| Author | Message | ||
| Jonathan Moore (jondanger) Username: jondanger Registered: 08-2010 |
Hi all. I've been reading these forums quite a bit, and have learned a lot, but have a couple questions before I (maybe) do a cap job on my 210 Sixty-Five. I did the filter caps in my old JCM 800, but that seems like an easy job in comparison. 1. The amp has been biased recently, do I need to re-bias it after I replace the caps? Planning on doing the 5 150-50's that are on the boards, and the ones in the pan. 2. I read in an old post in another section where Mike K said he has "rodeo-tied" caps above the board to keep from having to take the old PCB off. I assume this means clipping the leads off the old caps and twisting and soldering the new caps to the old leads. Is this correct? It seems like Mike knows what he's talking about, so I don't mind doing it this way if it works fine and keeps me from having to pull this PCB out. I'd bet it's pretty brittle after all this time, and looking at the wire ties inside, it has definitely never been off the mount screws before. 3. To discharge the old caps, I first unplug the amp with it on Hi power and not on standby, leave it for a few minutes, then put an alligator clip across the cap leads while they are still in the circuit, and then I'm good, right? Forgive me if I sound like a dummy. Just a player trying to educate myself a little bit more. Thanks! | ||
| Mike Kaus (mm210) Username: mm210 Registered: 05-2006 |
My method of what I call "rodeo tying" is kind of like a boat knot. If you have the room, I like to use what ACTUALLY is a square knot with one end of each cap loose. here's a pic of what I do but honestly, if you fold over, wrap and solder, they will NEVER come apart, IF they are soldered properly. I've been splicing stuff like this for over 30 years and being a musician, I have pretty much tortured EVERYTHING I have personally used and the stuff that I repair on the outside hase never come back for loose connections. Now Groove Tubes.......... Anyway, heres the pic of how I tie them.  | ||
| Jonathan Moore (jondanger) Username: jondanger Registered: 08-2010 |
Cap job is done. I tied them pretty much the same, and it worked pretty well except for one that came loose from the joint underneath the driver (?) board. The one near the power cord that has 2 150@50s on it. Sounds great, next thing is to re-tube and get it biased. One of these old Svetlanas has gone microphonic. I'm thinking Electro Harmonix EL34EH, unless someone has a horror story about them. Thanks again for the help! | ||
| Mike Kaus (mm210) Username: mm210 Registered: 05-2006 |
Sad part is, I have horror stories about ALL current production tubes. Personally, I use either JJ's or Winged C. If you had NEW Svetlana's, they aren't really any different from EH or even(GULP) Sovteks. THe old svets were a different tube. They are all from the same place, just the renaming shuffle that's going on right now. Even the old name Tung Sol has been bought and put back in use but they are NOT tung sol tubes. Just more sovtek crap that the importer has re-branded with that name. So it come down to a crapshoot no matter what. I use JJ's in mine but who the hell am I! | ||
| Jonathan Moore (jondanger) Username: jondanger Registered: 08-2010 |
Mike - The EH tubes that I was considering were actually the 6CA7s that they make. The JJs are on sale from Tube Depot right now though. At $25 for a matched pair the price is pretty right. The E34L is the one that it seems people on this board prefer. Unless the EH 6CA7s are half again as good, I'd probably just go with the JJs. Thanks for the tip. |
Tue, 03/25/2014 - 09:34
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