Tom Scholtz Rockman X100 repairs

[mikepukmel]

I had a Rockman X100 that got damaged by a nasty power surge, probably 1992. Back then, I opened it up, and got scared from the tiny parts, so I put it in a box and kept it all these years. somebody here on this forum was nice enough to post schematics, they were very close, worked up the courage to start probing and found one of the amps had one channel blown out. Luckily found what was supposed to be original spec op amps, replaced the ones in this unit and it sounds fantastic. Worked up the courage to re-cap, the electrolytics, (big step for me), fixed the flex cable, sounds even better now.

In the mean time, a friend gifted me 2 more X100's, both similar (not exact) to the first one I got. One sounds fantastic, like my other one, but the other is way too loud, and sounds terrible. The tone is awful, too much high frequency, sounds "screechy", doesn't have that silky smooth sound like the other two. Read a little bit, think maybe one or more of the op amp bias resistors has drifted. Pure guess, i don't have the chops to know for sure what to look for. I recapped this one as well, and it sounds exactly the same as before. So, at least I didn't "ruin it more'. Some of the resistors, its really hard to read the color bands, so not sure what the part is, and the schematics are not exact.

Then, I thought maybe to take the other 2 good ones, take some voltage measurements at the op amp pins, then measure the bad sounding one. Didn't do that but don't know what acceptable range is for these voltages. Or maybe Im way off and some other part is the problem. any suggestions greatly appreciated.

[Jazz P Bass]

Post the schematic.

[Mick Bailey]

I didn't think much of my X100 at the time, but after reading this post watched a few clips and the ones demonstrated have a much nicer sound than I remember. Mine had no bass to speak of and was all mids and top end. After that I never looked back (pun intended, Bolton fans) but perhaps mine had a fault.

[g1]

After that I never looked back (pun intended, Bolton fans)

I think you meant Boston fans. So never mind 'more than', just weren't feeling it at all?

[Helmholtz]

The headphones were junk.

[Chuck H]

The headphones were junk.

That happens People sell stuff everyday and make concessions relative to marketing. But the "Rockman" was a solid effort to bring the "Boston" SS tone to a tube world. It could (should) be noted that Tom himself always used this SS effected tone into an overdriven Marshall amp plus a power attenuator for all of the Boston tracks as far as I've known. So there's that. But the Rockman itself has always been considered a pretty cool tone and effect in multiple circumstances after marketing. So not fair to just berate the headphones. This was/is a real pice of gear for some musicians.

JM2C

[Helmholtz]

Point is that those cheap headphones were essential to the Rockman sound despite or rather because of their limited frequency response.
(I tried several other phones (e.g. Sony) but none of them gave the original sound.)
Unfortunately they didn't last long, typically due to broken conductors.
Also the foam pads soon desintegrated.
Original headphones were expensive over here.

I still have my x100 from the 80s somewhere as well as the Tom Scholtz Power Attenuator.

[Chuck H]

I still have my x100 from the 80s somewhere as well as the Tom Scholtz Power Attenuator.

Of course you do

Too cool not to

[Mick Bailey]

Hey, I just re-read my post and read Bolton. That's autocorrect for you. Bolton is an English town with quite a different appeal to Boston.

[g1]

Just so long as it had nothing to do with Michael.

[Chuck H]

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