Ebay Rev 20s

A family of high-end analog DI and effects gear.
GuitarBuilder
Posts: 245
Joined: Sat Aug 30, 2014 7:14 pm

Re: Ebay Rev 20s

Post by GuitarBuilder »

I can totally understand a company going after others who blatantly copy their designs while theirs is still in production. No issue there, just protecting intellectual property. I have done it myself!

SR&D is no longer in business; clearly Dunlop is not interested in supporting SR&D customers, or they would be a lot more forthcoming with service and information. So the message by the old and new owners of Rockman is: if you bought one in the past (and paid good money for it), you're on your own. If that is not abandoning your customers, I don't know what is.

With the vast majority of Rockman products out of production, there is no longer a question of IP protection. The original patents are essentially expired. Refusing to provide documentation to help a small group of die-hard fans troubleshoot and maintain their Rockman collection is simply not acceptable.
RockmanCentralBob
Posts: 414
Joined: Fri Feb 06, 2015 2:10 am

Re: Ebay Rev 20s

Post by RockmanCentralBob »

Wow, where to start?

So, one question seems to be, "why doesn't Dunlop give out schematics anymore?" I can't answer that one. But, it IS their property, so it's their decision to make. My guess is that they DO plan on re-issuing the Rockman modules (in some form) and don't want the schematics out there. Why else would they buy the rights to them? That's what Dunlop does... they buy the rights, and then they sit on them till they're ready to re-issue them (or use the design as the basis for a new product).

"Why don't they give out Rev 20 schematics?" How many people HAVE Rev 20's that would need them? Not many. So there's no reason to release them, and even less of a reason to release them than the regular Sustainor schematic.

Would having the Rev 20 schematics help you? Maybe, but maybe not. I've tried modding 2 Sustainors into a Rev 20, the first one is now completely scrapped and ended up becoming a board I use when I need a spare part. I mean, COMPLETELY destroyed!! The second one has been worked on for probably close to 20 years, and it's still not right! Yes, I'm a hack, but I can follow a schematic. I couldn't get it to work right, so I sent it to a friend of mine that is an electronic engineer for Intel. Get that? A REALLY smart guy!!! He worked on it for MONTHS, even getting advice from Cedro, and couldn't get it to work right either. So it sat in a box, as pretty much a "dead soldier", for over 10 years! I've recently pulled it out and started trying to troubleshoot it, and have FINALLY started to make some progress. But it's FAR from working properly. The auto clean pumps in and out, and the clean channel sounds pretty heavy in the low end. But, when I just use the Edge or Distortion settings, it sounds pretty amazing. I just did an A/B comparison with a stock Sustainor and there IS no comparison.... it just sounds lightyears better. The stock one sounded very "thick", whereas the Rev 20 is very "crisp" sounding.

I have another Sustainor that I've started to mod into a Rev 20, but am taking it slow this time. So far I've only changed a few of the parts affecting the gain level, and it does sound better. But what I'm probably going to do is just mod the main sections of the circuit, but leave the auto clean alone. I don't use the auto clean that much anyway, and so as long as it works somewhat, I probably won't mess with it because it's the area that REALLY plays havoc with it if you don't get it right.

Now, for the final question.... "Why don't you share the Rev 20 schematic?" There are several reasons.... the first of which is that they aren't mine to share. Again, they belong to Dunlop. Another reason would be what would happen to the value of those that DO have Rev 20's (and paid a LOT of money for them) if suddenly anyone could mod a Sustainor into a Rev 20? I don't think that would be very fair to those people. But the main reason is that I would be stabbing who I still consider to be a good friend in the back if I did. For those of you that can't understand that, well, I don't know what to tell you. I've made mistakes and said more than I should from time to time, and it still haunts me. But for me, friendship matters, and I do my best not to screw mine over if I can help it.

If I can ever get to where I can successfully and consistently mod a Sustainor, even partially, into a Rev 20, then maybe I can do that for some of you that really want one for your own use. But I'm not there yet. We'll see how things go over the next few weeks/months. Of course, the problem is that I don't know who's going to take it and try to reverse engineer the mods or wants it just so they can sell it for profit. So I would have to think about how to handle that. I can tell you that I've already put a lot of money into experimenting with all the mods I've done over the years. Killed a few units, some of them quite valuable. I've done other mods where people tried to take credit for them or profit from them. Most of that is water under the bridge at this point and I've gotten over it. But that doesn't mean I want to make the same mistakes over again!! Again, friendships are more important to me at this stage of my life.

I try to help where I can and tell you guys when some mod I'm working on works or doesn't work. The Ultimatum has been hit and miss. In the XPR, it works pretty good. But not so much in the Sustainor. And each time I work with it I discover other parts that matter more than I initially thought. So it's a learning process for me too.

On another front, I've been going through my schematics book a lot recently and took a little time to document the mods for the XPR -> XPRa conversion. They are fairly extensive, but they look doable. I have some questions about the instructions that I need to open up one of my XPRa's to confirm. But if I can nail all that down, maybe some of you with an XPR that wants it modded could finally get it done? It would depend on the revision you already have, so no promises....

I'm here to help, but unfortunately some things are really just beyond what I can do and still sleep at night. I'm sorry if that pisses some of you off... that's not my intention.
GuitarBuilder
Posts: 245
Joined: Sat Aug 30, 2014 7:14 pm

Re: Ebay Rev 20s

Post by GuitarBuilder »

Bob - I for one would be very interested in converting my XPR into an XPRa.
RockmanCentralBob
Posts: 414
Joined: Fri Feb 06, 2015 2:10 am

Re: Ebay Rev 20s

Post by RockmanCentralBob »

GuitarBuilder wrote:Bob - I for one would be very interested in converting my XPR into an XPRa.
Give me a little time to sort through my backlog and I'll try to open up my XPRa to verify the circuit changes.

On a side note, I guess the 3rd try really is the charm!!
After 20 years and 3 attempts, I was finally able to successfully modify my Sustainor into a full Rev 20.
As I was doing it, I was comparing it to the changes I made in my last attempt and was able to figure out easier ways to do things.
Now that this one is working correctly, I'm going to go back and fix the other one to sort out the auto clean to get it working correctly.

I will say that it is NOT an easy mod, and it took me several days to get through it all.
And for whoever it was that was wondering if you could figure it out from photo's, trust me, there's no way in hell!!!
Honestly, even if you had a Rev 20 sitting in front of you to look at for reference, without the schematic, I wouldn't even attempt it.
There's just too many little details that are VERY easy to miss, and any one of them could turn your Sustainor into a boat anchor!
There were several times where I thought I totally screwed it up again.... and it took a leap of faith to get through it.
Luckily, everything came together and it sounds wonderful!
User avatar
iZheil9152
Posts: 87
Joined: Mon Feb 24, 2014 3:56 am

Re: Ebay Rev 20s

Post by iZheil9152 »

RockmanCentralBob wrote: After 20 years and 3 attempts, I was finally able to successfully modify my Sustainor into a full Rev 20.
Luckily, everything came together and it sounds wonderful!
Fantastic! Now you can open a Rev 20 conversion business! (kidding)

As I was doing it, I was comparing it to the changes I made in my last attempt and was able to figure out easier ways to do things.
Now that this one is working correctly, I'm going to go back and fix the other one to sort out the auto clean to get it working correctly.
RockmanCentralBob wrote:I will say that it is NOT an easy mod, and it took me several days to get through it all.
And for whoever it was that was wondering if you could figure it out from photo's, trust me, there's no way in hell!!!
Honestly, even if you had a Rev 20 sitting in front of you to look at for reference, without the schematic, I wouldn't even attempt it.
I'm just wondering what revision you started with. I'm guessing it would be an easier job to complete the transformation the higher up you were in the revisions: a Rev 18 or 19 for example. Because as you said, all the revisions are working their way up to the Rev 20. Im also guessing its an impossibility to do it with a blue face sustainor. Not that I'm going to attempt anything with my understanding of electronics...
RockmanCentralBob
Posts: 414
Joined: Fri Feb 06, 2015 2:10 am

Re: Ebay Rev 20s

Post by RockmanCentralBob »

iZheil9152 wrote:Fantastic! Now you can open a Rev 20 conversion business! (kidding)
Well, I need to do a few for some guys that REALLY need them first. These guys travel all around the country using them so they'll get the first ones I mod. We'll see how things go after that. But like I said, it is a LOT of work and I have a life. So I'm not looking to make it a business, that's for sure. And like I said, it wouldn't be fair to those that already have them if I suddenly started pumping out Rev 20's for every Tom, Dick and Harry.
iZheil9152 wrote:I'm just wondering what revision you started with. I'm guessing it would be an easier job to complete the transformation the higher up you were in the revisions: a Rev 18 or 19 for example. Because as you said, all the revisions are working their way up to the Rev 20. I'm also guessing its an impossibility to do it with a blue face Sustainor. Not that I'm going to attempt anything with my understanding of electronics...
I haven't seen the interim schematics so I don't know exactly how they were numbered. I know of the Rev 6 (but have only seen a board layout for it, NOT a schematic), which I think is what the "Blue Face" Sustainors were. Then there's the Rev 9a, which is the "White Face" models that most people have. Then there's the Rev 19, which is pretty much a Rev 20 circuit wise, but the label on the faceplate was still inked "Preamp Gain", and covered with a sticker that said "Pre Treb". Then the Rev 20 which was inked "Pre Treb".

So yeah, I think I started with a Rev 9a. But if you have the schematics , theoretically you can modify any revision to whatever revision (up or down) you want.
User avatar
Guitarvamp
Posts: 174
Joined: Fri Feb 28, 2014 1:02 am

Re: Ebay Rev 20s

Post by Guitarvamp »

I'd love to see the schematics posted so we can ponder over them, dream, and discuss all the tiny nuances.

And maybe some day if I'm feeling saucy (and very lucky), I would try my hand at making the revisions on an actual unit.