Anybody know anything about the Arion MDS-1?

[Boy Howdy]

I have an old Arion SCH-1 chorus, you know the one everyone's gaga over lately. It's okay as a chorus, nothing special, but it does a fast Leslie sound that actually is quite nice. That's the effect that all the big names are buying these for.

Mine is missing a couple of knobs, so I was thinking about ordering a MDS-1 Distortion (on sale at Musicians Fiend for $10) and swiping the knobs offa it. I could then sell the pedal and not lose anything ... or keep it, if it had something interesting to offer.

I've heard that one of their old pedals (Tube something - not the Tubulator, an earlier one) is actually just a knockoff of a TS. Anybody know anything about the MDS-1 circuit? Any interesting mods, etc?

[Boy Howdy]

Well, I learned something....

I learned that when you ask yourself "how bad could it be?" you should find out the answer BEFORE you lay down your hard-earned.

Woowhee, what a stinker! Yeah, I ordered one. I've never heard a pedal that sounds this bad. Some pedals sound bad in a good way, not this one. It is really awful! I tried to imitate the sound of this pedal using another distortion pedal (an 80s Nady tube overdrive - a very nice, and natural, sounding pedal) and an old Ibanez 7-band graphic pedal. I found that if I boosted the lowest band and the highest two bands all the way and the up and cut the rest in the classic V pattern with the 500 hz band completely attenuated, it STILL didn't sound as bad as this MDS-1!

BUT, I don't regret buying it. I was able to rob the knobs off of it for my 70s Arion chorus (I love that thing more every day). I also robbed the part that you apply your foot to to switch the effect in and out. For some reason that part stood cocked up at an angle on the chorus pedal. Switching the new part from the MDS for the old one on the chorus fixed that problem. The chorus also has a problem with switching on and off, so I may end up swiping the switch from the new one as well, if that's what the problem turns out to be.

So, I think I've already got my $10 out of it.

That said, anybody know where I might get a schematic for the MDS-1? I'd love to see what I could get out of it with a few modifications.

Hard to believe, looking at the board, that they used twice as many parts as some pedals that don't sound half as bad.

[Boy Howdy]

Jump in anytime, guys.

I need to do something with this thing to make it sound better. And apparently there's no schematic to be had. Can someone suggest how I might start to experiment?

I think the biggest problem/opportunity are/is the diodes. This thing sounds very harsh, very screechy. I'd like to try some LEDs, I think. But, there are 5 or 6 diodes in there and I'm not sure which ones to change. In every pedal I can recall the clipping diodes were right together and facing in opposite directions. Not this one, the diodes are scattered all over. One clue though is that only two are located near each other and numbered sequentially (if that make any sense), D3 and D4. Would these likely be the ones I'm looking for?

Another problem: too much bottom end. Any clues what to change there?

Another problem: too much gain. Same question.

The thing ain't absolutely horrible (well...), but it could be a LOT better.

Can somebody help?

[DMW]

I need to do something with this thing to make it sound better. And apparently there's no schematic to be had. Can someone suggest how I might start to experiment?

I think the biggest problem/opportunity are/is the diodes. This thing sounds very harsh, very screechy. I'd like to try some LEDs, I think. But, there are 5 or 6 diodes in there and I'm not sure which ones to change. In every pedal I can recall the clipping diodes were right together and facing in opposite directions. Not this one, the diodes are scattered all over. One clue though is that only two are located near each other and numbered sequentially (if that make any sense), D3 and D4. Would these likely be the ones I'm looking for?

Another problem: too much bottom end. Any clues what to change there?

Another problem: too much gain. Same question.

The thing ain't absolutely horrible (well...), but it could be a LOT better.

Can somebody help?

I'm not going to be of any help...just yet. I bought three of the $9.95 boogers - now back up to $29.95 each - and sold one to someone else. So, I've still got two I've not even tried. The pedal I tried and sold - and hope it doesn't turn out to be the one I should have kept - did not seem to be quite so harsh as what you described. I would not trade it for any of my several modded Boss or Ibanez pedals (sorry don't own any expensive boo-teek pedals), but I thought it had potential. With such a modest investment involved I'm going to try some mods, too, and will try an LED mod first. If I get this done in a reasonable time frame, I'll report back and let you know if I've made a mediocre pedal useable, or it I just made it ready for the circular file.

[petemoore]

think the biggest problem/opportunity are/is the diodes. This thing sounds very harsh, very screechy. I'd like to try some LEDs, I think.
I'd consider doubling the number of clipping diodes, ie where there's on -->l--, put two -->l-->l--. This will reduce distortion and raise output.
If the problems is harshness, a cap [there's probably one there, make it bigger] across the diodes rounds the harsh clipping edges.
But, there are 5 or 6 diodes in there and I'm not sure which ones to change. In every pedal I can recall the clipping diodes were right together and facing in opposite directions. Not this one, the diodes are scattered all over. One clue though is that only two are located near each other and numbered sequentially (if that make any sense), D3 and D4. Would these likely be the ones I'm looking for?
If they are diodes from signal path to ground [like Dist+], look for ground on two of them, perhaps there are four [see above], two in each direction 'on' one gain stage, chance there are two clipping stages, and some BTB diodes used on each one. the other 'common way to use clipping diodes is like the Tube Screamer, between an opamp output and it's inverting input.
But the diodes may also have a DC blocking cap between the 'recognizable' nearby components...ie from an OA output through a cap to diodes [signal path] to ground..or between an opamp -input and it's output [perhaps a cap in series, less likely].
One way you might be able to tell is to pick a lower threshold diode like GE [if yours has Si's] putting that across an Si...the Ge having a lower clipping threshold does all the clipping...and should lower output/increase distortion...poke or clipping Ge diodes across Si's in your circuit and listening for the change in distortion output level and tone...
Another problem: too much bottom end. Any clues what to change there?
This one's pretty easy, and cap in series with the signal path can be made small enough to be a HP Filter, try near input or input cap, perhaps the input wire...you can splice a value right in there...it'll be in series with the existing input cap, reducing it's value. Same with the output cap, but if you want 'bass hash'...leaving the input cap big allows the bass to mess with the amplification, so the 'cleaner' method might be do more of bass rolloff toward input, or spread it through the circuit [troublesome, possibly diminished returns for the amount of effort..]
Another problem: too much gain. Same question. There's probably a gain pot, and maybe a stop resistor and a cap that set gain [as well as other things], I would mess with the diodes and voicing first, use your guitar volume to decide if you want a 'divider' at the input, this will reduce source voltage and reduce gain, you can see if you like it with your guitar volume, as a 'pre-gain' is duplicitave of the Guitar Volume control, it's just a 'second one', and pre-sets max gain lower, probably you have no room for a pot, but a pot could find the value or values you want [just a series resistor or a pot wired like volume control], then replace the pots value[s with resistor[s.