| Author | Message | ||
     Sam Powrie (savvas) Username: savvas Registered: 01-2008 |
Hi Folks, I have an RD-50-12 which appears to be in very good and original condition. I think it's the original circuit (no mods) and all original components. I've had it for a couple of years and have decided it needs some attention, basically because I don't think it sounds right. The clean channel often seems distorted. Not broken up - just a bit mushy and indistinct. The distortion channel also seems unmusical, harsh, muddy and for that reason, I hardly ever use it. But overall I really like the amp and want it to be performing at its best. I have a good friend who is a semi-retired techo (ex-Fender service accreditation) and who still has a complete workshop running as he contract builds various electronics for a solar power company. He's happy to look at the amp for me and undertake any work required. He reckons the first step is to run a signal through the amp 'and see what the CRO says'. I'm sure this is right, but I thought it might be useful to both him and I if I asked the experts first, particularly as I really value the original state the amp is in! So I have the following questions: #1. Where do we start with an appraisal of this amp with a view to likely service issues? What should we look for to anticipate likely problems after so many years? #2. Are there any minor mods which are worthwhile undertaking in the course of a normal service which might fix reliability issues or improve things? #3. What major mods might be worth considering? I've read many of the posts from Ed Goforth and others and his mods for the distortion channel in particular sound great. I'd love an OTS tone (or R Fords even though I'll never play like him). Unfortunately it's a long way from Australia to wherever Ed lives and the post cost is prohibitive. So is there any consensus on a 'must do' list for this little beast? Thoughts welcome. Thanks in advance for any comments and to Steve and moderators for the forum. It's really reassuring to know it's here. Sam. | ||
| Mike Kaus (mm210) Username: mm210 Registered: 05-2006 |
First off, mods are for AFTER everything is running right. Never mod (IMO) and amp that has problems. Too many things to look at if it goes south. Do ONE thing at a time and see what it sounds like at each stage. THEN, if you insist, mod one thing at a time. OK, back to the issue at hand. First off, that amp is 30 yrs old. Re-cap it. AND I mean all the electrolytics, not just the PS ones. There are electrolytics in the preamp stage as well and in the bias structure, if it has conventional bias or as in your case, the driver section. Clean and re-tension sockets, clean and check tension on the input jack. You'd be surprised how many evils are cured with a clean or new jack. Then move on to the tubes. I assume that being an RD that it has 6L6's in it. You might want to look into a new pair. If the amp has been hammered on for 30 years, the tubes could be weak. Then bias properly. I won't suggest any mods as I'm not that familair with the little rd's(though I'd love to have one) so my opinion is strictly in the maintenance area. Mike. | ||
| Sam Powrie (savvas) Username: savvas Registered: 01-2008 |
Thanks Mike for the guiding words - all to the wise I'm sure. I think it sounds like we should put it on the bench and bring it up to spec with new caps, bias adj. etc first. Sam | ||
| Mike Kaus (mm210) Username: mm210 Registered: 05-2006 |
That's the way I usually do it. you have to have a stable platform BEFORE you start screwing with it. I don't usually like mods that take away from the stucture of the amp but subtle "enhancements" are agreat way to learn and experiment. BUT, like I said, you HAVE to have a baseline. Mike. |