| Author | Message | ||
     Dirk Wacker (doc_holiday) Username: doc_holiday Registered: 02-2007 |
The two 60uF filtering caps (aka power caps) in my 112RD50 are worn out and I need to replace them. Over here 60uF seems to be an exotic value and I canīt find any caps. Do you know a source where I can buy such caps ? The closest value I can find is 100uF/450volt. Can I use this caps in my amp and how will the higher value of this caps influence my sound ? As an additional information .... my tech rebiased the amp to 13.5 mA for each 6L6GC output tube, maybe this is important. | ||
| Ed Goforth (ed_goforth) Username: ed_goforth Registered: 06-2006 |
Hi Dirk, 100uf works fine, I have modded many RD-50's with 80-100uf caps. That is as high as I would go though. The sound will have a tighter low end if thats what you prefer, and have slighty better filtering. As far as biasing the amp, I have not known any RD-50 that had a bias adjustment unless modified, since those RD-50's were self bias stock. Now the RD-65 and RD-100 has a bias adjustment, did yours get modified if its a RD-50? You can get 100uf/450vdc caps that fit nicely in the RD-50 from CE distribution. I would also change the 2uf 450 vdc cap to 10-20uf, it helps the overdrive tone a lot. But thats my opinion. Ed | ||
| Dirk Wacker (doc_holiday) Username: doc_holiday Registered: 02-2007 |
Hi Ed, thanks for the info, you saved my day ! The 100uF caps are available easily over here and I have the choice between a lot of companies, eg. TAD, Sprague, F&T etc. A tighter low end could be a nice thing for me, I will give it a try. As for the BIAS, yes my tech replaced some parts and put in two pots to regulate the BIAS for each of the two power tubes. When I got the amp, some parts had drifted and lost the nominal value, so the amp was self-biased with 3,5mA for each tube :-) Now with 13,5mA it sounds MUCH better ! Can you try to explain what difference the 10-20uF cap will have on the overdrive sound of the amp ? | ||
| Mike Kaus (mm210) Username: mm210 Registered: 05-2006 |
The overdrive sound may not change much but the Farting sound you sometimes get at extreme volumes with a lot of bass cranked in will be better. Also, the distortion will sound "tighter" (if that's the right term) than it did before. I think it depends a lot on which guitar that you are driving it with but that also is conjecture on my part. My MM's don't really seem to like buckers UNLESS they are cranked. Singles don't seem to make much difference. Of course, what the hell do I know. Too many tubes, too little talent. Mike. | ||
| Dirk Wacker (doc_holiday) Username: doc_holiday Registered: 02-2007 |
Hi Mike, thanks for the explanation, it sounds as if it would be a useful mod for me. I play mostly clean and I really like a tight bass for percussive sounding country chicken picking, surf, tiki and twangy Nashville stuff. As for overdrive, I like a classical overdrive, no high gain shredding twaddle. I only play Fender guitars with singlecoils, Strats and Tellies. |