EHX - Micro Synth XO Version [schematic]

[beavis]

Interesting in that it uses 9 volts. All SMD.

Shots:


biggie version: http://www.beavisaudio.com/gg/images/EHX_XO_Microsynth/ehx_xo_ms_0.jpg


biggie version: http://www.beavisaudio.com/gg/images/EHX_XO_Microsynth/ehx_xo_ms_1.jpg


biggie version: http://www.beavisaudio.com/gg/images/EHX_XO_Microsynth/ehx_xo_ms_2.jpg


biggie version: http://www.beavisaudio.com/gg/images/EHX_XO_Microsynth/ehx_xo_ms_3.jpg


biggie version: http://www.beavisaudio.com/gg/images/EHX_XO_Microsynth/ehx_xo_ms_4.jpg


monster big version (read the part #s!): http://www.beavisaudio.com/gg/images/EHX_XO_Microsynth/ehx_xo_ms_4_large.jpg


biggie version: http://www.beavisaudio.com/gg/images/EHX_XO_Microsynth/ehx_xo_ms_5_large.jpg

[Gila_Crisis]

i tryed one, once i went to jam with another guitarrist who had it. well it sounds cool like the original

[theehman]

Thanks for the pics! The use of the LM13700 really makes for a smaller size. I'll have to pick up one of these soon.

[analogguru]

Looks cool.... I think that some people in little chinatown could have had a lot of work with it.

Note the Piher-Trimmer-clone: Made in Taiwan.

analogguru

[Bernardduur]

Hmmmm, now the guitar and bass version differs on 6 points from each other

[Silent Fly]

Hmmmm, now the guitar and bass version differs on 6 points from each other

I sent an email to EHX a while ago asking what are differences between the guitar and the bass version and they told me that if I play guitar and bass I can use just the bass version.

According to EHX, the bass version can track guitar but the guitar version cannot track guitar. Moreover, some guitar players prefer the bass version because of the deeper sound. Apart from these two point, there are not noticeable functional differences.

[drfrankq]

did they take off the gate found in the previous reissue? liked it alot but not the gate

I picked up a vintage one that sounds great with not gate, but seems to be a noticeable AC hum with fuzz after it, could be why they added the gate, what do you guys think? Anyone try to get rid of the hum? Thanks!

[Bernardduur]

Hmmmm, now the guitar and bass version differs on 6 points from each other

I sent an email to EHX a while ago asking what are differences between the guitar and the bass version and they told me that if I play guitar and bass I can use just the bass version.

According to EHX, the bass version can track guitar but the guitar version cannot track guitar. Moreover, some guitar players prefer the bass version because of the deeper sound. Apart from these two point, there are not noticeable functional differences.

I dunno; the tracking of the guitar on the bass version was OK but not complete. And the trigger function worked different for the guitar (I couldn't get some to trigger the bass function). When playing bass over the guitar version the tracking ends on the B on the A string. It'll track but there is a serious lag between note played and note heard; a lag of about 3 seconds

[Silent Fly]

I dunno; the tracking of the guitar on the bass version was OK but not complete. And the trigger function worked different for the guitar (I couldn't get some to trigger the bass function). When playing bass over the guitar version the tracking ends on the B on the A string. It'll track but there is a serious lag between note played and note heard; a lag of about 3 seconds

What do you mean by "the tracking of the guitar on the bass version was OK but not complete"?

The higher (pitch-wise) notes of the guitar were not tracked?

[Bernardduur]

I dunno; the tracking of the guitar on the bass version was OK but not complete. And the trigger function worked different for the guitar (I couldn't get some to trigger the bass function). When playing bass over the guitar version the tracking ends on the B on the A string. It'll track but there is a serious lag between note played and note heard; a lag of about 3 seconds

What do you mean by "the tracking of the guitar on the bass version was OK but not complete"?

The higher (pitch-wise) notes of the guitar were not tracked?

Whahaha, I sometimes write weird things I guess

And that was exactly what I meant. I had no lag but the tracking was way off! That is why I added a switch to mine to switch between the 2 versions.

[JiM]

Great pictures ! One can almost trace it

Unfortunately, there's still no expression pedal option
I like the small "prototype area" next to the input jack : meant to be modded ?

If you're buying one, I'd suggest to get the bass version, as 5 out of the 6 resistor values that differ are higher on the bass version : you could then dip-switch some parallel resistors to get the guitar version as well.

[nothingmaker]

Hi, I’ve bought a new Micro Synth XO series.

I notice the problem of sustain loss, that was not in the vintage version.
When I play a note, after 3-4 seconds, the effect goes down with no sustain. With each voice there is the problem, after that time the effect disappears, and the volume goes down.

There is a way to mod the pedal? Or insert a squelch regulation?
I'd like to reach the sustain of the old version.

Thank you so much

[Sweetalk]

Did you adjusted the gain trimpot?. I had both, XO and the old version, the old is simply better but is big as hell!!.

[lufox15]

HI!!!!! everyone, i have a piece of the Micro Synth XO Version Schematic that i draw seeing a pictures on other topic on this forum, but now I have some problems with some stages (Sub-Octave that it's diferent, Attack Delay Stage) that i can't see on the pictures and MAYBE someone who have this pedal could help me , completing this schematic then when I'll have free days on december i could make a new little PCB using just LM13700 and not the expensive CA3094.

HELP ME PLEASE! AND THEN WE'LL have a nice topic about the new version of this amazing pedal!!!!!!!
with 9v normal supply and not expensive.

Cheers.

The Schematic.

microsynthxo.pdf

PD: I'm not sure if there are problem using normal components and not the SMD that uses the XO Version, could make a difference? (capacitors, resistors, transistors???) someone who answers this question? or make suggestions and corrections of the schematic or thread? maybe this topic must be on another board on the forum?

[lufox15]

someone?!

[Liquids]

Normal through hole components will work fine if the circuit is the same, just larger.

[lufox15]

thanks for the data Liquids .
But there is nobody that could help to conclude the schematic.

[bratpilot]

pieces of the scheme look very similar to the original scheme of the old version.
You could finish the circuit complete?

[rtstef]

Hi everybody,

My name is stephane, from France, 30y old, guitarist/bassist player since the end of 90's.
I really need a synth pedal for bass, but no money for a good one

I've build 3 pedals (fuzz, phaser and overdrive), 1 amp (nano head) and a copy of irig.

I don't have any knowledge in electronic, but I really want to build a micro synth, !XO model! (ca3094 is very expensive to buy from my country. About 30€ in my near elec shop )

So, someone have try to build it?
Diagram is finally complete? (i've seen pics of new µsynth have disappear from forum... EHX initiative?)
A good replacement for ca3094 (with update schematic for µsynth please!)

Thanks all,
and VERY thanks to this forum.

Stephane

[Dirk_Hendrik]

Stephane,
viewtopic.php?f=13&t=7502&hilit=microsynth


And buy parts online. Not in your local shop. Saves a fortune.