Gut shot of 80's OD-250 on Ebay.

[aron]

Yes, the black version.

[tungngruv]

I know the original 250's were not true bypassed. Can someone tell me if the if it was the input or the output in the original that was "unbypassed"?

Like this?
http://www.generalguitargadgets.com/diagrams/switch_lo_spdt_std_in.gif

Or this.
http://www.generalguitargadgets.com/diagrams/switch_lo_spdt_std_out.gif

I can't tell from the pics although it looks maybe like the output is connected when bypassed. Can't see the Ebay pics, my workplace doesn't allow that site. Thanks in advance.

[Ed G.]

The black one has some very cool ideas that we would use now! Look at the diodes and the IC type etc...

What do you mean by the black one eh?  Are you refering to the ross Distortion eh?

Yup, the black one went to asymmetrical clipping diode arrangement (wouldn't this predate the Boss patent and therefore make it void?) and used half of the 4558 opamp instead of the 741.

[analogmike]

The black one has some very cool ideas that we would use now! Look at the diodes and the IC type etc...

What do you mean by the black one eh?  Are you refering to the ross Distortion eh?

Yup, the black one went to asymmetrical clipping diode arrangement (wouldn't this predate the Boss patent and therefore make it void?) and used half of the 4558 opamp instead of the 741.

the OD1 came out in about 77 when the Ross were still beige and made in usa. So I think Ross was abusing Boss' patent (and MXRs circuits!)

[analogmike]

p.s. I am going to try the early DOD 250 mods above, just so busy... will let you know how it sounds. thanks JHS!!!!

[analogmike]

I had one of my guys build one to the '77 specs and finally had a chance to test it.

the 222 cap on the input is too dull/honky at lower dist settings so best to leave it off. Sounds fine at high dist settings though.

These specs do sound very different than the normal grey DOD pedal, not as processed/saturated sounding, more of a raw tone, a little less volume. Nice and gritty and vintage sounding. Very cool, thanks and have fun!!

[wampcat1]

I had one of my guys build one to the '77 specs and finally had a chance to test it.

the 222 cap on the input is too dull/honky at lower dist settings so best to leave it off. Sounds fine at high dist settings though.

These specs do sound very different than the normal grey DOD pedal, not as processed/saturated sounding, more of a raw tone, a little less volume. Nice and gritty and vintage sounding. Very cool, thanks and have fun!!

Thanks for the report back Mike, I was toying around with this circuit this week as well. A fun mod to do when using a dual opamp is to use the second half of the 4558 and put a 3 band tone stack on it, use the opamp to boost the level back up. Good fun.

Also, the correct home wrecker link is http://www.home-wrecker.com/ross.html

bw

[markm]

I just did a layout for the 1977 OD250 and added it to my layouts gallery but it is untested as of this writing.
I'll get to it though......soon I hope!

[MartyMart]

I had a very old "Tan" Ross distortion until about two years ago.
It was in a "Bud box" , must have been '70's , can't remember when I bought it but
it was very beaten up and the inside was cacked in old rotten foam.
I'm sure it had Ge diodes and single 741 opamp ....
I thought it was a little thin and scratchy, so sold it on Ebay and got about 150 bucks, sold to USA !

Maybe one of you guys has it !!

MM.