I believe the Hydra is only a Delay based on the FV-1, so it may only have one program, though it shows 4 heads options, so might 4 different programs.

The Arachnid platform offers a board with no program, you have to buy a separate EEPROM and load patch/programs on it yourself.

The Modulus 8 is the same as the Arachnid, however it comes with 8 programs pre-loaded on the EEPROM, if you want you can load different programs on it and use it as the Arachnid.


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## joelorigo (Jun 3, 2022)

Thanks for all of that. Very interesting.

I guess I’ll buy the board and give it a try. In the meantime I’ll be watching videos on surface mount soldering.

And just to be precise, is the flux pen I already have (linked above) good enough, or should I get a separate container?


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## EGRENIER (Jun 3, 2022)

joelorigo said:


> Thanks for all of that. Very interesting.
> 
> I guess I’ll buy the board and give it a try. In the meantime I’ll be watching videos on surface mount soldering.
> 
> And just to be precise, is the flux pen I already have (linked above) good enough, or should I get a separate container?


I never soldered SMDs but according to your pen description is good for SMD so...

I also saw videos of people solder surface mount components with a flux pen and it seemed to work just fine.


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## joelorigo (Jun 3, 2022)

Thanks!


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## joelorigo (Jul 1, 2022)

I am looking at the board and the parts for a Hydra build!  Quick question, does the X1 Chrystal Oscillator have polarity? I'm not seeing any thing on the part or on the PCB to indicate polarity.
And hopefully this is the correct part, because it's what I bought:









						32.768 kHz Crystal Cylender 3 x 8 mm
					

KDS - Get It Fast - Same Day Shipping




					www.taydaelectronics.com


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## MichaelW (Jul 2, 2022)

joelorigo said:


> I am looking at the board and the parts for a Hydra build!  Quick question, does the X1 Chrystal Oscillator have polarity? I'm not seeing any thing on the part or on the PCB to indicate polarity.
> And hopefully this is the correct part, because it's what I bought:
> 
> 
> ...


Nope, non-polarized part. Just mind that you need to leave enough "leg showing" to be able to bend it over horizontally on the board.


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## joelorigo (Jul 2, 2022)

Thanks!


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## joelorigo (Jul 6, 2022)

In the process of building now and had another one. Are the switches on/off for the heads? So if all of the switches are down there is no delay effect when engaged?


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## Robert (Jul 6, 2022)

Correct.   You want 2-position (ON/ON) SPDT switches.

Up enables the head, Down disables.


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## joelorigo (Jul 6, 2022)

Thank you.


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## joelorigo (Jul 7, 2022)

I finished it. One thing, well 2 things: 
1. It’s amazing!
2. I notice that the pedal rolls off a significant amount of high end. It that inherent to the circuit? If so, is there anything to replace to make it more “transparent?”


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## MichaelW (Jul 9, 2022)

joelorigo said:


> I finished it. One thing, well 2 things:
> 1. It’s amazing!
> 2. I notice that the pedal rolls off a significant amount of high end. It that inherent to the circuit? If so, is there anything to replace to make it more “transparent?”


How are you running it? (Signal chain I mean). Try running a buffered pedal before it and see if that helps. I had the same issue but I would not categorize it as "significant" loss of high end, just a tad for me and I'm not completely sure it's not my imagination. I would up building a dedicated buffered loop box to put the Hydra and Spatialist reverb is and it helps.


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## joelorigo (Jul 9, 2022)

I was running it after several pedals, and right after a Boss GE7 (that has a buffer right?), but activating the hydra with out any of the head switches up is when I noticed it.


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## MichaelW (Jul 10, 2022)

joelorigo said:


> I was running it after several pedals, and right after a Boss GE7 (that has a buffer right?), but activating the hydra with out any of the head switches up is when I noticed it.


I guess it depends on how much "significant amount of high end" loss is. It should not be that way. Does the loss of high end still happen with the MIX knob turned all the way off?

I just double checked my Hydra, heads turned off, engage and disengage and I don't hear the kind of drop you're talking about. Yah, the BOSS GE7 is buffered output, hmmm which has me thinking, have you tried it with the Boss out of the signal chain and see if it makes a difference?

My suspicion is that maybe you might have a couple of wrong value or out of spec caps. What did you use for the 1U caps? MLCC? Ceramic? Hmmm, noticed that there is still no schematic for the Hydra. Might be tough to try to pinpoint the issue.


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## Gt6371 (Jul 10, 2022)

Robert said:


> Correct.   You want 2-position (ON/ON) SPDT switches.
> 
> Up enables the head, Down disables.


Can you use a Spdt on off on in place of a on on?


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## Robert (Jul 10, 2022)

You could but you'll have two "off" positions.


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## joelorigo (Aug 5, 2022)

I have had a chance to play with this pedal some more. When it is guitar - Hydra - amp, with the Mix knob full CCW and all the switches off, there is a slight bit of high end loss, maybe wouldn’t even have noticed it.
When it is put in a chain of effects I’ve been using lately (guitar - Scream Honey - Honeysuckle - Tube Drive -GE7 - Hydra - Radial ABY - amp(s)) the high end loss is significant. 
I know that’s a lot of variables but wouldn’t all those variables effect the signal whether or not the Hydra is on or off? It becomes “darker” when the Hydra is activated.
Btw I can easily raise the highs and lower the lows a bit on the GE7 to compensate.


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## MichaelW (Aug 5, 2022)

Do you have a pedal with a buffered bypass? (Like any Klon clone) Put that between the GE and the Hydra and see if it helps.

I had the same issue and that's why I built this.

Definitely helped in my case.


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## joelorigo (Aug 5, 2022)

Interesting. I built the Aion Refractor which is a Klon that I chose the option to hardwire the buffer. I have other Boss pedals.


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## Robert (Aug 5, 2022)

joelorigo said:


> When it is guitar - Hydra - amp, with the Mix knob full CCW and all the switches off, there is a slight bit of high end loss, maybe wouldn’t even have noticed it.



There is a bit of lowpass filtering on the output to reduce noise from the FV-1.  

This isn't a Binson clone, it wasn't really intended to be used as a clean preamp.


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## MichaelW (Aug 5, 2022)

joelorigo said:


> Interesting. I built the Aion Refractor which is a Klon that I chose the option to hardwire the buffer. I have other Boss pedals.


That'll work. Having said that, referring back to @PedalPCB's comment, this isn't supposed to be a pristine digital delay. It does add some color.


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## joelorigo (Aug 5, 2022)

Cool thanks! Just to be clear I'm not complaining about anything. I'm trying to figure out if the change in tone when in a chain of pedals is normal. Like does more noise in make the FV-1 filter more? Or if there is something wrong that I did while building. I have an old, old Morley wah wah and just plugging it in the chain darkens the sound. This is only happening when the Hydra is turned on.


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## Robert (Aug 5, 2022)

When you have the Mix control at full CCW the FV-1 is essentially out of the circuit.

Any loss of highs is happening in the lowpass filter on the output of the circuit.

You could try lowering the values of C12 and/or C13.


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## joelorigo (Aug 5, 2022)

Robert said:


> When you have the Mix control at full CCW the FV-1 is essentially out of the circuit.
> 
> Any loss of highs is happening in the lowpass filter on the output of the circuit.
> 
> You could try lowering the values of C12 and/or C13.


I see. But why would the loss of highs be happening with several pedals in front but not with the guitar directly into the Hydra?


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## joelorigo (Aug 6, 2022)

MichaelW said:


> Do you have a pedal with a buffered bypass? (Like any Klon clone) Put that between the GE and the Hydra and see if it helps.
> 
> I had the same issue and that's why I built this.
> 
> Definitely helped in my case.


Oh! I just remembered I have a TC Electronic Bonafide Buffer. would that also work?


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## MichaelW (Aug 7, 2022)

joelorigo said:


> Oh! I just remembered I have a TC Electronic Bonafide Buffer. would that also work?


Yup that will work. Worth a try to see if it helps.


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## Robert (Aug 7, 2022)

joelorigo said:


> I see. But why would the loss of highs be happening with several pedals in front but not with the guitar directly into the Hydra?



Can't say I can explain that.   The input stage of the Hydra is a buffer so it should be offering essentially the same benefit as any external buffer.


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## joelorigo (Aug 7, 2022)

Thanks. I’ll mess around with it some more.

Does the Effecrode Tube Drive have any output weird thing that might cause it?


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## joelorigo (Aug 12, 2022)

Robert said:


> When you have the Mix control at full CCW the FV-1 is essentially out of the circuit.
> 
> Any loss of highs is happening in the lowpass filter on the output of the circuit.
> 
> You could try lowering the values of C12 and/or C13.


Okaaaaay, I don't know what was goin on with my ears before (I did get Covid the next day), but now it is showing the same amount high end loss whether directly into the Hydra or through a number of other pedals. Which makes more sense. I even had my son listen and we made a recording 

What value would you suggest for C12 and/or C13 to try? C12 is 220p and C13 is 470p.


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