How to convert your BOSS HM-2 from 12V ACA to 9V PSA

[@AIBCustomFx]

tip to avoid burning a component/trace by mistake when soldering/desoldering vintage circuits: Get a soldering wire with as much lead content as you can. Those have a very low boiling point. not only they melt much quicker with a low temperature but they'll "dilute" and blend with old stubborn solder points, making further jobs much easier!

[@HM2CULT]

Very good point there! I was using "Pb free" and there is a noticeable difference in melting time.

[@AIBCustomFx]

@@HM2CULT yup. lead is bad obviously but for a repair or part swap/mod, it's fine. Choose the largest amount of lead with flux core. You can't go wrong with that

[@Toology88]

Great video. Sold my Waza version and grabbed a MIJ version for the amount I sold the Waza for and immediately did this mod

[@replikasbuzi]

Thanks! With this tutorial I modded my oc-2. Cleanest mod and also the easiest:D

[@hiltonseawright]

Just did the mod on one of mine. It works perfectly, thanks a lot!!

[@WillyRaschke]

Awesome I like this better than the removal of the diode and resistor… FT-2 and OC-2 surgery this weekend…. I’m planning to label “converted to 9v PSA” and retain the ACA sticker

[@XChristianNoirX]

I should have done this method! It shall be done to my remaining pile of HM-2's and other BOSS pedals.

[@HM2CULT]

It's different pads to jump depending on the model of Boss pedal. You'll need to check the pedal specific schematic.

[@XChristianNoirX]

@@HM2CULT yes, I have all the data... But I will just be jumping from now on! 👍🏻👍🏻

[@normanvename3724]

Hell yeah thank you for the excellent tutorial!

[@riffsnoleads]

I should have known you would do the non destructive mod. I only ever modded a HM2 once years ago, but I did it the silly way and removed two resisters and jumped them, if I am not mistaken. Very nice work, as always. In my opinion, Boss pedals were designed to be modded to holy hell. I have not done my MIJ, but I always run it in a daisy chain with a tuner, so I have not had any need to.... yet. Get that VTM fixed so we can battle.

[@HM2CULT]

That short [new] intro was the VTM and Boss HM-2. I love the sound! Perfect for recording.

[@riffsnoleads]

@@HM2CULT fuck yeah! It really is a sound all its own. Are you still running the G12t-75 cab? That is what I use with mine for total gnar.

[@HM2CULT]

@@riffsnoleads I am. This however was a torpedo captor and Lynchback Celestion IR.

[@riffsnoleads]

@@HM2CULT nothing wrong with using an IR. I have some shitty video on instagram with my VTM going into a IR. I just gotta find an attenuator that can take 120 watts so I can stop pulling tubes. hahaha

[@HM2CULT]

@@riffsnoleads use the torpedo captor. I can use my 5150 just don't push it past 5 on the post gain.

[@JM.COSMIC]

Hi I have a question do you use a 9v or a 12v power supply for the Boss HM-2? I will buy one this week but I only have a Strymon Ojai wich is a 9v with 5 slots... The other option that I have is to power supply it through my TU-3 will that work?? and is it much difference between a 9v and a 12v in the HM-2? greetings from Chile

[@kekomixtli]

Hey man, thanks for the video. Quick questions, is it safe to run the pedal with a 12v 2A adapter? Or what's the maximum volts and amperes it can take? And why did you say "better than using a battery"? With the battery I guess there's no voltage dumping, that's why the led lights well.

[@HM2CULT]

All the old Boss HM-2 are 12V with a 10mA draw. Only run the pedal with a 9V battery or an adapter that is equal to the Boss issued 12V adapter.

[@HM2CULT]

I don't like using batteries, personally. It's unnecessary waste when they are dead and no battery is truly 9v brand new. They'll always be about 8.5V. Using a regulated/isolated power supply is the best way to go if you can get one. Or buy a new HM-2w Waza Craft and those run on 9V.

[@juanpablofernandez5191]

Thanks Bro!

[@ernestoo8313]

I did jumper only the resistor. But I probably would have opted for this mod instead if I knew about how fragile the grey cables are. Fortunately mine didn’t break. Only jumping the resistor has an advantage though. It leaves in the diode preventing possible damage by reverse voltage right?

[@HM2CULT]

That sounds right in theory, as a power protection diode, but I can't say for sure.

[@smedo666]

isnt kinda the same if you put 12V 500mA load? it also works.

[@HM2CULT]

500mA is unnessecary, Boss HM-2's only have a 10mA draw. And yes, IF you have a 12V adaptor or choose to run your pedal on a 9V battery that will work just fine. I simply wanted to fully moderize this pedal. In addition to the 9V PSA mod, I rebuilt most of the pedal to ensure reliability.

[@nameofchannel7648]

will a 9v aca work in the ns-2 daisy chain without mods?

[@HM2CULT]

For clarification, 9V is "PSA" and 12V is "ACA." If you have a stock/unmodified HM-2 12V "ACA," yes it will power up just fine being daisy-chained to an NS-2, TU-2, or TU-3.

[@nameofchannel7648]

@@HM2CULT ok cool, have a stock 87 mij hm-2 aca but my ns-2 is psa so wasnt sure.

[@HM2CULT]

@@nameofchannel7648 completely safe that way. Also better than using a battery.

[@nameofchannel7648]

@@HM2CULT any advice on how to connect the two to a teal bandit 112? So far best I've found is hm2 in the ns2 loop into the amps high gain input.

[@ericsalinas1839]

Thinking about doing this with my MIJ ds1

[@HM2CULT]

It will be different points as it is a different circuit.

[@beatlejuice5951]

Sound comparison please

[@HM2CULT]

sound comparison between the operating voltages? There is none. I will however have a side by side with the refurbished pedal and a stock HM-2 from the same year of production ['88].

[@beatlejuice5951]

@@HM2CULT oh, I thought it would sound different. Umm so what's the point of the mod than? A dimer light?

[@AIBCustomFx]

@@HM2CULT true as there can't be any. When unmodded, the 12v feed gets partially dumped to ground to get 9v at the circuit. The mod consists only in removing that voltage dumping arrangement.

[@HM2CULT]

@@beatlejuice5951 The point of this particular mod is to make these old Boss "ACA" 12V pedals compatible with the industry standard of 9V [power supply] operation. 12V power supplies are available but not as readily available as the 9V power supplies.

[@beatlejuice5951]

@@HM2CULT oh gotcha