I just acquired an RD50-112 in pretty good cosmetic shape and I don't think the amp has seen a lot of hours of playing. It was sold originally in 1981, the original receipt was inside.
Here are my questions:
Should I be getting a cap job done on this amp at this point? (It seems like it would be time for it)
What kind of difference in tone and response should I expect? It sounds pretty good now, kind of flabby on limiter side.
How much should I expect to pay for a cap job?
Where would I go to acquire the caps?
Should I be doing anything else for this amp besides a cap job?
Thank you in advance for your response!!!
Keith Shannon
Recap/cleaning
I also have an RD112 50 that I had recapped fairly recently after about 6 or 7 years of gigging 3-4 times a week. I was lucky enough to find a guy fairly close to me that is a pure tube amp repairman but was willing to work on my amp. He replaced all the caps except one. See my original post, "RD112 50 limiter channel "mushy" " to get the scoop on my experience.
I also replaced the tubes with JJ tubes from http://www.thetubestore.com and the amp is now back to its former glory. I had Groove Tubes in it but, they were 6L6 R's and sounded a bit flat. I also replaced the 12AX7 with a JJ and that helped with the limiter. The JJ's cost less and sound great!
There's also a guy on this site who was very helpful; mgriffin155. Perhaps he will chime in on your query. He is very knowledgeable and posts often.
As far as the difference in sound after the recap... I had to search a bit to find the tone I was looking for but, it was definitely there. Also, it cost me a bit under $200 for the recap.
I think most,if not all the caps are available at http://www.mouser.com
Hoping any of this helps! Good Luck and keep me(us) posted.
Re-Cap?
Congratulations on your recent addition. In response to your query, most likely yes about re-capping your RD-50 unless the previous owner recently did it. Electrolytic caps degrade with age even if the amp wasn't used. It's advisable to replace every one of them on your amp. Not just the power supply caps. Replace the amplifier electrolytic caps too. Mouser.com should have most if not all of the caps. Also, have your tech check all of the zener diode voltage regulators and replace any that are out of spec. or show signs of getting hot. After that, consider replacing the limiter tube and power amp tubes. Here's the schematic for your RD-50 in case you haven't found it in the Downloads and Resources section: http://pacair.com/mmamps3/sites/default/files/docs/2165-rp_and_2100-rp.pdf. Finally, get some DeOxit contact cleaner and clean all the pots to get rid of any scratchiness. You should also use DeOxit to clean all of the Phone and RCA jacks and plugs. You can order DeOxit from Amazon. Do these things and the amp will sound great and give many more years of service. Good luck and feel free to ask questions. -mgriffin
Howdy mgriffin!
I was hoping you'd be out there and share your expertise with humblepie. Your advice was SO helpful to me and I thank you again.
I was curious though about the schematic you referenced; I think it may be for the wrong amp and I'd hate to see anything go wrong for humblepie. I know that mine is the 1650-rd chassis. Please forgive me if I am muddying the waters; I mean no offense. If I am wrong, feel free to roast me. Hoping all is well with you!
Ooops Wrong Schematic
Good catch. My bad. This is the one. http://pacair.com/mmamps3/sites/default/files/docs/1650-rd.pdf
I just got a RD50 112 in the
I just got a RD50 112 in the mail today. Just bought it on eBay. It's damn near mint. Just need to get the rust off the chasis panels and tighten the grille cloth and it will look show room perfect! SO holy mother of god! This is the amp I've been waiting for! So LOUD, so clean and so small! Exactly everything I wanted it to be and more! I play Strats and this is just an absolute dream. It has Groovetubes in it now and an Eminence made generic Fender made speaker. Not sure if mine needs a cap job or not. Thinking about trying the JJ's if they made that much of a difference for you. What about speaker recommendation?
New in the mail
I saw that amp on eBay; looked like a gooder! I also play a Strat through mine most often and I would agree with your assessment.
As far as the JJ's; they were the final missing ingredient for me. After having the caps replaced and the pots cleaned, the new tubes restored the missing sparkle that I so love about MM amps.
With regard to the speaker, mine has the original MM 12" in it and seems to be good. I haven't tried any other so am unable to offer anything useful on that front.
For anything more useful than opinion or anecdote, I suggest following mgriffin155's advice and/or others who possess actual knowledge of amps and electronics as I am just a player.
Congratulations on entering the world of Music Man!
So I'm gonna tackle the grill
So I'm gonna tackle the grill cloth tomorrow night. It needs a straightening and a tightening. However, the hardwear...the chassis straps and strap handles are pretty rusted and worn. The rest of this amp is mint and if it wasn't, I probably wouldn't care but I really wanna get these things shining like the metal corners. I hit em with Brasso and steel wool and while the rust came off there's still a lot of wear and and they just looks worn and crappy. Two questions, is there anything else I can do to get these looking brand new again or can I buy replacement parts anywhere online?
Thanks so much for the help!,
Dustin
Sometimes its possible to
Sometimes its possible to tighten grill cloth with a hair dryer.
Keep moving to keep from scorching!
Buffing Wheel
The brightwork on my amp also had rust spots like yours. I used Krud Kleaner solution (Phosphoric acid) and steel wool and they looked a lot better. Krud Kleaner can be bought at an automotive paint store. Use eye protection and rubber gloves to protect your eyes and hands from acid burns. Don't get it on your clothes. After that, I used a table mounted buffing wheel and polishing compound to buff them to a shiny luster. Almost as good as new. If that doesn't work for you, you'll need to take the parts to a plating shop. -mgriffin
Not exactly off topic, but
Not exactly off topic, but when cars had bumpers, there were plating shops everywhere, and they would plate almost any ferrous item that you had. I contacted a few places last year to inquire about plating a couple of pedals for an old Fender steel I have, they didn't bother to even reply!